1

Chapter 1

1.1 Introduction

Science has been derived from the Latin word Scientia which means

knowledge, gained through careful experimentation and reasoning. It is a systematic

enterprise that builds and organizes knowledge in the form of testable

explanations and predictions about the universe [1-4]. Analytical Chemistry is an

ancient branch of science, and regarded as the mother of all sciences.

Analytical Chemistry involves the study of the separation, identification,

and quantification of the chemical components of natural and artificial materials [5].

It is a multidisciplinary branch of science wherein a large number of research workers

have contributed to its development [6]. No other branch of science finds such

extensive applications as analytical chemistry purely for two reasons: Firstly, it finds

numerous applications in various disciplines of chemistry such as inorganic, organic,

physical and biochemistry and secondly it finds wide applications in other fields of

related sciences such as environmental science, agricultural science, biomedical and

clinical chemistry, solid state research and electronics, oceanography, forensic science

and space research. However, the identification of a substance, the elucidation of its

structure and quantitative analysis of its composition are the aspects covered by

modern analytical chemistry. Analytical methods are the fundamental tools of the

analyst. The classical methods of analysis have dominated the scene of analysis for the

past few decades. Fortunately, with the discovery of modern methods of analysis,

mainly involving instruments, these methods have been relegated. Nevertheless, these

methods will not be phased out in spite of the greater advancement of newer methods

of analysis as the new methods have their own limitations. They cannot be applied if

the substance is present in large concentration and further in order to standardize the

newer methods it is absolutely essential to use classical (gravimetric or volumetric)

methods of analysis. According to the type of process used to perform the analysis,

methods used for chemical analysis can be categorized as given in (Figure 1.1).

Another trend is to designate newer methods involving instruments as instrumental

2

methods of analysis, which involves use of burette, pipette or weighing balance. In the

present circumstances when speed, simplicity, selectivity and sensitivity of analysis

are of utmost importance, it is better to categorize such methods as modern methods

of analysis instead of instrumental methods of analysis.

Figure 1.1: Major categories of chemical analysis

1.2 Separation Processes A separation process is a physical or chemical method to transform a mixture of

substances into two or more distinct components that differ in their chemical or

physical properties. There are three factors of importance to be considered in all

separations: (a) the completeness of recovery of the substance being isolated, (b) the

extent of separation from associated substances, and (c) the efficiency of the

separation. In industrial applications the ultimate goal is the isolation of a product of

high purity, whereas in analysis the primary goal is the determination of the amount

or concentration of substance in a sample. Based on a variety of properties of

materials (solubility, volatility, adsorption, and electrical and magnetic effects) there

are several separation methods as given below. (A) General methods of separation

like distillation, extraction, precipitation, crystallization, dialysis and diffusion. (B)

Modern methods of separation such as chromatography, electrophoresis, ion

exchange, etc.

1.3 Chromatography

Chromatography derived from Greek word χρώμα: chroma means color and

γραφειν: graphein means to write represents a collective term for a set of qualitative

3

and quantitative techniques used in separation of mixtures. It involves passing a

mixture dissolved in a "mobile phase" through a stationary phase, which separates the

analyte of interest from other molecules in the mixture based on differential

partitioning/sorption between the mobile and stationary phases. The mobile phase

may be either a liquid or a gas, while the stationary phase is either a solid or a liquid.

Each component has a characteristic time of passage through the system, called a

"retention time". The techniques find use in the separation, purification and

identification of compounds before quantitative analysis is taken up.

Chromatography may be preparative or analytical. The purpose of preparative

chromatography is to separate the components of a mixture for further use (and is thus

a form of purification). Analytical chromatography is done normally with smaller

amounts of material and is for measuring the relative proportions of analytes in a

mixture. Since its invention, the chromatography has become an essential part of bio-

chemical laboratories. A simple classification of chromatographic methods is

summarized in Table 1.1.

Table 1.1: Classification of chromatographic methods

S. No. Type of Chromatography Examples

1. Adsorption chromatography Column chromatography, Thin-Layer

Chromatography (TLC), Gas-Solid

Chromatography.

2. Partition chromatography Paper chromatography, Reversed-Phase

Thin Layer Chromatography (TLC),

Classical Liquid-Liquid Chromatography.

3. Modified partition (or bonded phase)

chromatography

High-Performance Liquid Chromatography

(HPLC) and High Performance (HP) TLC.

4. Ion-exchange chromatography Cation and Anion Exchange

Chromatography.

5. Exclusion chromatography Ion-Exclusion and Gel Permeation

Chromatography, Molecule Sieve

Chromatography.

6. Electro chromatography Capillary and Zone Electrophoresis.

4

The identification and separation of various species can be achieved by an

array of systematic procedures. Among the most versatile analytical separation

techniques, chromatography has wider applicability. In spite of the popular belief and

general acceptance of the contribution of Tswett as being the real discoverer of

chromatography, the starting of chromatography predated to the work of F.F. Runge

who investigated the separation of coloured substances (i.e. dyes) on paper [7]. The

work carried out by Goppelsroeder [8] and Schonbein [9] on chromatographic

separation of substances on filter paper has been included in a report published by

Fischer and Schmidner [10] in 1892. However, the concept of separation on column

may be attributed to Reed’s work, which was followed by Day who separated

petroleum fractions with the help of columns [11,12]. The paper published in 1906 by

M. Tswett a Lecturer of Botany at the University of Warsaw provided the first

description in nearly modern terms of chromatographic separation [13]. He described

the resolution of different components of pigments as coloured bands on a calcium

carbonate column like spectrum of light rays and termed it as “chromatogram”. The

actual importance of Tswett’s work remained dormant until about 1931, when

separations of plant carotene pigments were reported by prominent organic chemist

Kuhn [14,15]. His research attracted much attention and adsorption column

chromatography became invaluable tool in the field of natural product chemistry. In

1941, Martin and Synge [16,17] laid another milestone in development of

chromatography by reporting their discovery of liquid-liquid partition

chromatography.

As for as the knowledge of Human civilization concerned to the science and

technology, a wide variety of instrumental and non-instrumental chromatographic

techniques have been developed since the pre historic time. As the field is very

diverse it is very difficult to elaborate all the chromatographic techniques. Therefore,

we have chosen particularly thin layer chromatography and ion-exchange

chromatography to discuss.

1.4 Thin Layer Chromatography (TLC) TLC is a subdivision of liquid planar chromatography in which the mobile

phase migrates by capillary action through the stationary phase. Difference in the

affinity of individual components to stationary and/or mobile phase facilitates their

5

separation. In this chromatography the stationary phase consists of a thin layer of

adsorbent like silica gel, alumina or cellulose on a flat carrier like a glass plate, a thick

aluminum foil, or a plastic sheet.

1.4.1 History of TLC History of TLC has been reviewed by Stahl [18], Kirchner [19,20] and Pelick

et. al. [21]. The beginning of TLC can be ascribed to the report of Dutch biologist,

Beyerink [22], who separated hydrochloric and sulphuric acids in the form of fine

rings on thin layer of gelatin using a visualizing agent. Following the same method,

Wijsman [23] identified in the presence of two enzymes in malt diastase using a

fluorescent method for detecting separated enzymes on thin layer. He used the

bacteria obtained from sea water as fluorescent agent. However, the invention of TLC

is usually credited to two Russian Scientists, N. A. Izmailov and M. S. Schraiber, who

used binder free horizontal thin layers (2 mm thick) of alumina spread on glass plate

to the analysis of pharmaceutical preparations which led to the publication of their

classical paper [24] on “A Spot Chromatographic Method of Analysis and its

Application in Pharmacy” in 1938. Since their method consists of depositing a drop

of sample solution being investigated and the development by the application of

several drops of solvent on flat surface of adsorbent before observing the separated

zones, it was called “Drop Chromatography or Spot Chromatography”. Though

Izmailov is best known for his fundamental work on TLC, his main field of interest

was electrochemistry for which he received the Mendeleiv Prize of the Academy of

Science of USSR in 1961.

In 1940, Lapp and Erali used a loose layer of alumina spread on a glass slide

that was supported on an inclined aluminium sheet [25]. It is interesting that, in 1949,

two American Chemists, Meinhard and Hall [26] gave the concept of “Surface

Chromatography” and described their work on the use of microscope slides coated

with a mixture of alumina (an adsorbent) and celite (a binder) to separate Fe2+ and

Zn2+. Their work was probably the first application of TLC for the separation of

inorganic ions.

A major breakthrough in the field of TLC came in the early 1960’s with the

availability of precoated plates [27]. The next major advance was the advent of

HPTLC (High performance Thin-Layer Chromatography). In l973 Halpaap was one

6

of the first to recognize the advantage of using a smaller average particle size of silica

gel (about 5–6 mm) in the preparation of TLC. He compared the effect of particle size

on development time, RF values and plate height [28].

Commercially the plates were first called ‘‘nano-TLC’’ or ‘‘HPTLC”. In 1977

the first book on HPTLC ‘‘HPTLC high performance thin-layer Chromatography’’

edited by Zlatkis and Kaiser [29] was published. In 1982 Jost and Hauck reported an

amino (NH2–) modified HPTLC plate, which was soon followed by cyano-bonded

(1985) and diol-bonded (1987) phases [30-32]. In recent years TLC/HPTLC research

has entered the chiral separation field using a number of chiral selectors and chiral

stationary phases.

Automated multiple development (AMD) made its appearance in 1984 due to

the pioneering work of Burger [33]. This improvement enabled a marked increase in

number and resolution of the separated components. Numerous publications on

TLC/HPTLC applications attest to the versatility and applicability of this technique in

all branches of science. It has opened new fields of exploration and become an

invaluable aid to separation scientists. It had recently been realized that modern High

Performance Thin Layer Chromatography (HPTLC) initiated in 1975, rivals High

Pressure Liquid Chromatography (HPLC) and Gas Chromatography (GC) in its

ability to resolve complex mixtures and to provide analyte quantification.

Compared to conventional TLC, HPTLC provides faster separation, reduced

zone diffusion, better separation efficiency and higher sensitivity. At the present time

all steps of the TLC process can be computer controlled. The use of highly sensitive

charge coupled device (CCD) cameras has enabled chromatographer to electronically

store images of chromatograms for future use (identity or stability testing) and for

direct entry into reports at a later date.

1.4.2 Latest development in TLC

As a result of the recent innovations, several sub- techniques such as High

Performance Thin Layer Chromatography (HPTLC), Overpressurised Thin Layer

Chromatography (OPTLC), Centrifugal Layer Chromatography (CLC) and Reversed-

Phase Thin Layer Chromatography (RPTLC), Radial Chromatography, Hot Plate

Chromatography, Pyrolysis and TLC, Bioautography, Immunostaining and Enzyme

Inhibition techniques came into light.

7

The careful combination of TLC with other analytical techniques is more

useful to gather information regarding the analysis of a complex sample.

Spectrophotometry, high- performance liquid chromatography and gas

chromatography, in conjugation with TLC are the three most widely used techniques.

However, mass/GC, infrared and thermal analytical techniques in combination with

TLC has also been used.

1.5 TLC Procedure The TLC process is an off-line process in which all the procedural steps

(sample preparation, sample application, development, drying of chromatogram and

detection) are carried out independently (Figure 1.2). The differential migration of

components results due to varying degrees of affinity of the components in a mixture

for stationary and mobile phases.

8

Figure 1.2: Scheme of typical thin-layer chromatographic process

Sample Preparation

Relatively pure component

Crude Extract

Sample Purification

Sample Application Spotting/Streaking

Plate Development

Drying of Chromatogram

Zone Detection

Component Removal

Documentation and Reporting of Results

9

1.5.1 TLC systems It comprises the proper selection of stationary and mobile phase condition that

decides the degree to which effective separations of components in a mixture can be

achieved.

(i) Stationary phase (Layer sorbent) In present study, we have utilized two commonly used adsorbents (silica gel

and cellulose) as stationary phases and hence few words about these are worth

mentioning.

Silica gel is an amorphous, porous substance and slightly acidic in nature.

Binder is often incorporated into it to hold the adsorbent firmly on the plate. Thin

layers of silica gel G (gypsum binder) and silica gel S (starch binder) with or without,

fluorescent indicator have been used more frequently. At the surface of silica gel, the

free valencies of the oxygen are connected either with hydrogen (Si-O-H, silanol

groups) or with another silica atom (Si-O-Si, siloxane groups), Figure 1.3. The silanol

groups represent adsorption-active surface centres that are capable to interact with

solute molecules.

Figure 1.3: Structure of silica gel

Cellulose, an organic material is used as a sorbent in TLC when it is

convenient to perform a given paper chromatographic separation by TLC with

decreased development time and increase in the sensitivity of detection. Cellulose

used for chromatography is composed of β-glucopyranose units, which are connected

10

to one another at the 1, 4 positions Figure 1.4. Often cellulose thin layers need no

binders because of the strong hydrogen bonding of the cellulose hydroxyl groups with

the supports used.

Figure 1.4: Structure of microcrystalline cellulose

(ii) Mobile phase (Solvent system) Separation possibility of complex mixture is greatly improved by the proper

selection of mobile phase which in turn depends upon the nature of mixture to be

separated. Mobile phase should be as simple as possible and prepared from the purest

grade of solvent. The mobile phases used as developers in TLC may be categorized

into following groups.

Inorganic solvents: Solutions of mineral acids, bases, salts and mixture of

acids, bases or their salts.

Organic solvents: Acids, bases, hydrocarbons, alcohols, amines, ketones,

aldehydes, organophosphates and their mixture in different proportions.

Mixed solvents: Above mentioned organic solvents mixed with water, mineral

acids, inorganic bases or dimethyl sulphoxide and buffered salt solution.

Surfactant-mediated system: Aqueous and hybrid solutions of cationic, anionic

and nonionic surfactants.

Recently, aqueous solvent systems including pure water and aqueous solutions of

amino acids, carbohydrates, ethylene glycol, ethylene acetate and nonionic surfactants

have renewed great interest as the green mobile phase system for future use. These are

referred as “Green Eluents” for Chromatography.

11

1.5.2 Visualization The process of detecting the spots on the plates after development is called

visualization. Several methods exist to make colorless spots visible:

Often a small amount of a fluorescent dye is added to the adsorbent that allows

the visualization of UV absorbing spots under a black light ‘UV254’ as shown

in Figure 1.5.

Figure 1.5: UV Lamp with dark box

Iodine vapors are a general unspecific color reagent.

Specific color reagents are sprayed onto the plate.

A chromatogram showing separation of black ink on a TLC plate is given in Figure

1.6.

Figure 1.6: Chromatogram showing separation of black ink on a TLC plate

1.5.3 Identification and separation In TLC the identification of separated compounds is primarily based on their

12

mobility in a suitable solvent which is described by the RF value of each compound.

The RF values in TLC are dependent upon many variables [34]. Figure 1.7 shows a

chromatographic plate.

originthefrommigrationsolventofceDisoriginthefrommigrationsoluteofceDisRF tan

tan

Figure 1.7: TLC Plate showing distances travelled by the spot and the solvent

RF value ranges from 0.0 for a zone not leaving the point of application to

0.999 for zone migration with solvent front.

1.6 Amphiphiles

We have used amphiphilic molecules (i.e. surfactants) as eco-friendly mobile

phase or impregnent during our studies. It is, therefore, worthwhile to mention some

of their important physico-analytical aspects.

The word amphiphile was coined by Paul Winsor 50 years ago. It is derived

from two Greek words amphi means "double" or "from both sides" and the philos

means “affinity”. A typical amphiphilic molecule (Figure 1.8) comprises of two

parts: a polar group with heteroatoms such as O, S, P, or N, included in functional

groups (alcohol, thiol, ether, ester, acid, sulfate, sulfonate, phosphate, amine, amide

etc.) and an essentially apolar group which is in general an hydrocarbon chain of the

alkyl or alkylbenzene type, sometimes with halogen atoms and even a few non-

ionized oxygen atoms.

13

The polar portion exhibits a strong affinity for polar solvents, particularly

water, and it is often called hydrophilic part or hydrophile and vice-versa for apolar.

Figure 1.8: Representation of an amphiphile

Any substance that strongly influences the surface properties of a material is

called a Surface Active Agents [35]. It can be soaps or detergents, whose cleaning

powers depend on the surfactant's ability to increase the spreading and wetting power

of water [36,37]. Surfactants are also important in lubrication and water repellent

coatings.

1.7 Surfactants Surfactants are long chain amphiphilic organic or organometallic molecules

containing a highly polar (hydrophilic or lipophobic) or “ionic head group” attached

to a non-polar (hydrophobic or lipophilic) hydrocarbon tail of varying chain lengths.

These surface- active hydrocarbon molecules adsorbed at the oil/water interface by

reducing the bare oil-water tension to low values. Because of this property, surfactants

have been utilized (Figure 1.9) in many practical applications [38].

14

Figure 1.9: Fields of application of surfactants in analytical chemistry

The “head group” is either cationic (e.g. ammonium or pyridinium ion),

anionic (e.g. hydroxy compounds) or zwitterionic (e.g. amine oxide, carboxylate or

sulphonate betain) whereas the tail is hydrophobic and contain atleast 8 carbon atoms.

Depending upon the nature of hydrophilic group, surfactant can be classified as

anionic [R-X-M+], cationic [R-N+(CH3)3X-], zwitterionic [R-(CH3)2 N+CH2 X-] and

nonionic [R (OCH2CH2)]m OH, where R is a long aliphatic hydrocarbon chain, M+ is

a metal ion, X- is a halogen, COO- or SO42- and m is an integer. A list of some

common surfactants is provided in Table 1.2.

15

Table 1.2: Some typical surfactants, formulae and their CMCs

Surfactants Formulae CMC(M) Anionic

Sodium dodecyl sulfate (SDS) CH3(CH2)11OSO3Na+ 8.1103 Potassium perfluoroheptanoate C7F15COOK+ 3.0102 Sodium polyoxyethylene(12) - dodecyl ether

CH3(CH2)11(OCH2CH12)12OSO3 Na+ 2.0104

Cationic Cetylpyridinium chloride C16H33N+C5H5Cl 1.2104

Cetyltrimethyl ammonium bromide (CTAB)

CH3 (CH2) 15N+ (CH3) 3Br- 9.0104

Nonionic Polyoxyethylene (6) dodecanol CH3(CH2)11(OCH2CH2)6OH 9.0105 Polyoxyethylene (23)- dodecanol (brij-35)

CH3(CH2)11(OCH2CH2)23OH 1.0104

Triton X-100 (CH3)3CCH2C(CH2)2 O(CH2CH2O)9.5H

2.8103

Zwitterionic N-Dodecyl-N,N-dimethylammonium-3-propane-1 sulfonic acid (SB-12)

CH3(CH2)11N+(CH3)2(CH2)3SO3 3.0103

N,N-Dimethyl-N (carboxymethyl) octylammonium salt

C8H17N+(CH3)2CH2COO 25102

1.8 Micelles As the surface becomes crowded with surfactant, more molecules

spontaneously aggregate themselves forming self-assemblies called micelles. This

concentration is called the Critical Micelle Concentration (CMC) [39]. The various

structures formed in aqueous solution on increasing the concentration of surfactant is

illustrated in Figure 1.10.

16

Figure 1.10: Different shapes of micelles

There are mainly two types of micelles.

(a) Normal micelles Normal aqueous micelles are generally formed (above CMC) from singly-chain

surfactants in which the hydrophobic moieties (i.e. hydrocarbon tails) are oriented

inward forming a non-polar core. Figure 1.11 (a) and chain branching inhibits

micellization.

(b) Reverse micelles In contrast to the normal micelles which are formed in polar (i.e. aqueous

media) solvents, reverse micelles are formed in non-polar solvents like hexane or

chloroform and a trace of water where the polar head groups of the surfactant are

directed towards the interior of the aggregate and the hydrocarbon chains are in

17

contact with the non-polar solvent Figure 1.11 (b). An interesting aspect of reverse

micelles is their capability to solubilize water in the interior of micelle structure.

(a) (b)

Figure 1.11: Different types of micelles

1.9 Surfactant-Mediated TLC Systems Since the work presented in this thesis is related to the use of surfactant –

mediated mobile phase systems, it is worthwhile to describe briefly the behavior of

surfactants in aqueous medium. The following paragraphs are devoted to highlight the

utility of surfactants as eluents in chromatography.

Surfactant – mediated system contains surfactant as one of the components of

mobile phase or as impregnated stationary phase. Surfactants in the aqueous mobile

phase have been used as mobile phase in different forms.

(a) When the concentration of surfactant in aqueous mobile phase is restricted to

well below the Critical Micelle Concentration (CMC) of the surfactant.

These mobile phases are most suited to separate ionic species by Ion-Pair

Chromatography (IPC).

(b) When the concentration of surfactant is well above the CMC. These mobile

phases are very useful for simultaneous separation of ionic and non-ionic

compounds by Micellar Liquid Chromatography (MLC).

(c) When surfactant in the presence of water, oil (hydrocarbon) and co-

surfactant (i.e. medium chain length amine or alcohol) is used as transparent

solution.

It is well established that two immiscible liquids (e.g. water and oil) can be

brought into a single phase (macroscopically homogeneous but microscopically

heterogeneous) by addition of an appropriate surfactant or a surfactant mixture. This

unique class of optically clear, thermodynamically stable and usually low viscous

18

solutions, called “Microemulsions” have been the subject of extensive research over

the last two decades primarily because of their scientific and technological importance

[40-44].

The important applications of microemulsions include: enhanced oil recovery;

fuels; coatings and textile finishing; lubricants, cutting oils and corrosion inhibitors;

cosmetics; agrochemicals; food and pharmaceuticals; environmental remediation and

detoxification; production of microporous media synthesis; liquid membranes.

Microemulsion systems have been successfully applied in modifying chemical,

photochemical, electrochemical and electrocatalytic reactions; analytical and

bioseparations and polymerization processes.

There are two types of microemulsions (i) Oil-in-water and (ii) Water-in-oil.

In terms of chromatographic applications, the advantages of employing

surfactant micellar mobile phases includes enhanced selectivity, low cost, low toxicity

and the ability to simultaneously chromatograph both hydrophilic and hydrophobic

solutes among others.

