PROJECT REPORT

on

Kinetics of adsorptive Removal of CBSOL Red LE Dye on to Activated Carbon

Submitted in partial fulfillment of the requirement for the award of

degree of

Bachelor of Engineering

in

Chemical Engineering

SUBMITTED BY

Ashwini kumar prince

(ROLL No.-101181001)

Under the guidance

of

Dr. J. P. Kushwaha (Assistant Professor)

Department of Chemical Engineering Thapar University, Patiala

Department of chemical engineering

Thapar University, Patiala Patiala (Punjab)-147004

January, 2014

CERTIFICATE

This is to certify that the project report entitled Kinetics of adsorptive Removal of CBSOL

Red LE Dye on to Activated Carbon, is an authentic record of my own work carried out as requirements for the award of degree of B.E. in Chemical Engineering from Thapar University,

Patiala, under the supervision of Dr. J. P. Kushwaha, Assistant Professor, Department of

Chemical Engineering, Thapar University, Patiala, during July 2013 to January 2014.

Date: _____________ Ashwini Kumar Prince

(Roll No: 101181001)

It is certified that the above statement made by the student is correct to the best of our

knowledge and belief.

Dr. J.P. Kushwaha Assistant Professor Department of Chemical Engineering Thapar University, Patiala

Countersigned by: Dr. Rajeev Mehta Associate professor and HeadDepartment of Chemical Engineering Thapar University, Patiala, Punjab

ABSTRACT

Adsorption of CBSOL Red LE dye on granular activated carbon (GAC) from

aqueous solutions was studied. The potential for the adsorption of CBSOL RED LE dye at a

fixed initial concentration of 100 ppm and 50 ppm on GAC was carried out, and kinetic

study was conducted at optimized set of operational parameters like pH, time and adsorbent

dose. The kinetics of adsorption of CBSOL RED LE dye from aqueous solution onto

activated carbon has been investigated. The time dependent studies showed a rapid

adsorption in the initial time. A batch sorption model based on the assumption of the pseudo

first and second order mechanism, were applied to predict the rate constants. The adsorption

process follows the pseudo-second order kinetic, having a correlation coefficient 0.99. The

pseudo second order rate constant ks was found to generally increase from 0.012 to 0.018 as

the initial concentration increased from 50 to 100 ppm. In case of pseudo-first order kinetic

the value of kf also increases from 0.021 to 0.035 as the initial concentration increased from

50 to 100 ppm.

ACKNOWLEDGEMENT

I would like to make my deepest appreciation and gratitude to Dr. J. P. Kushwaha for

his valuable guidance, constructive criticism and encouragement during every stage of this

project.

I am accreted to offer my thanks to the department of chemical engineering, Thapar

University, Patiala for allowing my training under the sincere guidance of tentative faculty

members

I am grateful to Dr. Rajeev Mehta , Head of the Department, Chemical

Engineering for providing me the necessary opportunities for the completion of my

project. I also thank other staff members of my department for their invaluable help and

guidance.

(Ashwini kumar Prince)

CONTENTS S. No. Particulars Page Number

1 INTRODUCTION 1

1.1 Industrial impacts on water 1 1.2 Characteristics and applications of reactive dye 1

1.3 Methods of removal of reactive dye 5

1.4 Activated carbon 6

1.5 Adsorption versus other methods 9

1.6 Objective 11

2 LITERATURE VEIW 12

3 MATERIALS AND METHODS 30

3.1 Waste water 30

3.2 Analytical methods 30

3.3 Experimental programme 31

3.4 Kinetics of adsorption 31

4 RESULTS AND DISCUSSIONS 33

4.1 Adsorption experiment 33

5 CONCLUSION 36

6 REFERENCES 37

1

1 INTRODUCTION

1.1 General Rrapid development has improved the standard of living and quality of life for millions of

peoples the world over. This development has come at the cost of a thirty-fold increase in the

use of fossil fuels and a fifty-fold increase in industrial production over the 2 past centuries.

As a result, significant amounts of existing natural resources have been consumed by

industry, leaving the earth depleted for future generations. The requirement of fresh water for

industrial use will increase from 30 BCM (Billion Cubic Meters) to 120 BCM by 2025 AD

[1]. Much of the waste produced from these activities is directly discharged into natural

water bodies. One of the major challenges facing mankind today is to provide clean water

around the world.

1.2 Characteristics and application of reactive dye

1.2.1 Properties of Reactive Dye:

1. Reactive dyes are cationic dyes, which are used for dyeing cellulose, protein and

polyamide fibres.

2. Reactive dyes are found in power, liquid and print paste form.

3. During dyeing the reactive group of this dye forms covalent bond with fibre polymer and

becomes an integral parts of the fibre.

4. Reactive dyes are soluble in water.

5. They have very good light fastness with rating about 6. The dyes have very stable

electron arrangement and can protect the degrading effect of ultra-violet ray.

6. Textile materials dyed with reactive dyes have very good wash fastness with rating about

4-5 due to strong covalent bonds formed between fibre polymer and reactive group of

dye.

7. Reactive dye gives brighter shades and has moderate rubbing fastness.

8. Dyeing method of reactive dyes is easy. It requires less time and low temperature for

dyeing.

9. Reactive dyes are comparatively cheap.

10. Reactive dyes have good perspiration fastness with rating 4-5. Reactive dyes have good

perspiration fastness [2].

2

1.2.2 Composition of reactive dye

Various chemicals are used in dyeing with reactive type dyes. These chemicals and their uses are

as follows.

Dye Fixer: Dye fixer is a chemical called sodium carbonate. The fixer is the one chemical you absolutely must have to make these dyes work. Fixer causes the important

chemical reaction that makes these dyes become part of the fabric. In direct application

dyeing such as tie dyeing, the fabric is first soaked in a solution of dye fixer dissolved in

water. In vat dyeing, solid color dyeing, the dye fixer is added to the dye bath near the

end of the dyeing process. In tie dyeing, we estimate that one pound of dye fixer will

make approximately 20 adult T-shirts. A 5 pound bag will make approximately 100 T-

shirts. In solid color dyeing, one pound fixer will color about 6 pounds of dry fabric.

Urea: Urea is used in tie dyeing or other direct application dyeing. It is generally not used in Vat (solid color) dyeing. Urea does many things to help the dyeing process. Urea

helps large amounts of dye dissolve in small amounts of water. Urea helps the dye

penetrate the fabric. Moisture is an important component of the chemical reaction process

with these dyes, and urea helps draw moisture to the chemical reaction. We estimate that

on pound of urea will tie dye about 16 to 18 T-shirts. 5 pounds of urea will therefore tie

dye about 80 shirts.

Ludigol: Ludigol is used in tie dyeing or other direct application dyeing. It is generally not used in Vat dyeing. Once reactive dye is mixed with water, it slowly starts to break

down in the water. When this happens, over time the dye becomes less effective. Soon

the dye solution will lose all effectiveness. Ludigol is added to the dye to keep the dye

from reacting with, or breaking down in the water. It keeps the dye fresher longer, and

allows more dye to react with the fabric. Helping the colors to come out brighter. We

estimate that 2 ounces of ludigol with tie dye about 60 T-shirts. Therefore, an 8 ounce

bag should dye around 240 T-shirts.

Water Softener: Dyes work better in soft water. Water softener is used in both tie dye and solid color dyeing. One 8 ounce bag of water softener will tie dye approximately 160

shirts.

3

Sodium alginate: Sodium alginate is used to thicken dye mixtures for hand painting and silk screening. Most of our customers do not use sodium alginate unless they have a

specific reason that they want thicker dye mixtures. Two ounces of our sodium alginate

will thicken about 8 quarts of water to a hand painting consistency.

Synthrapol detergent: Synthrapol detergent is used to wash out loose dye after the fabric is dyed. Synthrapol is used to wash out different colored dyes, as in tie dyes and

keep those dyes from staining other parts of the fabric. Using Synthrapol is the best way

to ensure that your colors will stay pure during wash out, and that your white areas will

remain relatively white. One 16 ounce bottle of synthrapol will wash 8 to 24 wash loads

[3].

