TREATMENT OF LANDFILL LEACHATE USING

NANOPARTICALS

PROJECT REFERENCE NO.: 41S_BE_1927

COLLEGE : B.L.D.E.A‟s VACHANA PITAMAHA Dr. P. G. HALAKATTI

COLLEGE OF ENGINEERING AND TECHNOLOGY, VIJAYAPURA

BRANCH : DEPARTMENT OF CIVIL ENGINEERING

GUIDE : Mr. NAVEEN DESAI

STUDENTS : Ms. POOJA MATH

Ms. MADHUMALA.J.BAGALI

Mr. DEEPAK C KUSUR

Mr. RAJ GUTTEDAR

ABSTRACT

A trend of significant increase in the municipal solid waste generation has been recorded

worldwide. This hasbeen found due to over population growth rate, industrialization,

urbanization and economic growth.Most of the countries have adopted sanitary landfilling

as the best method for disposal of their MSW. One of the major pollution problems

caused by the sanitary landfill is landfill leachate, which is generated as consequences of

infiltration of water into landfills and squeezing of the waste due to self-weight. Landfill

leachate contains a wide variety of recalcitrant compounds such as organic matter, heavy

metals and inorganic salts, which makes it quite difficult to treat using conventional ways

of treatment due to its high chemical stability and/or low biodegradability.In recent years,

a great deal of attention has been focused on to the application of nanosized metal oxides

to treat heavy metals, organic and inorganic matter by nanosized titanium oxides, ferric

oxides, manganese oxides, aluminium oxides and magnesium oxides as adsorbents and

photocatalysts. The utilization of TiO2 nanomaterial as an adsorbent and photocatalytic

has received much attention due to its chemical stability, non-toxic and photostable.

In the present study, the photocatalytic degradation of synthetic leachate was investigated

in natural sunlight by using TiO2 as Nanomaterial. The parabolic trough collector is used

as solar photoreactor, which can efficiently bring solar photons and chemical reagents

into contact with the photocatalyst. The characterization of TiO2is conducted by X-Ray

Diffraction (XRD) and Scanning Electron Microscope (SEM).The influences of various

parameters such as photocatalytic dosage and contact time are studied on leachate

removal efficiency. The result indicates thatXRD and SEM confirm that the selected

photocatalyst TiO2 is an anatase with spherical in shape. The crystallite size is

approximately 19nm and specific surface area of 120.32 m2/gm. The recipe used for the

preparation of synthetic leachate have a similar composition of real landfill leachate. The

influencing parameters dosage and contact time are able to remove the maximum

percentage of organic and inorganic compounds from synthetic leachate.The average

removal efficiency of lead is 97.82% in alkaline pH 9 with contact time 80 minutes and

dosage of 0.3g/l

1. INTRUDUCTION

1.1 Solid Waste

Solid waste is the unwanted or useless solid materials generated from human activities in

residential, industrial or commercial areas. It may be categorised in three ways. Based on,

origin(domestic, industrial, commercial, construction or institutional), contents (organic

material, glass, metal, plastic paper etc) and hazard potential (toxic, non-toxin,

flammable, radioactive, infectious etc).

Municipal solid waste (MSW) consists of household waste, construction and demolition

debris, sanitation residue, and waste from streets, generated mainly from residential and

commercial complexes. In metro cities in India, an individual produces an average of 0.8

kg/ waste/ person daily. The total municipal solid waste (MSW) generated in urban India

has been estimated at 68.8 million tons per year (TPY). The average collection efficiency

of MSW ranges from 22% to 60%.MSW typically contains 51% organic waste, 17%

recyclables, 11% hazardous and 21% inert waste.

The remaining 40% of MSW lies littered in the city/town and finds its way to nearby

drains and water bodies, causing choking as well as pollution of surface water. The

collected MSW will be disposed by various methods such as sanitary land filling,

incineration, open burning, composting, and dumping into the sea. One of the most

commonly used MSW disposal method all over the world is sanitary landfill.

1.2 Sanitary Landfill

Sanitary landfills are a method of waste disposal where the waste is buried either

underground or in large piles. This method of waste disposal is controlled and monitored

very closely. The sanitary landfillare classified into three types, Mechanized sanitary

landfill, Semi-mechanised sanitary landfill and manual sanitary landfill.

For sanitary landfills, the process starts by digging a large hole in the ground that is then

lined with thick plastic (normally 2-4 feet thick) and a layer of impervious clay. The

bottom of the landfill is also lined with a network of plumbing that functions as a

collection system for any liquids. There will be two types of wastes are generated from

the sanitary landfill those are of methane gas and leachat.Leachate is the term used to

describe liquids that leach or leak from the landfill.