1.10 Ion-Exchange Chromatography Ion-exchange chromatography is a technique in which resolution of a mixture

is achieved by virtue of differences in migration rates of the components in the packed

column. The stronger the charge on the sample, the stronger it will be attracted to the

ionic surface and thus, the longer it will take to elute (Figure 1.12). In particular, the

stationary phase is usually: Positively charged ion-exchanger (anion-exchanger)

interacts with anions and Negatively charged ion-exchanger (cation-exchanger)

interacts with cations (Figure 1.13).

Figure 1.12: Ion-exchange chromatography

19

Figure 1.13: Structure of anion exchanger and cation exchanger

1.11 Ion-Exchange Properties of Materials

1.11.1 Ion-exchange phenomenon & its historical background The phenomenon of ion-exchange is not of a recent origin. The earliest of the

references were found in the Holy Bible establishing Moses’s priority that succeeded

in preparing drinking water from brackish water [45], by an ion-exchange method.

Later on, Aristotle found that the seawater loses part of its salt contents when

percolated through certain sand [46]. Basically, ion-exchange is a process of nature

occurring throughout the ages before the dawn of civilization, has been embraced by

analytical chemists to make use of difficult separations easier and possible.

Francis Bacon in 1623 brought the intentional use of ion-exchange,

Thompson and Way in 1850 described the exchange of calcium and magnesium ions

of certain types of soils for potassium and ammonium ions [47,48], Eichorn (in 1858)

demonstrated exchange processes in soils as reversible [49], and Boedecker proposed

an empirical equation describing the establishment of equilibrium on inorganic ion-

exchange sorbents in 1859. In the 20th century, the majority chemists believed that the

‘base exchange’ in soils is nothing but a sort of absorption. Strong supports to ion-

exchange come out with the synthesis of materials from clay, sand and sodium

carbonate by Gans [50].

Gans [50] developed the basis for the synthesis and technical application of

inorganic cation-exchangers at the beginning of the 20th century. He termed the

amorphous cation-exchangers based on aluminosilicate gels “permutites” which were

actually the first commercially available ion-exchangers. In 1917, Folin and Bell

20

developed an analytical method based on these materials for the separation of

ammonia [51]. During the period between the 1930s and 1940s, inorganic ion-

exchange sorbents were replaced in almost all fields by the new organic ion-

exchangers. The observation of Adam and Holms [52] that the crushed phonograph

records exhibit ion-exchange properties, eventually resulted in the more significant

development of synthetic ion-exchange resins (high molecular weight organic

polymers containing a large number of ionic functional groups)

in 1935.

Because of the limited applications of the organic resins due to breakdown in

aqueous systems at high temperatures and in the presence of high ionizing radiation

doses there had been a resurgence of interest in inorganic exchangers in the 1950s.

Pioneering work was carried out in this field by the research team at the Oak Ridge

National University led by Kraus, and by the English team led by Amphlett. Further

extensive research and study of inorganic ion-exchange sorbents were carried out in

the 1960s and 1980s. Clearfield and co-workers made great contributions in this area.

Since last two decades, intense research has continued on the synthesis of a number of

new ‘organic-inorganic’ composite materials. An interest of inorganic as well as

composite ion-exchange materials in ion-exchange operations in industries is

increasing day by day as their field of applications is expanding.

1.11.2 Ion-exchange process and its mechanism The ion-exchange process became established as an analytical tool in

laboratories and in industries, as it was studied chiefly by practical chemists interested

in effects and performance etc. The exchange of ion takes place stoichiometrically

[53], really by the effective exchange of ions between two immiscible phases,

stationary and mobile. A typical ion-exchange reaction may be represented as follows: AX + B (aq) BX + A (aq) …… 1.1

where A and B (taking part in ion-exchange) are the replaceable ions, and X is the

structural unit (matrix) of the ion-exchanger. Bar indicates the exchanger phase and

(aq) represents the aqueous phase.

In order to describe equilibria and to understand the mechanism of an ion-

exchange process occurring on the surface of exchanger and to evaluate its theoretical

behavior, it is important to have a study of its kinetics and thermodynamics. Since

21

inorganic ion-exchangers possess a rigid matrix they do not swell appreciably and

hence such studies are simpler to perform on them as compared to the organic resins

that swell appreciably. Ion-exchange equilibrium may be described by two theoretical

approaches viz. (i) Based on law of mass action, and (ii) Based on Donnan theory.

From the theoretical point of view the Donnan theory has an advantage of permitting

a more elegant interpretation of thermodynamic behavior in an ion- exchanger.

Probably, the first time, quantitative formation of ion-exchange equilibria was made

by Gane [54] using the mass action law in its simplest form without involving the

concept of activity coefficients. This concept was further accounted by Kielland [55]

and finally, a suitable choice of general treatment was given by Gaines and Thomas

[56]. Many workers have studied the thermodynamics of cation-exchange on

zirconium(IV) phosphate [57-60]. Ion-exchange isotherms and calorimetric heats of

exchange were determined on samples varying from amorphous to highly crystalline

[61-65].

However, from the practical point of view, the mass action approach is

simpler. Nancollas and coworkers [66,67] have interpreted the

thermodynamical functions in term of the binding nature between alkali metals

and the ion exchange matrix. The ion-exchange equilibria of Li(I), Na(I) and

K(I) on zirconium(IV) phosphate have also been studied by Larsen and Vissers

[68], who calculated the equilibrium constants and other thermodynamical

parameters viz. Go, Ho and So. Similar studies have also been made on

anion-exchangers [69]. Ion-exchange equilibria of alkaline earth metal ions on

different inorganic ion-exchangers such as tantalum arsenate [70], iron(III)

antimonate [71], antimony(V) silicate [72,73], zirconium(IV) phosphosilicate

[74,75] and alkali metal ions on iron(III) antimonate [76] and -cerium

phosphate [77] were studied. Other interesting thermodynamic studies related

to the adsorption of pesticides on inorganic and composite ion-exchangers

have also been performed in these laboratories [78,79]. The study has revealed

that the adsorption is higher at lower temperature and the presence of an ion-

exchange material in soil greatly enhances its adsorption capability for the

pesticides. Nachod and Wood [80] have made the first and detailed attempt on

kinetic studies of ion-exchange. They have studied the reaction rate with

which ions from solutions are removed by a solid ion-exchanger or conversely

22

the rate with which the exchangeable ions are released from the exchanger.

Later on Boyd et al. [81] have studied the kinetics of metal ions upon the resin

beads and have given a clear understanding about the particle and film

diffusion phenomenon that govern the ion-exchange processes. The former is

valid at higher concentrations while the later at lower concentrations. The

kinetic of metal ions on sulphonated polystyrene has been studied by

Reichenberg who again confirmed that at high concentrations the rate is

independent of the ingoing ion (particle diffusion); while at low concentrations

the reverse is true (film diffusion).

1.11.3 The journey from synthetic inorganic ion exchangers to

composite ion exchangers Synthesis of inorganic materials resembling to the natural zeolites was started

about six decades ago. The first commercially available inorganic materials were

prepared by fusion of mixture of potash, feldspar, soda, kaoline etc which bear the

resemblance to the natural zeolites with an exception of their irregular structures [82].

Later on some modification in preparation methods were tried to obtained the ion

exchangers with improved properties. An example to cite includes the precipitation

with caustic from acidic solutions of aluminium sulphate and sodium silicate,

followed by drying of gelatinous precipitates. The chemical structure of these gel-

permutits was very similar to the natural zeolites. These materials possessed irregular

structure which resembles that of silica and ion exchange resins. Nowadays, both

fusion and gel permutits are well known but are of historical interest.

Various zeolites have been synthesized by hydrothermal techniques [83-89].

The hydrothermal technique involves the crystallization at an elevated temperature

from solution containing silica, alumina and alkali. These zeolites were of completely

regular structure and exact counter parts of natural zeolites. These materials possessed

a little practical consideration as ion exchanger; but their use as highly selective

adsorbent has been reported [90-93]. Later on various ion exchangers have been

synthesized with a frame work other than alumino silicates, in which silicon was

partially or completely replaced by other tetravalent elements (titanium, thorium and

tin and aluminium) by other trivalent elements (iron, vanadium, manganese and

phosphorus). However, ion exchange properties of these modified ion exchangers

23

were not found to acceptable level and hence their practical applicability has been

unsatisfactory.

Hydrous oxides gels of iron, aluminium, chromium, bismuth, titanium,

thorium, tin, molybdenum and tungsten are of particular interest because most of

these gels can function as cation or anion-exchangers, and under certain conditions, as

amphoteric exchangers. Their dissociation may be schematically represented as

follows:

M – OH M+ + OH - ……. 1

M – OH M – O - + H+ ……. 2

(M represents the central atom)

Scheme ‘1’ is favoured by acid conditions when the substance can function as

anion-exchanger and scheme ‘2’ by alkaline conditions, when the substance can

function as cation-exchanger. Near the isoelectric point, dissociation according to

both schemes can take place and both types of exchange may occur simultaneously.

All of the hydrous oxide, except, zirconium and tin, are chemically unstable as they

are dissolved by acids and bases easily. Therefore, hydrous oxides are of little

practical importance. Recently, various inorganic ion exchangers with much more

satisfactory properties have been prepared by combining salts of group III and IV

such as aluminium, antimony, bismuth, cerium, chromium, iron, titanium, tin, thorium

and zirconium with the more acidic salts of group V and VI such as silicate, vanadate,

arsenophosphate, arsenotungstate, arsenomolybdate, arsenosilicate, arsenovanadate,

phosphotungstate, phosphomolybdtate, phospahovanadate, phosphosilicate, alkali

phosphates, selenomolybdate, tungstophosphate, molybdosilicate, vanadosilicate,

phosphoric, arsenic, molybdic, and tungstic acids etc.

These ion exchangers are extremely insoluble, non-stoichiometric and

possessed high ion exchange capacity (up to 12 meq g-1 of ion exchanger). The

materials also provided high rate of exchange and high thermal and radiation

stabilities as compared to organic ion exchange resins; however, they tend to lose

fixed ionic groups at higher pH due to hydrolysis and ion exchange properties are

reported to be not very much reproducible as well as ion exchangers are not granular,

thereby limiting their suitability for column operations.

Recently, composite materials prepared by the combination of insulating or

conducting polymers as supporting materials with the matrices of inorganic

precipitates (prepared by combining cationic group salts such as cerium, titanium, tin,

24

thorium and zirconium with any of the anionic species) are considered to be

alternatives to overcome the limitations associated with the organic resins and

inorganic ion exchangers [94-104].

In addition to the use of TLC for detection, identification and separation of

pesticides and spectrophotometric determination of glyphosate (nitrogen-containing

pesticide), we have used composite ion-exchange materials based on tin and cerium

for the removal of nitrogen-containing organic compounds (aniline, pyridine and

nicotinic acid) from aqueous media. Therefore, it is worthwhile to encapsulate the

recent developments and applications of composite cation exchangers prepared by

combining polymers with tin and cerium salts as cationic part with appropriate

anionic parts as listed in Tables 1.3 and 1.4

25

Table 1.3: Tin based composite ion exchangers S. No. Composite Ion-

Exchanger Remarks Ref.

01. Carboxymethyl cellulose Sn(IV) phosphate

Nano-rod like cation exchanger with diameter in the range of 20–40 nm, length in the range of 100–150 µm and particle size in the range of 21–38 nm was prepared and characterized. The thermodynamic parameters indicated that the adsorption of pyridine on the surface of cation exchanger was feasible, spontaneous and exothermic in nature which suggests for the potential application of pyridine removal from water.

[1]

02. Polyaniline stannic silicomolybdate

Distribution coefficient studies were performed for different metal ions in varied solvent systems such as Triton X-100, trichloroacetic acid and acetic acid. The effect of temperature on the distribution coefficient was also studied. The material was found to be selective for Pb2+ ion. On the basis of distribution coefficient values, some analytically important binary separations of metal ions viz. Mg2+-Pb2+, Zn2+-Pb2+, Cd2+-Pb2+ and Mg2+-Cu2+ were achieved.

[2]

03. Sodium bis(2-ethylhexyl) sulfosuccinate based tin(IV) phosphate

The ion exchange property was studied by determining the ion exchange capacity, elution and concentration behavior of the cation exchanger. Adsorption studies on the synthesized material showed that it is highly selective for Cd2+, Zn2+and Hg2+ ions. The separation observed to be quite effective in presence of acid, alkali, alkaline earth and other transition metals.

[3]

04. Acetonitrile stannic(IV) selenite

The sorption behavior of metal ions was studied in nonionic surfactants namely triton x-100 and tween. On the basis of distribution coefficient studies, several binary separations of metal ions were achieved. The practical applicability of this cation-exchanger was demonstrated in the separation of Th4+ from a synthetic mixture of Th4+, Ca2+, Sr2+, Ni2+, and Mg2+ as well as Cu2+ and Zn2+ from a brass alloy sample. Removes metal ions.

[4]

1. A. Mohammad, Inamuddin, A. Amin, J. Therm. Calorim. (2011) doi: 10.1007/s10973-011-1548-z. 2. S. A. Nabi, S. A. Ganai, A. M. Khan, J. Inorg. Organomet. Polymer. Mater. 21(1) (2011) 25. 3. N. Iqbal, M. Mohammad, M. Z. A. Rafiquee, Chem. Eng. J. 169 (2011) 43. 4. S. A. Nabi, R. Bushra, Z. A. Al-Othman, Mu. Naushad, Separ. Sci. Tech. 46 (2011) 847.

26

S. No. Composite Ion-Exchanger Remarks Ref. 05. Polypyrrole Sn(IV)

phosphate

Due to its selective nature, the material was used as an electroactive component for the construction of an ion-selective membrane electrode. The proposed electrode shows fairly good discrimination of mercury ion over several other inorganic ions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations for Mn(II) in water.

[5]

06. Polyvinyl alcohol Sn(IV) tungstate

The thermodynamics of aniline adsorption from aqueous solution on nano composite cation-exchanger was studied. The nano composite cation-exchanger possessed flakes like morphology with particle size in the nano range.

[6]

07. Poly-o-toluidine stannic molybdate

The experimental parameters such as concentration, mixing ratio and pH were established for the synthesis of the material. It also exhibits improved thermal stability, ion exchange capacity and selectivity for toxic heavy metal ions. The distribution coefficient studies of metal ions on the material were performed in different solvent systems and the material was found to be selective for Hg2+ and Pb2+ ions.

[7]

08. Acrylonitrile tin(IV)tungstophosphate

The effect of experimental parameter such as reagent mixing ratio, temperature effect on ion exchange properties of material has been studied. The material behaves as monofunctional acid with ion exchange capacity of 1.91 and 1.94 meq g-1 for Na+ and K+ respectively. It is quite stable in mineral acid, bases and fairly stable in organic solvent. The sorption studies reveals that the material is selective for Pb+2 and Sr+2 ions.

[8]

5. A. A. Khan, A. Khan, U. Habiba, L. Paquiza, S. Ali, Int. J. Adv. Res. Comput. Sci. 2(4) (2011) 341. 6. A. Mohammad, Inamuddin, A. Amin, J. Therm. Anal. Calorim. (2011) doi: 10.1007/s10973-011-1534-5. 7. S. A. Nabi, R. Bushra, Mu. Naushad, A. M. Khan, Chem. Eng. J. 165 (2010) 529. 8. Md. M. Ahmad, W. A. Siddiqui, T. A. Khan, Orient. J. Chem. 26(2) (2010) 429.

27

S. No. Composite Ion-Exchanger Remarks Ref. 09. Acrylamide stannic

silicomolybdate Distribution coefficient studies of the metal ions were performed in polar solvents such as trichloroacetic acid, formic acid, acetic acid and dimethylsulfoxide to know the ion exchange behavior and selectivity for different ions. Several binary separations of metal ions was achieved The quantitative separation of Cu2+ and Zn2+ were also achieved on commercially available pharmaceutical formulation I-Vit.

[9]

10. Poly-o-anisidine Sn(IV) phosphate

The physico-chemical properties of the material were determined using AAS, CHN elemental analysis, UV-vis spectrophotometry, FTIR, TGA-DTA, TEM, XRD and SEM studies. Electrical conductivity studies were carried out by four in-line probe DC electrical conductivity measuring instrument. Isothermal and cyclic techniques were also used to understand the stability in terms of DC electrical conductivity retention.

[10]

11. Acrylonitrile stannic(IV) tungstate

Ion exchange capacity, pH titrations, elution and distribution behavior were also carried out to understand the ion exchange behavior of the material. Some analytically important binary separations from aqueous solution on its columns. The practical applicability of acrylonitrile stannic(IV) tungstate was demonstrated in the quantitative separation of Fe3+and Zn2+ contents of a commercially available pharmaceutical sample namely Fefol-Z.

[11]

12. Nylon-6,6 Sn(IV) phosphate Ion-exchange capacity (IEC), ion-exchange properties, thermal stability and distribution behavior, etc. were carried out to understand the cation-exchange behavior of the material. On the basis of distribution studies, the material was found to be highly selective for Hg(II), a highly toxic environmental pollutant. The electrode was also found to be satisfactory in potentiometric titrations.

[12]

9. A. M. Khan, S. A. Ganai, S. A. Nabi, Colloid. Surface. Physicochem. Eng. Aspects. 337 (2009) 141. 10. A. A. Khan, A. Khan, Mater. Sci. Eng. B. 158 (2009) 92. 11. S. A. Nabi, Mu. Naushad, R. Bushra, Chem. Eng. J. 152 (2009) 80. 12. A. A. Khan, T. Akhtar, Electrochim. Acta. 54(12) (2009) 332.

28

S. No. Composite Ion-Exchanger Remarks Ref. 13. EDTA-stannic(IV)iodate The exchanger was characterized on the basis of X-ray, TGA, FTIR, UV–Visible

spectrophotometery and SEM studies. Ion exchange capacity, pH titration, elution and distribution studies were also carried out to determine the primary ion exchange properties of the material. The differential selectivity of metal ions on EDTA-stannic(IV)iodate has been utilized to perform analytically and industrially important binary separations.

[13]

14. Poly-o-anisidine Sn(IV) arsenophosphate

For the detection of lead in water a heterogeneous precipitate based ion-selective membrane electrode was developed by means of this composite cation exchanger as electroactive material. The selectivity coefficients were determined by mixed solution method and revealed that the electrode is sensitive for Pb(II) in presence of interfering cations. The practical utility of this membrane electrode has been established by employing it as an indicator electrode in the potentiometric titration of Pb(II).

[14]

15. TX-100 based Sn(IV) phosphate

Adsorption behaviour has also been studied for some alkaline earths and heavy metal ions in different acidic media. For Pb(II), Hg(II) and Fe(III) its selectivity has been found to be exceptionally good. On this basis, some binary separations have been performed involving these metal ions.

[15]

16. Pyridine based zirconium(IV) and tin(IV) phosphates

The distribution studies towards several metal ions in different media/concentrations have suggested that composites are selective for Hg(II) and Pb(II), respectively. As a consequence some binary separations of metal ions involving Hg(II) and Pb(II) ions have been performed on a column of these materials, demonstrating their analytical and environmental potential.

[16]

13. S. A. Nabi, A. H. Shalla, J. Porous. Mater. 16(5) (2009) 587. 14. A. A. Khan, U. Habiba, A. Khan, J. Anal. Chem. (2009) doi: 10.1155/2009/659215. 15. K. G. Varshney, M. Z. A. Rafiquee, A. Somya, J. Therm. Anal. Calorim. 90(3) (2007) 663. 16. K. G. Varshney, V. Jain, A. Agrawal, S. C. Mojumdar, J. Therm. Anal. Calorim. 86(3) (2006) 609.

29

S. No. Composite Ion-Exchanger Remarks Ref. 17. Polyaniline Sn(IV) phosphate Ion-exchange capacity, chemical stability, thermal stability and distribution behavior

were carried out to understand the cation-exchange behavior of the material. On the basis of distribution studies, the material was found to be highly selective for Pb(II). Its selectivity was examined by achieving some important binary separations like Pb(II)-Mg(II), Pb(II)-Sr(II), Pb(II)-Zn(II), and Pb(II)-Fe(III) on its column. This material possessed DC electrical conductivity in the semi-conducting range, i.e. 10-5-10-3 S cm-1.

[17]

18. Acrylamide tin(IV) phosphate A new thermally stable phase of hybrid inorgano-organic material has been synthesized, characterized and is found to be highly selective for Hg(II).

[18]

19. Polyaniline Sn(IV) tungstoarsenate

On the basis of distribution studies, the material was found to be highly selective for Cd(II) and its selectivity was tested by achieving some important binary separations like Cd(II)-Zn(II), Cd(II)-Pb(II), Cd(II)-Hg(II), Cd(II)-Cu(II), etc., on its column. A new heterogeneous precipitate based selective ion-sensitive membrane electrode was developed for the determination of Cd(II) ions in solutions applied in electrometric titrations.

[19]

20. Polyaniline Sn(IV) arsenophosphate

The material was characterized using X-ray, IR, TGA studies in addition to ion exchange capacity, pH-titration, elution and distribution behaviour. On the basis of distribution studies, the material has been found to be highly selective for Pb(II). Kinetic study of exchange for the metal ions has been performed and some physical parameters have been determined.

[20]

17. A. A. Khan, Inamuddin, React. Funct. Polym. 66(12) (2006)1649. 18. K. G. Varshney, P. Gupta, Indian J. Chem. Inorg. Phys. Theor. Anal. Chem. 42(12) (2003) 2974. 19. A. A. Khan, M. M. Alam, React. Funct. Polym. 55 (2003) 277. 20. R. Niwas, A. A. Khan, K. G. Varshney, Colloid. Surface. Physicochem. Eng. Aspect. 150(1-3) (1999) 7.

30

Table 1.4: Cerium based composite ion exchangers

S. No. Composite Ion-Exchanger Remarks Ref. 01. Poly-o-toluidine Ce(IV)

phosphate Effect of eluent concentration, elution behavior and pH-titration studies were carried out to understand the ion-exchange capabilities. The distribution studies revealed that the cation-exchange material is highly selective for Cd(II) and is employed as an indicator electrode in electrometric titrations.