1.2.3 General structure of reactive dye

The general structure of reactive dye is: D-B-G-X.

Here,

D= dye part or chromogen (color producing part)

Dyes may be direct, acid, disperse, premetallised dye etc.

B = bridging part.

Bridging part may be NH- group or NR- group.

G = reactive group bearing part.

X= reactive group.

4

Figure 1.1: Chemical structure of reactive dye [2]

1.2.4 USES OF DYE Rective dyes are used extensively in food, clothing, paints, plastics, etc.

dye in food One other class that describes the role of dyes, rather than their mode of use, is the food

dye. Because food dyes are classed as food additives, they are manufactured to a higher

standard than some industrial dyes. Food dyes can be direct, mordant and vat dyes, and

their use is strictly controlled by legislation. Many are azo dyes, although anthraquinone

and triphenylmethane compounds are used for colors such as green and blue. Some

naturally-occurring dyes are also used.

dye in painting of clothes Use PRO H-Reactive Dyes for Traditional Silk Painting with a resist. This technique can

also be used on Cotton, Linen and Rayon. We've found that H-Liquid Dye has an

improved flow property over powdered H Dyes, producing even fluid color.

dye in plastics reactive dye is used in dying of buckets ,bottels,households etc [4].

5

1.3 Methods for removal of reactive dye

The methodologies generally adopted to treat dye wastewater in four categories:

(i) physical

(ii) chemical

(iii) biological

(iv) accoustical, radiation, and electrical processes. Some of the methodologies lying in

above mentioned categories are discussed in brief in subsequent paragraphs.

Sedimentation is the basic form of primary treatment used at most municipal and industrial-wastewater treatment facilities (Cheremisinoff, 2002). There are a number of

process options available to enhance gravity settling of suspended particles, including

chemical flocculants, sedimentation basins, and clarifiers.

Filtration technology is an integral component of drinking water and wastewater treatment applications which includes microfiltration, ultrafiltration, nanofiltration, and

reverse osmosis. This has been investigated for colour removal

Chemical treatment of dye wastewater with a coagulating/flocculating agent (Shi et al., 2007, Wang et al., 2006a and Zhou et al., 2008) is one of the robust ways to remove

colour. The process involves adding agents, such as aluminum (Al3+), calcium (Ca2+) or

ferric (Fe3+) ions, to the dye effluent and induces flocculation.

Oxidation is a method by which wastewater is treated by using oxidizing agents. Generally, two forms viz. chemical oxidation and UV assisted oxidation using chlorine,

hydrogen peroxide, fenton's reagent, ozone, or potassium permanganate are used for

treating the effluents, especially those obtained from primary treatment (sedimentation).

They are among the most commonly used methods for decolourisation processes since

they require low quantities and short reaction times. They are used to partially or

completely degrade the dyes

Electrochemical methodology (Gupta et al., 2007b and Lin and Peng, 1994) as a tertiary treatment is also used to remove colour. Decolorisation can be achieved either by electro

oxidation with non-soluble anodes or by electro-coagulation using consumable materials.

Several anode materials, like iron, conducting polymer a boron doped diamond electrode

etc., with different experimental conditions, have been used successfully in the electro-

degradation of dyes

6

Biological treatment is the most common and widespread technique used in dye wastewater treatment (Barragan et al., 2007, Bromley-Challenor et al., 2000, dos Santos

et al., 2007, Frijters et al., 2006, van der Zee and Villaverde, 2005 and Zhang et al.,

1998). A large number of species have been used for decolouration and mineralization of

various dyes. The methodology offers considerable advantages like being relatively

inexpensive, having low running costs and the end products of complete mineralization

not being toxic. The process can be aerobic (in presence of oxygen), anaerobic (without

oxygen) or combined aerobicanaerobic [5].

1.4 Activated carbon

Activated carbon, is the oldest adsorbent known and is usually prepared from coal,

coconut shells, lignite, wood etc., using one ofthe two basic activation methods: physical and

chemical (Bansal et al., 1988 [6]; Carrott et al., 2003 [7]; Hassler, 1963 [8]; Lillo-Rodenas et

al.,2007 [9]; Phan et al., 2006 [10]). Generally, the physical activation requireshigh temperature

and longer activation time as compared tochemical activation, however, in chemical activation

the AC needa thorough washing due to the use of chemical agents. A schematicdiagram of the

process of producing activated carbons generallyadopted by workers is shown in Figure 1.2.

The product formed by either of the methods is known as activated carbon and normally

has a very porous structure with a large surface area ranging from 500 to 2000 m2 g_1 (Carrott et

al., 1991 [11]). It has been found that adsorption on activated carbon is not usually selective as it

occurs through van der Waals forces.

The ability of charcoal to remove odour and taste was recorded centuries ago. The

literature (Freeman, 1989; Tien, 1994 [12]) shows that according to a Sanskrit manuscript from

circa 200 BC, It is good to keep water in copper vessels, to expose it in sunlight and to filter it

through charcoal. However, the credit of developing commercial activated carbon (Smsek

and Cern_y, 1970 [13]) goes to Raphael von Ostrejko whose inventions were patented in 1900

and 1901.

7

Figure 1.2: Schematic diagram of the process of producing activated carbons generally adopted by workers

Source.

The applicability of activated carbon for water treatment has been demonstrated by

various workers (Stenzel, 1997 [14]; Weber Jr. et al., 1970 [15]). Besides these, various authors

(Bansal and Goyal, 2005 [16]; Hassler, 1963 [17]) have discussed and summarized in their book

the successful applications of activated carbons. Activated carbon is available in two main forms:

powdered activated carbon (PAC) and granular activated carbon (GAC). Most of the work on the

8

removal of pollutants from water has been on GAC, due to the fact that the granular form is more

adaptable to continuous contacting and there is no need to separate the carbon from the bulk

fluid.

On the other hand, the use of PAC presents some practical problems because of the

requirement to separate the adsorbent from the fluid after use. However, in spite of these

problems PAC is also used for wastewater treatment due to low capital cost and lesser contact

time requirement (Najm et al., 1991 [18]). Besides PAC and GAC two other forms of ACs are

also available, Activated Carbon Pellet and Activated Carbon Fiber (ACF). The pelletized

activated carbons are generally prepared from coal where coal is pulverized and reagglomerated

with suitable binder and then physically activated.These materials are made especially for use in

vapor applications. They are normally available in sizes of 1.5, 3 and 4 mm diameter. For ACF,

the carbon fibers are generally prepared from polymeric precursor materials such as

polyacrylonitrile(PAN), cellulose, pitch and polyvinylchloride; of these PAN based carbon fibers

pre-dominate and have good strength and modulus properties, whereas carbon fiber can be made

with a higher modulus, albeit a lower strength, using a pitch-based precursor.

These carbon fibers after activation using same methodology results in high surface area

carbons. The activated carbons which are used as adsorbents, not onlyremove different types of

dyes (Al-Degs et al., 2001[19]; DiGiano and Natter,1977 [20]; Pelekani and Snoeyink, 2000

[21]; Walker andWeatherley,1999 [22]), but also other organic and inorganic pollutants such as

metal ions (Carrott et al.,1998,1997 [23],[24]; Gabaldon et al., 2000 [25]; Kuennen et al.,1992

[26]; Macias-Garcia et al., 1993 [27]), phenols (Carrott et al., 2005 [28]; Caturla et al., 1988

[29]; Mourao et al., 2006 [30]; Paprowicz et al., 1990 [31]; Zogorski et al., 1976 [32]),

pesticides (Hu et al., 1998 [33]; Pirbazari et al., 1991 [34]; Pirbazari and Weber Jr., 1984 [35]),

chlorinated hydrocarbons (Urano et al., 1991 [36]), humic substances (Lee et al., 1983 [37]),

PCBs (Pirbazari et al., 1992 [38]), detergents (Bele et al., 1998 [39]; Malhas et al., 2002 [40]),

organic compounds which cause taste and odour (Flentje and Hager 1964 [41]; Lalezary et al.,

1986 [42]) and many other chemicals and organisms (Annesini et al., 1987 [43]; Carrott et al.,

2000 [44]; Donati et al., 1994 [45]; Giusti et al., 1974 [46]; McKay et al., 1985a [47]; Najm et

al., 1993 [48]; Saito, 1984 [49]; Smith,1991 [50]). It is well known that adsorption by activated

carbon is an effective and commercially applicable method for removing colour and other

pollutants from textile and dye wastes.