Fig 1 Sanitary Landfill

1.3 Landfill Leachate

Leachate may be defined as liquid that has percolated through solid waste and has

extracted dissolved or suspended materials from it. In most landfills, the liquid portion of

the leachate is composed of the liquid produced from the decomposition of wastes and

liquid that as entered the landfill from external sources such as surface drainage, rainfall,

ground water and water from underground springs. The black liquid contains organic and

inorganic chemicals, heavy metals as well as pathogens; it can pollute the ground water

and represents the health risk. Its composition varies a lot, both from time to time and

from site to site so that it is difficult to treat the liquid in the right way.

1.3.1 Leachate generation Leachates from landfill are generated by a number of factors, such as:

Infiltration of ground water;

Infiltration of leachate into the ground (a potential pollution of the ground water

may occur);

Rainfall (precipitation);

Water from the deposited waste, mainly due to the static pressure;

Evaporation from the site.

1.3.2 Leachate Treatment Methods

Leachate is highly complex and polluted waste water that is produced by the introduction

of percolation water through the body of landfill treatment. Leachate treatment is

essential as it could threaten the surrounding ecosystem when discharge as it is and when

it mixes with groundwater. There are different methods of leachate treatment such as

coagulation-Flocculation, chemical precipitation, flotation, activated carbon adsorption,

ion exchange chemical oxidation and advanced oxidation process and nanomaterial.

Table 1 General Characteristics of young leachate

Properties Young leachate

Ph 4.5-9.0

Conductivity, mS/m 1200-2500

COD, mg/l 600-60000

Sulphate, mg/l 10-420

Chloride, mg/l 100-5000

Calcium, mg/l 10-2500

Alkalinity, mg/l 50-1150

Sodium, mg/l 50-4000

Nitrate, mg/l 1-150

Iron, mg/l 20-2100

Copper, µg/l 4-1400

Chromium, µg/l 1-300

Cadmium, µg/l 0.5-140

Lead, µg/l 8-1020

Zinc, µg/l 30-4000

Nickel, µg/l 2-200

Source -N. MlKACet al. War. Sci. Tech. Vol. 37. No.8, pp. 37-44, 1998.

Heavy metals appear in the leachate due to batteries,consumers electronics, ceramics,

light bulbs, house dust and paint chips,. Concentration of heavy metals in a leachate is

generally higher at earlier stages because of higher metal solubility as a result of low pH

caused by production of organic acids. It is now recognised that most trace elements are

readily fixed and accumulate in soils, and providing threat to human health and

environment.

1.4 Nanoparticles

Nanoparticles are those which have structured components with at least one dimension

less than 100nm. In nanotechnology a nanoparticle is defined as a small object that

behaves as a whole unit with respect to its transport and properties. Particles are further

classified according to its diameter. Two principal factors cause the properties of

nanoparticles to differ significantly from other materials: Increased relative surface area

and quantum effects. These factors can change or enhance properties such as reactivity,

strength and electrical characteristics. As a particle decreases in size, a greater proportion

of atoms are found at the surface compared to those inside. Thus nanoparticles have a

much greater surface area per unit mass compared with large particles. Due to this unique

properties nanoparticles are used as adsorbent and photocatalyst in treatment of water

wastewater.

1.5 Photocatalysis

Photocatalysis is the acceleration of a photoreaction in the presence of a catalyst.A

photocatalyst is defined as a substance which is activated by adsorbing a photon and is

capable of accelerating a reaction without being consumed. There are two types of

photocatalysis they are homogeneousphotocatalysis and heterogeneousphotocatalysis.

In homogeneous photocatalysis, the reactants and photocatalysts exits in the same phase.

The most commonly used homogeneous photocatalysts include ozone and photo-Fenton

systems. The efficiency of Fenton type processes is influenced by several operating

parameters like concentration of hydrogen peroxide, pH and intensity of UV. The main

advantage of this process is the ability of using sunlight with light sensitivity up to

450nm, thus avoiding the high costs of UV lamps and electrical energy. These reactions

have been proven more efficient than the other photocatalysis but the disadvantages of the

processes are the low pH valueswhich are required, since iron precipitates at higher pH

values and the fact that iron has to be removed after treatment.