[1]

02. Sodium dodecyl benzene sulphonate–cerium(IV) phosphate(SDBS–CeP)

The surfactant based fibrous ion exchanger was characterized using various physico-chemical methods. Adsorption studies on the synthesized material have also been performed for heavy metal ions in alkalis and acidic media. The material has been found to be selective for Pb2+and therefore, the binary separations of Pb2+ from other metal ions have been performed.

[2]

03. Polyaniline Ce(IV) molybdate

A polymer supported organic-inorganic composite and strongly acidic cation-exchanger was chemically synthesized and demonstrated to be an excellent ion-exchange material due to its high selectivity for Cd(II), thermal stability and fast elution of an exchangeable H+ ion.

[3]

04. Unsaturated polyester Ce(IV) phosphate (USPECe(IV)P)

Recycling of polyethyleneterephthalate (PET), a non-biodegradable plastic, was carried out by preparing unsaturated composite cation exchanger and has been employed as adsorbents for the removal of Malachite green dye from waste water. Thermodynamic parameters (ΔH0 and ΔG0) suggest an endothermic and spontaneous process.

[4]

1. A. A. Khan, T. Akhtar, Solid State Sci. 13 (2011) 559. 2. N. Iqbal, M. Z. A. Rafiquee, Colloid. Surface. Physicochem. Eng. Aspect. 364(1-3) (2010) 67. 3. Z. Alam, Inamuddin, S. A. Nabi, Desalination. 250(2) (2010) 515. 4. A. A. Khan, R. Ahmad, A. Khan, P. K. Mondal, Arabian Journal of Chemistry. (2010) (in press) doi:10.1016/j.arabjc.2010.10.012

31

S. No. Composite Ion-Exchanger Remarks Ref. 05. Sodium dodecyl sulphate

cerium (IV) phosphate An intercalated fibrous ion exchanger, has been synthesized and characterized. The adsorption studies have also been carried out for some alkaline earths and heavy metal ions in different acidic media, showing a marked selectivity towards Pb (II), a toxic metal ion. The prepared material has shown good ion exchange capacity (2.92 meq/dry g basis), thermal stability and adsorption behaviour.

[5]

06. Triton X-100 based cerium(IV)phosphate (TX-100CeP)

A new phase of fibrous ion exchanger has been characterized using different physico-chemical methods. Its adsorption behaviour studied for some alkaline earths and heavy metal ions in different acidic media showed its selectivity for Hg(II), a toxic heavy metal ion.

[6]

07. Pyridine based cerium(IV) phosphate, (PyCeP)

A new phase of the hybrid fibrous ion exchanger has been synthesized in the form of a sheet like paper. This material has been characterized with the help of ion exchange capacity, elution and concentration and pH titrations behaviour in addition to some physicochemical studies like X-ray diffraction, IR, TG, DTG and SEM studies.

[7]

08. n-Butyl acetate cerium(IV) phosphate

A new Hg(II) selective intercalated fibrous ion exchanger was synthesized. Adsorption behaviour showed that for heavy metals ion, adsorption increases with concentration of anionic surfactants up to the CMC value and then decreases. However, for cationic surfactants, the reverse is true. For nonionic surfactants, adsorption remains constant up to the CMC value and then increases.

[8]

5. A. Somya, M. Z. A. Rafiquee, K. G. Varshney, Colloid. Surface. Physicochem. Eng. Aspect. 336(1-3) (2009) 142. 6. K. G. Varshney, M. Z. A. Rafiquee, A. Somya, Colloid. Surface. Physicochem. Eng. Aspect. 317(1-3) (2008) 400. 7. K. G. Varshney, A. Agrawal, S. C. Mojumdar, J. Therm. Anal. Calor. 90 (3) (2007) 731. 8. K. G. Varshney, M. Z. A. Rafiquee, A. Somya, M. Drabik, Indian J. Chem. Inorg. Phys. Theor. Anal. Chem. 45(8) (2006) 1856.

32

S. No. Composite Ion-Exchanger Remarks Ref. 09 Pectin based cerium (IV) and

thorium (IV) phosphates The X-ray study reveals the amorphous nature of the materials, while SEM studies confirm the fibrous nature of the materials. The thermal studies of these materials indicate that both of them are highly stable on heating as they retain about 97% of their ion-exchange capacity (i.e.c.) on heating up to 100°C and about 81% on heating up to 200°C.

[9]

10. Polystyrene cerium(IV) phosphate (PStCeP)

A hybrid ion exchanger with ion-exchange capacity of 2.95 meq/dry g was synthesized and characterized using IR, TGA, XRD and SEM studies. In addition, its ion-exchange capacity, elution, pH titration and distribution behaviour have also been studied.

[10]

11. Acrylamide cerium(IV) phosphate

Hybrid fibrous ion exchanger distribution studies reveal the exchanger to be highly selective for Hg2+ ion. As a consequence, some binary separations of metal ions have been achieved on a column of this material, demonstrating its analytical potential.

[11]

12. Acrylonitrile based cerium (IV) phosphate

Separation factors and Kd values for various metal ions have also been determined and a marked selectivity for Hg2+ has been found. As a consequence, some binary separations of metal ions have been performed on a column of this material, demonstrating its analytical potential.

[12]

9. K. G. Varshney, A. Agrawal, S. C. Mojumdar, J. Therm. Anal.Calor. 81(1) (2005) 183.

10. K. G. Varshney, N. Tayal, P. Gupta, A. Agrawal, M. Drabik, Indian J. Chem. Inorg. Phys. Theor. Anal. Chem. 43(12) (2004) 2586. 11. K. G. Varshney, P. Gupta, N. Tayal, Indian J. Chem. Inorg. Phys. Theor. Anal. Chem. 42(1) (2003) 89. 12. K. G. Varshney, N. Tayal, U. Gupta, Colloid. Surface. Physicochem. Eng. Aspect. 145(1-3) (1998) 71.

33

1.11.4 Nano composite Large varieties of systems such as one-dimensional, two-dimensional, three

dimensional and amorphous materials have been significantly encompassed to the

definition of nano composite. Nano science is the study of the fundamental principle

of molecules and structures with the dimensions roughly between 1-100 nanometers.

These structures are appropriately termed nanostructures. Nanostructures are the

smallest solid things possible to make and are described as being at the confluence of

the smallest of human made devices. The properties of nano-composite materials

depend not only on the properties of their individual parent but also on their

morphology and interfacial characteristics. Another exciting aspect is the possibility

of creating hetro-structures composed of different kinds of inorganic layers, which

could lead to new multifunctional materials.

Nano-composites promise new applications in many fields such as

mechanically reinforced lightweight composites, non-linear optics, battery cathodes

and ionics, nano-wire sensors and others systems. Nano-composite offers the

possibility to combine diver’s properties, which are impossible within a single

material, e.g. flexible mechanical properties and super conducting properties [105-

120].

1.11.5 Applications of ion-exchange materials Ion-exchangers find applications in a wide variety of industrial, domestic,

governmental and laboratory operations. The hybrid ion-exchangers have good ion-

exchange capacity, higher stabilities, reproducibility and selectivity for specific heavy

metal ions indicating its useful environmental applications. In general, these materials

have been used: water softening [121-123], separation and preconcentration of metal

ions [124-126], removal of oxygen [127], analysis of food and beverages, [128-130]

nuclear separations [131-134], nuclear medicine [135], synthesis of organic

pharmaceutical compounds [136], catalysis [137-139], redox systems [140],

electrodialysis [141], hydrometallurgy [142], effluent treatment [143], ion-exchange

membranes, chemical and biosensors, ion memory effect [144], ion-exchange fibers

[145-147], ion-selective electrodes [149-152], fuel cells [153] and proton conductors

[154,155].

34

1.12 Nitrogen and Its Compounds Nitrogen occurs in all living organism. It is a key constituent in a number of

compounds which are chemically and biologically of great importance. In this chapter

we describe briefly some of the nitrogen compounds which are being used by human

beings as well as plants, their importance, the threats they impose on living beings and

the environment. Also methods for their separation, detection and effective removal

are being discussed.

Nitrogen is an important constituent of amino acids, proteins and nucleic

acids (DNA and RNA). As part of the symbiotic relationship, the plant converts the

'fixed' ammonium ion to nitrogen oxides and amino acids to form proteins and other

molecules, (e.g., alkaloids). Nitrogen compounds are basic building blocks in animal

biology as well. Nitrogen is a constituent of molecules in every major drug class in

pharmacology and medicine. Nevertheless, some of the most toxic and carcinogenic

of known chemicals are nitrogen containing compounds.

1.12.1 Nicotinic acid Also known as vitamin B3, niacin and vitamin PP is an organic nitrogen

compound (Figure 1.14), one of the forty to eighty essential human nutrients.

Figure 1.14: Structure of niacin

Nicotinic acid is a precursor to NAD+/NADH and NADP+/NADPH, which

play essential metabolic roles in living cells [156]. Niacin is involved in both DNA

repair, and the production of steroid hormones in the adrenal gland. Niacin blocks the

breakdown of fats in adipose tissue. Pharmacological doses of niacin (1.5 - 6 g per

day) occasionally lead to side effects such as skin flushing, itching, dry skin, eczema,

nausea, liver toxicity etc. Side effects of liver damage, hyperglycemia, cardiac

arrhythmias and birth defects have also been reported [157]. Niacin at extremely high

doses can cause life-threatening acute toxic reactions [158]. Tertiary nitrogen-

containing compounds like nicotinic acid are suspected to have carcinogenic

behaviour, and hence their systematic study might reveal some interesting results.

Several important studies have been carried out and are listed as shown in Table 1.5.

35

Table 1.5: List of adsorption studies performed on nicotinic acid

S. No. Adsorbent Remarks Ref. 01. Bentonite and

dodecylammonium-bentonite

Dodecylammonium bentonite (DAB) and bentonite (B) were used as sorbents for nicotine (N), nicotinic acid (NA), iso-nicotinic acid (INA), nicotinic acid hydazide (NH), and iso-nicotinic acid hydrazide (INH).

[1]

02. Monolayer of mercaptoacetic acid coated gold electrode

A novel and sensitive method for the determination of nicotinic acid was proposed and based on voltammetric behavior of nicotinic acid on a self-assembled monolayer of mercaptoacetic acid coated gold electrode.

[2]

03. Imprinted polymer stationary phase

The adsorption isotherms of nicotinamide and nicotinic acid and the competitive adsorption isotherms of nicotinamide and nicotinic acid on the imprinted stationary phase are determined using rectangular pulse frontal analysis and static method.

[3]

04. _ The separations of nicotinic acid and its derivatives analyzed by adsorption and reversed phase TLC and HPLC were compared.

[4]

05. _ Separations of nicotinic acid and its derivatives on different stationary phases (silica gel, a mixture of silica gel and kieselguhr, polyamide 11, and RP-18) have been compared.

[5]

1. G. Akçay, K. Yurdakoç, J. Sci. Ind. Res. 67(6) (2008) 451. 2. N. Yang, X. Wang, Coll. and Surf. B: Biointerfaces. 61(2) (2008) 277. 3. Z. Li, G. Yang, S. Liu, Y. Chen, J. Chrom. Sci. 43(7) (2005) 362. 4. A. Pyka, J. Śliwiok, A. Niestrój, Acta Poloniae Pharmaceutica - Drug Research. 60(5) (2003) 327. 5. A. Pyka, A. Niestroj, A. Szarkowicz, J. Sliwiok, J. Planar. Chromgr. - Modern TLC. 15(6) (2002) 410.

36

S. No. Adsorbent Remarks Ref.

06. Poly(acrylamide/maleic acid) hydrogels (AAm/MA)

AAm/MA hydrogel sorbed only nicotine and did not sorb nicotinamide, nikethamide and nicotinic acid in the binding experiments.

[6]

07. Polycrystalline gold electrode Adsorption behavior of three isomeric pyridinecarboxylic acids (picolinic acid: 2-PCA, nicotinic acid: 3-PCA, and isonicotinic acid: 4-PCA) in 0.1 M (M = mol dm-3) HClO4 solution on a smooth polycrystalline gold electrode surface was investigated by in situ infrared reflection absorption spectroscopy (IRAS).

[7]

08. (110) Face of silver

The adsorption of nicotinic acid, nicotinamide and nipecotamide at Ag(110) single crystal electrode has been studied from aqueous solutions of 0.1 KF.

[8]

09. Silver sol surface Adsorption of picolinic and nicotinic acids on a silver sol surface has been investigated over a wide range of solution pH by surface-enhanced Raman scattering.

[9]

10. Activated charcoal The effects of various factors on the adsorption of nicotinic acid onto and desorption from activated charcoal were investigated in vitro.

[10]

11. Mercury electrode Differential capacity measurements are reported for the adsorption of nicotinic acid (Nc) at the mercury electrode in water using buffered solutions at various pH and aqueous solutions with KF as a supporting electrolyte.

[11]

6. D. Saraydin, E. Karada, Y. Çaldiran, O. Güven, Int. J. Radiat. Phys. Chem.. 60(3) (2001) 203. 7. N. Nanbu, F. Kitamura, T. Ohsaka, K. Tokuda, Electrochemistry. 67(12) (1999) 1165. 8. M. Miłkowska, M. Jurkiewicz-Herbich, Pol. J. Chem. Tech. 70(6) (1996) 783. 9. S. M. Park, K. Kim, M. S. Kim, J. Molecular. Struct. 344(3) (1995) 195. 10. L. Roivas, P. J. Neuvonen, J. Pharmaceutical Sci. 81(9) (1992) 917. 11. M. Jurkiewicz-Herbich, J. Electroanal. Chem. 332(1-2) (1992) 265.

37

S. No. Adsorbent Remarks Ref. 12. Activated carbon Activated carbon has been used for the adsorption of nicotinic acid. [12]

13. Platinized platinum electrode The electrosorption of C-14 labelled nicotinic acid was studied at a platinized platinum electrode in both acid (1 mol dm-3 H2SO4) and alkaline (0.1 mol dm-3 NaOH) media.

[13]

14. Hydroxyapatite Adsorption of nicotinic and isonicotinic acid derivatives by hydroxyapatite from aqueous solutions.

[14]

15. Monodispersed sols of α-Fe2O3 and Cr(OH)3

The adsorption of nicotinic, picolinic, and dipicolinic acids on α-Fe2O3 and Cr(OH)3 sols consisting of spherical particles of narrow size distributions was measured at solute concentrations up to 4 × 10-4 mole dm-3 and over a range of pH values at 25°C.

[15]

16. Activated polyamide-powder A new method is described for the isolation of nicotinic acid (niacin) from pharmaceutical products. Niacin is separated by adsorption on activated polyamide-powder in a microchromatographic column.

[16]

12. M. Qureshi, K. G. Varshney, K. Z. Alam, A. Ahmad, Coll. and Surf. 50(C) (1990) 7. 13. G. Horányi, J. Electroanal. Chem. 284(2) (1990) 481. 14. N. Nambu, T. Nagai, Chemical and Pharmaceutical Bulletin. 29(7) (1981) 2093. 15. C. G. Pope, E. Matijević, R. C. Patel, J. Colloid. Interface Sci. 80(1) (1981) 74. 16. G. Lehmann, H. G. Hahn, Fresenius' Zeitschrift für Analytische Chemie. 243(1) (1968) 554.

38

1.12.2 Pesticides These are the major cause of pollution in the environment (soil, water and air)

that are extensively used to control, destroy, repel or attract a pest [159,160]. Pests

can be animals (insects, mice or deer), unwanted plants (weeds), or microorganisms

(Plant and human diseases). However, they have a wide range of toxicity and hence

poses great threat to the environment by entering in the food chain [161-169] or the

water bodies which results in eutrophication [170] (nitrogen-driven bacterial growth

depletes water oxygen to the point that all higher organisms die). The work performed

on TLC analysis of pesticides has been well described in literature [165,171-177] and

Table 1.6.

39

Table 1.6: List of important TLC studies of pesticides and their derivatives

S. No. Title Analyte Remarks Ref. 01. Development and validation of a

HPTLC method for simultaneous analysis of temephos and fenitrothion in green tea.

Temephos and fenitrothion

The plates were developed with acetone–hexane 3+7 (v/v), in an unsaturated glass twin-trough chamber with glassbacked silica gel 60F254 as stationary phase. The developed HPTLC plates were evaluated densitometrically.

[1]

02. A new spray reagent for selective detection and quantification of dichlorvos in bluish tinged maize grains by TLC–spectrophotometry.

Dichlorvos Silica gel G as stationary phase with cyclohexane–acetone–methanol 8:3:0.5 (v/v) as mobile phase was identified as the best TLC system for detection and migration (RF) of dichlorvos. The method has been used for identification of dichlorvos in cereals, pulses, vegetables, and fruit.

[2]

03. Separation of organophosphorus fungicides by high-performance thin-layer chromatography: A new approach in forensic analysis.

Three organophosphorus fungicides (OPF)

Optimum HPTLC separation of ditalimfos (D), edifenfos (E), and tolclofos-methyl (TM), three organophosphorus fungicides (OPF), has been achieved on silica gel 60F254 plates with n-hexane-acetone 9:1 (v/v) as mobile phase.

[3]

04. Thin-layer chromatographic studies of the mobility of pesticides through soil-containing static flat-beds.

Pesticides The chromatographic behavior of some pesticides has been studied on silica, soil, and mixed layers containing soil, with aqueous ammonium or sodium salt solutions, with or without added N-cetyl-N,N,N-trimethylammonium bromide (CTAB), with pure organic solvents, and with aqueous CTAB systems.

[4]

1. W. Fan, Y. Yue, F. Tang, H. Cao, J. Wang, X. Yao, J. Planar Chromatogr. 24(1) (2011) 53. 2. A. Mohammad, A. Moheman, J. Planar Chromatogr. 24(2) (2011) 113. 3. P. M. Nagaraju, P. U. Sanganalmath, K. Kemparaju, B. M. Mohan, J. Planar Chromatogr. 24(2) (2011) 108. 4. A. Mohammad, I. A. Khan, N. Jabeen, J. Planar Chromatogr. 14 (2011) 283.

40

S. No. Title Analyte Remarks Ref. 05. New chromogenic spray reagent for

detection and identification of carbosulfan.

Carbosulfan Alkaline hydrolysis of carbosulfan yields the sodium salt of 2,3-dihydro-2,2-dimethylbenzofuran-7-ol, which forms a purple complex with potassium ferricyanide in the thiochrome reaction.

[5]

06. Multi-enzyme inhibition assay for the detection of insecticidal organophosphates and carbamates by high-performance thin-layer chromatography applied to determine enzyme inhibition factors and residues in juice and water samples.

Twenty one organophosphorous and carbamate pesticides

Due to high selectivity of enzyme inhibition, oxon impurities of thionophosphate standards were strongly detected, although only present in low traces. The exemplary application of HPTLC–EI (RLE) to apple juice and drinking water samples spiked with paraoxon (0.001 mg/L), parathion (0.05 mg/L) and chlorpyrifos (0.5 mg/L) resulted in mean recoveries between 71 and 112% with standard deviations of 2.0–18.3%.

[6]

07. Application of HPLC-DAD and TLC-DAD after SPE to the quantitative analysis of pesticides in water samples.

Pesticides in lake water

A new procedure for the analysis of pesticides in water samples with use of solid phase extraction (SPE) and high performance chromatography with diode array detection (HPLC-DAD) and thin layer chromatography with diode array scanning (TLC-DAD).

[7]

08. Application of SPE-HPLC-DAD and SPE-HPTLC-DAD to the analysis of pesticides in lake water.

Pesticides in lake water

HPTLC of 11 pesticides on silica gel with ethyl acetate-n-heptane 1:4 and 3:7. quantitative determination by diode array densitometry.

[8]

5. K. V. Kulkarni, D. B. Shinde, D. V. Mane, R. B. Toche, M. V. Garad, J. Planar Chromatogr. 23(5) (2010) 373. 6. R. Akkad, W. Schwack, J. Chrom. B, 878 (2010) 1337. 7. T. Tuzimski, Jan Sobczyński. 32(9) (2009) 1241. 8. T. Tuzimski, J. Planar. Chromatogr. 22 (2009) 235.

41

S. No. Title Analyte Remarks Ref. 09. Spectrophotometric analysis of

carbamate pesticides after thermal gradient separation.

Carbamate pesticides

Detection of carbamate on silica gel and diazotized p-aminoacetanilid applied to form colored derivatives.

[9]

10. Effect of dissolved organic matter on mobility and activation of chlorotoluron in soil and wheat.

Chlorotoluron The effect of dissolved organic matter extracted from sludge (SL) and straw (ST) on chlorotoluron sorption/desorption and mobility using several techniques including batch experiment, soil column, soil thin- layer chromatography and bioefficacy were estimated.

[10]

11. Microwave assisted thin layer chromatography - an improved separation technique.

Dye and pesticide mixture

Microwave assisted TLC for the reduced migration distance of target compounds was used. Silica gel and cellulose with toluene, n-propanol-water was employed for the detection of pesticides.

[11]

12. Crucial role of formaldehyde and its reaction products in the antiproliferative activity of some potential pesticides.

Thirteen potential herbides.

Silica gel or RP-18 and hexane- 1,2- dichloroethane 2:3 was employed for the detection of herbicides. The lipophilicity of the substances was described by retention factors in water and log kw.

[12]

13. Application of SPE-HPLC-DAD and SPE-TLC-DAD to the determination of pesticides in real water samples.

Pesticides HPTLC of pesticides on silica gel with ethyl-acetate-n heptane 2:8. [13]

9. U. Tamrakar, V. K. Gupta, A. K. Pillai, J. Planar. Chromatogr. 22 (2009) 77. 10. N. H. Song, L. Chen, H. Yang, Geoderma. 146 (2008) 344. 11. M. L. Soran, I. Bros, E. Surducan, V. Surducan, J. Planar. Chromatogr. 21 (2008) 243. 12. M. Janicka, E. Tyihak, A. M. Moricz, B. O. Mendyk, J. Planar. Chromatogr. 21 (2008) 161. 13. T. Tuzimski, J. Sep. Sci. 31 (2008) 3537.