9

Studies have shown that activated carbons are good materials for the removal of different

types of dyes in general but there use is sometimes restricted in view of higher cost. Also, the

activated carbons after their use (treatment of wastewater) become exhausted and are no longer

capable of further adsorbing the dyes. Once AC has been exhausted, it has to be regenerated for

further use in purifying water and a number of methods like thermal, chemical, oxidation,

electrochemical (Freeman, 1989 [51]; Hemphill et al., 1977 [52]; Kilduff and King, 1997 [53];

Martin and Ng, 1987 [54]; Narbaitz and Cen, 1994 [55]; Newcombe and Drikas, 1993 [56];

Notthakum et al., 1993 [57]; Rollar et al., 1982 [58]; Taiwo and Adesina, 2005 [59]; Zhou and

Lei, 2005 [60]) are used for this purpose, the most common being thermal. It is worthwhile

noting that regeneration of activated carbon adds cost, furthermore, any regeneration process

results in a loss of carbon and the regenerated product may have a slightly lower adsorption

capacity in comparison with the virgin activated carbon.

1.5 Adsorption Vs other methods

Among various water purification and recycling technologies, adsorption is a fast,

inexpensive and universal method. The development of low-cost adsorbents has led to the rapid

growth of research interests in this field. The present protocol describes salient features of

adsorption and details experimental methodologies for the development and characterization of

low-cost adsorbents, water treatment and recycling using adsorption technology including batch

processes and column operations. The protocol describes the development of inexpensive

adsorbents from waste materials, which takes only 12 days, and an adsorption process taking

15120 min for the removal of pollutants. The applications of batch and column processes are

discussed, along with suggestions to make this technology more popular and applicable.

10

Table 1.1: Adsorption capacity of various adsorbents.

Adsorbent Adsorption capacity (mg/g)

AC-Charcoal 101

AC Rice husk 50

Modified silica 45.8

Peat 12.7

Treated cotton 589

Bagasse pith(raw) 17.5

Wood 7-11.6

Pine sawdust (raw) 280.3

Activated sewage sludge 60.04

Activated clay 57.8

Banana pith 4.42

Coir pith (raw) 16.67

Activated bentonite 360.5

Coal 0.7691

Fly ash 0.7428

Rice husk carbon 86.9

Sawdust carbon 183.8

Pine sawdust (raw) 398.8

Orange peel (raw) 19.88

Lignite coal (raw) 30.9

Orange peel 20.5

Source: V.K. Gupta et al., 2009 [61]

\

11

1.6 Objective

To study the adsorption kinetics of CBSOL Red LE dye on Activated carbon from the

aqueous solution in batch study.

12

2 LITERATURE REVIEW

In this chapter, various adsorption studies of reactive dye on activated carbon have

been reviewed.

Vinod K. Gupta et al., (2007) studied the removal of Vertigo Blue 49 and Orange

DNA13 from aqueous solutions using carbon slurry developed from a waste material. Waste

material (carbon slurry), from fuel oil-based generators, was used as adsorbent for the removal of

two reactive dyes from synthetic textile wastewater. The study describes the results of batch

experiments on removal of Vertigo Blue 49 and Orange DNA13 from synthetic textile

wastewater onto activated carbon slurry. The utility of waste material in adsorbing reactive dyes

from aqueous solutions has been studied as a function of contact time, temperature, pH, and

initial dye concentrations by batch experiments. pH 7.0 was found suitable for maximum

removal of Vertigo Blue 49 and Orange DNA13. Dye adsorption capacities of carbon slurry for

the Vertigo Blue 49 and the Orange DNA13 were 11.57 and 4.54 mg g1 adsorbent,

respectively. The adsorption isotherms for both dyes were better described by the Langmuir

isotherm. Thermodynamic treatment of adsorption data showed an exothermic nature of

adsorption with both dyes. The dye uptake process was found to follow second-order kinetics

[62].

S. Nethaji et al., (2011) studied adsorptive removal of an acid dye by lignocellulosic

waste biomass activated carbon. Chemically prepared activated carbon material derived from

palm flower was used as adsorbent for removal of Amido Black dye in aqueous solution. Batch

adsorption studies were performed for the removal of Amido Black 10B (AB10B), a di-azo acid

dye from aqueous solutions by varying the parameters like initial solution pH, adsorbent dosage,

initial dye concentration and temperature with three different particle sizes such as 100 m,

600 m and 1000 m. The zero point charge was pH 2.5 and the maximum adsorption occurred

at the pH 2.3. Experimental data were analyzed by model equations such as Langmuir,

Freundlich and Temkin isotherms and it was found that the Freundlich isotherm model best fitted

the adsorption data and the Freundlich constants varied from (KF) 1.214, 1.077 and 0.884 for the

three mesh sizes. Thermodynamic parameters such as G, H and S were also calculated for

the adsorption processes and found that the adsorption process is feasible and it was the

endothermic reaction. Adsorption kinetics was determined using pseudo first-order, pseudo

13

second-order rate equations and also Elovich model and intraparticle diffusion models. The

results clearly showed that the adsorption of AB10B onto lignocellulosic waste biomass from

palm flower (LCBPF) followed pseudo second-order model, and the pseudo second-order rate

constants varied from 0.059 to 0.006 (g mg1 min) by varying initial adsorbate concentration

from 25 mg L1to 100 mg L1. Analysis of the adsorption data confirmed that the adsorption

process not only followed intraparticle diffusion but also by the film diffusion mechanism [63].

Liang-Gui Wang et al ., (2011) investigated the adsorptive removal of direct yellow

161dye from aqueous solution using bamboo charcoals activated with different chemicals. The

adsorption of direct yellow 161 dye from aqueous solution on derived bamboo charcoals

activated with orthophosphoric acid, nitric acid, potassium hydroxide and zinc chloride was

investigated. Batch adsorption results showed that under optimal sorption condition including

initial dye concentration 24.62 mg/L, pH 1.0, contact time 21 h, and temperature 298 k the

maximum and the minimum adsorption capacities were 2.401 mg/g and 1.705 mg/g for bamboo

charcoals activated with orthophosphoric acid and with potassium hydroxide, respectively.

Avrami kinetic model provided the best fit to experimental data compared with Elovich, pseudo-

first-order, pseudo-second-order and intra-particle diffusion models. Fitting of the equilibrium

data using Langmuir, Freundlich, Jovanovic, Khan and Koble-Corrigan isotherm models

indicated that Koble-Corrigan model was the best and three-parameter models gave better fitting

than two-parameter models did. Thermodynamic parameters revealed that the adsorption process

was spontaneous and endothermic with a physical nature. Compared with the other activated

bamboo charcoals the bamboo charcoal activated with orthophosphoric acid was the best

adsorbent for removal of direct yellow 161 dye [64].

Attouti Salima et al.,(2013) studied application of Ulva lactuca and Systoceira

stricta algae-based activated carbons to hazardous cationic dyes removal from industrial

effluents. Marine algae Ulva lactuca (ULV-AC) and Systoceira stricta (SYS-AC) based

activated carbons were investigated as potential adsorbents for the removal of hazardous cationic

dyes. Both algae were surface oxidised by phosphoric acid for 2 and subsequently air activated at

600 C for 3 h. Dyes adsorption parameters such as solution pH, contact time, carbon dosage,

temperature and ionic strength were measured in batch experiments. Adsorption capacities of

400 and 526 mg/g for Malachite green and Safranine O by the SYS-AC and ULV-AC

respectively were significantly enhanced by the chemical treatments. Model equations such as

14

Langmuir, Freundlich and Temkin isotherms were used to analyse the adsorption equilibrium

data and the best fits to the experimental data were provided by the first two isotherm models.

