the rmodynamic study of the adsorption of (e110, 122, …

www.wjpps.com │ Vol 10, Issue 8, 2021. │ ISO 9001:2015 Certified Journal │

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Mohammed et al. World Journal of Pharmacy and Pharmaceutical Sciences

THE RMODYNAMIC STUDY OF THE ADSORPTION OF (E110, 122,

102, 133, 124, 123, 127) DYES EMPLOYED IN THE FOOD INDUSTRY

USING ACTIVATED CARBON AS ADSORBENT SUBSTANCE

Ibrahim Y. Mohammed* and Khaleel Ibraheem A. Al-Niemi

College of Education for Pure Sciences - Dep. of Chemistry. Mosul University- Iraq.

ABSTRACT

This research included a thermodynamic study of the adsorption of

some food coloring dyes (E110, 122, 102, 133, 124, 123, 127) on the

surface of commercial activated carbon as an adsorbent. The analytical

method was used to opted the calibration curves for each dye and to

estimate the amount of adsorbed and remain of food coloring dyes

according to (Beer's –Lambert law) by using spectrometer

photometricmethod for UV- visible spectrophotometric . The effect of

temperature on the adsorption of food coloring dyes or food coloring

molecules was studied within an experimental temperature range (298-

318 kº) and calculate the thermodynamic functions of the adsorption

process (∆H, ∆G°, ∆S°, ∆S) from the adsorption equilibrium

constant(Kc) using the (Vant-Hoff) equation, as well as, calculating those functions from the

adsorption isotherms from the Langmuir and Freundlich constants, All results showed that

the adsorption process is endothermic and of a physical nature through positive ∆H values at

all concentrations with range of temperatures used in this study. It was also found that the

adsorption process occurs spontaneously, where the values of (∆G°) were negative and few,

as well as, it turns into more spontaneous with increasing temperature, but some food

coloring dyes have positive (∆Gº) values refers to that the adsorption process is a non-

spontaneous process, In general, the entropy values (∆S°) were slightly greater than the

values of ( ∆S) that is, the regularity of the adsorbed molecules at equilibrium is greater than

their regularity at any step of adsorption. The results obtained for the thermodynamic

functions calculated from the Langmuir and Freundlich constants showed great agreement

with those that were calculated from the equilibrium constants, which indicates the possibility

of using those Constants to calculate thermodynamic functions successfully.

WORLD JOURNAL OF PHARMACY AND PHARMACEUTICAL SCIENCES

SJIF Impact Factor 7.632

Volume 10, Issue 8, 2202-2227 Research Article ISSN 2278 – 4357

*Corresponding Author

Dr. Ibrahim Y.

Mohammed

College of Education for

Pure Sciences - Dep. of

Chemistry. Mosul

University- Iraq.

Article Received on

17 June 2021,

Revised on 07 July 2021,

Accepted on 27 July 2021

DOI: 10.20959/wjpps20218-19646


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KEYWORDS: Adsorption, Thermodynamic functions, Activated carbon, Adsorption

isotherms.

INTRODUCTION

Food coloring dyes are organic chemicals containing aromatic rings that are widely used

globally in the food, pastry, soft drinks and various juice industries, and this has led to water

pollution mainly in the places of their manufacture or from their domestic or artisanal use for

their manufacture or in dry mixes and dairy products and others.[1-4]

These food colorings are

chemical compounds that did not exist in nature and are manufactured with high purity,

which constitutes an important and very wide sector and one of the important industries as

well.[5]

Chemically, food coloring dyes are involved In the presence of the chromophore azo

group(N N), sulfur (C S), aryl and ionic rings.[6-12]

To treatment the problem of water

pollution with food pollutants, the adsorption technique was used among other methods, for

its efficiency, ease and economically inexpensive, and the use of different effective adsorbent

materials such as clay and activated carbon, and other natural or synthetic materials.[13-20]

Adsorption process is usually accompanied by a change in free energy (∆G) of the surface on

which adsorption occurs and is accompanied by a decrease in entropy due to the adsorption

of molecules on the surface and their attachment to it, loss of some degrees of its freedom

compared to its state before the adsorption process and as a result of the decrease in free

energy and entropy simultaneously. One, this will cause a decrease in enthalpy (∆H).[21-24]

The values of thermodynamic functions are calculated based on certain equations, assuming

that the adsorption process occurs according to the following:

Food coloring dye + Activated carbon prod.

at t = 0 0

at t = teq ( Ce) Cads.

Cads. = Ci – Ce ………….(1)

Where

C0 = the initial concentration of the dye (mg/L).

Ce = the residual concentration of the dye after adsorption (mg/L).

Cads. = adsorbed concentration of dye (mg/L).

and the value of the equilibrium constant is represented as follows:

Kc = Cads. / Ce ……………….(2)

∆G° = -RT ln Kc ………………(3)


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Ln Kc = lnC - ∆H/ RT ………….(4) (Vant-Hoff equation)

Where

Kc = equilibrium constant.

R = gas constant.

T = temperature (k°).

It has been assumed that the values of (∆G) = 0 at equilibrium state.

The Vant - Hoff equation is usually used to calculate the enthalpy values (∆H) of the

adsorption process, and it represents one of the important measures in determining the type of

bonding forces between the adsorbed food dye molecules and the activated carbon surface,

and at the same time represents the amount of energy required to recover the adsorbent from

the solid surface, as well as, the type of adsorption physical or chemical. Also, the negative or

positive sign of (∆H) values indicates that the adsorption process is exothermic or

endothermic respectively.[25]

The value of (∆H) less than (40 kJ / mole) confirms that the

forces controlling the adsorption process are of a physical nature and more than (80 kJ /

mole) It indicates that the adsorption is chemical with real bonds. Thus, each quantity has a

thermodynamic function that gives an indication and an accurate description of the

thermodynamic adsorption process in terms of whether it occurs spontaneously or non-

spontaneously through (∆Gº) values, as well as, the randomness of the adsorption system of

the adsorbed molecules before and after adsorption. The isotherms constant for Langmuir

isotherm (kL) and Freundlich isotherm (kf) of adsorption process used to calculated

thermodynamic functions on the surface of activated carbon for adsorption of food coloring

dyes on surface activated carbon to calculate thermodynamic functions. The Langmuir

constant (kL) which is related to the maximum adsorption capacity, and Freundlich constant

(kf) which is related to the adsorption capacity,were calculated at the same temperature range

(25-45c°) that is used to calculate the equilibrium constant (Kc) for the adsorption process

and for a range of concentrations of the food coloring dyes under study, When The values of

thermodynamic functions obtained from the isotherms constants are consistent with those

calculated from the equilibrium constant, then it can be described as a correct and successful

study.[24,26,27]


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Experimental

Scientific research depends widely on the practical results, which the methods of preparing

stander solution of food coloring dyes chemicals and laboratory devices in accomplishing this

research.