Heterogeneous photocatalysis has the catalyst in different phase from the reactants. The

most commonly used heterogeneous photocatalysts are transition metal oxide and

semiconductors. Semiconducting oxide photocatalyst have been increasingly focused in

recent years due to their potential applications in solar energy conversion and

environmental purification. Semiconductor heterogeneous photocatalysis has enormous

potential to treat organic contaminants in water and air, this process is known as advanced

oxidation process (AOP) and is suitable for the oxidation of wide range of organic

compounds. Among AOPs, heterogeneous photocatalysis have been proven to be of

interest due to its efficiency in degrading recalcitrant organic compounds.

The several semiconductors Tio2, ZnO, Fe2O3, CdS and ZnS can act as photocatalysts but

TiO2 has been most commonly used due to its ability to break down organic pollutants

and even achieve complete mineralization. Photocatalytic and hydrophilic properties of

TiO2 makes it close to an ideal catalyst due to its high reactivity, less toxic, chemical

stability and lower costs.

Fig 2 Mechanism of photocatalysis

1.6 Photocatalytic Process

Photocatalytic treatments by advanced oxidation processes utilizing the combination of

strong oxidants such as O2, H2O2, irradiation light, and catalysts to produce hydroxyl

radicals have been considered as a promising technique for landfill leachate treatment.

The photocatalytic treatment has revealed a great potential as a low cost, nontoxic,

chemically stable, high photo activity, environmental friendly, and sustainable treatment

to fulfill the zero waste scheme in landfill waste treatments. The photocatalytic processes

can either break down or rearrange molecular structures of different bio-recalcitrant

compounds or convert them to more readily biodegradable intermediates, improving the

efficiency and reducing the cost of further biological steps.

1.7 Photoreactors

Photochemical reactions may be carried in the most of the photoreactors types used for

the thermal or thermal catalytic process. Generally, photoreactors are used for the study

of photochemical reactions are parabolic collectors and compound parabolic collecting

reactors. The parabolic trough collector is used as solar photoreactor, which can

efficiently bring solar photons and chemical reagents into contact with the photocatalyst.

Photocatalytic experiments were carried out in compound parabolic collector specifically

developed for photo-Fenton application.

1.8 Objectivesof the Study

The main aim of this work is to study the performance and suitability of semiconductor

TiO2 nanomaterials in treatment of heavy metals and organic compounds in the landfill

leachate. In this context objectives are as listed below.

1. Characterization study of TiO2nanomaterial, such as particle size, specific surface

area, and surface morphology.

2. Preparation of synthetic leachate in mark with young landfill leachate.

3. To study the influencing parameters on photocatalytic such as dosage and contact

time

4. To determine the photocatalytic activity of titanium dioxide in removal of heavy

metal lead.

5. To determine photocatalytic activity of titanium dioxide in removal of other

parameters of leachate such as COD, nitrate, sulphates.

2. LITERATURE REVIEW

1. J. S. Sudarsanet. al. (2015) carried out work on “Role of Titanium Oxide on Heavy

Metal Reduction in Electroplating Waste Water Treatment”. The objective of this study is

to compare the efficiency of the wetland technique conventionally and with nanoparticles.

Nanoparticles in constructed wetlands give good result due to its high surface area and

this can be used large scale water purification, from the analysis of samples in the

lab.Study shown that lower concentrations (between 30-100 ppm) Titanium dioxide has

the highest percentage removal. At 30-ppm concentration, all the TiO2 and Fe3O4

nanoparticles were able to remove Cr with 100% efficiency. Values of nZVI and

Magnetite reduced with increase in concentration. At 100 ppm concentration, nZVI

caused 42.25% removal and Fe3O4 caused 90% removal while, TiO2 caused almost 95%

removal. In case of magnetite nanoparticles, it is possible to reuse particles for 5-7 times.

It is a good adsorbent but it has a less life because it is made up of Iron. On the other hand

TiO2 needed UV source for irradiation but it shows very high efficiency in the treatment

of heavy metals and there is no harm from the product during treatment. Since it does not

contain Fe, it has no risk of oxidation. So, from all the three particles, TiO2 is found to be

most efficient in the removal of heavy metals from the effluents, as it has an efficiency of

over 96% removal of Cr and Pb impurities from the polluted water.

2. Kavitakabra et.al. (2008) studied about“Solar Photocatalytic Removal of Metal Ions

from Industrial Wastewater”.The objective is to describe the photocatalytic reaction and

deposition of force metal ions i.e, Cr, Ni, Zn and Cu present in the waste water from

chrome plating industry using solar energy irradiated TiO2. The solar photocatalytic

process is effective in removing most of the metal ions in specific condition. This paper

describes the photocatalytic reduction and deposition of four metal ions Cr (VI), Ni (II),

Zn (II), and Cu (II) present in the wastewater from a chrome plating industry using solar

energy irradiated TiO2. A parabolic trough reactor was used to carry out the reaction.