BET, FT-IR, iodine number and methylene blue index determination were also performed to

characterize the adsorbents. To describe the adsorption mechanism, kinetic models such as

pseudo-second-order and the intra particle diffusion were applied. Thermodynamic analysis of

the adsorption processes of both dyes confirms their spontaneity and endothermicity. Increasing

solution ionic strength increased significantly the adsorption of Safranine O. This study shows

that surface modified algae can be an alternative to the commercially available adsorbents for

dyes removal from liquid effluents [65].

S. Senthilkumaar et al., (2006) studied the adsorption of dissolved Reactive red dye

from aqueous phase onto activated carbon prepared from agricultural waste. The adsorption of

Reactive red dye (RR) onto Coconut tree flower carbon (CFC) and Jute fibre carbon (JFC) from

aqueous solution was investigated. Adsorption studies were carried out at different initial dye

concentrations, initial solution pH and adsorbent doses. The kinetic studies were also conducted;

the adsorption of Reactive red onto CFC and JFC followed pseudosecond-order rate equation.

The effective diffusion coefficient was evaluated to establish the film diffusion mechanism.

Quantitative removal of Reactive red dye was achieved at strongly acidic conditions for both the

carbons studied. The adsorption isotherm data were fitted well to Langmuir isotherm and the

adsorption capacity were found to be 181.9 and 200 mg/g for CFC and JFC, respectively. The

overall rate of dye adsorption appeared to be controlled by chemisorption, in this case in

accordance with poor desorption studies [66].

Yahya S. Al-Degs et al., (2008) studied the effect of solution pH, ionic strength, and

temperature on adsorption behavior of reactive dyes on activated carbon. The adsorption

behavior of C.I. Reactive Blue 2, C.I. Reactive Red 4, and C.I. Reactive Yellow 2 from aqueous

solution onto activated carbon was investigated under various experimental conditions. The

adsorption capacity of activated carbon for reactive dyes was found to be relatively high. At pH

7.0 and 298 K, the maximum adsorption capacity for C.I. Reactive Blue 2, C.I. Reactive Yellow

2 and C.I. Reactive Red 4 dyes was found to be 0.27, 0.24, and 0.11 mmol/g, respectively. The

shape of the adsorption isotherms indicated an L2-type isotherm according to the Giles and

Smith classification. The experimental adsorption data showed good correlation with the

Langmuir and Ferundlich isotherm models. Further analysis indicated that the formation of a

15

complete monolayer was not achieved, with the fraction of surface coverage found to be 0.45,

0.42, and 0.22 for C.I. Reactive Blue 2, C.I. Reactive Yellow 2 and C.I. Reactive Red 4 dyes,

respectively. Experimental data indicated that the adsorption capacity of activated carbon for the

dyes was higher in acidic rather than in basic solutions, and further indicated that the removal of

dye increased with increase in the ionic strength of solution, this was attributed to aggregation of

reactive dyes in solution. Thermodynamic studies indicated that the adsorption of reactive dyes

onto activated carbon was an endothermic process. The adsorption enthalpy (Hads) for C.I.

Reactive Blue 2 and C.I. Reactive Yellow 2 dyes were calculated at 42.2 and 36.2 kJ/mol,

respectively. The negative values of free energy (Gads) determined for these systems indicated

that adsorption of reactive dyes was spontaneous at the temperatures under investigation (298

328 K) [67].

Fernando M. Machado et al., (2011) studied the adsorption of Reactive Red M-2BE

dye from water solutions by multi-walled carbon nanotubes and activated carbon. Multi-walled

carbon nanotubes and powdered activated carbon were used as adsorbents for the successful

removal of Reactive Red M-2BE textile dye from aqueous solutions. The adsorbents were

characterised by infrared spectroscopy, N2 adsorption/desorption isotherms and scanning

electron microscopy. The effects of pH, shaking time and temperature on adsorption capacity

were studied. In the acidic pH region (pH 2.0), the adsorption of the dye was favourable using

both adsorbents. The contact time to obtain equilibrium at 298 K was fixed at 1 h for both

adsorbents. The activation energy of the adsorption process was evaluated from 298 to 323 K for

both adsorbents. The Avrami fractional-order kinetic model provided the best fit to the

experimental data compared with pseudo-first-order or pseudo-second-order kinetic adsorption

models. For Reactive Red M-2BE dye, the equilibrium data were best fitted to the Liu isotherm

model. Simulated dye house effluents were used to check the applicability of the proposed

adsorbents for effluent treatment [68].

Gehan M. Nabil et al., (2013) studied the enhanced decolorization of reactive black 5

dye by active carbon sorbent-immobilized-cationic surfactant (AC-CS). Activated carbon-

immobilized-cationic surfactant (AC-CS) was designed to enhance the decolorization behavior

of reactive black 5 (RB5), as an anionic dye, from aqueous and industrial wastewater samples in

presence of various controlling experimental conditions. Experimental data indicated that the dye

adsorption capacity by (AC-CS) was higher in strongly acidic and basic solutions. An anion

16

exchange and ionion interaction mechanisms were proposed in the acidic solution, while only

anion exchange mechanism was suggested in the basic aqueous solution. The adsorption

behavior and thermodynamic parameters were also evaluated. Treatments of textile industrial

wastewater and real water samples were successfully established (95.23100.00%) [69].

Nevine Kamal Amin et al., (2008) studied the removal of reactive dye from aqueous

solutions by adsorption onto activated carbons prepared from sugarcane bagasse pith. Bagasse

pith, which is the main waste from sugarcane industry in Egypt, has been used as a raw material

for the preparation of different activated carbons. Activated carbons were prepared from bagasse

pith by chemical activation with 28% H3PO4 (AC1), 50% ZnCl2 (AC2) followed by pyrolysis at

600C and by physical activation at 600C in absence of air (AC3). Different activated carbons

have been used for the removal of reactive orange (RO) dye from aqueous solutions. Batch

adsorption experiments were performed as a function of initial dye concentration, contact time,

adsorbent dose and pH. Adsorption data were modeled using the Langmuir and Freundlich

adsorption isotherms. Adsorption kinetic data were tested using pseudo-first-order, pseudo-

second-order and intraparticle diffusion models. Kinetic studies showed that the adsorption

followed pseudo-second-order reaction with regard to the intraparticle diffusion rate [70].

K.Santhy et al., (2006) studied the removal of reactive dyes from wastewater by

adsorption on coir pith activated carbon. The removal efficiency of activated carbon prepared

from coir pith towards three highly used reactive dyes in textile industry was investigated. Batch

experiments showed that the adsorption of dyes increased with an increase in contact time and

carbon dose. Maximum decolorisation of all the dyes was observed at acidic pH. Adsorption of

dyes was found to follow the Freundlich model. Kinetic studies indicated that the adsorption

followed first order and the values of the Lagergren rate constants of the dyes were in the range

of 1.77 1022.69 102 min1. The column experiments using granular form of the carbon

(obtained by agglomeration with polyvinyl acetate) showed that adsorption efficiency increased

with an increase in bed depth and decrease of flow rate. The bed depth service time (BDST)

analysis carried out for the dyes indicated a linear relationship between bed depth and service

time. The exhausted carbon could be completely regenerated and put to repeated use by elution

with 1.0 M NaOH. The coir pith activated carbon was not only effective in removal of colour but

also significantly reduced COD levels of the textile wastewater [71].