1- The chemicals: All chemicals from used these materials from BDH and Fluka a

company:

a) Activated charcoal (Adsorbent)

b) Hydrochloric acid

c) Sodium hydroxide

d) The food coloring dyes that were used in this study were produce from market of our city

in bottles from well-known companies.

Table 1: The names and molecular formulas of the food coloring Dyes and Some of their

physical Properties and Optimum conditions.

coloring

dyes

Dye name Molecular formula The

color

Meltin

g point

cº

λmax.

nm.

M.wt.

g/ mol

ɛ max.

L/mol.Cm.

optimum conditions.

C0

T c° gm/L PH

E110 Sunset C16H10N2Na2O7S2 Yellow 300 480 452.37 19707 45 45.237 8.11

E122 Azorubine C20H12N2Na2O7S2 Food

Red

300 515 502.431 17256 45 50.243 7.71

E102 Tartrazine C10H11N2Na3O10S3 Yellow 870 426 534.3 8592.7 45 53.430 6.50

E124 Ponceau C20H11N2Na3O10S3 Red - 503 604.46 19361 45 60.446 7.12

E123 Amaranth C20H11N2Na3O10S3 Red 120 523 604.473 13122 45 60.447 6.93

E133 Billiant C37H34N2Na3O10S3 Blue - 630 792.85 81630 45 7.929 7.88

E127 Erythrosine C20H6N4Na2O5 Red - 530 879.86 12680 45 87.986 7.42

2- Instruments

a) Electrothermol melting point of the type (9300 meter).

b) The pH measurement device of the type (JENWAY 3510).

c) An absorbance measuring device of the type (T92+ UV spectrophotometric PG lin) which

used to find the values of (λ max) for all food coloring dyes and measure the absorbance

spectrum for them using a device

d) (CECIL spectrophotometer 1000S) measure the adsorption for food coloring dyes

solution before and after adsorption process using distilled water as a solvent and (blank)

with glass cells with a thickness of (1 cm ).

e) Water bath with a program vibrator (Julabo Sw 23) to shake solutions at a speed of (100

rpm).


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3- Preparation of standard solutions

The standard solutions of the studied food coloring dyes were prepared by dissolving (1 gm)

of each dye in a liter of distilled water, then solutions were prepared with concentrations

(2,4,6,8,10)*10-5

M. for all the dyes under study except for the dye E133, which was prepared

in concentrations (2,4,6,8,10)*10-6

M., was tracked by diluting the calculated volume from

the original standard solution.

4- Analytical method

a) A UV-VIS spectrophotometric device of the type (T92+ spectrophotometric) was used to

estimate the concentration of food coloring pigments in the solutions under study. The

test was done based on the ability of these food colorings to absorb electromagnetic rays

in the UV-visible range. To complete this work, at first, the value of the maximum

absorption wavelength (λ max ) was determined for each dye separately, then the amount

of adsorbent material was tracked after a period of time according to the nature of each

dye. Draw the relationship between absorbance and concentration to choose the best

concentration for the study

b) The best five concentrations were selected from the calibration curve to prepare (5)

solutions containing different concentrations of solutions of each food coloring dye, and

to each of them the necessary amount of activated carbon was added.

c) These solutions were then shaken separately for (60) minutes and at a range of

temperatures (25, 30, 35, 40 and 45 °C) respectively using the programmed vibrator after

setting the temperature.

d) The five solutions were filtered and the absorbance value was recorded before and after

adsorption using equations (1,5 to find the adsorption capacity and efficiency.

The change of quantity adsorbed material from food coloring dye with time using Lambert

Beer, s law to draw the calibration curve at (λ max) for each dye between absorbance and

concentration, as in the following equation:

A= ɛ L C ………………5

Where

A = absorbance (nm) before adsorption.

ɛ = molar absorption coefficient (L/ mol .cm).

C = food coloring dye concentration (M.).

L = length of the absorber cell (1 cm.).


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5- Determination of the concentration of solutions of food coloring dyes

The concentration of dyes before and after adsorption was estimated using a UV - visible

spectrometer, and the results were obtained in (mg/L) using the standard curve that was

prepared previously for each dye. Express the amount of the adsorbent in terms of adsorption

capacity (qe) and adsorption efficiency (%) by estimating the amount of residual and

adsorbent from the food coloring dye solution as in the following equations:

Cads.= C0 –Ce ……………………….6

qe = ((C0-Ce) /m ) * VL……………7

%= ( (C0 – Ce ) / C0 ) * 100 ………..8

Where

Ce = residual dye concentration (mg/L).

C0 = the initial concentration of the dye (mg/L).

VL = volume of the model (ml) .

m = weight of the adsorbent (activated carbon)( g/L).

6- Determining the amount of adsorbent material

Five different weights of the adsorbent material (0.01-0.09 g) were tested at the natural

acidity function and the initial concentration was stable to choose the best weight for it to

adsorb these food coloring dyes until reaching the equilibrium state.

7- Determination of the adsorption isotherm

To find the adsorption isotherm, concentration solutions were used for each dye described

previously, where (50 ml) of each solution were taken and placed in contact with a known

weight of activated carbon in a standard flask of (250 ml) capacity equipped with a tight seal

and placed in a water bath equipped with a vibrator at a temperature of (298-318k0).) for a

specified period of time. After filtration, the absorption was measured with a UV-visible

spectrometer and the residual concentration after adsorption was calculated, including

calculating the amount of adsorbent per unit weight of the adsorbent based on equation (7)

and the following equation:

Ce= Ai / ɛ ............................................ 9

Where:

Ai = absorbance after adsorption.


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8- The effect of temperature

To estimate the effect of temperature on the adsorption rate, the adsorption of each food

coloring dye solution was studied at temperatures (25,30,35,40,45 C0) and by the same steps

mentioned previously. These results were used for application in the Vant - Hoff equation by

drawing the relationship between (ln Kc) versus (1/T) The thermodynamic values were found

according to equations.[2,3,4,5]

RESULTS AND DISCUSSION

In the adsorption process of food coloring dyes on the surface of activated carbon we can

expected that bond formation include this process consequently, the molecules of food

coloring dyes will be associated with a change in the thermodynamic parameters of the

adsorption system. The parameters were used to explain the variation food coloring removal

efficiency at different temperatures and to confirm the adsorption nature of food coloring

dyes on the surface of activated carbon.