42

S. No. Title Analyte Remarks Ref. 14. Strategy for separation of complex mixtures by

multidimensional planar chromatography. Pesticides TLC and HPTLC of 22 pesticides on silica gel

with ethyl acetate- n-heptane for TLC (2:3) and HPTLC (1:1).

[14]

15. Determination of pesticides in water samples from the Wieprz-Krzna canal in the Leczynsko-Wlodawskie lake district of southeastern Poland by thin layer chromatography with diode array scanning and high-performance column liquid chromatography with diode array detection.

Pesticides HPTLC of nine pesticides on silica gel with ethyl acetate–n- heptane 1:4, 3:7, 2:3 or 7:3 was performed. Detection was done by TLC-DAD scanner.

[15]

16. A new procedure for separation of complex mixtures of pesticides by multidimensional planar chromatography.

Pesticides mixture The silica gel plate was developed with different combination of mobile phases such as ethyl acetate– n –heptane 1:3, chloroform–n-heptane 19:1, acetone– n-heptane 1:59, toluene and ethyl acetate–dicholoromethane 1:9.

[16]

17. Separation of multicomponent mixtures of pesticides by graft thin-layer chromatography on connected silica and octadecyl layers.

Twenty eight pesticides Graft TLC separation was performed on connected layers- silica and octadecyl silica wettable with water by non-aqueous mobile phase and aqueous reversed -phase in the first and second dimension.

[17]

14. T. Tuzimski, J. Planar chromatogr. 21 (2008) 49. 15. T. Tuzimski, J. AOAC Int. 91 (2008) 1203. 16. T. Tuzimski, J. Sep. Sci. 30 (2007) 964. 17. T. Tuzimski, J. Planar chromatogr. 20 (2007) 13.

43

S. No. Title Analyte Remarks Ref. 18. Comparison of normal and reversed-

phase TLC for separation of selected pesticides.

Urea pesticides TLC and HPTLC of pesticides on RP-18 with methanol-water and mixed organic-0.1% aqueous orthophosphoric acid as mobile phase and silica gel with benzene –methanol and benzene –ethanol mobile phases.

[18]

19. A cost-effective screening method for pesticide residue analysis in fruits, vegetables, and cereal grains.

Pesticides The Rf values of 118 pesticides were tested in eleven elution systems with UV, and eight biotest methods and chemical detection reagents. The best separation (widest Rf range) was achieved with silica gel (SG)--ethyl acetate (0.05-0.7), SG--benzene, (0.02-0.7) and reverse phase RP-18 F-254S layer with acetone: methanol: water/30:30:30 (v/v) (0.1-0.8).

[19]

20. Determination of pesticides in honey by ultrasonic solvent extraction and thin-layer chromatography.

Atrazine and simazine

The procedure was based on the extraction of pesticides by sonication with benzene:water = 1:1 (v/v) mixture and HPTLC silica gel 60 F254 plates.

[20]

21. Two stage fractionation of a mixture of 10 pesticides by TLC and HPLC.

Pesticides mixture Separation of mixtures of pesticides on silica gel with ethyl acetate- diisopropyl ether 1:9.

[21]

18. M. Miszczyk, A. Pyka, J. Planar chromatogr. 19 (2006) 15. 19. A. Ambrus, I. Füzesi, M. Susán, D. Dobi, J. Lantos, F. Zakar, I. Korsós, J. Oláh, B. B. Beke, L. Katavics, J. Environ. Sci. Health B. 40(2)

(2005) 297. 20. I. Rezic, A. J. M. Horvat, S. Babic, M. K. Macan, Ultrason. Sonochem. 12 (2005) 477. 21. T. Tuzimski, J. Liq. Chromatogr. Relat. Technol. 28 (2005) 463.

44

S. No. Title Analyte Remarks Ref. 22. Thin-layer chromatographic

methods for the analysis of eighteen different 14C-labeled pesticides.

14C- labeled pesticides

TLC of pesticides on silica gel and RP-18 with isopropanol-ethyl acetate-acetic acid 30:70:0.1, isopropanol-ethyl acetate-hexane-acetic acid 10:40:50:0.1 and 30:40:30:0.1, isopropanol –hexane-acetic acid 30:70:0.1, hexane-diethyl ether 1:1, methanol-water 3:2, methanol-water-acetic acid 3:2, methanol-water-ethyl acetate 13:5:2, acetonitrile-water 3:2, acetonitrile –water-phosphoric acid 1:9.

[22]

23. Two-dimensional TLC with adsorbent gradients of the type silica gel-octadecyl silica and silica-cyanopropyl for the separation of mixtures of pesticides.

Pesticides HPTLC of pesticides on silica gel, RP-18W, RP-18 and cyano phases was performed. In adsorbent gradient TLC silica gel plates with tetrahydrofuran-n-heptane 1:4 was used.

[23]

24. HPTLC of 16 pesticides on silica gel and RP-18 with ethyl acetate-diisopropyl ether 2.5:97.5 and acetonitrile-water 17:3; or methanol-water 4:1.

Pesticides HPTLC of 16 pesticides on silica gel and RP-18 with ethyl acetate- diisopropyl ether 2.5:97.5 and acetonitrile-water 17:3;or methanol-water 4:1.

[24]

25. Two-stage fractionation of a mixture of pesticides by micropreparative TLC and HPLC.

Pesticides Preliminary fractionation on silica gel with tetrahydrofuran-n- heptane 1:4. HPTLC of the separated fractions on RP-18W with methanol-water 3:2 and acetonitrile-water 3:2; densitometry at 254nm.

[25]

22. J. Rasmussen, O. S. Jabobsen, J. Planar Chromatogr.18 (2005) 248. 23. T. Tuzimski, J. Planar chromatogr. 18 (2005) 349. 24. T. Tuzimski, J. Wojtowicz, J. Liq. Chromatogr. Relat. Technol. 28 (2005) 463. 25. T. Tuzimski, J. Planar chromatogr. 18 (2005) 39.

45

S. No. Title Analyte Remarks Ref. 26. Use of database of plots of pesticide

retention (RF) against mobile-phase compositions for fractionation of a mixture of pesticides by micropreparative thin-layer chromatography.

Urea herbicides and fungicides

Complete separation of the fractions was carried out by two-dimensional thin-layer chromatography on plates with chemically bonded-cyanopropyl silica stationary phase using non-aqueous eluent in the first direction and aqueous reversed-phase eluent in the second direction.

[26]

27. Separation of a mixture of eighteen pesticides by two-dimensional thin-layer chromatography on a cyanopropyl-bonded polar stationary phase.

Pesticides HPTLC was performed on cyano phase by combining nonaqueous normal-phase mobile phase and aqueous reversed phases in the first and second direction respectively; densitometry at 254nm was done.

[27]

28. Multiresidue screening methods for the determination of pesticides in tomatoes.

Pesticide residues The possibility of applying thin layer chromatography (TLC) detection for the analysis of pesticide residues in tomatoes was investigated. The pesticides were eluted with ethyl acetate and dichloromethane as mobile and silica gel as the stationary phase.

[28]

29. Correlation of retention parameters of pesticides in normal and RP systems and their utilization for the separation of a mixture of ten urea herbicides and fungicides by two dimensional TLC on cyanopropyl-bonded polar stationary phase and two –adsorbent-layer multi-k plate.

Herbicides and fungicides

Cyanopropyl-bonded polar adsorbents in combination of non-aqueous np systems with ethyl acetate on silica and rp systems comprising a polar solvent (methanol) in water on octadecyl silica adsorbent was used.

[29]

26. T. Tuzimski, E. Soczewinski, Chromatographia. 59(1-2) (2004) 121. 27. T. Tuzimski, J.Planar Chromatogr. 17 (2004) 328. 28. S. L. Moraes, M. O. Rezende, L. E. Nakagawa, L. C. Luchini. J. Environ. Sci. Health B. 38(5) (2003) 605. 29. T. Tuzimski, A. Bartosiewicz, Chromatographia 58(11-12) (2003) 781.

46

S. No. Title Analyte Remarks Ref.

30. Fluorescence screening of organophosphorous pesticides in water by an enzyme inhibition procedure on TLC plates.

Organophosphorous pesticides

TLC of seven organophosphorous pesticides on silica gel with n-hexane-acetone 15:6 was performed. Quantitation was done by fluorescence quenching.

[30]

31. Combination of high-performance liquid chromatography and microplate scintillation counting for crop and animal metabolism studies: A comparison with classical on-line and thin-layer chromatography radioactivity detection.

Radio labeled pesticides

Thin layer radiochromatography of radiolabeled pesticides on silica gel by dichloromethane-methanol-NH3, 25% 40:10:1 and ethyl acetate-acetonitrile –formic acid 39:10:1 was performed.

[31]

32. OPLC and TLC in the prediction of retention factors of solutes in pure water.

Benzanilides, benzamide and pesticides

RP-18 with aqueous solutions of acetonitrile or methanol with different organic modifier concentrations.

[32]

33. Correlation of retention data of pesticides in normal –and reversed-phase systems and utilization of the data for the separation of a mixture of ten urea herbicides by two-dimensional thin-layer chromatography on cyanopropyl-bonded polar stationary phase and on a two-adsorbent-layer Multi-K SC5 plate.

Urea pesticides 2D-TLC of pesticides on cyanopropyl-modified silica gel, normal phase with ethyl acetate-heptane 1:4 and reversed- phase with dioxane- water 2:3 was performed.

[33]

30. M. Hamada, R. Wintersteiger, J. Planar Chromatogr. 16 (2003) 4. 31. M. Kiffe, A. Jhele, R. Ruembeli, Anal. Chem. 75 (2003) 723. 32. M. Janicka, J. K. Rozylo, Proc. Intern. Symp. on Planar Separations Plan. Chrom. (2003) 13. 33. T. Tuzimski, E. Soczewinski, J. Planar Chromatogr. 16 (2003) 263.

47

S. No. Title Analyte Remarks Ref. 34. Correlation of retention parameters of

pesticides in normal- and reversed-phase systems and their utilization for the separation of a mixture of 14 triazines and urea herbicides by means of two-dimensional thin-layer chromatography.

Mixture of 14 triazines and urea herbicides

The greatest spread of points, indicative of individual selectivity, was obtained for nonaqueous mobile phases on silica and aqueous mobile phases on octadecyl silica adsorbent wettable with water (RP-18 W).

[34]

35. Thin-layer chromatographic separations of some common pesticides on mixed stannic oxide-silica gel G layers.

Pyrethroid pesticides

TLC of pesticides on stannic oxide- silica gel G layers with a variety of mixed aqueous and organic mobile phase was performed. Quantitative determination by spectrophotometry was done.

[35]

36. Fate of 14C-labeled soybean and corn pesticides in tropical soil of Brazil under laboratory conditions.

Pesticides TLC on silica gel with n-hexane –ethyl acetate 1:1, n-hexane-toluene 7:3, toluene-cyclohexane 7:3, n-hexane-acetone 9:1, acetonitrile-water 3:2, n-hexane-acetone 1:1, n-hexane-acetone 3:1 was performed.

[36]

37. Chemometric characterization of the RF values of pesticides in thin-layer chromatography on silica with mobile phases comprising a weakly polar diluents and a polar modifier.

Polar pesticides Silica gel-heptane + modifier (ethylacetate, tetrahydrofuran, and dioxane). HPTLC on silica gel; detection under UV 254 nm.

[37]

34. T. Tuzimski, E. Soczewinski, J. Chrom. 961 (2002) 277. 35. S. A. Nabi, A. Gupta, M.A. Khan, A. Islam, Acta Chrom. 12 (2002) 201. 36. V. Laabs, W. Amelung, G. Fent, W. Zech, R. Kubiak, J. Agric. Food Chem. 50 (2002) 4619. 37. T. Tuzimski, J. Planar Chromatogr. 15 (2002) 124.

48

S. No. Title Analyte Remarks Ref.

38. Chemometric characterization of the Rf values of pesticides in thin-layer chromatography on silica with mobile phases comprising a weakly polar diluents and a polar modifier.

Pesticides Determination of the relationships between Rf values and mobile phase composition of pesticides on silica gel with heptane and a polar modifier. 2D-TLC with ethyl acetate-n-heptane 1:4 for the first and methanol-water 3:2 for the second direction.

[38]

39. Thin-layer chromatographic studies of the mobility of pesticides through soil-containing static flat-beds.

Pesticides TLC of six pesticides on silica gel, soil and mixed layers with aqueous ammonium or sodium salt solutions, with or without added N-cetyl-N,N,N-trimethylammonium bromide (CTAB), with pure organic solvents, and with aqueous CTAB systems.

[39]

40. Chemometric characterization of the Rf values of pesticides for thin-layer chromatographic systems of the type silica-nonpolar diluent + polar modifier.

Pesticides TLC of 20 pesticides on silica gel with heptane and polar modifier was performed. Detection was done at UV 254 or 366nm.

[40]

41. Relationship between the lipophilic and specific hydrophobic surface area of some pesticides by RP-HPLC and HPTLC.

Pesticides Retention behaviours of 37 pesticides by reversed-phase HPTLC using methanol-water mixtures was studied.

[41]

42. Binding characteristics of a water-soluble β-cyclodextrine polymer.

Commercial pesticides

Interaction of pesticides with a water soluble β-cyclodextrine polymer by charge-transfer reversed phase TLC was determined.

[42]

38. T. Tuzimski, E. Soczewinski, J. Planar Chromatogr. 15 (2002) 164. 39. A. Mohammad, I. A. Khan, N. Jabeen, J. Planar Chromatogr. 14 (2001) 283. 40. T. Tuzimski, E. Soczewinski, J. Planar Chromatogr. 13 (2000) 271. 41. L. Zhang, M. Zhang, L. X. Wang, Q. S. Wang, Chromatographia. 52(5/6) (2000) 305. 42. T. Cserhati, E. Forgacs, G. Oros, J. Liq. Chromatogr. 23 (2000) 411.

49

1.12.3 Pyridine Pyridine [Figure 1.17] is used as an important precursor in manufacturing of

vitamins, agrochemicals and pharmaceuticals as well as solvents and reagents for dyes and

rubber [178,179]. However, increased demand for pyridine leads to its disposal in water

bodies’ directly as industrial residue or indirectly as breakdown products and consequently

harms both animals and plants in aquatic systems. [180,181].

Figure 1.15. Structure of pyridine

Pyridine is harmful if inhaled, swallowed or absorbed through the skin. Effects of

acute pyridine intoxication include dizziness, headache, nausea, salivation, loss of appetite

and may progress into abdominal pain, liver damage, pulmonary congestion, unconsciousness

and even death [182-185]. Various methods such as biodegradation, photo-degradation,

catalytic oxidation, liquid membrane separation and adsorption have been developed to

remove pyridine from wastewater [186-188]. Some of the effective adsorption techniques for

the removal of pyridine are listed in Table 1.7.

50

Table 1.7: Adsorption techniques used for removal of pyridine

S. No. Adsorbent Remarks Ref. 01. Zeoadsorbents Zeoadsorbents on the basis of copper forms of synthetic zeolite ZSM5 and natural zeolite of the

clinoptilolite type (CT) have been studied taking into account their environmental application in removing harmful pyridine (py) from liquid and gas phase.

[1]

02. Fenton oxidation Isolated Pseudomonas pseudoalcaligenes-KPN in batch culture experiments, wherein the residual pyridine and 3-cyanopyridine removal efficiency was observed to be 84% and >99%, respectively.

[2]

03. Scandium oxide This investigation showed that scandium oxide, which is a recycled catalyst, is capable of removing organic nitrogen compounds from fuels.

[3]

04. Natural phosphate rock and two synthetic mesoporous hydroxyapatites

Experiments performed by the batch method showed that the sorption process occurs by a first order reaction for both pyridine and phenol. In contrast, the Freundlich model was able to describe sorption isotherms for phenol but not for pyridine.

[4]

05. Bio-zeolite A specific bio-zeolite composed of mixed bacteria (a pyridine-degrading bacterium and a quinoline-degrading bacterium) and modified zeolite was used for biodegradation and adsorption in two types of wastewater: sterile synthetic and coking wastewater.

[5]

06 Paracoccus sp. The effect of different co-substrates including glucose, ammonium chloride and trace elements on biodegradation and removal of pyridine by Paracoccus sp. KT-5 was investigated.

[6]

1. M. Reháková, L. Fortunová, Z. Bastl, S. Nagyová, S. Dolinská, V. Jorík, E. Jóna, J. Hazard. Mater. 186 (2011) 699. 2. K. V. Padoley, S. N. Mudliar, S. K. Banerjee, S. C. Deshmukh, R. A. Pandey, J. Chem. Eng. 166 (2011) 1. 3. J. W. Bauserman, G. W. Mushrush, H. Willauer, J. H. Wynne, J. P. Phillips, J. L. Buckley, F. W. Williams, Petrol. Sci. Tech. 28 (2010)

1761. 4. H. Bouyarmane, S. E. Asri, A. Rami, C. Roux, M. A. Mahly, A. Saoiabi, T. Coradin, A. Laghzizil, J. Hazard. Mater. 181 (2010) 736. 5. Y. Bai, Q. Sun, R. Xing, D. Wen, X. Tang, J. Hazard. Mater. 181 (2010) 916. 6. L. Qiao, J. Wang, J. Hazard. Mater. 176 (2010) 220.

51

S. No. Adsorbent Remarks Ref. 07. Paracoccus denitrificans W12

and biological activated bamboo charcoal (BABC)

Paracoccus denitrifican W12, was isolated and cultivated to grow on the surface of activated bamboo charcoal (ABC) particles so that the ABC turned into BABC covered with biofilm of the W12. Free cells of the W12 and the BABC were separately tested in removing pyridine from aqueous solution.

[7]

08. Microporous and mesoporous materials

The adsorption process primarily occurs in the pores of Ti-HMS, which is confirmed by comparing the adsorptive denitrogenation performance of Ti-HMS with uncalcined Ti-HMS.

[8]

09. Rice husk ash (RHA) and granular activated carbon (GAC)

The simultaneous removal of Pyridine (Py), α-picoline (αPi), and γ-picoline (γPi) from aqueous solutions by sorption onto rice husk ash (RHA) and granular activated carbon (GAC).

[9]

10. Shewanella putrefaciens The corn-cob packed biotrickling filter inoculated by S. putrefaciens should provide excellent performance in the removal of gaseous pyridine.

[10]

11. Bagasse fly ash (BFA) The simultaneous removal of Pyridine (Py) and its derivatives 2-picoline (2Pi) and 4-picoline (4Pi) by adsorption from aqueous solutions using bagasse fly ash (BFA) as an adsorbent.

[11]

7. R. Yu, C. Zhao, J. J. Liu, L. J. Chen, D. H. Wen, Huanjing Kexue/Environmental Sci. 31 (2010) 1053. 8. H. Zhang, G. Li, Y. Jia, H. Liu, J. Chem. Eng. Data. 55 (2010) 173. 9. D. H. Lataye, I. M. Mishra, I. D. Mall, Practice Periodical of Hazardous, Toxic, and Radioactive Waste Management. 13 (2009) 218. 10. A. K. Mathur, C. B. Majumder, Clean - Soil, Air, Water. 36 (2008) 180. 11. D. H. Lataye, I. M. Mishra, I. D. Mall, Ind. Eng. Chem Res. 47 (2008) 5629.

52

S. No. Adsorbent Remarks Ref. 12. Rice husk ash (RHA) and

granular activated carbon (GAC).

The adsorption of pyridine (Py) from synthetic aqueous solutions by rice husk ash (RHA) and commercial grade granular activated carbon (GAC) and reports on the kinetic, equilibrium and thermodynamic aspects of Py sorption.

[12]

13. Carbon nanotubes

The original CNTs and four treated CNTs were first used as adsorbents to remove pyridine from water and the adsorption isotherms of pyridine on CNTs were studied. At the same time, the effect of pH, temperature, and the adsorption kinetics on the adsorption of pyridine were also evaluated.

[13]

14. Bagasse fly ash (BFA) The present study examines the adsorption of pyridine (Py) from aqueous solutions, using bagasse fly ash (BFA), which is a solid waste that is generated from bagasse-fired boilers, as an adsorbent.

[14]

15. π-complexation sorbents. The sulfur and nitrogen compounds in transportation fuels (gasoline, diesel and jet fuels) can be selectively removed by a new class of adsorbents, referred to as π-complexation sorbents.

[15]

16. Activated carbons Investigates the ability of activated carbons developed from coconut shell to adsorb α-picoline, β-picoline, and γ-picolin from aqueous solution.

[16]

17. Low cost activated carbons

Activated carbons developed from agricultural waste materials were characterized and utilized for the removal of pyridine from wastewater. The results indicate that the Langmuir adsorption isotherm model fits the data better as compared to the Freundlich adsorption isotherm model.

[17]

12. D. H. Lataye, I. M. Mishra, I. D. Mall, J. Hazard. Mater. 154 (2008) 858..

13. B. Zhao, H. D. Liang, D. M. Han, D. Qiu, S. Q. Chen, Separ. Sci. Tech. 42 (2007) 3419. 14. D. H. Lataye, I. M. Mishra, I. D. Mall, Ind. Eng. Chem. Res. 45 (2006) 3934. 15. A. J. Hernández-Maldonado, F. H. Yang, G. Qi, R. T. Yang, J. Chinese Institute of Chemical Engineers. 37 (2006) 9. 16. D. Mohan, K. P. Singh, S. Sinha, D. Gosh, Carbon. 43 (2005) 1680. 17. D. Mohan, K. P. Singh, S. Sinha, D. Gosh, Carbon. 42 (2004) 2409.

53

S. No. Adsorbent Remarks Ref.

18. Polymeric ligand exchangers (PLE)

The chelating resins with nitrogen donor atoms served as excellent metal hosting polymers and pyridine-nitrogen atoms in polymer phase binds with metal ions more effectively than amine-nitrogen atoms.

[18]

19. High-area C-cloth electrodes

The use of high-area carbon cloth (C-cloth) electrodes as quasi-3-dimensional interfaces, coupled with in situ UV-Vis spectrophotometric techniques and scanning kinetics for quantitatively monitoring the adsorption/desorption processes and simultaneously obtaining kinetic parameters are described.