17

Palanivel Sathishkumar et al ., (2012) studied the utilization of agro-industrial

waste Jatropha curcas pods as an activated carbon for the adsorption of reactive dye Remazol

Brilliant Blue R (RBBR) . Jatropha curcas is a non-edible oil crop predominately used to

produce biodiesel. J. curcas pod contains 80% as dried vegetable and remaining 20% are seeds

that are used for the biodiesel production in industries. In the present study, J. curcas pods were

used for activated carbon preparation and successfully employed as adsorbent for the removal of

reactive dye, Remazol Brilliant Blue R (RBBR). Batch adsorption experiments were performed

as a function of contact time, pH, adsorbent dosage and initial dye concentration. The

experimental results indicate that 0.2 g of activated carbon removed 95% of 50 mg L1dye.

Adsorption data were modeled using the Langmuir and Freundlich isotherms. Langmuir isotherm

was obeyed for the adsorption. Equilibrium parameter value (RL) was observed to be in the

range of 01. The dye adsorption followed the pseudo-first-order kinetics model with regard to

the intraparticle diffusion rate. Physico-chemical properties of activated carbon were analyzed by

SEM, FTIR and XRD before and after dye adsorption. The adsorbed dye from activated carbon

was successfully desorbed (80%) by 1 N NaOH. Bench scale removal of RBBR dye as well as

real textile effluent was carried out by J. curcas pods activated carbon (JCPAC). This option will

make the agro-industrial waste JCPAC adopted in textile industrial effluent treatment for

environmental cleansing [72].

A.A. Ahmad et al., (2010) studied the fixed-bed adsorption of reactive azo dye onto

granular activated carbon prepared from waste. In this work, the adsorption potential of bamboo

waste based granular activated carbon (BGAC) to remove C.I. Reactive Black (RB5) from

aqueous solution was investigated using fixed-bed adsorption column. The effects of inlet RB5

concentration (50200 mg/L), feed flow rate (1030 mL/min) and activated carbon bed height

(4080 mm) on the breakthrough characteristics of the adsorption system were determined. The

highest bed capacity of 39.02 mg/g was obtained using 100 mg/L inlet dye concentration, 80 mm

bed height and 10 mL/min flow rate. The adsorption data were fitted to three well-established

fixed-bed adsorption models namely, Adam'sBohart, Thomas and YoonNelson models. The

results fitted well to the Thomas and YoonNelson models with coefficients of

correlation R2 0.93 at different conditions. The BGAC was shown to be suitable adsorbent for

adsorption of RB5 using fixed-bed adsorption column [73].

18

Natali F. Cardoso et al., (2012) studied the comparison of Spirulina

platensis microalgae and commercial activated carbon as adsorbents for the removal of Reactive

Red 120 dye from aqueous effluents. Spirulina platensis microalgae (SP) and commercial

activated carbon (AC) were compared as adsorbents to remove Reactive Red 120 (RR-120)

textile dye from aqueous effluents. The batch adsorption system was evaluated in relation to the

initial pH, contact time, initial dye concentration and temperature. An alternative kinetic model

(general order kinetic model) was compared with the traditional pseudo-first order and pseudo-

second order kinetic models. The equilibrium data were fitted to the Langmuir, Freundlich and

Liu isotherm models, and the thermodynamic parameters were also estimated. Finally, the

adsorbents were employed to treat a simulated dye-house effluent. The general order kinetic

model was more appropriate to explain RR-120 adsorption by SP and AC. The equilibrium data

were best fitted to the Liu isotherm model. The maximum adsorption capacities of RR-120 dye

were found at pH 2 and 298 K, and the values were 482.2 and 267.2 mg g1 for the SP and AC

adsorbents, respectively. The thermodynamic study showed that the adsorption was exothermic,

spontaneous and favourable. The SP and AC adsorbents presented good performance for the

treatment of simulated industrial textile effluents, removing 94.499.0% and 93.697.7%,

respectively, of the dye mixtures containing high saline concentrations [74].

Ali Rza Diner et al., (2007) studied the comparison of activated carbon and bottom

ash for removal of reactive dye from aqueous solution. The adsorption of reactive dye from

synthetic aqueous solution onto granular activated carbon (GAC) and coal-based bottom ash

(CBBA) were studied under the same experimental conditions. As an alternative to GAC, CBBA

was used as adsorbent for dye removal from aqueous solution. The amount of Vertigo Navy

Marine (VNM) adsorbed onto CBBA was lower compared with GAC at equilibrium and dye

adsorption capacity increased from 0.71 to 3.82 mg g1, and 0.73 to 6.35 mg g1 with the initial

concentration of dye from 25 to 300 mg l1, respectively. The initial dye uptake of CBBA was

not so rapid as in the case of GAC and the dye uptake was slow and gradually attained

equilibrium [75].

Jae-Wook Lee et al., (2006) studied the evaluation of the performance of adsorption

and coagulation processes for the maximum removal of reactive dyes. Physicochemical

processes of adsorption and coagulation were systematically evaluated for the removal of

reactive dyes (Orange 16 and Black 5) in a laboratory scale experimental setup. The

19

effectiveness of combined processes of adsorption and coagulation for complete removal of dyes

was also investigated. The right sequence of operation was identified for the combined treatment

system. A coconut-based powdered activated carbon (PAC) was used as an adsorbent and alum

chloride was chosen as a coagulant. The results indicated that adsorption capacity of Orange 16

was much higher than that of Black 5. Also, adsorption capacity on PAC was highly dependent

on the pH of solution. The dye removal efficiencies for 100 mg l1 of Black 5 and Orange 16 by

coagulation were almost 99% and 80% under the determined optimal conditions for Black 5

(250 mg l1 coagulant dose and pH 6) and for Orange 16 (350 mg l1 coagulant dose and pH 6).

Coagulation followed by adsorption was found to be more efficient than having adsorption prior

to coagulation. There was a significant increase in adsorption capacity of PAC for the combined

process where coagulation was carried out prior to adsorption. The combined coagulation

adsorption process has the capability of complete dye removal and thus total decolourization,

reduction in coagulant and adsorption amounts and thereby produce less amount of sludge [76].

Wen-Hong Li et al., (2011)., studied the preparation and utilization of sludge-based

activated carbon for the adsorption of dyes from aqueous solutions. Sludge-based activated

carbon (SAC) was prepared from paper mill sewage sludge by carbonization at low temperature

followed by physical activation with steam in this study and the utilization of SAC in removing

Methylene Blue (MB) and Reactive Red 24 (RR 24) from aqueous solutions was investigated.

SAC was characterized by iodine number, specific surface area, zeta potential, scanning electron

microscope and X-ray diffraction. Adsorption experiments were conducted as function of

particle size, SAC dosage, pH, salt concentration, contact time and initial concentration.

Desorption of dyes on SAC was studied in deionized water with different pH values and the dye-

exhausted carbon was regenerated by thermal treatment. The results showed that the equilibrium

adsorption data were well represented by the Langmuir isotherm equation. The maximum

adsorption capacity (263.16 mg/g for MB and 34.36 mg/g for RR 24), high regeneration

efficiency and low cost (365 US$/t) of SAC provided strong evidence of the potential of SAC for

removing dyes from aqueous solutions [77].

Jae-Wook Lee et al.,(2006) studied the Submerged microfiltration membrane coupled

with alum coagulation/powdered activated carbon adsorption for complete decolorization of

reactive dyes. Even the presence of very low concentrations of dyes (1 mg L1) in the effluent is

highly visible and is considered aesthetically undesirable. It must be removed from wastewater

20

completely. This study systematically evaluates the performance of adsorption (three kinds of

powdered activated carbons), coagulation (AlCl36H2O) and membrane (submerged hollow

fiber microfiltration) processes individually in treating two kinds of reactive dyes (Orange 16

and Black 5) and then using a hybrid process with combined coagulationadsorptionmembrane

treatment system. Adsorption capacity and kinetics of Orange 16 were much higher and faster

than those of Black 5. The dye removal efficiency by coagulation was highly dependent on dye

concentration and solution pH. The hybrid process performance was far more superior that

individual process in removing both kinds of dyes. It was evident that the combined coagulation

adsorptionmembrane process has a great potential application for complete reactive dye

removal, production of high-quality treated water and allows the reduction in the use of

coagulant and adsorbent [78].