The calculated of thermodynamic parameters give feasibility of using different temperatures

in adsorption process and the spontaneous nature of this process.

Temperature is a factor affecting the adsorption process,[28]

as the increase in temperature

leads to an increase in the kinetic energy of the non adsorbed molecules in the solution, and

thus the ease of their transfer to the solid surface for adsorption and an increase in the

efficiency of adsorption.

The increase of temperature useful to over come on the intermolecular interactions[29,30]

and

electrical attractions, as well as, solvent effect at a high concentration of dyes solutions, on

other hand, the effect of increasing at temperature on the adsorbing molecules on the surface

of adsorbent material in the case of physical adsorption leads to decrease the efficiency of

adsorption system, because the increase of temperature cause increase in the kinetic energy of

adsorbed molecules on the surface leads to their disengagement from the adsorbent surface

and their return to the solution , for this reason the adsorption efficiency will decrease,[31,32]

this situation is prevalent in exothermic adsorption system.

The results of effecting of temperature in adsorption process tabulated in table (2) at optimum

conditions.


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Table 2: The effect of temperature on the percentage of adsorption of food coloring dyes

under study at the best dye Concentration and The best weight of activated carbon at

optimum conditions.

% qe mg/g Ce mg/L T k0

C0 mg/L Activated

Carbon (gm)

Dye

81.032 5.236 1.716 298 9.047 0.07 E110

84.039 5.431 1.444 303

87.278 5.640 1.151 308

90.052 5.819 0.900 313

92.141 5.954 0.711 318

86.128 6.182 1.394 298 10.049 0.07 E122

86.864 6.235 1.320 303

87.611 6.289 1.245 308

89.342 6.413 1.071 313

91.820 6.591 0.822 318

84.611 6.459 1.644 298 10.686 0.07 E102

87.422 6.673 1.344 303

89.000 6.794 1.175 308

91.701 7.000 0.886 313

95.313 7.275 0.501 318

76.166 2.013 0.378 298 1.586 0.03 E133

81.463 2.153 0.294 303

86.255 2.280 0.218 308

87.831 2.322 0.193 313

90.984 2.405 0.143 318

80.045 6.912 2.412 298 12.089 0.07 E124

82.080 7.088 2.166 303

84.580 7.303 1.864 308

88.208 7.617 1.425 313

93.424 8.067 0.795 318

39.518 3.412 7.312 298 12.089 0.07 E123

46.849 4.045 6.425 303

56.746 4.900 5.229 308

71.408 6.166 3.456 313

89.369 7.717 1.285 318

40.430 5.082 10.482 298 17.597 0.07 E127

44.604 5.606 9.748 303

52.572 6.608 8.346 308

63.955 8.039 6.343 313

79.132 9.947 3.672 318

When checking the results in table (2) about the effect of temperature on the adsorption of

food coloring dyes on the surface of activated carbon, we clearly noticed an increase in the

values of the adsorption capacity, and efficiency with the increase in temperature. Therefore,

the amount of adsorbed dye is proportional to the amount of heat absorbed by the adsorption


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system, because the largest possible number of molecules possessing sufficient activation

energy to bind to the surface.

The conclusions that were reacted to it from the practical data of adsorption were within the

temperature range used (25-45cº), which is expected to be the dominant forces on the process

of binding food coloring molecules on the surface of activated carbon of a physical nature,

and include an sorption process for diffusion with its various particles and process. In any

case, the results of the values and sign of the enthalpy(∆H) of adsorption pores will confirm

these conclusion through later thermodynamic study, in other words, a decrease in the energy

absorbed by the adsorption system with an increase in concentration within temperature rang

used, and this leads to a decrease in the amount of food coloring dyes adsorbed on the surface

of activated carbon, causing a decrease in its adsorption efficiency at constant concentration

and a certain temperature range, the high heat absorbed by the adsorption system it is

accompanied by a high adsorption efficiency.

1- Thermodynamic study

In order to understand in detail the effect of temperature on the adsorption process at

equilibrium, It was necessary to calculate the thermodynamic parameters of the adsorption

system. In order to know the path way of adsorption process and the type of forces affecting

it, and the nature of the molecular interactions [33,34]

that it can be known through the value of

the enthalpy (heat of adsorption) which gives an indication of the nature of these bonding

forces between the adsorbed molecules and the adsorpted surface, which can be calculated

from Vant- Hoff equation (equation 4) after calculation the values of the equilibrium constant

for the adsorpting process:

The value of (∆H) can be calculated from drawing the relationship between (ln Kc) with (1/

T), which is supposed to give a straight line with an slope equal (- ∆H / R) and high

coloration confection (R2) (Figures 1 A,B,C).


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A B

C

Figures 1: The relationship between (ln Kc) with (1/ T) for the adsorption of food

coloring dyes at different temperatures.

After calculated (∆H) value, the other thermodynamic parameters (∆Gº, ∆Sº and ∆S ) values

calculated from it, the (∆Gº) value represent the change in the free energy at any step of

adsorption process, while the (∆G) value which represent the free energy at equilibrium state

of adsorption for this reason the (∆S) and (∆Sº) values was calculated which represent the

randomness of the adsorption system :

∆Gº = ∆H - T∆Sº ……………. 10

∆Sº = (∆H - ∆Gº) / T ……………11

∆S = ∆H / T ………………………..12

The thermodynamic parameters values of (∆H, ∆Gº, ∆Sº and ∆S) were listed in table (3):


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Table 3: Thermodynamic Parameters and Equilibrium constants for the adsorption of

food coloring dyes at different temperatures.