Experiments were carried out to find an optimum dosage of hole scavenger used (citric

acid). The adsorption and reduction of the metal ions at different pH values was also

investigated.. Alkaline pH was found to be more suitable for removal of nickel and zinc.

However, Cr (VI) reduced completely even at catalyst concentrations as low as 0.5 mg/l

at pH 2. Maximum reaction was completed in the first 4 hr of solar exposure.

3. Elisangela M.R. Rocha et al. (2010) carried out their work on “Landfill leachate

treatment by solar driven AOP’s”. Advanced oxidation treatment technologies are

investigated for leachates using natural solar radiation as UV photon sources. The

Photo-Fenton reaction presents a much higher degradation rate, more than 20 times

higher than the heterogeneous photocatalytic. In this study, different heterogeneous

(TiO2/UV, TiO2/H2O2/UV) and homogenous (H2O2/UV, Fe2+

/H2O2/UV) photocatalytic

processes were investigated as an alternative for the treatment of a mature landfill

leachate. The addition of H2O2 to TiO2/UV system increased the reduction of the aromatic

compounds from 15% to 61%, although mineralization was almost the same. The DOC

and aromatic content abatement is similar for the H2O2/UV and TiO2/H2O2/UV processes,

although the H2O2 consumption is three times higher in the H2O2/UV system. The low

efficiency of TiO2/H2O2/UV system is presumably due to the alkaline leachate solution,

for which the H2O2 becomes highly unstable and self-decomposition of H2O2 occurs. The

efficiency of the TiO2/H2O2/UV system increased 10 times after a preliminary pH

correction to 4. The photo-Fenton process is much more efficient than heterogeneous

(TiO2, TiO2/H2O2/UV) or homogeneous (H2O2/UV) photocatalysis, showing an initial

reaction rate more than 20 times higher, and leading to almost complete mineralization of

the wastewater. However, when compared with TiO2/H2O2/UV with acidification, the

photo-Fenton reaction is only two times faster.

4. Xin Zhang et al. (2012) investigated on “Effects of Electron Donors on the TiO2

Photocatalytic Reduction of Heavy Metal Ions under Visible Light”. Photocatalytic

reduction of Cr could be encouraged by methanol, methanal and formic acid Cr could

hardly be reduced by TiO2 without electron donors. The effects on TiO2 photocatalytic

reduction of Cr (VI) under visible light, using methanol, methanal and formic acid as

electron donors were investigated. The results showed that the photocatalytic reduction of

Cr (VI) could be encouraged by methanol, methanal and formic acid. The fastest rate of

Cr (VI) photoreduction was observed in the presence of formic acid followed by methanal

and methanol. Cr (VI) could hardly be reduced by TiO2 without electron donors. The

conversion percent of Cr (VI) was 100% using formic acid as electron donors after 80

min. For the methanal and methanol systems, the conversion percent of Cr (VI) were

93.62% and 22.69% after 6 hr, respectivel

5. Reza Barati et al. (2014) conducted their work on “Photocatalytic removal of

cadmium and lead from simulated wastewater at continuous and batch system”. The

reactors used in this study consists of Ultra Violet (UV) source, reaction cell and mixing

chamber. The increasing TiO2 dose and pH the cadmium and lead removal increases. The

aim of this study was to evaluate the photocatalytic processes for cadmium (Cd2+

) and

lead (Pb2+

) removal at continuous and batch system. This study was performed at

laboratory scale. The reactors used in this study consisted of three parts: Ultraviolet (UV)

source, reaction cell, and mixing chamber. The experiments were carried out in a batch

and continuous reactor for synthetic wastewater. The concentration of Cd2+

and Pb2+

was

constant (25 mg/l) in all experiments and effect of titanium dioxide (TiO2) dosage, pH,

and air dispersion was investigated on the removal efficiency. The results showed that

with increasing TiO2 dosage and pH, the cadmium and lead removal increase. The

maximum removal of cadmium and lead was obtained in TiO2 dosage of 0.9 g/l and pH

11 that were equal to 99.8 and 99.2% respectively. Furthermore, when air dispersion

increased, the removal efficiency increased; while in the air dispersion 2cm3/l the removal

efficiency was maximum. According to these results the TiO2 has been considered as

photocatalyst is the separable and recyclable, so UV/TiO2 process is an environment

friendly process for toxic metal removal.