Sanja Papic et al., (2004) studied the removal of some reactive dyes from synthetic

wastewater by combined Al(III) coagulation/carbon adsorption process. This study was designed

to investigate the removal of reactive dyes, C.I. Reactive Red 45 and C.I. Reactive Green 8, from

wastewater using a two-step, Al(III) coagulation/activated carbon adsorption method. The effect

of pH and coagulant dosage as well as the effects of contact time and a powdered activated

carbon dosage on dye removal have been studied. The process was optimized with reasonable

consumption of coagulant and quantity of obtained sludge. Coagulation as a main treatment

process followed by adsorption achieved almost the total elimination of both dyes from

wastewater with significant reduction (90%) of chemical oxygen demand (COD), total organic

carbon (TOC) and adsorbable organic halide (AOX). Besides high efficiency of dye removal, the

combined treatment process offers many advantages for potential application such as coagulant

savings, minimal amount of sludge formation and also a economic feasibility since it does not

require high costs for chemicals and equipment [79].

Y.S. Al-Degs et al., (2011) studied the adsorption characteristics of reactive dyes in

columns of activated carbon. Adsorption behaviour of reactive dyes in fixed-bed adsorber was

evaluated in this work. The characteristics of mass transfer zone (MTZ), where adsorption in

column occurs, were affected by carbon bed depth and influent dye concentration. The working

lifetime (tx) of MTZ, the height of mass transfer zone (HMTZ), the rate of mass transfer zone

(RMTZ), and the column capacity at exhaustion (qcolumn) were estimated for the removal of

remazol reactive yellow and remazol reactive black by carbon adsorber. The results showed that

21

column capacity calculated at 90% of column exhaustion was lower than carbon capacity

obtained from equilibrium studies. This indicated that the capacity of activated carbon was not

fully utilized in the fixed-bed adsorber. The bed-depth service time model (BDST) was applied

for analysis of reactive yellow adsorption in the column. The adsorption capacity of reactive

yellow calculated at 50% breakthrough point (N0) was found to be 0.1 kg kg1 and this value is

equivalent to about 14% of the available carbon capacity. The results of this study indicated the

applicability of fixed-bed adsorber for removing remazol reactive yellow from solution [80].

Y. Al-Degs et al., (2000) studied the effect of carbon surface chemistry on the

removal of reactive dyes from textile effluent. The removal efficiency of activated carbon

Filtrasorb 400 (F-400) towards three highly used reactive dyes in the textile industry was

investigated. In this work, the adsorption capacities for the anionic reactive dyes, namely;

Remazol Reactive Yellow, Remazol Reactive Black and Remazol Reactive Red were

determined. The adsorption capacity data showed a high removal ability for the three reactive

dyes and a distinguished ability for R. Yellow. The high adsorption capacities for F-400 were

attributed to the net positive surface charge during the adsorption process. Surface acidity,

surface basicity, H+ and OH adsorption capacities and pHZPC for F-400 were estimated and

compared with other reported values [81].

Franciele Regina Furlan et al., (2010) studied the removal of reactive dyes from

aqueous solutions using combined coagulation/flocculation and adsorption on activated carbon.

The removal of two reactive dyes (Black 5 and Orange 16) was investigated. The objective of

this study was to investigate the removal of reactive dyes through a combined treatment process

with coagulation/adsorption on activated carbon. Activated carbon derived from coconut shells

was used as the adsorbent and aluminum chloride was used as the coagulant. In order to obtain

the best conditions for the removal of the dyes, the influence of the following parameters was

verified: coagulant and alkalizer dosage, aqueous solution pH, temperature of the mixture and

salt addition (sodium chloride). Spectrophotometry was the analysis technique used to measure

the concentration of dye remaining in the fluid phase. The results for the adsorption of the

reactive dyes were fitted to the models of the Langmuir, Freundlich and Radke-Prausnitz

isotherms and showed good correlation. The removal efficiencies were approximately 90% and

84% for the Black 5 and Orange 16, respectively. In order to evaluate the final effluent obtained

after the coagulation and adsorption process, acute toxicity tests were carried out with Artemia

22

salina and Daphnia magna, which verified that the effluent was atoxic. The combined

coagulation/adsorption process was shown to be an excellent option for the removal of reactive

dyes [82].

Mohd Azmier Ahmad et al., (2011) studied the optimization of rambutan peel based

activated carbon preparation conditions for Remazol Brilliant Blue R removal. The optimal

conditions for preparation of rambutan peel based activated carbon (RPAC) for removal of

Remazol Brilliant Blue R (RBBR) reactive dye from aqueous solution were investigated. The

RPAC was prepared using physiochemical activation method which consisted of potassium

hydroxide (KOH) treatment and carbon dioxide (CO2) gasification. The central composite

design (CCD) was used to determine the effects of the preparation variable, activation

temperature, activation time and KOH impregnation ratio on RBBR percentage removal and

RPAC yield. Two quadratic models were developed to correlate the preparation variables for

both responses. The significant factors on each experimental design response were identified

from the analysis of variance (ANOVA). The optimum conditions for RPAC preparation were

obtained by using activation temperature of 789 C, activation time of 1.8 h and IR of 3.5, which

resulted in 78.38% of RBBR removal and 18.02% of RPAC yield [83].

Tatiana Calvete et al., (2010) studied the application of carbon adsorbents prepared

from Brazilian-pine fruit shell for the removal of reactive orange 16 from aqueous solution:

Kinetic, equilibrium, and thermodynamic studies. Activated (AC-PW) and non-activated (C-PW)

carbonaceous materials were prepared from the Brazilian-pine fruit shell (Araucaria

angustifolia) and tested as adsorbents for the removal of reactive orange 16 dye (RO-16) from

aqueous effluents. The effects of shaking time, adsorbent dosage and pH on the adsorption

capacity were studied. RO-16 uptake was favorable at pH values ranging from 2.0 to 3.0 and

from 2.0 to 7.0 for C-PW and AC-PW, respectively. The contact time required to obtain the

equilibrium using C-PW and AC-PW as adsorbents was 5 and 4 h at 298 K, respectively. The

fractionary-order kinetic model provided the best fit to experimental data compared with other

models. Equilibrium data were better fit to the Sips isotherm model using C-PW and AC-PW as

adsorbents. The enthalpy and entropy of adsorption of RO-16 were obtained from adsorption

experiments ranging from 298 to 323 K [84].

23

Alvin W.M. Ip et al., (2010) investigate the kinetics and mechanisms of removal of

Reactive Black 5 by adsorption onto activated carbons and bone char.The adsorption of a large

reactive dye, Reactive Black 5, onto four adsorbents has been studied. A commercial active

carbon, F400, was selected as a standard and two active carbons prepared from bamboo, a

biomaterial. The two bamboo derived carbons, BACX2 and BACX6 had high specific surface

areas, namely, 2123 and 1400 m2/g, respectively. A fourth widely used adsorbent, bone char,

was also tested. The adsorption capacities for F400, bone char, BACX2 and BACX6 were 198,

160, 286 and 473 mg/g, respectively. A series of batch kinetics were carried out to investigate

the rate and possible mechanism of Reactive Black 5 adsorption. Two pseudo-kinetic models and

one intraparticle diffusion model were tested. The experimental concentration versus time decay

curves were best explained by the intraparticle diffusion model [85].