∆S

J/mole.k0

∆S0

J/mole.k0

∆G0

kJ/mole

R2

∆H

kJ/mole

kc T k0

C0 mg/ L Dye

42.607 39.829 +0.828 0.9753 12.697 0.716 298 45.237 E110

42.904 39.752 +0.652 0.772 303

41.224 40.068 +0.356 0.870 308

40.565 40.125 +0.138 0.948 313

39.928 39.786 +0.045 0.983 318

25.396 27.601 -0.657 0.9115 7.568 1.304 298 50.243 E122

24.977 28.063 -0.935 1.449 303

24.571 27.932 -1.035 1.498 308

24.179 28.096 -1.226 1.601 313

23.799 28.057 -1.354 1.669 318

62.785 63.349 -0.168 0.9879 18.710 1.070 298 53.430 E102

61.749 63.244 -0.453 1.197 303

60.747 63.381 -0.812 1.373 308

59.776 62.064 -0.716 1.316 313

58.836 65.953 -2.263 2.354 318

35.218 37.678 -0.733 0.9889 10.495 1.345 298 7.929 E133

34.637 41.455 -2.066 2.270 303

34.075 41.565 -2.307 2.462 308

33.530 41.629 -2.535 2.649 313

33.003 41.509 -2.705 2.781 318

16.24295 15.55633 +0.204614 0.9784 4.8404 0.920732 298 60.446 E124

15.97492 15.46951 0.153138+ 0.941021 303

15.71558 15.45163 0.081299+ 0.96875 308

15.46454 15.48716 -0.00708 1.002725 313

15.22138 15.60605 -0.12232 1.047354 318

75.48725 68.58355 +2.057304 0.9935 22.4952 0.435888 298 60.447 E123

74.24158 68.81647 1.643808+ 0.520728 303

73.03636 68.49045 1.400142+ 0.578812 308

71.86965 68.58628 1.027693+ 0.673734 313

70.73962 68.95422 0.567758+ 0.806746 318

176.1339 159.4284 +4.978247 1.000 52.4879 0.134079 298 87.986 E127

173.2274 159.6712 4.107536+ 0.195826 303

170.4153 159.925 3.231008+ 0.283155 308

167.693 160.3599 2.295248+ 0.413948 313

165.0563 161.1474 1.243011+ 0.624908 318

To confirm the adsorption nature of the food coloring dyes and to explain the variation in it

removal efficiency by changing of temperature and the spontaneous nature of adsorption

process, It is observed that (∆H) have a positive value, which thermodynamically

substantiates the assumption that the adsorption of food coloring dyes on the surface of

activated carbon is endothermic . Its values ranged (12.697 – 52.4879 kJ/ mole) and this


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indicates that the physical adsorption predominate in the adsorption system. When studying

the effect of increasing the initial concentration of food coloring dyes in the solution, we

noticed that the enthalpy values (∆H) decrease with their positive with increase in the initial

concentration of the food coloring dyes within the temperature range used. In addition,

increasing, the concentration of food coloring dyes works to resist the mass transfer of the

adsorbed substance between the liquid and solid phase and the enthalpy values appears from

the strength of the bonding of the adsorbed molecules to the surface, the amount of energy

required to recover the adsorbed substance from the surface and the type adsorption.[35, 36]

The enthalpy values(∆H) decrease with increase of dyes concentration, in other words, a

decrease in the value of energy absorbed by the adsorption system, this mean decrease in the

number of food coloring dyes molecules allowed to transition from the solution to the

surface. At it is known that increasing the food coloring dye in the solution leads to the

closeness of the molecules to each other, which in itself is a large molecule that contains

aromatic rings and different active groups depending on the type of dye, as will as, the effect

of the solvent. In this research the system of adsorption, it is basically an endothermic and

accordingly, the number of food dye molecules that have the ability to overcome those

interaction or have more freedom of movement than other and the temperature used are the

ones that have opportunity to move from the solution and adsorption on the surface of

activated carbon. As the concentration increases, the number of molecules absorbing energy

decrease for adsorption system, because of this, the absorbed energy will decrease steadily .

The results of effect the concentration on the enthalpy values listed in table (4,5,6)for some

food coloring dyes. It is also notice from the results in table (4,5,6), that increasing the

concentration of food coloring dyes leads to a degrease in the values of the equilibrium

constant when the temperature is constant, while the values of (∆G°) decreases it is negative

values, with in creasing concentration to convert in to a positive values at the highest

concentration due to a degrease in spontaneous adsorption.

So the adsorbed energy decreases within the temperature range used and this leads to a

decrease in the amount of food coloring dyes adsorbed on the surface and that’s a decrease in

adsorption efficiency. At a constant concentration and a certain temperature range, the high

energy absorbed is accompanied by a high adsorption efficiency. The positive enthalpy

indicate the occurrence of an sorption within the adsorption process to the inner micro- pores


2214


of activated carbon , and this requires additional external energy to be received by adsorption

system.

The negative values of (∆Gº) which listed in Table (3) indicated the spontaneity and

feasibility of adsorption of food coloring dyes on the surface of activated carbon.

Increasing the temperature of the food coloring dyes solution at constant concentration leads

to an increase in the negative value of the Gibbs free energy, meaning an increase in its

spontaneous adsorption from solution to the surface with an increase in temperature, because

the process of its adsorption is endothermic. In this type of adsorption system, the thermal

energy added to this system is also useful in removing molecular interactions between the

food coloring molecules and the surface, because the predominate values of (∆Gº) are less

than (-2.705 kJ/mole).[37]

and inductive that the physical adsorption is prenominal in the

sorption process, as well as, this values refers to that the energy of adsorption process for

food coloring dyes are less than liberation of the previously adsorbed water.

In the sorption system, the (∆Gº) is the driving force, as will as, the basic criterion for the

spontaneous realization of the sorption. In any case, some food coloring dyes showed a

difference in the values of (∆Gº) from the other food coloring dyes under study, such as

(E123) and (E127) dyes, where the values of (∆Gº) had less than (1 kJ/mole) and the positive

value decreased with increase in temperature, meaning it is shift towards spontaneity. Also

(E110) dye had positive values of (∆Gº) at the highest concentration, with the temperature

range used. This indication thermodynamically unfavorable and non spontaneous adsorption

process as is not self-evident, as well as, the driving force is important to manning adsorption

possible. The small positive value of (∆Gº) for (E110) dye difficult to tell us if the sorption

process occurred spontaneously, and we can say the adsorption of (E110) dye take place and

close to spontaneous process. This conclusion indicated by the value of (∆H) at (45 cº) at the

same concentration, while the (∆Gº) values for (E123) and (E127) dyes coloring are very

small even under normal condition it seems that at low concentration the values for it

converted from non spontaneous to spontaneous process with increasing of temperature, but

at other high concentration the (∆Gº) obtained positively at all temperatures, but decreased

with increasing of temperatures by means close to spontaneous adsorption process.

Thermodynamically the entropy (∆S) represent the degree of random (non-regularity) in

adsorption process for adsorbed molecules and refers to the adsorption system condition

resulting from the binding of food coloring dye molecules to the surface of activated carbon .


2215


The results obtained for entropy values (∆Sº, ∆S) are presented in table (3), the positive

values for entropy parameters of the adsorption of food coloring dyes on activated carbon

give evidence of irregularity during adsorption process between the solid-solution interface.