3. MATERIALS AND METHODOLOGY

3.1 Characterization of TiO2 Nanomaterial

The Scanning Electron Microscope (SEM) and X-Ray powder diffraction (XRD) is used

to study particle size, specific surface area and morphology of TiO2 Nanomaterials. Tests

are carried out at Shivaji University Kolhapur. The titanium dioxide (TiO2) used was

supplied from Sisco Research Laboratories Pvt. Ltd.

3.2 Construction of Parabolic collector (Trough)

After conducting more research on solar energy and solar collection, the decision was

made to attempt to build a parabolic trough solar concentrator. In parabolic concentrator

all the incoming rays from a light source are reflected back to the focal point of the

parabola.Parabola is built by eccentricity method. The photoreactor used was a

transparent borosilicate glass tube with 3 cm internal diameter, 20.4 cm length, mounted

on a parabolic collector of aperture length 38 cm and aperture width 18.2 cm (Fig. 3.1).

The parabolic collector is coated with Aluminium foil to bring about 100% reflection of

sunlight during photocatalysis. The photoreactor used for the study will be prepared with

borosilicate glass tube with 38mm internal diameter, 1.8m length, mounted on a parabolic

trough reflector of aperture length 172cm and aperture width 57.75cm.

Fig 3: Construction of parabolic concentrator(diagram)

3.3 Preparation of Solutions

3.3.1 Preparation of Synthetic Leachate:-

The synthetic landfill leachate was prepared in line with the real landfill leachate .The

synthetic landfill leachate was prepared by dissolving the corresponding analytical grades

of chemicals in distilled water as per table 3.1.

Table 2 constituents of synthetic landfill leachate

Constituents Per litre

Acetic acid (99%) 7ml

K2HPO4 30mg

KHCO30 312mg

K2CO3 324mg

NaNO3 50mg

NaHCO3 3012mg

CaCL2.2H2O 2882mg

MgCL2.6H2O 3114mg

MgSO4 156mg

NH4HCO3 2439mg

CO(NH2)2 695mg

3CdSO4.8H2O 80mg

NiSO4.6H2O 80mg

NaOH solution (4mol/l) 125ml, titrate to a pH of 5.8-6.1

To make the presence of heavy metal into the leachate solution, along with this

constituents lead of 20ml were added, mixed it well.

3.4COD, Nitrate and Sulphate test procedures

3.4.1 Chemical Oxygen Demand Test Procedure

COD is a measure of total quantity of oxygen required for oxidation of nearly all oxygen

compounds in waste water, by the action of strong oxidising agent.

Reagents used:

Standard potassiumdichromate (0.25 N), COD reagent, Standard ferrous ammonium

sulphate (0.1 N), Mercuric sulphate, Ferroin indicator.

Procedure for chemical oxygen demand test

1. Place 0.4 gm HgSO4 in a reflux flask.

2. Add 20 ml sample or an aliquot of sample diluted to 20ml. Mix well.

3. Add glass beads followed by 10ml standard potassium dichromate.

4. Add 30ml COD reagent (while adding the reagent cool the flask). Mix well. If the

colour turns green either take fresh sample or with a lesser aliquot.

5. Connect the flask to condenser and reflux for 2 hours.

6. Cool the flask to room temperature.

7. Add 4-5 drops of Ferroin indicator. Bluish green colour is observed.

8. Titrate this solution against 0.1 N Standard Ferrous Ammonium Sulphate till colour

changes to wine red.

9. Note down the burette reading.

Calculation

COD in mg/l = (A−B)× Normality of titrant ×Equivalent weight of oxygen ×1000

ml of sample titrated

Where, A= ml of titrant used for blank

B= ml of titrant used for sample

3.4.2 Nitrate Test procedure

This method is suitable for screening samples that have low organic matter contents. The

NO3 calibration curve follows Beer‟s law up to 11 mg/l. Measurements of UV absorption

at 220nm enables rapid determination of NO3.

Reagents used:

Stock nitrate solution, Standard nitrate solution.

Procedure for nitrate test

1. Pipette 10, 20, 30, 40 ml (2, 4, 6, 8mg/l) of standard nitrate solution in 50ml Nessler‟s

tubes/volumetric flask.

2. Switch on the instrument which is located of the left hand rear side of the instrument.

3. The display will show „Elico‟ *SL 210*.

4. Press ENTER, the display will show D2 lamp testing alignment in progress.

5. Press ENTER, the display will show base line scan. Then press YES.

6. Press ENTER, the display will show MENU.

7. Then the different modes are displayed. Select the required mode. Example,

quantitative from the main MENU.