. Hyun-Doc Choi et al., (2008) studied the removal characteristics of reactive black 5

using surfactant-modified activated carbon. Reactive dyes are non-degradable and toxic to

environments and human being, and their solutions have some color even after wastewater

treatment. To remove toxic dyes, adsorption is common choice. In this study, to improve the

adsorption capacity, the effect of cationic surfactant was studied to remove reactive black 5

(RB5) by activated carbon (AC) using cetylpyridinium chloride (CPC). Three different ACs

were studied; pure AC, AC in CPC solution and precoated AC by CPC. Regardless of surfactant

presence, the sorption kinetics followed pseudo-second-order kinetic model. Equilibrium

adsorption capacities were determined by fittings experimental data to three well-known

isotherm models; Langmuir, Freundlich and double scheme of Langmuir model. A double

scheme of Langmuir model was more proper to explain experimental data than the conventional

Langmuir and Freundlich model. Cationic surfactant could enhance sorption capacity of RB5 on

activated carbon, and the extent of enhancement is highly dependent on pore size distribution of

activated carbon [86].

Dilek Angn et al., (2013) studied the production and characterization of activated

carbon prepared from safflower seed cake biochar and its ability to absorb reactive dyestuff. The

use of activated carbon obtained from biochar for the removal of reactive dyestuff from aqueous

solutions at various contact times, pHs and temperatures was investigated. The biochar was

chemically modified with potassium hydroxide. The surface area and micropore volume of

activated carbon was 1277 m2/g and 0.4952 cm3/g, respectively. The surface characterization of

24

both biochar and activated carbon was undertaken using by Fourier transform infrared

spectroscopy and scanning electron microscopy. The experimental data indicated that the

adsorption isotherms are well described by the DubininRadushkevich (DR) isotherm equation.

The adsorption kinetics of reactive dyestuff obeys the pseudo second-order kinetic model. The

thermodynamic parameters such as G, H and S were calculated to estimate the nature

of adsorption. The activation energy of the system was calculated as 1.12 kJ/mol. According to

these results, prepared activated carbon could be used as a low-cost adsorbent to compare with

the commercial activated carbon for the removal reactive dyestuff from wastewater [87].

25

Table 2.1: Removal of reactive dye using different adsorbents.

Adsorbate Adsorbent Results/conclusion Refrence

Reactive

Procion

Dyes

Clay

Adsorbents

The removal efficiencies of synthetic talc

stable above 80% until the initial dye

concentration reached at 160 mg.L-1 of

both reactive procion dyes when the

liquid/solid ratio of 50 mL.g-1. Synthetic

talc and kaolin showed higher adsorption

capacity under acidic condition because of

higher zeta potential.

[88].

Reactive

orange 16

Quaternary

chitosan salt

Adsorption was shown to be independent of

solution pH. The experimental data best

fitted the pseudo-second-order model. The

adsorption rate was dependent on dye

concentration at the surface of the

adsorbent. The maximum adsorption

capacity determined was 1060 mg of

reactive dye per gram of adsorbent,

corresponding to 75% occupation of the

adsorption sites.

[89].

Reactive

Blue 114

(RB114),

Reactive

Yellow 64

(RY64) and

Reactive

Red 124

(RR124)

Calcined

alunite.

Acidic pH was favorable for the adsorption

of RB114 and alkaline pH was favorable to

both RY64 and RR124. The adsorption

capacities were found to be 170.7, 236 and

153 mg dye per gram of calcined alunite for

RB114, RY64 and RR124, respectively.

The experimental data were fitted by the

second-order kinetic model, which indicates

that chemicalsorption is the rate limiting

step, inside of mass transfer

[90].

26

Reactive

blue MR

Modified silk

cotton hull

Adsorption depended on solution pH, dye

concentration, carbon concentration and

contact time. Equilibrium was attained with

in 60 min. The adsorption capacity was

found to be 12.9 mg/g at an initial pH of

2 0.2 for the particle size of 125250 m

at room temperature (30 2 C).

[91]

Naphthol

Blue Black,

NBB;

Reactive

Black 5,

RB5; and

Remazol

Brilliant

Blue R,

RBBR

Mesoporous

carbon

(MCSG60)

The maximum adsorption capacities

obtained for the dyes were: 270 mg/g for

Naphthol Blue Black; 270 mg/g for

Reactive Black 5 and 280 mg/g for Remazol

Brilliant Blue. Further batch experiments

showed Mesoporous carbon (MCSG60)

successfully adsorbed the dyes over a wide

pH range and at low adsorbate

concentration.

[92].

Reactive

blue 19 and

reactive red

198

Porous MgO

powder

Experimental results indicate that the

prepared MgO powder can remove more

than 98% of both dyes under optimum

operational conditions of a dosage of 0.2 g,

pH 8 and a contact time of 5 min for initial

dye concentrations of 50300 mg/L. The

maximum predicted adsorption capacities

were 166.7 and 123.5 mg of dye per gram

of adsorbent for RB 19 and RR 198,

respectively.

[93].

Reactive

Black 5 dye

Material

consisted of

cross-linked

chitosan (CH)

The adsorption evaluation of the composite

material presented high adsorption capacity

(277 mg/g at 25 C).

[94].

27

and graphite

oxide (GO)

Methylene

Blue (MB)

and

Reactive

Red 4

(RR4)

Sludge

(collected

from a

biological

coke

wastewater

treatment

plant)

With the solution pH increase, the MB

uptake increased; whereas the RR4 uptake

decreased. The maximum uptake of RR4 by

protonated sludge was 73.7 mg/g at pH 1,

and the maximum uptake of MB by sludge

was 235.3 mg/g at pH 9.

[95].

Reactive

textile dye

(Remazol

Brilliant

Blue)

Industrial

waste sludge

mainly

composed by

metal

hydroxides

Dye adsorption equilibrium isotherms were

determined at 25 and 35 C and pH of 4, 7

and 10 revealing reasonably fits to

Langmuir and Freundlich models. At 25 C

and pH 7, Langmuir fit indicates a

maximum adsorption capacity of 91.0 mg/g.

A pseudo-second-order model showed good

agreement with experimental data.

[96].

Reactive

dye

Chitosan-

modified

palygorskite

The adsorption behavior of Chitosan-

modified palygorskite showed that the

adsorption kinetics and isotherms were in

good agreement with the pseudo-second-

order equation and the Langmuir equation,

and the maximum adsorption capacity of

Chitosan-modified palygorskite calculated

by the Langmuir model was 71.38 mg g 1,

which was much higher than that of the

unmodified palygorskite (6.3 mg g 1).

[97].

Reactive

blue 5

Nanoparticles

of delafossite-

type

The nanoparticles showed the excellent

adsorption properties towards reactive dye,

reactive blue 5 (RB5). The kinetic studies

[98].

28

LiCo0.5Fe0.5

O2

indicate that the removal process obeys the

second-order kinetic equation. Also, the

isotherm evaluations reveal that the

adsorption of reactive blue 5 by the

nanoparticles follows the Freundlich model.

Congo Red

(anionic

reactive

dye).

Sludge

generated in

removal of

heavy metal

by

electrocoagula

tion.

The adsorption is highly pH dependent due

to formation of various charged

hydroxylated species. The maximum

adsorption capacity (qm) increases from

271 to 513 mg/g when the initial pH is

adjusted to 3.0 instead of 10.4. Preferable

fitting of Langmuir isotherm over

Freundlich isotherm suggests monolayer

coverage of adsorbate at the surface of

adsorbent.

[99].

Reactive

Red 120

(RR-120)

Spirulina

platensis micr

oalgae (SP)

and

commercial

activated

carbon (AC)

The maximum adsorption capacities of

reactive red-120 dye were found at pH 2

and 298 K, and the values were 482.2 and

267.2 mg g1 for the Spirulina

platensis microalgae and activated carbon

adsorbents, respectively.% removal

efficiency of Spirulina platensis microalgae

and commercial activated carbon was 94.4

99.0% and 93.697.7% respectively.

[100].

Reactive

Black 5

(RB5)

Sunflower

seed shells

(SS) and

mandarin

peelings (MP)

Sunflower seed shells led to a percentage of

dye removal higher than mandarin peelings

(85% and 71% after 210 min, respectively,

for an initial reactive black 5 concentration

of 50 mg L1 and an initial pH of 2.0). On

the whole, the results in this study indicated

that SS were very attractive materials for

[101].