The (∆Sº) values refers to random for adsorption process at any step of adsorption, it has

positive values that are close to each other and depend on the nature of the dye. The

convergence in the values of (∆Sº) and its stability with increasing temperature and within the

studied range, supports the fact that the adsorption system is of physical nature, it refers to the

increase in randomness on the surface of activated carbon and the interactions in the food

coloring dye solution during the adsorption process, and this significant of increasing

freedom degree for adsorbed dye molecules, which dose not suffer obstruction on the surface

of activated carbon, and all this confirms the predominate of physical adsorption for food

coloring dyes. This statement supports by the lower values of (∆Gº). Finally, the change of

entropy has an important role in the process of adsorption, the (∆Sº) value had been estimated

to be so large which indicated an increase of entropy as a result of adsorption .Before

adsorption, the molecules of dyes near the adsorbent surface were in ordered from than in

subsequent adsorption state and the ratio of free dye molecular to the interacting dye

molecular with the adsorbent will be higher than in the adsorbed state. The distribution and

translational energy will increase with increasing adsorption by giving a positive entropy

value, at high temperature the adsorption is likely to occurs spontaneously because the (∆H)

and (∆Sº) value more than zero value.

Table 4: Effect of concentration on the thermodynamic parameters at optimum

Condition and Different temperatures for the adsorption of (E110) dye.

∆S

J/mole.k0

∆S0

J/mole.k0

∆G0

kJ/mole

R2

∆H

kJ/mole

kc T k0

C0 mg/

L

129.752 141.822 -3.597 0.9956 38.666 4.272 298 9.047

127.611 141.419 -4.184 5.265 303

125.539 141.552 -4.932 6.860 308

123.534 141.850 -5.733 9.052 313

121.591 142.060 -6.509 11.724 318

110.138 117.903 -2.314 0.9527 32.821 2.545 298 18.095

108.320 117.366 -2.741 2.967 303

106.562 118.893 -3.798 4.405 308

104.859 117.706 -4.021 4.690 313

103.211 118.151 -4.751 6.030 318

63.819 65.738 -0.572 0.9107 19.018 1.260 298 27.142

62.766 67.132 -1.323 1.691 303

61.747 66.445 -1.447 1.760 308


2216


60.760 66.738 -1.871 2.052 313

66.107 66.107 -2.004 2.133 318

52.047 51.490 +0.166 0.9717 15.510 0.935 298 36.190

51.188 52.429 -0.259 1.109 303

50.357 51.370 -0.312 1.130 308

49.553 51.780 -0.697 1.306 313

48.774 51.783 -0.957 1.436 318

42.607 39.829 +0.828 0.9753 12.697 0.716 298 45.237

42.904 39.752 +0.652 0.772 303

41.224 40.068 +0.356 0.870 308

40.565 40.125 +0.138 0.948 313

39.928 39.786 +0.045 0.983 318


condition and different temperatures for the adsorption of (E133) dye.

∆S

J/mole.k0

∆S0

J/mole.k0

∆G0

kJ/mole

R2

∆H

kJ/mole

kc T k0

C0 mg/

L

141.507 151.168 -2.879 0.9817 42.169 3.196 298 1.586

139.172 151.475 -3.728 4.395 303

136.912 152.185 -4.704 6.275 308

134.725 151.163 -5.145 7.218 313

132.607 151.830 -6.113 10.091 318

104.631 113.020 -2.500 0.9413 31.180 2.744 298 3.171

102.904 114.370 -3.474 3.970 303

101.234 114.146 -3.977 4.724 308

99.617 112.984 -4.184 4.994 313

98.050 114.072 -5.095 6.868 318

87.403 93.698 -1.876 0.9486 26.046 2.132 298 4.757

85.960 96.894 -3.313 3.724 303

84.565 95.834 -4.477 3.889 308

83.214 94.240 -3.451 3.766 313

81.906 96.796 -4.735 5.996 318

58.926 63.342 -1.316 0.9542 17.560 1.700 298 6.343

57.954 65.195 -2.194 2.390 303

57.013 65.510 -2.617 2.780 308

56.102 65.297 -2.878 3.022 313

55.220 66.969 -3.736 4.107 318

35.218 37.678 -0.733 0.9889 10.495 1.345 298 7.929

34.637 41.455 -2.066 2.270 303

34.075 41.565 -2.307 2.462 308

33.530 41.629 -2.535 2.649 313

33.003 41.509 -2.705 2.781 318


2217



condition and different temperatures for the adsorption of (E172) dye.

∆S

J/mole.k0

∆S0

J/mole.k0

∆G0

kJ/mole

R2

∆H

kJ/mole

kc T k0

C0 mg/

L

213.4634 210.2412 0.960222 0.9240 63.6121 0.678707 298 17.597

209.9409 208.1394 0.545856 0.805185 303

206.5328 207.3889 -0.26367 1.108456 308

203.2335 208.0008 -1.49214 1.774284 313

200.0381 211.1196 -3.52394 3.791946 318

200.797 193.9007 2.055086 0.9902 59.8375 0.436278 298 35.197

197.4835 192.7241 1.442105 0.564137 303

194.2776 192.1562 0.653384 0.774795 308

191.1741 192.2201 -0.32739 1.134065 313

188.1682 193.1414 -1.58148 1.818791 318

186.7302 176.5548 3.032266 0.9925 55.6456 0.294085 298 52.792

183.6488 175.7074 2.406259 0.384739 303

180.6675 175.3328 1.643092 0.526421 308

177.7815 175.339 0.764487 0.745444 313

174.9862 175.8004 -0.25892 1.102888 318

179.3228 165.4518 4.133574 0.9992 53.4382 0.188549 298 70.389

176.3637 165.5771 3.268344 0.27324 303

173.5006 165.6114 2.429892 0.387162 308

170.7291 165.7296 1.564837 0.548081 313

168.0447 165.9876 0.654131 0.780816 318

176.1339 159.4284 4.978247 1.000 52.4879 0.134079 298 87.986

173.2274 159.6712 4.107536 0.195826 303

170.4153 159.925 3.231008 0.283155 308

167.693 160.3599 2.295248 0.413948 313

165.0563 161.1474 1.243011 0.624908 318

The all values of (∆S) are positive at all concentration in a range of temperature used , which

calculated at equilibrium state, and its values less than (∆Sº) values, this a clear confirmed

indication that the adsorption system of food coloring dyes on activated carbon is less regular

when the adsorption process reaches at equilibrium state compare to the other steps that this

process goes through. We note that the values of (∆S) gradually decrease with increasing

temperature in all concentration, This means that increasing the temperature at constant

concentration reduces the random of the adsorption system and that the food coloring dyes

molecules are more regular in the solution compare to their regularity on the surface of

activated carbon.

The (∆Sº, ∆S) values decreased with increasing the concentration of dyes in solution with the

range of temperatures used, this means decrease the random in the adsorption system,


2218


because of decreasing in the number of adsorbed molecules on the activated carbon surface,

this is clear from the efficiency of adsorption.