[19]

20. Rhodococcus sp. KCTC 3218

Pyridine, a representative nitrogen compound in heavy oil - was degraded by Rhodococcus sp. KCTC 3218 in a water-heavy oil two-phase system.This microorganism formed floes which could be a barrier to mass transfer between the cells in floes and the pyridine dissolved in water.

[20]

21. Combined ozonation/fluidized bed biofilm treatment

3-Methylpyridine (MP) and 5-ethyl-2-methylpyridine (EMP) were quantitatively removed in batch ozonation. In continuous combined experiments, wastewater was fed to a fluidised bed biofilm reactor with a mixed culture. The liquid was circulated through an ozonation bubble column. Ozone supply was controlled to keep the dissolved ozone concentration at a low level in the oxidation reactor.

[21]

22. Hydroxyls in NaHZSM-5 zeolite

The effect of removal of some hydroxyls by dehydroxylation and of pyridine sorption on the acid strength of OH groups remaining in the zeolite and contributing to the 3609 cm-1 band was studied.

[22]

18. W. D. Henry, D. Zhao, A. K. SenGupta, C. Lange, React. Funct. Polym. 60 (2004) 109. 19. J. Niu, B. E. Conway, J. Electroanal. Chem. 521 (2002) 16. 20. J. H. Do, W. G. Lee, K. Theodore, H. N. Chang, Biotechnol. Bioproc. Eng. 4 (1999) 205. 21. M. Stern, E. Heinzle, O. M. Kut, K. Hungerbühler, Water Sci. Tech. 35 (1997) 329. 22. J. Datka, M. Boczar, Zeolites. 11 (1991) 397.

54

S. No. Adsorbent Remarks Ref. 23. Spent rundle oil shale Adsorption of pyridine from aqueous solutions onto the solids generated by the processing of

Rundle oil shale shows that the adsorption isotherm is of Langmuir type (L-4) with two plateaux.

[23]

24. Coal, coal extracts and coal residues

Techniques for the removal of pyridine and quinoline from coal, coal extracts and coal residues have been developed.

[24]

25. Construction and erection of extractors

Describes a technique for recovery of pyridine and phenols from industrial wastewaters. [25]

23. S. Zhu, P. R. F. Bell, P. F. Greenfield. Water Res. 22 (1988) 1331. 24. N. E. Cooke, R. P. Gaikwad, Fuel. 63 (1984) 1468. 25. Pajak, Maksymilian, Sobesto, Jacek. Przemysl Chemiczny. 62 (1983) 460.

55

1.12.4 Aniline (C6H5NH2) Aniline also known as phenylamine, aminobenzene or benzenamine [Figure

1.16] is a nitrogen containing organic compound, widely used as a raw materials and

intermediate chemicals in manufacturing of pesticides, herbicides, rubber, dyestuff,

varnishes, organic paints and pigments, azo dyes, pharmaceuticals, petrochemicals

and other industries [189,190].

Figure 1.16: Structure of aniline

These are considered to be very toxic water pollutants even in very low

concentration to aquatic life and human beings [191-195]. Due to negative impact of

aniline on environment and its derivatives in wastewater, various methods such as

biological degradation [196-200], catalytic oxidation process [201-204],

electrochemical techniques [205], irradiation treatment [206], adsorption [192-

194,198,207-209] and other methods [203,210-212] have been proposed for the

successful removal of aniline compounds from wastewater. The adsorption of aniline

on various adsorbents has been listed in Table 1.8.

56

Table 1.8: List of adsorbents used for removal of aniline, its isomers and aniline derivatives by adsorption techniques

S. No. Adsorbent Remarks Ref. 01. Hyper-cross-linked

Macronet resin (MN200) This work was conducted to evaluate the sorption performance of hyper-cross-linked Macronet resin (MN200) compared to the granular activated carbon in order to remove phenol and aniline from aqueous solution in both single and binary solutions.

[1]

02. poly(ethylene terephthalate) (PET) fibers

Experiments were conducted in aniline monomer and hydrochloric acid solution with the variables such as contact time, initial concentration, and temperature, which can enhance the equilibrium adsorption capacity to aniline of poly(ethylene terephthalate) (PET) fibers.

[2]

03. Nanostructured Co3O4/CeO2 catalyst

Kinetic modeling of catalytic wet air oxidation (CWAO) of aniline was investigated in a bubble reactor over a nanostructured Co3O4 (10 wt %)/CeO2 catalyst.

[3]

04. Hypercrosslinked polymeric resin (AH-1)

In the present work, a modified hypercrosslinked polymeric resin (AH-1) with tertiary amino groups was adopted for adsorbing aniline from aqueous solution, and a traditional hypercrosslinked polymeric adsorbent NDA-100 was selected for comparison.

[4]

05. Au(111) electrode In situ scanning tunneling microscopy (STM) was used to study the adsorption and polymerization of aniline on Au(111) single-crystal electrode in 0.1 M perchloric acid and 0.1 M benzenesulfonic acids (BSA) containing 30 mM aniline, respectively.

[5]

06. Polymeric adsorbent by multiple phenolic hydroxyl groups

A hyper-cross-linked polymeric adsorbent functionalized with multiple phenolic hydroxyl groups HJ-03 was prepared in this study and its adsorptive characteristics for p-nitroaniline from aqueous solution were studied as compared with Amberlite XAD-4.

[6]

1. C. Valderrama, J. I. Barios, A. Farran, J. L. Cortina, Water Air Soil Pollut. 215 (2011) 285. 2. Y. Zhao, Z. Cai, Z. Zhou, X. Fu, J. Appl. Polymer Sci. 119 (2011) 662. 3. G. Ersoäz, S. Atalay, Ind. Eng. Chem. Res. 50 (2011) 310. 4. G. Ersoäz, S. Atalay, Ind. Eng. Chem. Res. 50 (2011) 310. 5. Y. Lee, S. Chen, H. Tu, S. Yau, L. Fan, Y. Yang, W. Dow, Langmuir. 26 (2010) 5576. 6. C. He, K. Huang, J. Huang, J. Colloid. Interface Sci. 342 (2010) 462.

57

S. No. Adsorbent Remarks Ref. 07. Activated carbon from

shell of carya cathayensis. The conditions for preparation of activated carbon from walnut (Carya cathayensis S.) shell were studied with phosphate method, and optimized with orthogonal experiments taking phosphate concentration, carbonizing temperature and time as influential factors, methylene blue adsorption, iodine value and yield as indexes, the adsorption process was analyzed in thermodynamics.

[7]

08. Polyvinylchloride (PVC) and polystyrene (PS)

The fibers had bigger hydrophilicity, better ability of acid, and alkali corrosion resistance, so they had better practical application value. This type of ion exchange fibers had faster absorption property and better working stability to aniline and could be used repeatedly, so they were applied for treatment of waste water containing aniline with a promising prospect.

[8]

09. Polyaniline (PANI) multiwalled carbon nanotubes (MWCNTs)

Polyaniline multiwalled carbon nanotube magnetic composite was prepared by plasma-induced graft technique and its application for removal of aniline and phenol.

[9]

10. Carbonate hydroxylapatite (CHAP)

The effects of pH value, adsorption period and aniline initial concentration on the adsorption performance of aniline from aqueous solution onto CHAP were investigated.

[10]

11. α-zirconium phosphate (α-ZrP)

Molecular dynamics simulation of adsorption of aniline by α-zirconium phosphate.

[11]

12. Wetland soil Batch equilibrium experiments were performed to assess adsorption and desorption characteristics of nitrobenzene and aniline by wetland soil.

[12]

7. X. J. Yu, C. S. Zhou, Y. X. Wang, L. J. Pang, Guocheng Gongcheng Xuebao, The Chinese Journal of Process Engineering. 10 (2010)

65. 8. Z. J. Ding, L. Qi, J. Z. Ye, J. Appl. Polym. Sci. 117 (2010) 1914. 9. D. Shao, J. Hu, C. Chen, G. Sheng, X. Ren, X. Wang, J. Phys. Chem. C. 114 (2010) 21524. 10. W. Tang, R. Zeng, X. Li, R. Yu, Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society. 38 (2010) 2167. 11. R. Y. Chen, J. Zhong, C. R. Gu, C. L. Chen, J. Theor. Comput. Chem. 9(5) (2010) 861. 12. Y. Song, C. Song, 4th International Conference on Bioinformatics and Biomedical Engineering, iCBBE 2010; Chengdu; 18 June 2010

through 20 June 2010; Category number CFP1029C; Code 81521

58

S. No. Adsorbent Remarks Ref. 13. Granular activated carbon

and hypercrosslinked polymeric resin (MN200)

Sorption equilibrium of phenol and aniline onto the granular activated carbon and hyperreticulated un-functionalized polymeric resin (MN200) was investigated in single and binary component aqueous systems.

[13]

14. Poly-methacrylic acid silicon dioxide. (PMAA/SiO2)

The adsorption properties and mechanism of PMAA/SiO2 towards aniline were researched through batch and column adsorption methods.

[14]

15. Activated carbon fibers (ACFs)

Activated carbon fibers (ACFs) were prepared for the removal of p-nitroaniline (PNA) from cotton stalk by chemical activation with NH4H2PO4 and subsequent physical activation with steam.

[15]

16. Phenolic resin Dumwald-Wagner model can illuminate the adsorption process of aniline onto LM-4 much better due to higher correlation coefficient. Kannan-Sundaram model indicates that the adsorption of aniline onto LM-4 is a favorable adsorption.

[16]

17. Activated carbon and hypercrosslinked polymeric resin (MN200)

Kinetic adsorption of phenol and aniline from aqueous solution onto activated carbon and hypercrosslinked polymeric resin MN200 were evaluated in single and binary system.

[17]

18. β-cyclodextrin polymer (β-CDP)

Removal of aniline from aqueous solutions by β-cyclodextrin polymer (β-CDP) using batch adsorption experiments.

[18]

13. C. Valderrama, J. I. Barios, A. Farran, J. L. Cortina, Water, Air, and Soil Pollut. 210(1-4) (2010) 421. 14. F. An, X. Feng, B. Gao, J. Hazard. Mater. 178(1-3) (2010) 499. 15. K. Li, Y. Li, Z. Zheng, J. Hazard. Mater. 178(1-3) (2010) 553. 16. X. H. Yuan, Z. R. Han, L. M. Lui, J. Hu, S. S. Cao, Gaofenzi Cailiao Kexue Yu Gongcheng/Polym. Mater. Sci. Eng. 26(4) (2010) 36. 17. C. Valderrama, J. I. Barios, M. Caetano, A. Farran, J. L. Cortina, React. Funct. Polym. 70(3) (2010) 142. 18. N. Li, X. L. Xiong, R. Q. Wang, 3rd International Conference on Bioinformatics and Biomedical Engineering, ICBBE (2009)

2009, Article number 5162288 (Category number CFP0929C; Code 79013).

59

S. No. Adsorbent Remarks Ref. 19. Cr-bentonite The sorption characteristics of aniline on Cr-bentonite prepared using synthetic wastewater

containing chromium was investigated in a batch system at 30 °C. [19]

20. Rice bran The effects of particle size, biosorbent dosage, pH and temperature on biosorption capacity were studied with static experiments, and the adsorption process was analyzed in thermodynamics and kinetics, and the adsorption mechanism analyzed by infrared spectroscopy.

[20]

21. Carboxylated diaminoethane sporopollenin (CDAE-S)

A dynamic method called stepwise frontal analysis (SFA) was used to derive equilibrium sorption data of copper and aniline on a sporopollenin (CDAE-S) solid phase.

[21]

22. Polymeric adsorbent and XAD-4 (highly adsorbent resin)

Phenolic hydroxyl groups modified hyper-cross-linked polymeric adsorbent HJ-02 was prepared and it was applied to remove p-nitroaniline in aqueous solution as compared with Amberlite XAD-4.

[22]

23. Cross-linked starch sulfate A new environment friendly adsorbent, cross-linked starch sulfate (CSS), was prepared and used to adsorb aniline from aqueous solution.

[23]

24. Phenolic resin Using liquid paraffin as disperse phase, span80 as dispersant, ethylene glycol as porogen, adsorbents of LM-3 and LM-4 were prepared by inverse suspension polymerization, and their performance were compared with LM-1 and LM-2 which prepared by solution polycondensation.

[24]

19. H. Zheng, D. Liu, Y. Zheng, S. Liang, Z. Liu, J. Hazard. Mater. 167 (2009) 141. 20. F. C. Li, Y. Z. Dai, Y. P. Luo, Z. M. You, Guocheng Gongcheng Xuebao/The Chinese Journal of Process Engineering. 9 (2009)

274. 21. O. Gezici, A. Ayar, Clean - Soil, Air, Water. 37 (2009) 349. 22. J. Huang, X. Wang, K. Huang, Chem. Eng. J. 155(3) (2009) 722. 23. L. Guo, G. Li, J. Liu, P. Yin, Q. Li, Ind. Eng. Chem. Res. 48(23) (2009) 10657. 24. X. H. Yuan, W. Song, L. M. Lui, J. Hu, W. C. Sheng, S. S. Cao, Gaofenzi Cailiao Kexue Yu Gongcheng/Polym. Mater. Sci. Eng.

25(10) (2009) 13.

60

S. No. Adsorbent Remarks Ref. 25. Polyacrylamide silicon

dioxide (PAM/SiO2) In this paper, functional monomer acrylamide (AM) was grafted step by step onto the surface of silica gel particles using 3-methacryloxypropyl trimethoxysilane (MPS) as coupling agent and the grafted particle PAM/SiO2 was prepared.

[25]

26. Activated carbon fiber Activated carbon fiber prepared from cotton stalk was used as an adsorbent for the removal of p-nitroaniline (PNA) from aqueous solutions.

[26]

27. Activated carbon Activated carbon prepared from cotton stalk fibre has been utilized as an adsorbent for the removal of 2-nitroaniline from aqueous solutions.

[27]

28. Si (5 5 12) -2×1 surface A scanning tunneling microscopy and first-principles calculations study of the adsorption structures of aniline on a Si (5 5 12) -2×1 surface.

[28]

29. Humus fractions of selected wetland soils

Batch equilibrium experiments were performed to assess adsorption characteristics of nitrobenzene and aniline by humus fractions of selected wetland soils.

[29]

30. CuO doped activated carbon

Adsorption of aniline, benzene and pyridine from water on a copper oxide doped activated carbon (CuO/AC) at 30 °C and oxidation behavior of the adsorbed pollutants over CuO/AC in a temperature range up to 500 °C are investigated in TG and tubular-reactor/MS systems.

[30]

31. Anatase TiO2 (100) surface

A computational technique based on semiempirical SCF MO method MSINDO, has been used for the investigation of adsorption and initial oxidation step for the photodegradation of aniline on anatase TiO2 (100) surface.

[31]

25. F. An, X. Feng, B. Gao, Chem. Eng. J. 151(1-3) (2009) 183. 26. K. Li, Z. Zheng, J. Feng, J. Zhang, X. Luo, G. Zhao, X. Huang, J. Hazard. Mater. 166(2-3) (2009) 1180. 27. K. Li, Z. Zheng, X. Huang, G. Zhao, J. Feng, J. Zhang, J. Hazard. Mater.. 166(1) (2009) 213. 28. S. H. Jang, S. Jeong, J. R. Hahn, J. Chem. Phys. 130(23) Article Number 234703. 29. Y. Song, C. Song, J. Chai, J. Guo, Q. Zhao, G. Li, Huanjing Kexue Xuebao / Acta Scientiae Circumstantiae, 29(5) (2009) 997. 30. B. Li, Z. Liu, Z. Lei, Z. Huang, Kor. J. Chem. Eng. 26(3) (2009) 913. 31. H. S. Wahab, A. D. Koutselos, Chem. Phys. 358(1-2) (2009) 171.

61

S. No. Adsorbent Remarks Ref. 32. Modified montmorillonite Adsorption of phenol and aniline onto original and with quaternary ammonium salts (QASs)-

modified montmorillonite was described by sorption isotherms of type III and II respectively [32]

33. Multi-walled carbon nanotubes Aqueous adsorption of a series of phenols and anilines by a multiwalled carbon nanotube material (MWCNT15), which depends strongly on the solution pH and the number and types of solute groups was investigated in this study.

[33]

34. Wetland soils Batch equilibrium experiments were performed to assess adsorption and desorption characteristics of aniline by wetland soils from the Sanjiang Plain. Wetland soils had strong adsorption capability for aniline, and the mechanisms primarily include hydrophobic portioning and cation exchange.

[34]

35. XDA-1 resin A combined physical-biological method consisted of the physical adsorption of aniline from hypersaline effluents by resins and the biodegradation of the adsorbate and the regeneration of the adsorbent in the subsequent stage.

[35]

36. A solid catalytic adsorbent The focus of the work described was the development of a solid catalytic adsorbent material capable of being regenerated, with the ability of adsorbing aniline from aqueous solution and the subsequent catalytic oxidation of the adsorbed aniline.

[36]

37. Cu-Beta adsorbent materials The aim of this research was to develop a solid regenerable catalytic adsorbent capable of removing aniline from aqueous solutions.

[37]

38. Multiwalled carbon nanotubes In this work, oxidized multiwalled carbon nanotubes (MWCNTs-COOH) coated on the outer surface of the fused-silica tube and inserted in the polyether ether ketone (PEEK) tubing, which was fixed directly on the six-port injection valve to substitute for the sample loop.

[38]

32. H. Kostelníkova, P. Praus, M. Turicová, Acta Geodynamica et Geomaterialia. 5 (2008) 83. 33. K. Yang, W. Wu, Q. Jing, L. Zhu, Environ. Sci. Tech. 42 (2008) 7931. 34. Y. Y. Song, C. C. Song, J. H. Chai, J. Guo, Q. D. Zhao, G. Li, Zhongguo Huanjing Kexue/China Environmental Science. 28 (2008) 781. 35. X. Gu, J. Zhou, A. Zhang, P. Wang, M. Xiao, G. Liu, Desalination. 227 (2008) 139. 36. J. O'Brien, T. Curtin, T. F. O'Dwyer, Adsorpt. Sci. Technol. 26(5) (2008) 311. 37. J. O'Brien, T. F. O'Dwyer, T. Curtin, J. Hazard. Mater. 159(2-3) (2008) 476. 38. X. Y. Liu, Y. S. Ji, H. X. Zhang, M. C. Liu, J. Chromatogr. A. 1212(1-2) (2008) 10.

62

S. No. Adsorbent Remarks Ref. 39. Silicate monoliths (HOM-2) Hexagonally highly ordered monolithic mesoporous silica and aluminosilicate composites

(HOM-2 and Al/HOM-2, respectively) were used as adsorbents for removal of aniline in aqueous solution.

[39]

40. Dimethyl ditallowylammonium montmorillonite

The expansion behaviour of an organically modified montmorillonite during the adsorption of increasing amounts of an organic pollutant: 2-chloroaniline (2-CA).

[40]

41. Sodium tetraborate-modified Kaolinite clay adsorbent

Raw Kaolinite clay obtained from Ubulu-Ukwu, Delta State of Nigeria and its sodium tetraborate (NTB)-modified analogue was used to adsorb aniline blue dye.

[41]

42. Fuel oil fly ash

Fuel oil fly ash has been tested as low-cost carbon-based adsorbent of 2-chlorophenol (CP), 2-chloroaniline (CA) and methylene blue (MB) from aqueous solutions.

[42]

43. Macroporous kaolin adsorption kinetics of small molecular mass anilines (<205 g/mol) over macroporous kaolin was studied.

[43]

44. Mesoporous materials, Na-AlMCM-41 and Na-AlSBA-15 catalysts

In this work we study the water adsorption and adsorbed aniline interaction onto the mesoporous materials Na-AlMCM-41, compared with aniline adsorption onto Na-AlSBA-15.

[44]

45. Imprinted polymer (MIP) The synthesized MIP was then tested by equilibrium-adsorption method, and the MIP demonstrated high removal efficiency to the aniline.

[45]

39. S. A. El-Safty, F. Mizukami, T. Hanaoka, Int. J. Environ. Pollut. 34(1-4) (2008) 97. 40. L. Zampori, P. Gallo Stampino, G. Dotelli, D. Botta, I. Natali Sora, M. Setti, Appl. Clay Sci. 41(3-4) (2008) 149. 41. E. I. Unuabonah, K. O. Adebowale, F. A. Dawodu, J. Hazard. Mater. 157(2-3) (2008) 397. 42. S. Andini, R. Cioffi, F. Colangelo, F. Montagnaro, L. Santoro, J. Hazard. Mater. 157(2-3) (2008) 599. 43. F. López-Linares, L. Carbognani, C. Sosa Stull, P. Pereira-Almao, Energ. Fuel. 22(4) (2008) 2188. 44. O. A. Anunziata, M. B. Gómez Costa, M. L. Martínez, Catal. Today. 133-135(1-4) (2008) 897. 45. J. Yao, X. Li, W. Qin, Anal. Chim. Acta. 610(2) (2008) 282.

63

S. No. Adsorbent Remarks Ref. 46. Polyurethane foams, diffuse

reflectance spectroscopy The adsorption of aniline as its 4-nitrophenylazo derivative was studied on polyurethane foams depending on phase contact time, reagent concentration, and type of adsorbent.

[46]

47. Zeolite beta Zeolite beta was investigated in this study with a view to examining it's potential to function as both adsorbent and catalyst in the removal of aniline from aqueous solutions.

[47]

48. Zeolite ZSM-5 Zeolite ZSM-5 was investigated with a view to examining its potential to function as both adsorbent and catalyst in the removal of aniline from aqueous solutions.

[48]

49. Multi-walled carbon nanotubes

The thermodynamic behaviors of aniline adsorption on the surface of chemical modified carbon nanotubes (CNTs) are studied, which indicate to understand their surface chemical characteristics.

[49]

50. Organo-clays The aims of this study were to make use of organo-clays (i.e., Cloisite-10A, Cloisite-15A, Cloisite-30B and Cloisite-93A), to remove p-nitrophenol, phenol and aniline of organic pollutants.