29

removing anionic dyes from dyed effluents.

The rate of adsorption followed a pseudo-

second-order kinetic model.

Reactive

Red and

Acid Brown

dye

Adsorbent

prepared by

pyrolysing a

mixture of

carbon and

flyash at 1:1

ratio

The optimum pH, temperature, particle size

and time were found to be 10.8, 59.25 C,

0.0525 mm and 395 min, respectively, for

Reactive Red 3GL and those for Acid

Brown 29 were 1.4, 27.5 C, 0.0515 mm

and 285 min, respectively. Complete

removal (100%) was observed for both the

dyes using the hybrid adsorbent.

[102].

Reactive

Red 120

(RR-120)

Jatropha

curcas shells

in natural

form (JN) and

treated by

non-thermal

plasma as

biosorbents

(JP).

The maximum sorption capacity for

adsorption of the dye occurred at 323 K,

attaining values of 40.94 and

65.63 mg g1 for JN and JP, respectively.

% removal was obseved 68.2% and 94.6%,

for Jatropha curcas shells in natural form

and Jatropha curcas shells

treated by non-thermal plasma, respectively.

[103].

30

3. MATERIALS AND METHODS

3.1 Waste water

Aqueous solution of CBSOL Red LE wool dye was taken as waste water. Initially 100

mg/l of stock solution was prepared which was diluted to make the working solution to suit the

feasibility of experiments.

3.2 Analytical Methods

The determination of the concentration of reactive CBSOL Red LE wool dye was

performed by finding out the absorbance characteristic wavelength using UV/VIS

spectrophotometer (Perkin Elmer, Schimadzu, Japan). A solution of known concentration was

taken and the absorbance was determined at different wavelengths to obtain a plot of

absorbance versus wavelength. The wavelength corresponding to maximum absorbance (max) was determined. The max for reactive CBSOL Red LE wool dye solution was found to be 504 nm. Calibration curve was plotted between the absorbance and the concentration of reactive

CBSOL Red LE wool dye solution (Figure: 3.1).

Figure 3.1: calibration curve between the absorbance and the concentration of reactive

CBSOL Red LE wool dye solution.

y = 0.0124xR = 0.9974

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 5 10 15 20 25 30

Abso

rban

ce

Dye Concentration (mg/L)

31

3.3 Experimental Programme

For each experiment, a known amount of the adsorbent was introduced into 250 ml

stoppard conical flasks in which 100 ml of the reactive CBSOL Red LE wool dye solution of

known pH was already present. This was kept in a temperature controlled shaker at a constant

speed of 150 rpm at a pre-decided constant temperature for 7 hour to attain the equilibrium. The

adsorbent and adsorbate were separated from the reactive CBSOL Red LE wool dye solution

after 7 hour and analyzed for concentration. The percentage removal efficiency and adsorption

capacity of reactive CBSOL Red LE wool dye aqueous solution was calculated using the

following relationship:

Removal efficiency, R =

100 (3.1)

Adsorption capacity, qt =

x100 (3.2)

Where, Ci is initial reactive CBSOL Red LE wool dye aqueous solution concentration, Cf is the

equilibrium reactive CBSOL Red LE wool dye aqueous solution concentration (mg/l), Cj =

activated carbon loading (adsorbent dosage), g/100ml and qt = amount of dye adsorbed per unit

weight of activated carbon.

3.4. Kinetics of adsorption: Pseudo-first-order and pseudo-second-order models were used to

calculate the kinetic parameters at various Ci values (50-100 mg/l). Optimum adsorbate dose of

Activated carbon was used. The amount of adsorbate adsorbed, qt (mg/g), at any time t was

calculated as:

( )V

mCC

q tit= (3.3)

Where, Ct is the Red LE Dye concentration (mg/l) at time t, V is the volume of the

solution (litre).

32

The adsorption of adsorbate from solution to adsorbent can be considered as a reversible

process with equilibrium being established between the solution and the adsorbate. Since, non-

dissociating molecular adsorption of adsorbate molecules on adsorbent was assumed; the

sorption phenomenon can be described as the diffusion controlled process.

Using first order kinetics it can be shown that with no adsorbate initially present on the

adsorbent, the uptake of the adsorbate by the adsorbent at any instant t is given as:

(3.4)

where, qe is the amount of the adsorbate adsorbed on the adsorbent under equilibrium

condition, kf is the pseudo-first order rate constant.

The pseudo second-order adsorption kinetic rate equation is expressed by the integrated equation

after using the boundary conditions as:

(3.5)

Marquardts percent standard deviation (MPSD [104] was used to find out the error function to

represent the experimental data.

This error function is given as:

=

=n

i it

calitit

pm qqq

nnMPSD

1

2

exp,,

,,exp,,1100 (3.6)

In this equation, the subscript exp and cal represent the experimental and calculated

values, is the number of measurements, and np is the number of parameters in the model.

( )[ ]tkqq fet = exp1

eS

eSt qtk

qtkq += 1

2

mn

33

4. RESULTS AND DISCUSSION

4.1 Adsorption experiments The % dye removal efficiency and adsorption capacity was determined from the dye

concentration in the solution before and after adsorption with activated carbon. Effect of

activated carbon dosage, pH of reactive dye solution and time on the removal efficiency and

adsorption capacity was studied using different activated carbon dosage, pH of reactive dye

solution and time (Saran et al., 2013) [105]. The optimum values of operational parameters were

found to be m = 2.92 g/100 ml, t = 6.75 h and pH = 3.95 (Saran et al., 2013) [105]. At these

operational parameters, kinetics and isothermal study were conducted.

4.2Adsorption Kinetics

Pseudo-first-order and pseudo-second-order kinetic models used to examine their validity

with the experimental kinetic adsorption data. The best-fit values of the model parameters,

correlation coefficients and MPSD values are given in Table 4.1.

It may be concluded that pseudo second-order kinetic model with non-linear regression

best fits the adsorption kinetics. The fitting of pseudo second-order and pseudo first-order model

with kinetic experimental data is shown in Fig. 4.1.

From Table 4.1, it is observed that the qe and ks values were found to be increase with an

increase in Ci. The uptake rate is limited by the Ci of Red LE Dye and the Red LE Dye affinity to

the adsorbent, diffusion coefficient of the Red LE Dye in the bulk and solid phases, The increase

in Ci of Red LE Dye also enhances the interaction between Red LE Dye and the adsorbent. The

rate of adsorption also increases with the increase in Ci due to increase in the driving force.

34

Table 4.1 Best-fit values of the model parameters

Pseudo-first-order model

Ci (mg/l)

qe,exp (mg/g)

qe,cal

{mg/g)

kf (min-1)

R2

(non-linear)

MPSD

100 2.832 2.565 0.035 0.97 31.34

50 1.462 1.397 0.021 0.98 21.65

Pseudo-second-order model

Ci (mg/l)

qe,exp

(mg/g)

ks (g/mg min)

h

(mg/g min)

R2

(non-linear) MPSD

100 2.780 0.018 0.137 0.99 17.60

50 1.647 0.012 0.033 0.99 17.77

35

Fig.4.1 Kinetics of CBSOL red LE dye on activated carbon. (Experimental results are shown by data points, Solid line shows pseudo second-order kinetic model fitting, and

dotted line shows pseudo first-order kinetic model)

0

1

2

3

4

0 100 200 300 400 500

q t(m

g/g)

Time (min)

100 mg/l 100, cal S100 cal F 50 mg/l50 cal S 50 cal F

Ci (mg/l)

36

5. CONCLUSIONS

On the basis of the results and discussion presented for the removal of CBSOL Red LE

Wool dye from aqueous solution by adsorption process with activated carbon, following

conclusion can be drawn.

1. qe and ks value increases with increase in Ci.

2. The uptake rate is limited by the Ci of Dye.

3. The rate of adsorption increases with increases with increases in Ci.

4. Psuedo second-order was found to best for Equilibrium Data.

37

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