The same applies to the rest of the food coloring dyes (E122,102,124,1232).

2. Calculation of thermodynamic parameters using Langmuir and Freundlich constants

Langmuir and Freundlich constants can be used to calculate the thermodynamic parameters

for adsorption process of food coloring dyes on activated carbon surface as are suitable,

Therefore, Langmuir constant is considered as an equilibrium constant calculated at a range

of concentration, and the same range of temperature to calculate the equilibrium constant.

The apparent thermodynamic function calculated from Langmuir and Freundlich constants

were estimates in the some range of concentration and temperature used to calculate the

equilibrium constants from which the thermodynamic function were calculated where the

equilibrium constant represents the ratio between the amount of the dye adsorbed and remain

in the solution at different concentration, as well as, all results are tabulated in table (7) for

food coloring dyes. Also the Langmuir (kL) and Freundlich (kf) is calculated from the

following relationship:

kL = Qmax x b …………….13

Where :

Qmax = maximum capacity of adsorption for adsorbent substance

(mg of adsorbent substance/gm of the solid adsorbent substance)

b = Langmuir constant (L / mg), which have relation with adsorption energy.

The values of both Q and b were calculated from plotting the linear relationship between Ce

versus Ce/ qe

Q = 1 / slope, intercepts = 1/ (Q* b)

When using Vant- Hoff equation to express the Langmuir constant (kL) as an equilibrium

constant, we get the following relationship :

Ln kL = (-∆H / RT) + X ………….14

Where

X= constant.

When drawing the relation between ln kL versus 1 / T , we get a liner relationship through

which the enthalpy (∆H) value can be calculated from the slope of the straight line from

drawing the (ln kL) verse (1/T) as the following equation(14), then (∆Gº, ∆Sº∆S) values are

calculated after that(equation 3,10,11,12), and in the same way the thermodynamic


2219


parameters are calculated from Freundlich constants (kf), when it is considered as an

equilibrium constant and then the thermodynamic parameters are obtained for adsorption

process.

The value of enthalpy (∆H) is calculated from drawing the ln kf verse 1 / T from following

equation

Ln kf = (-∆H / RT) + X ………………15

The value of kf was calculated from the graph of the relationship between log qe versus log

Ce:

Intercepts = log kf

The apparent thermodynamic function calculated from Langmiar and Frendlich constant ,

were estaimeted in the same rang of concentration and temperature used to calculated the

equilibrium constants from which the thermodynamic function were calculated where the

equilibrium constant represents the ratio between the amount of the dye adsorbed and remain

in the solution at different concentration. All results are tabulated in table (7) for food

coloring dyes.

Table 7: Isotherm constants of the Langmuir and Freundlich models for adsorption of

food coloring (dyes at different temperatures and concentration.

Dye T kº kL R2 kf R

2

E110 298 4.174 0.9946 4.721 0.9553

303 5.665 0.9999 5.237 0.9474

308 7.078 0.9959 6.112 0.9117

313 8.354 0.9979 6.584 0.9500

318 10.474 0.9971 7.263 0.9343

E122 298 4.135 0.9316 5.030 0.9596

303 5.379 0.9864 5.554 0.9994

308 5.955 0.9866 5.583 0.9855

313 6.614 0.9903 6.193 0.9904

318 8.078 0.9855 6.775 0.9610

E102 298 4.792 0.9980 6.578 0.8029

303 6.337 0.9989 8.498 0.9124

308 7.005 0.9840 9.296 0.9594

313 8.329 0.9933 10.486 0.9970

318 14.627 0.9883 11.912 0.9614

E133 298 6.663 0.9987 3.929 0.9786

303 9.539 0.9368 5.332 0.9650

308 11.623 0.9891 5.936 0.9897

313 12.728 0.9789 6.179 0.9983

318 18.112 0.9860 7.327 0.9714


2220


E123 298 4.3459 0.9838 5.0720 0.9302

303 4.8662 0.9868 5.509 0.9359

308 5.6306 0.9893 6.0954 0.9428

313 7.1276 0.9914 7.0632 0.520

318 10.2145 0.9916 8.8288 0.9670

E124 298 0.5388 0.9828 0.7718 0.9907

303 0.6859 0.9728 1.0914 0.9997

308 1.0019 0.9521 1.8344 0.9984

313 1.5019 0.8786 3.2931 0.9427

318 7.4239 0.9984 7.6243 0.9709

E127 298 0.9160 0.9981 2.0526 0.9718

303 1.1122 0.9935 2.4592 0.9263

308 1.5659 0.9940 3.3643 0.9081

313 2.0864 0.9996 4.3782 0.9533

318 3.9420 0.9912 6.7251 0.9886

The results show that the values of (kL) increase with increase in temperature and this

confirms the increase in the transfer of food coloring molecules from the solution and their

overcoming of the effective forces of adsorption on the surface of activated carbon leading an

increase in the values of the adsorption efficiency. Looking at table(8):

Table 8: Langmuir thermodynamic parameters for the adsorption of food coloring dyes

at different temperatures.

∆S J/mole.k0

∆S0 J/mole.k

0 ∆G

0

kJ/mole

R2

∆H

kJ/mole

T k0

Dye

113.047 124.926 -3.540 0.9898 33.688 298 E110

111.182 125.597 -4.368 303

109.377 125.646 -5.011 308

107.629 125.281 -5.525 313

105.937 125.465 -6.210 318

68.084 80.218 -3.516 0.9621 20.289 298 E122

66.960 80.954 -4.240 303

65.873 80.705 -4.568 308

64.821 80.527 -4.916 313

63.802 81.170 -5.523 318

140.443 153.470 -3.882 0.9678 41.852 298 E102

138.125 153.472 -4.650 303

135.883 152.071 -4.986 308

133.712 151.339 -5.517 313

131.610 153.915 -7.093 318

115.909 131.681 -4.700 0.9604 34.541 298 E133

114.000 132.746 -5.681 303

112.146 132.539 -6.281 308

110.355 131.504 -6.620 313

108.619 132.704 -7.659 318

105.5820 117.7974 -3.6401 0.9380 31.4635 298 E124


2221


103.8400 116.9953 -3.9861 303

102.1542 116.5226 -4.4255 308

100.5224 116.8508 -5.1108 313

98.9418 118.2620 -6.1438 318

171.6896 166.5481 1.5322 0.9844 51.1635 298 E123

168.8564 165.7219 0.9498 303

166.3453 166.1310 -0.0049 308

163.4617 166.8438 -1.0586 313

160.8915 177.5586 -5.3001 318

178.9295 178.2001 0.2174 0.9455 53.3210 298 E127

175.9769 176.8610 -0.2679 303

173.1201 176.8486 -1.1484 308

170.3546 176.4691 -1.9138 313

167.6761 179.0803 -3.6265 318

It is observed that the enthalpy have a positive value which refers to endothermic adsorption

of food coloring dyes on surface of activated carbon including sorption process is receiving

energy from adsorption system and the physical adsorption predominate, the range of (∆H)

values for food coloring dyes are between (20-53) kJ/mole .Figures (2A,B) represent the

drawing of (ln kL) constant values verses (1/ T) from Vant-Hoff equation in terms of