[50]

51. Carboxylated polymeric adsorbent ZK-1

In the present study a carboxylated polymeric adsorbent ZK-1 was synthesized for enhanced removal of p-nitroaniline (PNA) from aqueous solution.

[51]

52. Basic activated carbon

The interaction of phenol and aniline with the surface of highly microporous ash-free carbon was systematically studied in aqueous solutions in the pH range 3-11 under oxic conditions.

[52]

46. E. V. Kuz'mina, L. N. Khatuntseva, S. G. Dmitrienko, J. Anal. Chem. 63(1) (2008) 34. 47. J. O'Brien, T. Curtin, T. F. O'Dwver, Proceedings of the Second IASTED International Conference on Advanced Technology in

the Environmental Field, ATEF (2006) (2007) 7-12. 48. J. O'Brien, T. Curtin, T. F. O'Dwyer, WIT Transactions on Ecology and the Environment. 103 (2007) 447. 49. X. Xie, L. Gao, J. Sun, Colloid. Surface. Physicochem. Eng. Aspects. 308(1-3) (2007) 54. 50. C. H. Ko, C. Fan, P. N. Chiang, M. K. Wang, K. C. Lin, J. Hazard. Mater. 149(2) (2007) 275. 51. K. Zheng, B. Pan, Q. Zhang, W. Zhang, B. Pan, Y. Han, Q. Zhang, D. Wei, Z. Xu, Q. Zhang, Separ. Purif. Tech. 57(2) (2007)

250. 52. K. László, E. Tombácz, C. Novák, Colloid. Surface. Physicochem. Eng. Aspect. 306(1-3) (2007) 95.

64

S. No. Adsorbent Remarks Ref. 53. Activated carbon fiber Electrosorption-enhanced solid-phase microextraction (EE-SPME) based on activated carbon

fiber (ACF) was developed for determination of aniline in aqueous solution. [53]

54. Activated carbons (ACs) The heterogeneity of activated carbons (ACs) prepared from different precursors is investigated on the basis of adsorption isotherms of aniline from dilute aqueous solutions at various pH values.

[54]

55. Carboxylated polymeric sorbent In the present study a carboxylated styrene-divinylbenzene (St-DVB) polymeric sorbent (CSPS) was prepared for enhanced removal of p-chloroaniline from aqueous solution.

[55]

56. Modified bentonite The self-made modified bentonite is used in the experiment as the adsorbent to find out how it adsorbs the single-component solution of phenol and aniline respectively under the conditions of different pH values, different adsorptive temperature, different initial concentrations and different adsorptive time.

[56]

57.

Polymer adsorbents (NDA-100, XAD-4, NDA-16 and NDA-1800)

The adsorption equilibria of phenol and aniline on nonpolar polymer adsorbents (NDA-100, XAD-4, NDA-16 and NDA-1800) were investigated in single- and binary-solute adsorption systems at 313 K.

[57]

58. Nonpolar adsorbents Adsorption equilibria of phenol and aniline onto nonpolar macroreticular adsorbents were investigated in single and binary-solute aqueous systems at 293 K and 313 K.

[58]

53. X. Chai, Y. He, D. Ying, J. Jia, T. Sun, J. Chromatogr. A, 1165(1-2) (2007) 26. 54. P. Podkościelny, K. László, Appl. Surf. Sci. 253(21) (2007) 8762. 55. K. Zheng, B. Pan, Q. Zhang, Y. Han, W. Zhang, B. Pan, Z. Xu, Q. Zhang, W. Du, Q. Zhang, J. Hazard. Mater. 143(1-2) (2007)

462. 56. F. Zhang, Y. Li, X. Xue, Shenyang Jianzhu Daxue Xuebao (Ziran Kexue Ban)/Journal of Shenyang Jianzhu University (Natural

Science). 23(2) (2007) 303. 57. W. M. Zhang, Q. J. Zhang, B. C. Pan, L. Lv, B. J. Pan, Z. W. Xu, Q. X. Zhang, X. S. Zhao, W. Du, Q. R. Zhang, J. Colloid.

Interface Sci. 306(2) (2007) 216. 58. W. Zhang, Z. Xu, B. Pan, Q. Zhang, W. Du, Q. Zhang, K. Zheng, Q. Zhang, Chen, J. Chemosphere. 66(11) (2007) 2044.

65

S. No. Adsorbent Remarks Ref. 59. Gold nanoparticles Surface-enhanced Raman scattering (SERS) spectra of p-, m-, and o-nitroaniline (PNA, MNA, and

ONA) adsorbed on gold nanoparticles were studied, respectively, in a gold colloidal solution and on dried gold-coated filter paper.

[59]

60. Montmorillonite and kaolinite

The sorption-desorption behavior of the environmentally hazardous industrial pollutants and certain pesticides degradation products, 3-chloroaniline, 3,4-dichloroaniline, 2,4,6-trichloroaniline, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol on the reference clays kaolinite KGa-1 and Na-montmorillonite SWy-l.

[60]

61. Activated carbon fibers This study describes the anodic polarization of activated carbon fibers (ACFs), which can enhance the adsorption rate and capacity of aniline.

[61]

62. Carbon nanotubes (MWNT) Aniline-modified multi-walled carbon nanotubes (MWNT) have been obtained through interaction between carboxylated MWNT and aniline in aqueous solution.

[62]

63. Multi-walled carbon nanotubes (designated as c-MWNTs and a-MWNTs)

Based on the π-π* electron interaction between aniline monomers and functionalized MWNT and hydrogen bonding interaction between the amino groups of aniline monomers and the carboxylic acid/acylchloride groups of functionalized MWNT, aniline molecules were adsorbed and polymerized on the surface of MWNTs.

[63]

64. Hypercrosslinked polymeric adsorbents

Competitive and cooperative simultaneous adsorptions of phenol and aniline from aqueous solutions by hypercrosslinked polymeric adsorbents (NDA103, NDA101, NDA100) were investigated.

[64]

59. W. Ma, Y. Fang, J. Colloid. Interface Sci. 303 (2006) 1. 60. S. Polati, F. Gosetti, V. Gianotti, M. C. Gennaro, J. Environ. Sci. Health - Part B Pesticides, Food Contaminants, and

Agricultural Wastes. 41(6) (2006) 765. 61. Y. Han, X. Quan, S. Chen, H. Zhao, C. Cui, Y. Zhao, Separ. Purif. Tech. 50(3) (2006) 365. 62. X. Xie, L. Gao, Chem. Lett. 35(6) (2006) 624. 63. T. M. Wu, Y. W. Lin, Polymer. 47(10) (2006) 3576. 64. W. Zhang, J. Chen, Q. Zhang, B. Pan, Acta Polymerica Sinica. (2) (2006) 213.

66

S. No. Adsorbent Remarks Ref. 65. Nonpolar resin

adsorbents A new model was developed to describe the synergistic adsorption in the binary system (phenol/aniline in aqueous solution) onto nonpolar resin adsorbent Amberlite XAD-4 and NDA-100.

[65]

66. Ultrafine coal powder

Seven Shenfu coal powders with different particle sizes were used for adsorption tests to probe the adsorption properties of aniline on different granularity coal powders, especially the ultrafine ones.

[66]

67. Coal containing apricot cores

We considered the fixing of aniline on carbon prepared from apricot stones, treated beforehand with the acids sulphuric, hydrochloric and phosphoric.

[67]

68. Modified bentonite The adsorption capacities of clay-organic complexes (bentonite-EDTA and bentonite-HDTMA) are higher than those of bentonite-HNO3 and pure bentonite.

[68]

69. Montmorillonite and kaolinite

This study reports the sorption-desorption behavior of the environmentally hazardous industrial pollutants and certain pesticides degradation products, 3-chloroaniline, 3,4-dichloroaniline, 2,4,6-trichloroaniline, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol on the reference clays kaolinite KGa-1 and Na-montmorillonite SWy-l.

[69]

70. Nonpolar macroreticular adsorbents

The adsorption behaviors of phenol and aniline on nonpolar macroreticular adsorbents (NDA100 and Amberlite XAD4) were investigated in single or binary batch system at 293K and 313K respectively in this study. The results indicated that the adsorption isotherms of phenol and aniline on both adsorbents in both systems fitted well Langmuir equation, which indicated a favourable and exothermic process.

[70]

65. W. Zhang, J. Chen, B. Pan, Q. Chen, M. He, Q. Zhang, F. Wang, B. Zhang, React. Funct. Polym. 66(4) (2006) 395. 66. Z. N. Liu, A. N. Zhou, Q. T. Jin, J. Fuel Chem. Tech. 34(1) (2006) 20. 67. H. Tizi, Z. Bendjama, T. Berrama, CHISA 2006 - 17th International Congress of Chemical and Process Engineering, (2006) 7. 68. A. Yildiz, A. Gür, H. Ceylan, Russ. J. Phys. Chem. A, 80(1) (2006) S172. 69. S. Polati, F. Gosetti, V. Gianotti, M. C. Gennaro, J. Environ. Sci. Health - Part B Pesticides, Food Contaminants, and

Agricultural Wastes. 41(6) (2006) 765. 70. W. M. Zhang, J. L. Chen, B. C. Pan, Q. X. Zhang, J. Environ. Sci. 17(4) (2005) 529.

67

S. No. Adsorbent Remarks Ref. 71. Bifunctional polymeric

resin (LS-2) with sulfonic groups

a hydrophilic bifunctional polymeric resin (LS-2) with sulfonic groups was synthesized, and the adsorption performance of three aniline compounds, aniline, 4-methylaniline, and 4-nitroaniline onto LS-2 was compared with that on the commercial Amberlite XAD-4.

[71]

72. Bifunctional polymeric adsorbent modified by sulfonic groups

A new bifunctional polymeric resin (LS-2) was synthesized by introducing sulfonic groups onto the surface of the resin during the post-crossing of chloromethyl low crosslinking macroporous poly-styrene resin, and the comparison of the adsorption properties of LS-2 with Amberlite XAD-4 toward aniline and 4-methylaniline in aqueous solutions was made.

[72]

73. Ru/SiO2 catalyst

(Ru/SiO2 catalyst) heterogeneous catalyst was found to be very effective in the complete degradation of aniline and also to be active in the conversion of the -NH 2 group in aniline into N2 gas.

[73]

74. Activated carbons Microporous carbons of similar surface area (1200-1500 m2/g) and porosity but different surface composition were prepared from poly(ethyleneterephthalate) (PET) based activated carbon by chemical (cc HNO3) and thermal (700°C) post-treatment. The waste removal capacity was studied by adsorption from buffered aqueous phenol and aniline solutions.

[74]

75. Silver, Ag(111) The adsorption of submonolayer aniline on the Ag(1 1 1) surface has been characterized using temperature programmed desorption (TPD) and electron energy loss spectroscopy (EELS).

[75]

76. H-beta zeolites and copper-exchanged beta zeolites

Zeolite beta, a large-pore zeolite, was investigated in this study with a view to examining it as a potential adsorbent for the removal of aniline from aqueous solutions.

[76]

71. C. Jianguo, L. Aimin, S. Hongyan, F. Zhenghao, L. Chao, Z. Quanxing, Chemosphere. 61(4) (2005) 502. 72. C. Jianguo, L. Aimin, S. Hongyan, F. Zhenghao, L. Chao, Z. Quanxing, J. Hazard Mater. 124(1-3) (2005) 173. 73. G. R. Reddy, V. V. Mahajani, Ind. Eng. Chem. Res. 44(19) (2005) 7320. 74. K. László, Colloid. Surface. Physicochem. Eng. Aspects. 265(1-3) (2005) 32. 75. T. J. Rockey, M. Yang, H. L. Dai, Surf. Sci. 589(1-3) (2005) 42. 76. J. O'Brien, T. Curtin, T. F. O'Dwyer, Adsorpt. Sci. Tech. 23(3) (2005) 255.

68

S. No. Adsorbent Remarks Ref. 77. Aminated-macroporous

hypercrosslinked resins The sorption of phenol and aniline on the synthesized resins in aqueous and nonaqueous solutions was investigated.

[77]

78. QSAR model by using artificial neural networks (ANNs).

Based on descriptors of n-octanol/water partition coefficients (log K ow), molecular connectivity indices, and quantum chemical parameters, several QSAR models were built to estimate the soil sorption coefficients (log Koc) of substituted anilines and phenols.

[78]

79. Benzoyl-containing polymeric adsorbents

New polymeric adsorbents (ZH-02, ZH-03) containing benzoyl group for adsorbing and removing 4-methylaniline from its aqueous solutions were prepared.

[79]

80. Cobalt(II)-poly(vinyl chloride)-carboxylated diaminoethane (PVC-CDAE) resin

The adsorption of aniline from aqueous solutions onto cobalt(II)-poly(vinyl chloride)-carboxylated diaminoethane (PVC-CDAE) resin has been studied using a mini-column apparatus at 25 ± 0.1°C.

[80]

81. High-area carbon-cloth The adsorption of anilinic compounds; aniline, p-toluidine, 1-napthylamine and sodium salt of diphenylamine-4-sulfonic acid from solutions in H2O, in 1 M H2SO4 or in 0.1 M NaOH onto activated carbon-cloth was studied by in situ UV spectroscopy.

[81]

82. Nanofiltration membranes (polyamide and cellulose acetate)

This study evaluates the performance of two nanofiltration membranes in removing a herbicide: dichloroaniline. The membranes, one polyamide and one cellulose acetate, have a cut-off in the range 150-300 g/mol.

[82]

77. R. Wang, Z. Shi, R. Shi, J. Zhang, L. Ou, Acta Polymerica Sinica. 3 (2005) 339. 78. G. Liu, J. Yu, Water Res. 39(10) (2005) 2048. 79. G. C. Zhang, H. S. Wu, Z. H. Fei, Chin. J. Polymer Sci. (English Edition). 23(3) (2005) 255. 80. A. A. Gürten, S. Uçan, M. A. Özler, A. Ayar, J. Hazard. Mater. 120(1-3) (2005) 81. 81. O. Duman, E. Ayranci, J. Hazard. Mater. 120(1-3) (2005) 173. 82. C. Causserand, P. Aimar, J. P. Cravedi, E. Singlande, Water Res. 39(8) (2005) 1594.

69

S. No. Adsorbent Remarks Ref. 83. Kaolinite and

montmorillonite

Batch experiments have been performed in order to evaluate the ability of the two reference clays kaolinite (KGa-1) and Na-montmorillonite (SWy-1) to retain three representative chloroanilines: 3-chloroaniline, 3,4-dichloroaniline and 2,4,6-trichloroaniline.

[83]

84. Commercial activated carbon

Studies on the removal of aniline blue (AB) and acid violet (AV) by commercial activated carbon (CAC), have been made at 30°C.

[84]

85. Sediment In natural water systems, sorption of an organic pollutant to soil/sediment is often influenced by coexisting organic compounds.

[85]

86. Copper-exchanged ZSM-5 and unmodified H-ZSM-5

Three medium-pore aluminosilicates were investigated with a view to examining their potential as adsorbents for the removal of aniline from aqueous solutions. H-ZSM-5 was exchanged with copper to prepare two different metal-loaded zeolites.

[86]

87. Inorgano-organo-montmorillonites

The adsorption behavior of aniline on four modified montmorillonite samples was also studied and the results show that the adsorbability of inorgano-organo-montmorillonites is much better than that of Na-montmorillonites.

[87]

88. Alkyl-grafted MCM-41 Molecular selective adsorption of alkylphenols and alkylanilines onto n-alkyl grafted MCM-41 with different alkyl chain lengths and Al contents was studied. Octyl groups gave better adsorbent performance than pentyl and dodecyl groups.

[88]

83. S. Angioi, S. Polati, M. Roz, C. Rinaudo, V. Gianotti, M. C. Gennaro, Environ. Pollut. 134(1) (2005) 35. 84. N. Kannan, C. Thamaraichelvi, Indian J. Environ. Protect. 25(1) (2005) 1. 85. L. Zhu, B. Lou, K. Yang, B. Chen, Water Res. 39(2-3) (2005) 281. 86. J. O'Brien, T. Curtin, T. F. O'Dwyer, Adsorpt. Sci. Technol. 22(9) (2004) 743. 87. G. Ren, Y. Zhai, E. Song, C. Zhang, X. Wang, Kuei Suan Jen Hsueh Pao/ Journal of the Chinese Ceramic Society. 32(8) (2004)

988. 88. K. Inumaru, Y. Inoue, S. Kakii, T. Nakano, S. Yamanaka, Phys. Chem. Chem. Phys. 6(12) (2004) 3133.

70

S. No. Adsorbent Remarks Ref. 89. Organo-zeolite In batch tests, the adsorption capacity of aniline and nitrobenzene onto natural zeolite surface is

very low or almost nil but becomes significant upon modifying the zeolite surface by hexadecyltrimethylammonium (HDTMA).

[89]

90. Particulate soil organic matter The distribution of TNT* (the sum of TNT and its degradation products), aniline, and nitrobenzene between particulate organic matter (POM), dissolved soil organic matter (DOM), and free compound was studied in controlled kinetic (with and without irradiation) and equilibrium experiments with mixtures of POM and DOM reflecting natural situations in organic rich soils.

[90]

91. Microwave-assisted headspace solid-phase microextraction and gas chromatography

Determination of aniline in wastewater was investigated by microwave-assisted headspace solid-phase microextraction (MA-HS-SPME), for one-step in-situ sample preparation, and gas chromatography.

[91]

92. Carbon materials: a mesoporous high surface area graphite (HSAG) and a microporous activated carbon (AC).

The adsorption behavior of phenol, aniline and phenol-aniline mixtures in water over carbonaceous material surfaces has been studied.

[92]

93. Absorbance ratio derivative method

A method of simultaneous determination of phenol and aniline in waste water by absorbance ratio derivative is reported in this paper.

[93]

94. Silver and gold colloid Raman and surface-enhanced Raman scattering (SERS) spectra of o-, m-, and p-nitroaniline in silver and gold colloidal solutions were measured under off-resonance conditions.

[94]

89. B. Ersoy, M. S. Çelik, Environ. Technol. 25(3) (2004) 341. 90. J. Eriksson, S. Frankki, A. Shchukarev, U. Skyllberg, Environ. Sci. Technol. 38(11) (2004) 3074. 91. C. T. Yan, J. F. Jen, Chromatographia. 59(7-8) (2004) 517. 92. D. M. Nevskaia, E. Castillejos-Lopez, A. Guerrero-Ruiz, V. Muñoz, Carbon. 42(3) (2004) 653. 93. Y. N. Ni, X. Q. Zhou, P. Qiu, Guang pu xue yu guang pu fen xi = Guang pu. 24(1) (2004) 118. 94. T. Tanaka, A. Nakajima, A. Watanabe, T. Ohno, Y. Ozaki, J. Mol. Struct. 661-662(1-3) (2003) 437.

71

S. No. Adsorbent Remarks Ref. 95. MCM-41 mesoporous material

The adsorption of aniline on Na-AlMCM-41 synthesized by us has been characterized by infrared spectroscopy, temperature programmed desorption (TPD), and differential thermal analysis methods.

[95]

96. Fe-bound and Zn-bound SDS micelles

The co-adsorption of aniline by complex-formation with Zn-bound and Fe-bound micelles of anionic surfactant SDS (sodium laurylsulphate) causes redox reactions.

[96]

97. Silica gel with immobilized 4-chloro-5,7-dinitrobenzofurazan and for the subsequent HPLC determination with diode-array detection.

Conditions were found for the chemisorption preconcentration of aniline, 4-chloroaniline, and 2,5-dichloroaniline from air using tubes packed with silica gel with immobilized 4-chloro-5,7-dinitrobenzofurazan and for the subsequent HPLC determination with diode-array detection.

[97]

98. Enzymes such as peroxidases Enzymes such as peroxidases, in the presence of hydrogen peroxide, and laccases, in the presence of oxygen, catalyze the oxidation of a wide variety of phenols, biphenyls, anilines, benzidines and other related aromatic compounds. Various peroxidases and laccases have been used to treat waste'waters.

[98]

99. NaX and different cation exchanged zeolites

The equilibrium isotherms and the rate of adsorption have been measured for anilines and cresols on different zeolites by the usual gravimetric method using Microforce balance system.

[99]

100. Carbon cloth (C-cloth) Removal of aniline, 2,2′-bipyridyl,4,4′-bipyridyl and their protonated cations from dilute aqueous solutions, simulating polluted waste-waters, by adsorption and electrosorption at high-area carbon cloth (C-cloth) electrodes is described.

[100]

95. G. A. Eimer, M. B. Gómez Costa, L. B. Pierella, O. A. Anunziata, J. Colloid. Interface Sci. 263(2) (2003) 400. 96. F. I. Talens-Alesson, Chem. Eng. Tech. 26(6) (2003) 684. 97. M. I. Evgen'ev, I. I. Evgen'eva, S. Yu. Garmonov, R. N. Ismailova, J. Anal. Chem. 58(6) (2003) 542. 98. R. Mantha, N. Biswas, K. E. Taylor, J. K. Bewtra, Conference Proceedings - Joint 2002 CSCE/ASCE International Conference

on Environmental Engineering – An International Perspective on Environmental Engineering, (2002) 585. 99. E. Titus, A. K. Kalkar, V. G. Gaikar, Separ. Sci. Tech. 37(1) (2002) 105. 100. J. Niu, B. E. Conway, J. Electroanal. Chem. 536(1-2) (2002) 83.

72

S. No. Adsorbent Remarks Ref. 101. Chromium ferrocyanide The interaction of aniline and p-anisidine with chromium ferrocyanide has been studied. [101]

102. Resin-bound cobalt ion Studies have been made of the sorption equilibria of chlorinated anilines in aqueous solution on ligand exchange resin. The chlorinated anilines used included 2-chloroaniline, 3-chloroaniline, 4-chloroaniline and 2,5-dichloroaniline.

[102]

103. Activated carbon

The accessability of 3,4-dichloroaniline (DCA) sorbed by activated carbon to degradative microorganisms was studied.

[103]

104. Quasi-3-dimensional porous electrodes

Applications are made to removal of pollutants such as salts of S-containing anions, K-ethylxanthate, phenol, aniline and its sulphate, and choline hydroxide from aqueous solutions at low concentrations.