8. Press the „1‟ and select „Standard‟ option.

9. Keep the prepared samples and distilled water in reference point.

10. Press ENTER and feed the wave length value.

11. Press ENTER number of standards.

12. Press ENTER and select the concentration units Ex. Ppm.

13. Press ENTER and cuter values standard 1 concentration value. Similarly enter values

for all standards.

14. Press ENTER and select mode of absorbance input Ex. Measure.

15. Press ENTER and enter number of samples.

16. Keep cuvette filled with reference and other cuvettes filled with standards in the

cuvette holder drum.

17. Display will show auto zero option say always „NO‟.

18. The spectrophotometer will start reading the reference and all the standards.

19. Then the display will ask for samples. Remove the standards and place the samples in

the cuvettes and press „ENTER‟.

20. Now the instrument will start reading the samples.

21. Now the display will show different option like 1.View, 2. Print, 3. Modes.

22. Press view to see readings.

23. The data option like standards and samples are displayed.

24. Press „ESCAPE‟ to come back to main menu.

25. Switch of the Instrument.

. 3.4.3 Sulphate Test procedure

Sulphate is widely distributed in nature and may be present in natural waters in

concentrations ranging from a few to several thousand milligrams per litre. Mine drainage

wastes may contribute large amounts of SO4 through pyrite oxidation. Sodium and

magnesium sulphate exert a cathartic action.

Reagents used:

Conditioning reagent, Barium chloride, Standard sulphate solution (1000mg/l)

Procedure for sulphate test

1. Prepare standards containing 20, 40, 60, 80, 100, & 120 mg/l of sulphate.

2. Take distilled water in the test tube. Add 5ml conditioning reagent. Add few grains of

barium chloride. Mix well and adjust set 0 controls to get 0 displayed on the read out.

3. Replace the distilled water filled test tube with reference standards of the highest

known concentration (120 mg/l). Add 5 ml conditioning reagent. Add few grains of

barium chloride. Mix well and adjust set 1000 control to get 1000 displayed on the

read out.

4. Repeat step 3 for all the standards and find the respective turbidity values.

5. Plot a standard graph with concentration (mg/l) on X-axis and turbidity(NTU) on Y-

axis.

6. Take suitable volume of sample in volumetric flask and dilute to 100ml.

7. Add 5ml conditioning reagent accurately mix well.

8. Keep the flask constantly stirred with the help of stirrer. Add BaCl2 crystals while

stirring.

9. Measure the turbidity developed after every 30 seconds on nephelometer.

10. Find the sulphate concentration of the sample with the help of standard graph.

11. Samples having higher turbidity require dilution. Then the turbidity can be calculated

as follows

Nephelometric Turbidity Unit (NTU) = 𝐴×(𝐵+𝐶)

𝐶

Where, A= NTU found in diluted sample

B=volume of dilution water, ml and

C=sample volume taken for dilution, ml.

3.4.4 Conductivity Test procedure

Conductivity is a numerical expression of the ability of an aqueous solution to carry an

electric current. This ability depends on the presence of ions, their total concentration,

mobility, valence and relative concentrations and on the temperature of measurement.

Reagents used:

Standard conditioning solution

Procedure for conductivity test

1. Switch on the instrument by pressing on/off key.

2. The full LCD lights up for a few second to display all segments as a self-diagnostic

test of the LCD. Then display the conductivity measurement.

3. Rinse the electrode thoroughly with deionised water

4. Note that mode is (COND).

5. Immerse the electrode into the selected standard solution (1413 micro mhos/cm) and

press CAL. Now the primary display shows the measured reading while the secondary

display indicates the temperature of calibrating solution.

6. Use MI/∆ or MR/∇ key to scroll to the correct standard solution value on the meter.

7. Press ENTER to confirm the calibration value. The programme will resume to its

measurement mode.

8. Immerse the electrode in the given sample and note down the conductivity value.

3.5 Experimental work

The experiments were carried out in a batch sequence under natural sunlight at Vijayapur,

(16.83°N 75.71°E) Karnataka state, India. The parabolic trough (Fig3.1) is used with an

angle of 450to receive the maximum sunrays. The 100ml glass tube is used for

experimental work. At the end of each experiment, filter paper is used for separation of

TiO2 particles. The lead and zinc analysis was done by using Atomic Absorption

Spectroscopy (Varian 240). The COD, Nitrate, Sulphate, Conductivity and pH analysis

done as per the above procedure.