Langmuir constants, which Give a good relationship with a high correlation coefficient we

also noticed a convergence in the values of (∆Gº) calculated from the equilibrium constant

for adsorption process and the Langmuir constants, and they are similar to each other in terms

of increasing its negative values with an increase in temperature when the concentration is

constant , when checking the positive (∆Sº) and (∆S) values ,we noticed that the (∆S) values

are less than (∆Sº) meaning that the adsorption process at the equilibrium state is less random

than the other adsorption steps .The values of (∆S) decrease with increase of the temperature

and this confirms the decrease in the randomness of the adsorption system , because the

thermal energy that the adsorption process receives reduces the associations and interactions

of the food coloring dye molecules on the solution and increase its degree of freedom and it is

more regular at equilibrium state.


2222


A B

Figures 2: The relationship between (ln kL) with (1/ T) for the adsorption of food

coloring dyes onto activated carbon at different temperatures.

While the positive values of (∆Sº) fluctuate with increase or decrease with close values very

stable and within the temperature range used at any step of adsorption process and its little

change indicates the physical nature of adsorption and also indicates that the adsorption dyes

molecules are less regular on the surface of activated carbon because they are not in specific

sites and pores.

The application of (Vant- Hoff) equation on Freundlich constant(kf) gave a linear relationship

with a high correlation coefficient to get the value of the enthalpy of the adsorption process

and then calculation other thermodynamic function (∆Gº, ∆Sº, ∆S), figures (3A,B,C):

A B


2223


C

Figures 3: The relationship between (ln kf) with (1/ T) for the adsorption of food

coloring dyes onto activated carbon at different temperatures.

This relationship show where the results included in the table (7) indicate that the values of

(kf) increase with increasing of temperature , so the adsorption efficiency increases .Positive

(∆H) value within the range of temperature used confirms that the adsorption process is

endothermic and physical in nature(table 9) :

Table 9: Freundlich thermodynamic parameters for the adsorption of food coloring

dyes at different temperatures.

∆S J/mole.k0

∆S0 J/mole.k

0 ∆G

0

kJ/mole

R2

∆H

kJ/mole

T k0

Dye

55.225 68.128 -3.845 0.9850 16.457 298 E110

54.313 68.083 -4.172 303

53.432 68.481 -4.635 308

52.578 68.249 -4.905 313

51.752 68.239 -5.243 318

35.785 49.211 -4.001 0.9582 10.664 298 E122

35.195 49.452 -4.320 303

34.623 48.922 -4.404 308

34.407 49.227 -4.744 313

33.534 49.440 -5.058 318

71.107 86.772 -4.668 0.9700 21.190 298 E102

69.934 87.726 -5.391 303

68.799 87.338 -5.710 308

67.700 87.236 -6.115 313

66.635 87.236 -6.551 318

70.883 82.255 -3.389 0.9147 21.123 298 E133

69.713 83.630 -4.217 303

68.581 83.390 -4.561 308


2224


67.486 83.968 -4.739 313

66.425 82.987 -5.267 318

68.554 82.0541 -4.0229 0.9515 20.4292 298 E124

67.423 81.610 -4.2986 303

66.329 81.356 -4.6286 308

65.269 81.522 -5.0872 313

64.243 82.351 -5.7584 318

242.2164 240.0629 0.6418 0.9849 72.1805 298 E123

238.2195 238.9466 -0.2203 303

234.3523 239.3965 -1.554 308

230.6086 240.5175 -3.1015 313

226.9830 243.8713 -5.3706 318

149.0047 154.9834 -1.7816 0.9737 44.4034 298 E127

146.5459 154.0271 -2.2668 303

144.1669 154.2536 -3.1067 308

141.8639 154.1407 -3.8426 313

139.6333 155.4785 -5.0388 318

The values of (∆Gº) are few and negative, and its negative value increases with increasing

temperature and this confirms an increase in the spontaneous adsorption of food coloring

dyes on the surface of activated carbon (table 9) .The values of (∆Sº) are positive and close to

other ,this confirms that the food coloring dyes molecules in the solution are move regular

than they are on the surface and at any step of the adsorption process, because of the increase

in the number of adsorbed molecules on the surface and a decrease in their number in the

solution, these results are consistent with the values of thermodynamic parameters calculated

from the values of the equilibrium constant (table 9). When comparing the values of the

apparent thermodynamic function obtained from the Langmuir and Freundlich constants

calculated at different concentrations and temperature with those calculated from the

equilibrium constant, we arrived to the following conclusion:

1) The (∆H) value calculated from Langmuir and Freundlich constants are positive too, the

(∆H) value calculated from Langmuir constant close to values of (∆H) calculated from

equilibrium constant at The lower concentration (dilute solution), this refers to agreement

between two methods, while the (∆H) calculated from Freundlich constant was less than

that. In away, it can be said that those is confirming that the adsorption process is

endothermic and physical in nature.

2) When comparing the (∆Gº, ∆Sº, ∆S) values of all food coloring dyes with those

calculated from the Langmuir and Freundlich constants, we notice in general a clear

agreement between them, despite, the presence some slight discrepancy in the values with


2225


increase or decrease in some dyes, but it a achieves the desired purpose of calculating it,

as well as, being realistic to significant and reliable in describing the adsorption system.

REFERENCES

1. Zheng, Y. M., Zhao, Q. B., Yung, H. I., Adsorption of Cationic dye onto aerobic

granules, proc. Biochem, 2005; 3777-3782.

2. Ndifor-Angwafor et al., J. Mater. Environ. Sci, 2017; 8 (12): 4199-4212.

3. A. Mittal et al. Journal of Hazardaus Materials, 2007; (146): 243-248.

4. Saad A. Alkahtani et al. Interational Journal of Food and Allied Sciences, 2017; 3(1):

10-19

5. M. Safarikova, L. Ptackova, I. Kibrikova and I. Safarik, Chemosphere, 2005; (59): 831.

6. Khatri, A., Peerzada, M. H., Mohsin, M., & White, M. “A review on developments in

dyeing cotton fabrics with reactive dyes for reducing effluent pollution”. Journal of

Cleaner production, 2015; (87): 50- 57.