[104]

105. Ion-exchanged montmorillonites The adsorption of 2-(trifluoromethyl)aniline (2TFMA) on the interlamellar surfaces of KSF, K-10, Cu2+-, Ni2+-, Fe3+- and Al3+-montmorillonites has been investigated.

[105]

106. Activated carbon. Pilot plant study was made of the extraction of aniline from soil. It is a two-step integrated plant comprising CO2 supercritical extraction and pollutant adsorption onto activated carbon.

[106]

107. Carbon-paste electrodes The relationship between the energies of adsorption of molecules on active carbons and the peak current constants was determined.

[107]

101. T. Alam, H. Tarannum, S. R. Ali, Kamaluddin, J. Colloid Interface Sci. 245(2) (2002) 251. 102. M. Uçan, A. Ayar, Colloid. Surf. Physicochem. Eng. Aspects. 207(1-3) (2002) 41. 103. L. P. Bakhaeva, Mikrobiologiya. 70(3) (2001) 329. 104. B. E. Conway, E. Ayranci, H. Al-Maznai, Electrochimic. Acta, 47(5) (2001) 705. 105. M. W. Kowalska, J. D. Ortego, A. Jezierski, Appl. Clay Sci. 18(5-6) (2001) 233. 106. M. J. Cocero, E. Alonso, S. Lucas, J. Arevalo, Chemie-Ingenieur-Technik. 73(6) (2001) 725. 107. V. N. Maistrenko, S. V. Sapel'nikova, F. Kh. Kudasheva, F. A. Amirkhanova, J. Anal. Chem. 55(6) (2000) 586.

73

S. No. Adsorbent Remarks Ref. 108. Cu(II)-montmorillonite Batch adsorption experiments in the presence of oxygen were performed to study the interlayer

reactions of aniline on Cu(II)-montmorillonite in aqueous solutions. [108]

109. Dual-cation organobentonites The influential factors, mechanisms and characteristics of polar and ionizable organic contaminants, such as p-nitrophenol, phenol, and aniline, and sorption to dualcation organobentonites from water are investigated systematically and described quantitatively.

[109]

110. Zeolites

The adsorption sites inside the zeolite channels and the diffusion characteristics of acylated products of 4-aminophenol are analyzed in detail.

[110]

111. Si(100)(2 × 1) The chemisorption of aniline (C6H5NH2) on Si(100)(2 × 1) at room temperature has been studied for the first time with scanning tunneling microscopy (STM) and spectroscopy (STS).

[111]

112. Solid adsorbent Determinations of the adsorption of aniline and pyridine at solid liquid interfaces from n-hexane solutions have been performed.

[112]

113. Co-precipitated Co/Al2O3 and Ni/Al2O3 catalysts

The adsorption and catalytic properties of Co/Al2O3 were compared with those of Ni/Al2O3 catalysts containing the same metal content and prepared under similar conditions.

[113]

114. Activated carbon Nitrobenzene, aniline, and phenol removal in toxic industrial wastewater was performed by simultaneous adsorption and biodegradation processes.

[114]

108. M. Ilic, E. Koglin, A. Pohlmeier, H. D. Narres, M. J. Schwuger, Langmuir. 16(23) (2000) 8946. 109. L. Zhu, B. Chen, X. Shen, Environ. Sci. Technol. 34(3) (2000) 468. 110. P. Bharathi, R. C. Deka, S. Sivasanker, R. Vetrivel, Catal. Lett. 55(2) (1998) 113. 111. R. M. Rummel, C. Ziegler, Surf. Sci. 418(1) (1998) 303. 112. S. Ardizzone, H. Høiland, C. Lagioni, E. Sivieri, J. Electroanal. Chem. 447(1-2) (1998) 17. 113. S. Narayanan, R. P. Unnikrishnan, J. Chem. Soc. - Faraday Transactions. 93(10) (1997) 2009. 114. Orshansky, Frieda, Narkis, Nava Proceedings of the Industrial Waste Conference. (1997) 159.

74

S. No. Adsorbent Remarks Ref. 115. Si(100)-2 × 1 The chemisorption of benzoic acid (C6H5-COOH) and aniline (C6H5-NH2) on Si(100)-2 × 1 at

room temperature has been studied with high resolution electron energy loss spectroscopy (HREELS) and low electron energy diffraction (LEED)

[115]

116. Zeolites Separation of N-alkyl-substituted anilines by selective sorption on zeolites is investigated [116]

117. Smooth polycrystalline platinum electrode

Adsorption of aniline on smooth polycrystalline platinum was studied in 0.5 M H2SO4 aqueous medium as a function of the aniline concentration (10-8 -10-3M) and electrode potential (-670 to + 1000 mV (MSE)) by potential programmed voltammetry.

[117]

118. Ni(100) The bonding and reactions of adsorbed aniline have been characterized on the Ni(100) surface both in hydrogen and in vacuum with a combination of surface spectroscopies.

[118]

119. Bentonite Bentonite was exposed to aniline through batch experiments and flexible wall conductivity tests. [119]

120. Activated carbon This paper examines the influence of molecular oxygen and pH on the adsorption of aniline to F-300 Calgon Carbon.

[120]

121. Polycrystalline Pt, Rh and Pd electrodes

The different metals show remarkable differences concerning the stability of the adsorbed layers. The anodic desorption products of preadsorbed aniline are CO2 (on Pd) or CO2, HCN and NO (on Pt and Rh).

[121]

115. T. Bitzer, T. Alkunshalie, N. V. Richardson, Surf. Sci. 368(1-3) (1996) 202. 116. V. G. Gaikar, T. K. Mandal, R. G. Kulkarni, Separ. Sci. Tech. 31(2) (1996) 259. 117. F. Fiçicio lu, S. Kuliyev, F. Kadirgan, J. Electroanal. Chem. 408(1-2) (1996) 231. 118. S. X. Huang, D. A. Fischer, J. L. Gland, J. Phys. Chem. 100 (1996) 10223. 119. N. Gnanapragasam, B. A. G. Lewis, R. J. Finno, J. Geotechnol. Engg. - ASCE. 121(2) (1995) 119. 120. Fox, Peter, Pinisetti, Kamalesh National Conference on Environmental Engineering. (1994) 617. 121. U. Schmiemann, Z. Jusys, H. Baltruschat, Electrochim. Acta. 39(4) (1994) 561.

75

S. No. Adsorbent Remarks Ref. 122. Montmorillonite In order to assess the ability of clay liner material to restrict the mobility of amine compounds under a

variety of chemical conditions and to further elucidate amine adsorption characteristics, the adsorption of aniline and o-, m-, and p-toluidine on Ca2+- and K+-saturated Wyoming bentonite (SWy-1) was investigated.

[122]

123. Layer silicate clays and an organic soil

The characteristics of isotherms for aniline adsorption on Ca-saturated kaolinite, montmorillonite, vermiculite, and an organic soil were determined for a wide range of aqueous concentrations at acid and neutral pH.

[123]

124. Organo-clay In this study, the time-dependent adsorption and desorption of phenol and aniline on hexadecyltrimethyl-ammonium-montmorillonite (HDTMA-montmorillonite) from aqueous solutions were determined in a stirred-flow chamber.

[124]

125. Zeolites The formation of the aniline radical cation was observed on H-mordenite and H-faujasite in which the distribution of aluminum among different framework and nonframework coordination sites has been characterized by high-resolution solid-state NMR.

[125]

126. Nonlinear optical We have measured the optical second harmonic generation (SHG) at a mercury electrode. The influence of the applied potential and of the adsorption of aniline on the nonlinear optical response were studied by simultaneously measured differential capacitance.

[126]

127. Granular activated carbon samples

Adsorption equilibrium studies of some aromatic organic pollutants in water with some commercially available standard grades of granular activated carbons have been carried out at 35°C.

[127]

122. M. E. Essington, Soil Sci. 158(3) (1994) 181. 123. O. P. Homenauth, M. B. McBride, Soil Sci. Soc. Am. J. 58(2) (1994) 347. 124. Peng-Chu Zhang, D. L. Sparks, Soil Sci. Soc. Am. J. 57(2) (1993) 340. 125. F. R. Chen, J. J. Fripiat, J. Phys. Chem. 96(2) (1992) 819. 126. L. Werner, F. Marlow, W. Hill, U. Retter, Chem. Phys. Lett. 194(1-2) (1992) 39. 127. M. K. N. Yenkie, G. S. Natarajan, Separ. Sci. Tech. 26(5) (1991) 661.

76

S. No. Adsorbent Remarks Ref. 128. Cadmium selenide Adsorption of ring-substituted aniline derivatives, presumably through the amino group, onto the (0001)

face of single-crystal n-CdSe or n-CdS [CdS(e)] profoundly affects the semiconductor's photoluminescence (PL) by effecting charge transfer between surface states and the bulk semiconductor.

[128]

129. Polycrystalline gold electrode

Combined capacity and electroreflectance measurements have been employed to investigate the adsorption of aniline on a polycrystalline gold electrode in neutral aqueous solution.

[129]

130. Coals The adsorption of phenol and aniline from aqueous solutions by hard coals of types D and Zh during vaccum treatment of the samples and the passage of helium and carbon dioxide has been investigated.

[130]

131. Gold The electrosorption of aniline on a polycrystalline gold electrode from acidic and neutral electrolyte solutions has been studied using surface enhanced Raman spectroscopy and tensametry.

[131]

132. Ag electrode The adsorption of aniline on an Ag electrode in acidic aqueous solutions has been studied by surface-enhanced Raman scattering.

[132]

133. Carbon-paste electrode The voltammetric behaviour of aniline and some of its N-alkylated derivatives at a carbon-paste (Nujol/graphite) electrode is examined.

[133]

134. Mercury The parameters for the adsorption of aniline molecules from neutral sodium sulfate solutions were calculated.

[134]

128. C. J. Murphy, G. C. Lisensky, L. K. Leung, G. R. Kowach, A. B. Ellis, J. Am. Chem. Soc. 112(23) (1990) 8344. 129. C. N. Van Huong, J. Electroanal. Chem. 264(1-2) (1989) 247. 130. V. A. Kompanets, Solid Fuel Chem. 23(1) (1989) 89. 131. R. Holze, J. Electroanal. Chem. 250(1) (1988) 143. 132. H. Shindo, C. Nishihara, J. Chem. Soc. Faraday Transactions 1: Physical chemistry in Condensed Phases. 84(2) (1988) 433. 133. N. E. Zoulis, C. E. Efstathiou, Anal. Chim. Acta. 204(C) (1988) 201. 134. A. B. Ershler, E. M. Kuminov, Sov. Electrochem. 23(1) (1987) 54.

77

S. No. Adsorbent Remarks Ref. 135. A gold electrode The adsorption and polymeridation of aniline in an acidic electrolyte solution on a gold electrode were

investigated using Surface Raman Spectroscopy. [135]

136. Silver The potential- and pH-dependent adsorption of aniline on silver has been studied using Surface Enhanced Raman Spectroscopy.

[136]

137. Modified silica surfaces

Adsorption of benzene and aniline on C18 modified silica columns is investigated as a function of solute concentration and solvent composition.

[137]

138. Lead Effects in electroreflectance (ER) at the metal/electrolyte interface are discussed which are due to charge transfer between the adsorbed molecules and the electrode and to intramolecular optical transitions.

[138]

139. Active anthracite The possibility is investigated of the final treatment of biologically treated wastewater by adsorption using powdered active carbon (PAC) in a vortex bed device.

[139]

140. Bilayer lipid membranes

The results are explained by the fact that the plane of adsorption of ANS is located within the membrane and adsorption is influenced by the discrete distribution of the adsorbed charge and the non-electrical interaction of the ions in the adsorption plane.

[140]

141. Metamorphosed coal

The adsorption of aniline from aqueous solutions by type D coal bearing different amounts of oxygen-containing groups has been studied. An increase in adsorption with a rise in the degree of oxidation and of the temperature has been shown.

[141]

135. R. Holze, J. Electroanal. Chem. 224(1-2) (1987) 253. 136. R. Holze, Electrochimic. Acta. 32(10) (1987) 1527. 137. J. Gorse III, M. F. Burke, G. K. Vemulapalli, Langmuir. 3(2) (1987) 179. 138. M. I. Urbakh, L. I. Daikhin, Sov. Electrochem. 20(8) (1984) 962. 139. V. I. Ostrovka, R. M. Bekher, V. A. Livke, et al Sov. J. Water Chem. Tech. (English Translation of Khimiya i Tekhnologiya Vo. 5(1)

(1983) 82. 140. V. V. Chernyi, M. M. Kozlov, V. S. Sokolov, Yu. A. Yermakov, V. S. Markin, Biophys. 27(5) (1982) 852. 141. R. V. Przhegorlinskaya, T. E. Galukhina, I. B. Kovaleva, Solid Fuel Chem. 14(4) (1980) 130.

78

S. No. Adsorbent Remarks Ref. 142. Granular activated

carbon. A linear correlation between adsorptive affinity and acidic properties of adsorbates is evidenced when phenol. aniline and their o-, m-, and p-nitro-derivatives are adsorbed on granular activated carbon.

[142]

143. Powdered carbon Adsorption of some phenylcarbamates, phenylureas and anilide pesticides on powdered activated carbon was investigated.

[143]

144. Clay minerals Adsorption of IPC, CIPC, Linuron, Neburon and Vitavax on bentonite clays (H, Fe and Ca forms) was investigated.

[144]

145. HY zeolites The position of the N1s level of aniline adsorbed on HY zeolite undergoes a shift of approximately-2 eV when the calcination temperature exceeds 400°C which is the dehydroxylation temperature for the zeolite.

[145]

146. Mercury A preliminary study has been made of the amplitude modulation signal connected with adsorption-desorption of aniline on mercury using a 2 MHz modulation polarograph.

[146]

147. Montmorillonite and hectorite

Quantitative measurements are made of the adsorption of benzidine and aniline from aqueous hydrochloride solutions by Na-, Li-, and Ca-montmorillonite and of the displaced inorganic cations.

[147]

148. Alumina and HCl-treated alumina

Infrared spectra of adsorbed aniline on alumina showed bands at 1605, 1575, 1495 and 1470 cm-1 in the region of ring stretching vibration.

[148]

149. Alumina Linear isotherm free energies of adsorption from n-pentane onto 3.6% H2O-Al2O3 are reported for 66 nitrogen compounds related to pyridine, aniline or pyrrole.

[149]

142. V. Amicarelli, G. Baldassarre, V. Balice, L. Liberti, Thermochimic. Acta. 36(2) (1980) 107. 143. M. A. El Dib, O. A. Aly, Water Res. 11(8) (1977) 617. 144. M. A. El Dib, O. A. Aly, Water Res. 10(12) (1976) 1051. 145. C. Defosse, P. Canesson, React. Kinet. Catal. Lett. 3(2) (1975) 161. 146. G. C. Barker, D. McKeown, J. Electroanal. Chem. 59(3) (1975) 295. 147. T. Furukawa, G. W. Brindley, Clay. Clay Miner. 21(5) (1973) 279. 148. M. Tanaka, S. Ogasawara, J. Catal. 25(1) (1972) 111. 149. L. R. Snyder, J. Phys. Chem. 67(11) (1963) 2344.

79

1.13 Aim of The Present Work The present work was undertaken to explore the analytical applicability of the

newly synthesized composite ion-exchangers. In this direction the following work

was planned:

a. Synthesis of new composite ion-exchange materials.

b. Characterization of the newly synthesized composite ion-exchange materials

using various analytical techniques such as SEM, TEM, TGA, FTIR and

XRD. c. Adsorption studies of aniline, pyridine and nicotinic acid on synthesized

composite ion-exchangers. d. Mechanism of kinetics for the adsorption of heavy metals. e. Thin layer chromatography of pesticides. f. Spectrophotometric determination of pesticides.

80

References: [1]. "Online dictionary". Merriam-Webster. Retrieved (2011).

[2]. Popper (2002) 3.

[3]. Wilson, Edward, Consilience: The Unity of Knowledge, New York.

Vintage. ISBN 0-679-76867-X (1999).

[4]. L. Fleck, Genesis and Development of a Scientific Fact. (1935).

[5]. F. Holler, James; Skoog, Douglas A.; West, Donald M. (1996).

Fundamentals of analytical chemistry. Philadelphia: Saunders College

Pub. ISBN 0-03-005938-0.

[6]. K. Danzer, Fresenius, J. Anal. Chem. 343 (1992) 827.

[7]. F. Runge, “Der Biddhungstriebder stoffe” Verenschlaulicht in

Selbstaqndiggewachsenan Bedern. Sebsterlag Oranenberg, Germany

(1855).

[8]. F. Goppelsroeder, Verk Naturforsch, Ces. Basel. 3 (1861) 268.

[9]. C. F. Schonbein, Verk Naturforsch, Ces. Basel. 3 (1861) 249.

[10]. E. Fisher, E. Schmidner, Annalen. 272 (1892) 156.

[11]. L. Reed, Proc. Chem. Soc. 9 (1893) 123.

[12]. D. T. Day, Amer. Phil. Soc. 36 (1897) 112.

[13]. M. S. Tswett, Ber. Duet. Boatan. Ges. 24 (1906) 235.

[14]. R. Kuhn, E. Lederer, Ber. 64 (1931) 1349.

[15]. R. Kuhn, A. Winterstein, E. Lederer, Hoppe – Seyler’sz. Physiol. Chem.

197 (1931) 141.

[16]. A. J. P. Martin, R. L. M. Synge, J. Biochem. 35 (1941) 91.

[17]. A. J. P. Martin, R. L. M. Synge, J. Biochem. 35 (1941) 1358.

[18]. E. Stahl, in “Thin Layer Chromatography”, 2nd edn. E. Stahl (ed.) Springer-

Verlag, Berlin 1 (1961).

[19]. J. G. Kirchner, J. Chromatogr. Sci. 13 (1975) 558.

[20]. J. G. Kirchner, in “Thin Layer Chromatography”, 2nd edn. Wiley-

Interscience, New York (1978).

[21]. N. Pelick, H. R. Bolliger, H. K. Mangold, in “Advances in

Chromatography” 3, J. C. Giddings and R. A. Keller (eds.), Marcel Dekker,

New York 85 (1996).

81

[22]. M. W. Beyerink, R. L. M. Synge, J. Biochem. 35 (1941) 1358.

[23]. H. P. Wijsman, D. De Beshouwdals, Mengsel Van. Mattase en Dentrinase,

Amsterdam (1898).

[24]. N. A. Izmailov, M. S. Schraiber, Farmatsiya (Sofia) 3 (1938) 1.

[25]. C. Lapp, Erali, Bull. Sci. Pharmacol. 47 (1940) 49.

[26]. J. E. Meinhard, N. F. Hall, Anal. Chem. 21 (1949) 185.

[27]. E. P. Przybylowicz, W. J. Staudenmayer, E. S. Perry, A. D. Baitsholt, T. N.

Tisher, J. Chromatogr. 20 (1956) 506.

[28]. H. Halpaap, J. Chromatogr. 78 (1973) 77.

[29]. A. Zlatkis, R. E. Kaiser, in HPTLC high performance Thin Layer

Chromatography, A. Zlatkis, R.E. Kaiser (eds) Elsevier, Amsterdam,

Netherlands, 12 (1977).

[30]. H. E. Hauck, W. Jost, Instrumental High Performance, Thin Layer

Chromatography, Proceedings of 2nd International Symposium, R.E. Kaiser

(ed), Interlaken, Switzerland, (1982) 25.

[31]. H. E. Hauck, W. Jost, Instrumental High Performance, Thin Layer

Chromatography, Proceedings of 3rd International Symposium, R.E. Kaiser

(ed), Wu”rzburz, Germany (1985) 83.

[32]. H. E. Hauck, W. Jost, Instrumental High Performance, Thin Layer

Chromatography, Proceedings of 4th International Symposium, R.E. Kaiser,

H. Traitler, A. Studer (eds), Selvino/Bergamo, Italy (1987) 241.

[33]. K. Burger, Z. Anal. Chem. 318 (1984) 228.

[34]. S. Nyiredy, C. A. J. Erdelmeier, O. Sticher, Instrumental Preparative Planar

Chromatography, in: “Planar Chromatogr. Vol. 1.” (ed) by R.E. Kaiser,

Heidelberg, Hiithig Verlag.

[35]. L. J. Cline Love, J. G. Harbarta, J. G. Dorsy, Anal. Chem. 56 (1984) 1132.

[36]. D. Oakenfull, In “Aggregation Processes in Solution”; E. Wyn-Jones, J.

Gormally, Eds.; Elsevier: New York, (1983) Chapter 5.

[37]. M. Ash, I. Ash, “Encyclopedia of Surfactants”; Chemical Publishing Co.,

Inc.: New York, (1981) Vol. I-III; (1985).

[38]. S. N. Shtykov, J. Anal. Chem. 55 (2000) 608.

[39]. J. Moilliet, B. Collie, W. Black, Van Nostrand, Princeton, New Jersey.

(1961).

82

[40]. T. P. Hoar, J. H. Schulman, Nature. 152 (1943) 102.

[41]. C. Solans, H. Kunieda, Industrial Applications of Microemulsions, Marcel

Dekker, New York. (1997)

[42]. Kumar, K. L. Mittal, Handbook of Microemulsions: Science and

Technology, Marcel Dekker, New York. (1999).

[43]. S. P. Moulik, K. Mukherjee, Proc. Indian Natl. Sci. Acad. A. 62 (1996) 215.

[44]. B. K. Paul, S. P. Moulik, J. Disp. Sci. Technol. 18 (1997) 301.

[45]. The Second Book of Moses, Exodus, Ch. 15, Verse 25.

[46]. Aristotle, Works, about 330 BC, Clarenndon Press, London, 7 (1927) 933b.

[47]. H. S. Thompson, J. Roy, Agr. Soc. Engl. 11 (1850) 68.

[48]. J. T. Way, J. Roy, Agr. Soc. Engl. 11 (1850) 313.

[49]. E. Eichorn, Pogg. Ann. Phys. Chem. 105 (1850) 126.