4 RESULTS AND DISCUSSION

4.1 Analysis of TiO2 Photocatalytic characteristics

4.1.1 Particle size of Titanium dioxide adsorbent

The XRD pattern of TiO2 Photocatalytic is shown in table 3. The results shows six peaks

at 25.29, 37.92, 48.09, 53.86, 55.12, and 62.7. The 2θ peaks at 25.29˚ and 48.09˚ confirm

its anatase structure according to JCPDS Card.

Table 3 XRD pattern of TiO2 Photocatalytic

Average crystallite size is calculated by considering the 2θ peak values. The simplest and

most widely used method for estimating the average crystallite size is from the full width

half maximum (FWHM) of diffraction peak using Debye-Scherer formula

D= 0.9𝜆

𝛽𝑐𝑜𝑠𝜃

Where, λ is wave length of X-Ray (0.1540 nm), β is FWHM, θ is diffraction angle, and D

is crystallite size. The average crystallite size obtained by the above equation is 19 nm.

The intensity of XRD peaks of the sample reflects that the smaller the crystal size the

broader the peak confirming small size crystallite

4.1.2 Specific Surface Area (SSA) by X-ray diffraction

SSA is a material property. It has a particular importance in case of adsorption,

heterogeneous catalysis and reactions on surfaces. SSA is the Surface Area (SA) per

mass. The specific surface area and surface to volume ratio increase dramatically as the

size of materials decrease. The SSA can be calculated using following equations and both

the equations yield the same result. The observed results are in Table 4.

𝑆𝑆𝐴 =𝑆𝐴𝑃𝑎𝑟𝑡

𝑉𝑃𝑎𝑟𝑡 ×𝜌

S=6000

𝐷𝑃×𝜌

Where SSA and Sare the specific surface area, VPart is particle volume and SApart is

surface area, Dp is the size (Spherical Shaped) and ρ is the density of thematerial.

Table 4 Specific Surface Area of TiO2 Nanoparticles

Particle size (nm) Surface area

(nm2)

Volume (nm3) Density (g.cm

-3) SSA (m

2.g

-1)

19 1134.262 3597.82 2.62 120.32

The results show 120.32 m2/gmSSA which is responsible for the enhanced photocatalytic

degradation of lead.

4.1.3 Scanning Electron Microscope (SEM)

The surface morphology is studied by Scanning Electron Microscopy (SEM) in the

physical Instrumentation Facility Centre (PIFC), Department of Physics, Shivaji

University, Kolhapur, Maharashtra. The SEM images of TiO2 at different magnifications

are shown in Fig 4, which confirms that the TiO2 used for the study is spherical in shape.

Fig.4 SEM images of TiO2

nanoparticles with different

magnification

4.2Analysis of synthetic leachate

4.2.1 Initial characteristics of synthetic

leachate

Initial characteristics of synthetic leachate are

determined with the standard procedures. The

initial characterisation study is carried out to

compare the synthetic leachate with the real

landfill leachate characteristics. Table 4.3

shows the comparison table. The results

obtained on synthetic leachate are almost

resembling with the real landfill leachate.

Parameters Prepared synthetic

leachate Real leachate

pH 9.07 4.5-9.0

Conductivity 13860µmhos/cm 12000-25000 µmhos/cm

Chemical oxygen

demand

12800 mg/l 600-60000 mg/l

Nitrate 117.83 mg/l 1-150mg/l

Sulphate 280mg/l 10-420 mg/l

Table 5 comparison of synthetic leachate and real leachate characteristics

The heavy metal Pb2+

concentration considered in synthetic leachatewas higher level

compare to the real landfill leachate. This higher level concentrations help in the proper

analysis ofthe degradation of the heavy metal by TiO2.

4.2.2Degradation study of COD, conductivity,sulphate and nitrate by TiO2

Photocatalytic

Table 6 shows the organic and inorganic compounds reduction by TiO2photocatalyst.

These studies have been carried out with different dosages of TiO2 and time variation.