7. Santos, S. C., Oliveira, A. F., & Boaventura, R. A. Bentonitic. “clay as adsorbent for the

decolourisation of dyehouse effluents”. Journal of cleaner production, 2016; (126):

667- 676.

8. Copaciu, F., Opris, O., Coman, V., Ristoiu, D., Niinemets, Ü., & Copolovici, L“ . Diffuse

water pollution by anthraquinone and azo dyes in environment importantly alters foliage

volatiles”, carotenoids and physiology in wheat (Triticum aestivum). Water, Air, & Soil

pollution, 2013; 224 (3): 1478.

9. Hamzah, M. A. M., Jebur, I. K., & Ahmed, A. K. Synthesis,“ Characterization and

Biological Activity Evaluation of Some New Azo Derivatives from 2- Amino

Benzothiazole and Their Derivatives”. Kirkuk university journal for scientific studies,

2018; 13(1): 212-227.

10. Stawinski, W., Wegrzyn, A., Fritas, O., chmielarz, L., Mordarski, G., and gueiredo, S.,

“Simultaneous removal of dyes and metal cations using an acid, acid-base and base

modified vermiculite as a ustainable and recyclable adsorbent”, Science of the total

Environment, 2017; (576): 398- 408.

11. DiCesare, N., & Lakowicz, J. R. “New color chemosensors for monosaccharides based on

Azo dyes”. Organic letters, 2001; 3(24): 3891- 3893.

12. Yamjala, K., Nainar, M. S., & Ramisetti, N. R..“ Methods for the analysis of azo dyes

employed in food industry- a review”. Food chemistry, 2016; (192): 813- 824.

13. I.G.Laing Rev.Prog. Coloration, 1991; (21): 56


2226


14. P. A. Meginn, J. state of world, 2002.

15. J. Ren, Q. Zho, D. D. Goe, L. Tao, M. W. Zhang., Advanced Materials Research, 2015;

1065-1069, 1867-1870.

16. Ira N., physical chemistry, 2002; 5.

17. Schiewer S. and Volesky, B. Env. Micr.- Metal interaction. Washington, ASM press,

2000; 329.

18. K. E. Noll, G. Vassilios, W. S. Hou, Adsorption Technology for air and water pollution

control, Lewis Publishers, Chelsea, MI, USA, 1992.

19. Liang, T. W., Huang, C.T., Dzung, N.A., Wang, S. L. Squid pen chitin chitoolugomers as

food colorants absorbers. Mar Drugs, 2015; (13): 681-96.

20. Abdel- Aziz HM, Abdel-Gawad SA. Removal of sunset yellow Azo dye using activated

carbon entrapped in alginate from aqueous solutions. Open Access Journal of science,

2020; 4(1): 1-6.

21. P. W. Atkins., (physical chemistry), Oxford university press, Oxford, 2006.

22. G. M. Barrow (physical chemistry) Mc. Graw-Hill, Inc. New York, 1988; 418-424.

23. D. Basmadjian, (The litte Adsorption Book), London university, London, 1996; 336-372.

24. Hema M., Arivoli S., J. Appl. Sci. Environ. Manage. March, 2008; 12(1): 43-51.

25. Sushmita B., Chattopadhyaya M.C., Arabian Journal of chemistry, 2017; (10):

S1629-S1638.

26. S. Knaebel Kent, (Adsorbent selection), Adsorption Research, Inc., Dublin Ohio, 2003;

43016: 1-23.

27. Ademoriyo Co, et al., J.Biomed Res Environ Sci, Sep., 2020; 23, 6(9): 163-172.

28. Fu, J, Chen Z., Wang, M., Liu, S., Zhang, J., Zhang, J., and Xu Q. Adsorption of

methylene blue by a high-efficiency adsorbent (polydopamine microspheres): Kinetics,

isotherm, thermodynamics and mechanism analysis. Chemical Engineering Journal, 2015;

(259): 53-61.

29. Jyotirmoy, Shkh. M. “Adsorption of substituted benzoic acid on to surface in mixed-

adsorbate mode 1, 2,4- dihydroxy benzoic acid -2,6- dihydroxy benzoic acid and 1,2,4-

benzene tri carboxy acid ” . J. Environmental chemical engineering, 2017; 5(3):

2976-2985.

30. Xiaofeng. J, Wenxue. Z, Shicheng. Z, Yao, Shi and Zhorgxin, “Effects of benzoic acid

and surface modified alumina nanoparticles on the mechanical properties and

crystallization behavior of isotatic polypropylene nano composites ”royl Society of

Chemistry RSC adv, 2018; 8: 20790.

https://www.sciencedirect.com/journal/chemical-engineering-journal


2227


31. Seo Young Yoon, Chang Gu Lee, Jeong Ann Park, Jae Hyun Kim, Song Bae Kim, Sang

Hyup Lee, Jae Woo Choi, Kinetic, equilibrium and thermodynamic studies for phosphate

adsorption to magnetic iron oxide nanoparticles, 2014; (6): 341-347.

32. Bedin, K. C., Martins, A. C., Cazetta, A. L., Pezoti, O., & Almeida, V. C., KOH-activated

carbon prepared from sucrose spherical carbon: Adsorption equilibrium, kinetic and

thermodynamic studies for Methylene Blue removal. Chemical Engineering Journal,

2016; (286): 476-484.

33. Khaleel, I. A., Feda, H. M., & Ammar, A. H. Experimental and Theoretical Study of The

Adsorption Behavior and Electrical properties For Some Substituted Benzoic Acid And

The Complexation Surface Model From Electrical Conductivity. Journal of university of

Anbar for Pure science, 2018; 12(3).

34. Pimentel, G. C., and Mecellellan, The Hydrogen Bond. Freeman W.H.San Francusco,

1960; 169-195.

35. AL-Niemi, K. I. , Mechanism, Kinetic and Thermodynamic For Transport of Citric Acid

Ions To Removal By Adsorption Using Electrical Conductivity, Potential Difference And

Acidity Function. JOURNAL OF EDUCATION AND SCIENCE, 2019; 28(2): 85-102.

36. Michael. H. J, Ayebeami. Electronic. I, Spiff, Electronic Journal of Biotechnology, 2003;

8(2): 162-169.

37. Alniemi, K. I., Calculation Values of potential Stickiness (S*) and Apparent Activation

Energy (AAE) from Adsorption of Some Aromatic Carboxylic Acids on the Surface of a

New Adsorbent Substance. JOURNAL OF EDUCATION AND SCIENCE, 2020; 29(4):

76-89.

the rmodynamic study of the adsorption of (e110, 122, …

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