[50]. R. Gans, Jahrb. Preuss. Geol. Landesanstalt, Berlin, 26 (1905) 179; 27

(1906) 63.

[51]. O. Folin, R. Bell, J. Biol. Chem., 29 (1917) 329.

[52]. B. A. Adams, E. L. Homes, J. Soc. Chem. Ind, London. 54 (1935) 17.

[53]. F. Hellferich, Ion-Exchange, McGraw-Hill, New York (1962).

[54]. R. Gane, Zentrabl. Mineral. Geo. U. Palaeontol. 699 (1913) 728.

[55]. J. Kielland, J. Soc. Chem. Ind. London, 54 (1935) 232.

[56]. G. L. Gaines, Jr., H. C. Thomas, J. Chem. Phys. 21 (1953) 714.

[57]. G. Alberti, U. Costantino, S. Alluli, M. A. Massucci, J. Inorg. Nucl. Chem.

35 (1973) 1339.

[58]. A. L. Ruvarac, V. D. Marizonac, J. Chromatogr. 76 (1973) 22.

[59]. G. Alberti, U. Costantino, M. Pelliccioni, J. Inorg. Nucl. Chem. 33 (1973)

1327.

[60]. A. L. Ruvarac, V. Pekarek, Nucl. Sci. Chem. 22 (1971) 1.

[61]. A. Clearfield, D. A. Tuhtar, J. Phys. Chem. 80 (1976) 1296.

[62]. L. Kullberg, A. Clearfield, Ibid., 85 (1981) 1578.

[63]. Idem, Ibid. 84 (1980) 165; 85 (1981) 1585.

[64]. A. Clearfield, J. M. Kallnius, J. Inorg. Nucl. Chem. 38 (1976) 849.

[65]. A. Clearfield, G. A. Day, A. Ruvaracr, S. Milonjic, Ibid, 43 (1981) 165.

[66]. G. H. Nancollas, B. V. K. S. R. A. Tilak, J. Inorg. Chem. 31 (1969) 3643.

83

[67]. G. P. Harkin, G. H. Nancollas, R. Paterson, J. Inorg. Chem. 26 (1964) 305.

[68]. E. M. Larsen, D. R. Vissers, J. Phys. Chem. 64 (1960) 1732.

[69]. G. H. Nancollas, D. S. Reid, J. Inorg. Nucl. Chem. 31 (1969) 213.

[70]. J. P. Rawat, P. S. Thind, J. Indian. Chem. Soc. 57 (1980) 819.

[71]. J. P. Rawat, K. P. S. Muktawat, J. Inorg. Nucl. Chem. 43 (1981) 2121.

[72]. K. G. Varshney, R. P. Singh, S. Rani, Proc. Indian Natl. Sci. Acad. 51

(1985) 726.

[73]. K. G. Varshney, R. P. Singh, S. Rani, Acta. Chem. Hung. 115 (1984) 403.

[74]. K. G. Varshney, R. P. Singh, U. Sharma, Proc. Indian Natl. Sci. Acad. 51

(1985) 726.

[75]. K. G. Varshney, R. P. Singh, U. Sharma, Coll. Surf.(A). 16 (1985) 207.

[76]. J. P. Rawat, B. Singh, Bull. Chem. Soc. Jpn., 57 (1984) 862.

[77]. R. G. Herman, A. Clearfield, J. Inorg. Nucl. Chem. 38 (1976) 853.

[78]. K. G. Varshney, S. Rani, R. P. Singh, Ecotox. Environ. Safety, 10 (1985)

309; 11 (1986) 179.

[79]. A. A. Khan, R. Niwas, O. P. Bansal, J. Indian Chem. Soc. 76 (1999) 44.

[80]. F. C. Nachod, W. Wood, J. Inorg. Am. Chem. Soc. 66 (1944) 1350.

[81]. G. E. Boyd, A. W. Adamson, L. S. Myers. J. Am. Chem. Soc. 69 (1947)

2386.

[82]. F. Helfferich, Ion Exchange, McGraw-Hill, New York. (1962) Chap-2.

[83]. R. M. Barrer, Hydrothermal Chemistry of Zeolites, Academic Press, New

York. (1982) Chap 3-5.

[84]. C. S. Cundy, Chem. Rev. 103 (2003) 663.

[85]. R. Szostak, Molecular Sieves - Principles of Synthesis and Identification,

1st ed., Van Nostrand Reinhold, New York. (1989); 2nd ed., Blackie,

London. (1998).

[86]. B. Ghosh, D. C. Agrawal, S. Bhatia, Ind. Eng. Chem. Res. 33 (1994) 2107.

[87]. D. W. Breck, Zeolite Molecular Sieves, Structure, Chemistry and Use,

Wiley, New York. (1974).

[88]. H. Tahir, Chem. 4 (2005) 1021.

[89]. H. G. Smolka, M. J. Schwuger, in Natural Zeolites: Occurrence, Properties,

Use, eds SandL B, MumptonF A(Pergamon, New York. (1978) 487.

84

[90]. D. W. Breck, Zeolite Molecular Sieves, John Wiley & Sons, New York,

(1974).

[91]. E. Erdem, N. Karapinar, R. Donat, J. Coll. Interf. Sci. 280 (2004) 309.

[92]. T. Motsi, N. A. Rowson, M. J. H. Simmons, International Journal of

Mineral Processing, 92 (2009) 42.

[93]. J. W. Roddy, Survey: Utilization of Zeolites for the Removal of

Radioactivity from Liquid Waste Streams, National Technical Information

Service, Springfield, VA. (1981).

[94]. A. A. Khan, Inamuddin, M. M. Alam, Mater. Res. Bull. 40 (2005) 289.

[95]. M. Islam, R. Patel, J. Hazard. Mater. 156 (2008) 509.

[96]. S. A. Nabi, A. H. Shalla, J. Hazard. Mater. 163 (2009) 657.

[97]. A. A. Khan, A. Khan, Inamuddin, Talanta. 72 (2007) 699.

[98]. K. G. Varshney, N. Tayal, Langmuir (2001) 2589.

[99]. K. G. Varshney, N. Tayal, A. A. Khan, R. Niwas, Colloids Surf. A:

Physicochem. Eng. Aspects. 181 (2001) 123.

[100]. L. Huang, H. Liu, C. Wang, J. Appl. Polym. Sci. 120 (2011) 944.

[101]. A. A. Muxel, S. M. N. Gimenez, F. A. D. S. Almeida, R. V. D. S. Alfaya,

A. A. D. S. Alfaya, Clean - Soil, Air, Water. 39 (2011) 289.

[102]. D. J. Guo, S. J. Fu, W. Tan., Z. D. Dai, J. Materials Chem. 20 (45) (2010)

10159.

[103]. S. A. Nabi, M. Shahadat, R. Bushra, A. H. Shalla, F. Ahmed, Chem. Engg.

J. 165 (2) (2010) 405.

[104]. A. A. Khan, M. Khalid, U. Baig, React. Func. Polym. 70(10) (2010) 849.

[105]. A. A. Khan, L. Paquiza, Desalination. 265 (2011) 242.

[106]. B. C. Pan, Q. Su, W. M. Zhang, Q. X. Zhang, H. Q. Ren, Q. R. Zhang,

Chinese Patent No. ZL 200710134050.9 (2007).

[107]. T. Kasuga, M. Hiramatsu, A. Hoson, T. Sekino, K. Niihara, Adv. Mater. 11

(1999) 1307.

[108]. A. A. Khan, A. Khan, Inamuddin, Talanta. 72 (2007) 699.

[109]. A. A. Khan, T. Akhtar, Electrochimic. Acta. 53 (2008) 5540.

[110]. S. A. Nabi, M. Shahadat, R. Bushra, A. H. Shalla, A. Azam, Colloids Surf.

B: Biointerf. 87 (2011) 122.

[111]. A. A. Khan, T. Akhtar, J. Appl. Polym. Sci. 119 (2011) 1393.

85

[112]. S. C. Mojumdar, L. Raki, J. Thermal Anal. Calorim. 82(2) (2005) 89.

[113]. G. S. Mukherjee, J. Thermal Anal. Calorim. 96(1) (2009) 21.

[114]. P. R. S. Bittencourt, G. L. D. Santos, E. A. G. Pineda, Hechenleitner, J.

Thermal Anal. Calorim. 79 (2005) 371.

[115]. L. Cuiying, Z. Wei, Z. Bo, L. Mei, L. Canhui, J. Thermal Anal. Calorim.

103(1) (2011) 205.

[116]. G. Vlase, T. Vlase, N. Doca, M. Perta, G. Ilia, N. Plesu, J. Thermal Anal.

Calorim. 97 (2009) 473.

[117]. S. A. Nabi, R. Bushra, M. Naushad, A. M. Khan, Chem. Engg. J. 165(2)

(2010) 529.

[118]. S. A. Nabi, R. Bushra, Z. A. Al-Othman, M. Naushad, Separ. Sci. Tech. 46

(2011) In Press. DOI: 10.1080/01496395.2010.534759.

[119]. Z. A. Al-Othman, Inamuddin, M. Naushad, Chem. Engg. J. 166(2) (2011)

639.

[120]. Z. A. Al-Othman, Inamuddin, M. Naushad, Chem. Engg. J. 46 (2011) In

press. DOI: 10.1016/j.cej.2011.02.046.

[121]. I. Y. Jang, O. -H. Kweon, K. -E. Kim, G. -J. Hwang, S. -B. Moon, A. -S.

Kang, J. Membr. Sci. 322(1) (2008)154.

[122]. A. Masuyama, C. Endo, S. Takeda, M. Nojima, D. Ono, T. Takeda,

Langmuir 15 (2000) 368.

[123]. J. Lee, D. F. Hussey, G. L. Foutch, In Ion Exchange at the Millennium J. A.

Greig, ed., 61, Imperial College Press, London. (2000).

[124]. M. J. Shaw, S. J. Hill, P. Jones, P. Nesterenko, J. Chromatogr. A. 876

(2000)127.

[125]. Y. Kaya, I. Vergili, S. Acarbabacan, H. Barlas, Fresenius Environmental

Bulletin. 11 (2002) 885.

[126]. K. Vaaramaa, J. Lehto, Desalination. 144 (2003)157.

[127]. V. Sinha, K. Li, Desalination. 127 (2000)155.

[128]. J. A. Dale, N. V. Nikitin, R. Moore, D. Opperman, G. Crooks, D. Naden, E.

Belsten, P. Jenkins, In ‘‘Ion Exchange at the millennium (J.A. Greig, ed.),

Imperial College Press, London. 261 (2000).

[129]. F. Gaucheron, Y. Le Graet, J. Chromatogr. A. 893 (2000)133.

[130]. E. Vera, J. Ruales, M. Dornier, J. Sandeaux, F. Persin, G. Pourcelley, F.

Vaillant, M. Reynes, J. Food Engg., 59 (2003) 361.

86

[131]. T. Nakanishi, N. Higuchi, M. Nomura, M. Aida, Y. Fujii, J. Nuc. Sci.

Techn. 33 (1996) 341.

[132]. M. L. D. P. Godoy, J. M. Godoy, L. A. Roldao, L. Tauhata, J. Environ.

Radioact. 100 (2009) 613.

[133]. C. Galindo, L. Mougin, A .Nourreddine, Appl. Radiat. Isotope. 65 (2007) 9.

[134]. M. Rozmaric, A. G. Ivsic, Z. Grahek, Talanta. 80 (2009) 352.

[135]. A. H. Bond, M. L Dietz, P. Sylvester, A. Clearfield, 216th ACS National

Meeting, Boston, M.A. (1998).

[136]. M. Gordon, M. Popvtzer, M. Greenbaum, M. MacArthur, J. R. De Palma,

M. H. Maxwell, Proc. Eur. Dialysis Transplant Assoc. 5 (1968) 86.

[137]. Z. Wang, M. A. Al-Daous, E. R. Kiesel, F. Li, A. Stein, Microporous and

Mesoporous. Mat. 120(3) (2009) 351.

[138]. C. Placek, Ion Exchange Resins, Noyes Data Corp, Park Ridge, NJ. (1970)

329.

[139]. A. Clearfield, D. S. Thakur, Appl. Catal. 26 (1986) 1.

[140]. A. LaGinestra, C. Ferragina, M. A. Massucci, P. Patrono, R. DiRocco, A.

A. G. Tomoilson, Gazz. Chim. Ital. 113 (1983) 357.

[141]. K. H. Meyer, W. Strauss, Hclv. Chim. Acta. 23 (1940) 795.

[142]. A. B. Mindler, C. Paulson, National Meeting of the American Institute of

Mining and Metallurgical Engineers, Los Angeles, Calif. (1953).

[143]. B. A. Bolto, L. Pawlowaski, Effluent Water Treat. J. 23 (1983) 55, 157,

208, 233, 317, 371.

[144]. X. M. Shen, A. Clearfield, J. Solid State Chem. 64 (1986) 270.

[145]. P. Bajaj, D. K. Paliwal, Indian J. Fibre Text. Res. 16 (1991) 89.

[146]. M. H. Kotze, F. L. D. Cloete, Ion Exch. Adv., Proc. IEX’ 92 (1992) 366.

[147]. P. Bajaj, M. Goyal, R. V. Chavan, J. Appl. Polym. Sci. 51 (1994) 423.

[148]. A. A. Khan, Inamuddin, M. M. Alam, React. Funct. Polym. 63 (2005) 119.

[149]. A. A. Khan, L. Pakiza, Desalination. 272 (2011) 278.

[150]. Y. Du, B. Qi, X. Yang, E. Wang, J. Phy. Chem B. 110(43) (2006) 21662.

[151]. A. A. Khan, M. M. Alam, React. Funct. Polym. 55 (2003) 277.

[152]. R. Niwas, A. A. Khan, K.G. Vershney, Coll. Sur. A, 150 (1999) 7.

[153]. G. G. Kumar, A. R. Kim, K. S. Nahm, D. J. Yoo, Current Appl. Phys.. 11(3)

(2011) 896.

87

[154]. Ph. Colomban, Proton Conductors, Cambridge Univ. Press, Cambridge,

U.K. (1992).

[155]. E. W. Stein, Sr., A. Clearfield, M. A. Subramanian, Solid State Ionics. 83

(1996) 113.

[156]. M. Cox, Lehninger, L. Albert, Nelson, R. David R, Lehninger principles of

biochemistry, New York. Worth Publishers. (2000) ISBN 1-57259-153-6.

[157]. K. Parker, L. Brunton, Goodman, L. Sanford, Lazo, S. John, Gilman,

Alfred. Goodman & Gilman's the pharmacological basis of therapeutics.

New York: McGraw-Hill. (2006) ISBN 0071422803.

[158]. M. K. Mittal, T. Florin, J. Perrone, J. H. Delgado, K. C. Osterhoudt. Ann

Emerg Med. 50(5) (2007) 587.

[159]. C. A. Edwards, Environmental pollution by pesticides, Plenum, New York.

(1973).

[160]. C. Cox, M. Surgan, Environ. Hlth. Persp. 114 (2006) 1803.

[161]. M. Kuwano, A. Ramesh, D. Thiov, A. N. Subramanium, Int. J. Environ.

Anal. Chem. 48 (1995) 163.

[162]. W. Liji, F. Yinsheng, Z. Fuguo, Huanjing Gongchenz, China. 13 (1995) 53.

[163]. A. G. Nikalenko, D. V. Amirkhanov, Agrokhimia. 4 (1993) 115.

[164]. C. G. Wright, R. B. Leidy, H. E. Dupre, Environ. Contam. Toxicol. 4 (1991)

689.

[165]. K. D. Racke, R. N. Lubinski, ACS Symp. Ser. 522 (1993) 70.

[166]. K. G. Valsenko, T. T. Kuznetsova, D. K. Shtundyuk, Agrokhimia 68 (1993)

73.

[167]. L. B. Taiwo, B. A. Oso, Agric. Ecosyst. Environ. 65 (1997) 59.

[168]. X. Zhou, C. Hexin, L. Yitong, Zhejiang Huanjing Kexue. 16 (1997) 35.

[169]. H. P. Malkomes, T. Dietze, Agribiol. Res. 51 (1998) 143.

[170]. M. K. Nielsen, Bm. Jørgensen, J. Agricultural and food chemistry. 52 (12)

(2004) 3814.

[171]. D. W. Armstrong, R. Q. Terrill, Anal. Chem. 51 (1979) 2160.

[172]. T. Endo, T. Kusaka, N. Tan, M. J. Sakai, Pestic. Sci. 7(1982)101.

[173]. S. U. Khan, N. N. Khan, F. A. Khan, Environ. Pollut. 47 (1987) 115.

[174]. H. Ming, Y. Zhao, Y. LU, J. Rural Eco-Environ. 3 (1993) 40 (Ch).

[175]. H. S. Rathore, T. Begum, J. Chromatogr. 643 (1993) 271.

[176]. S. U. Khan, J. Singh, Indian J. Environ. Hlth. 38 (1996) 269.

88

[177]. E. Martikainen, J. Haimi, Ahtiainen, J. Appl. Soil Ecol. 9 (1998) 381.

[178]. R. L. Ramos, R. O. Perez, O. L. T. Rivera, M. S. B. Mendoza, N. A. M.

Castillo Journal for the Basic Principles of Diffusion Theory, Experiment

and Application. 11 (2009) 1.

[179]. C. E. Terry, R. P. Ryan, S. S. Leffingwell: Toxicology Desk Reference: The

Toxic Exposure & Medical Monitoring Index: The Toxic Exposure and

Medical Monitoring Index, 5th ed., p. 1062, Taylor & Francis, ISBN 1-

56032-795-2.

[180]. G. D. Henry, Tetrahedron 60 (2004) 6043.

[181]. Z. Yanli, L. Dongguang, J. Sci. Ind. Res. 69 (2010) 73.

[182]. G. Aylward, "SI Chemical Data 6th Ed.", ISBN 978 0 470 81638 7 (pbk.)

(2008)

[183]. IARC Monographs, OSHA, Washington D.C. 77 (1985).

[184]. N. Bonnard, M. T. Brondeau, S. Miraval, F. Pillière, J. C. Protois, O.

Schneider, Pyridine, Fiche Toxicologique, INRS (in French) Retrieved

(2002).

[185]. International Agency for Research on Cancer (IARC) (2000). "Pyridine

Summary & Evaluation. IARC Summaries & Evaluations. IPCS INCHEM.

Retrieved (2011).

[186]. J. M. Herrmann, Catal. Today. 53 (1999) 115.

[187]. D. Drijvers, H. V. Langenhove, M. W. Bechers, Water Res. 33 (1998) 1187.

[188]. B. Zhao, H. D. Liang, D. M. Han, D. Qiu, S. Q. Chen, Sep. Sci. Technol. 42

(2007) 3419.

[189]. L. Guo, G. Li, J. Liu, P. Yin, Q. Li, Ind. Eng. Chem. Res. 48 (2009) 10657.

[190]. C. Jianguo, L. Aimin, S. Hongyan, F. Zhenghao, L. Chao, Z. Quanxing, J.

Hazard. Mater. B. 124 (2005) 173.

[191]. F. S. H. Abram, I. R. Sims, Water Res. 16 (1982) 1309.

[192]. K. Laszlo, E. Tombacz, C. Novak, Colloids Surf. A: Physicochem. Eng.

Aspects. 306 (2007) 95.

[193]. W. M. Zhang, Q. J. Zhang, B. C. Pan, L. Lv, B. J. Pan, Z. W. Xu, Q. X.

Zhang, X. S. Zhao, W. Du, Q. R. Zhang, J. Colloid Interface Sci. 306

(2007) 216.

[194]. C. M. Castilla, Carbon. 42 (2004) 83.

[195]. K. Yang, W. Wu, Q. Jing, L. Zhu, Environ. Sci. Technol. 42 (2008)7931.

89

[196]. S. H. Gheewala, A. P. Annachhatre, Water Sci. Tech. 36 (1997) 53.

[197]. F. J. O’Neill, K. C. A. Bromley-Challenor, R. J. Greenwood, J. S. Knapp,

Water Res. 34 (2000) 4397.

[198]. F. Orshansky, N. Narkis, Water Res. 31 (1997) 391.

[199]. L. Wang, S. Barrington, J. W. Kim, J. Environ. Manage. 83 (2007) 191.

[200]. X. Y. Liu, B. J. Wang, C. Y. Jiang, K. X. Zhao, L. D. Harold, S. J. Liu, J.

Environ. Sci. 19 (2007) 530.

[201]. G. Deiber, J. N. Foussard, H. Debellefontaine, Environ. Pollut. 96 (1997)

311.

[202]. X. H. Qi, Y. Y. Zhuang, Y. C. Yuan, W. X. Gu, J. Hazard. Mater. B. 90

(2002) 51.

[203]. J. O’Brien, T. F. O’Dwyer, T. Curtin, J. Hazard. Mater. 159 (2008) 476.

[204]. J. Garcia, H. T. Gomes, P. Serp, P. Kalck, J. L. Figueiredo, J. L. Faria.

Carbon. 44 (2006) 2384.

[205]. J. Anotai, M. C. Lu, P. Chewpreecha, Water Res. 40 (2006) 1841.

[206]. L. Wojna´rovits, E. Taka´cs, Radiat. Phys. Chem. 77 (2008) 225.

[207]. F. M. T. Luna, A. A. Pontes-Filho, E. D. Trindade, I. J. Silva, Jr., C. L.

Cavalcante, D. C. S. Azevedo. Ind. Eng. Chem. Res. 47 (2008) 3207.

[208]. Y. Han, X. Quan, S. Chen, H. Zhao, C. Cui, Y. Zhao, Sep. Purif. Technol.

50 (2006) 365.

[209]. X. Xie, L. Gao, J. Sun, Colloids Surf. A. 308 (2007) 54.

[210]. H. L. Du, L. L. Yao, J. Environ. Prot. Sci. 29 (2003) 23.

[211]. S. Datta, P. K. Bhattacharya, N. Verma, J. Membr. Sci. 226 (2003) 185.

[212]. R. Devulapalli, F. Jones, J. Hazard. Mater. B. 70 (1999) 157.