Table 6 Experimental results for organic and Inorganic compounds

Sl.No Dosage

(gm\lit)

Irradiation

(minutes)

COD

(mg\lit)

Conductivity

(μmohs/cm)

Sulphate

(mg\lit)

Nitrate

(mg\lit)

Pb2+

%

removal

1 0.2 20 10000 11288 268 100.48 95.28

2 0.2 40 9200 10085 243 93.76 96.38

3 0.2 60 8400 1255 230 82.45 98.28

4 0.2 80 8000 1223 200 74.32 98.92

5 0.2 100 7200 1215 189 60.09 97.28

6 0.3 20 6400 1190 171 55.39 96.68

7 0.3 40 6000 1162 156 50.01 97.15

8 0.3 60 5600 1134 140 44.21 97.92

9 0.3 80 4800 1096 128 39.69 98.55

10 0.3 100 4400 1058 110 33.33 96.23

Lead 19.28 mg/l 0.008-1.020mg/l

100009200

8400 80007200

6400 6000 56004800 4400

0

2000

4000

6000

8000

10000

12000

20 40 60 80 100

CO

D r

emo

val i

n m

g/l

Irradiation time in minutes

Series1

Series2

268

243230

200189

171156

140128

110

0

50

100

150

200

250

300

20 40 60 80 100

Sulp

hat

e re

mo

val i

n m

g/l

Irradiation time in minutes

Series1

Series2

COD Removal by photocatalysis process: -The Graph 5 shows the reduction of COD in

the synthetic leachate with 0.2g/l and 0.3g/l. As the catalysis dosage plays an important

role in photocatalytic activity as the density of particle in the area of illumination

increased. This was attributed to the increased availability of catalyst sites for the

adsorption of the reactant molecules, better generation of reactive free radicals and their

interaction.

Fig 5

COD removal with 0.2g/l and 0.3g/l dosage

Nitrate and Sulphate Removal by photocatalysis process: - The Graphs 4.3 & 4.4

shows the reduction of sulphate and Nitrate in the synthetic leachate for 0.2g/l and 0.3g/l

for TiO2 dosage at different time intervals in minutes. As expected, solar photocatalytic

reaction rates increase with increasing solar irradiance. In heterogeneous photocatalysis,

reaction rate profiles areproportional to the number of incoming photons on the solid

photocatalyst. Performance is almost linear when solar irradiance is low.

Fig 6

Sulphate removal with 0.2g/l and 0.3g/l dosage

100.4893.76

82.4574.32

60.0955.39

50.0144.21

39.6933.33

0

20

40

60

80

100

120

20 40 60 80 100

Nit

rate

rem

ova

l in

mg/

l

Irradiation time in minutes

Series1

Series2

20 40 60 80 100

Series1 95.28 96.38 98.28 98.92 97.28

Series2 96.68 97.15 97.92 98.55 96.23

92

93

94

95

96

97

98

99

100

%re

mo

val o

f le

ad

Irradiation time in minutes

Fig 7

Nitrate removal with 0.2g/l and 0.3g/l dosage

4.2.3Degradation of lead (Pb2+

)

Heavy metals are one of the major concerns in the sanitary landfill leachate. Heavy

metals enter in the landfill by electroplating waste, painting waste, used batteries etc.

Heavy metal lead (Pb2+

) can cause a harmful effects such as anemia, abdominal pain,

irritability, as well as it disturbs the functioning of the brain resulting in memory loss and

headache. Therefore lead is considered for the study and results are shown in below graph

4.6

The results of lead show that as the time interval increases the removal efficiency of lead

increases. The longer irradiation time accelerates mixing and dispersion of adsorbent into

the solution and providing more vacant sites for metal ions. Furthermore, theincrease of

irradiation time leads to precipitation of the adsorbed lead back into the solution.It was

seen that at the lower adsorbent dosage, the increasing pH caused a higher adsorption

capacity, due to deprotonation of the more adsorption sites

Fig 8 Lead removal with 0.2g/l and 0.3g/l dosag

5 CONCLUSIONS

In the present study, TiO2Photocatalytic nanomaterial is used for the removal of organic

and inorganic compounds from synthetic leachate. Based on the present study following

conclusions were drawn.

1. The TiO2 characteristics study, such as XRD and SEM results confirms that the

selected photocatalyst TiO2 is an anatase with spherical in shape. The crystallite

size is approximately 19nm and specific surface area of 120.32 m2/gm

2. The recipe used for the preparation of synthetic leachate have a similar

composition of real landfill leachate.

3. To major two influencing parameters dosage and contact time, selected for the

photocatalytic study has the ability to remove the maximum percentage of organic

and inorganic compounds from synthetic leachate.

4. The removal efficiency of lead is maximum in alkaline pH 9 with contact time 80

minutes and dosage of 0.3g/l

5. The removal efficiency of COD, nitrate and sulphates were studied. COD removal

efficiency found lesser due to the high pH value (alkaline) in synthetic leachate.

The nitrate and sulphate removal efficiency were comparatively good by the

TiO2photocatalyst