Modeling and optimization of reactive yellow 145 dye removal process onto synthesized MnOX-CeO2 using response surface methodology

Accepted Manuscript Title: Modeling and Optimization of Reactive Yellow 145 Dye Removal Process onto Synthesized MnOX -CeO2 Using Response Surface Methodology Author: P. Gharbani PII: DOI: Reference:

S0927-7757(18)30223-1 https://doi.org/10.1016/j.colsurfa.2018.03.046 COLSUA 22371

To appear in:

Colloids and Surfaces A: Physicochem. Eng. Aspects

Received date: Revised date: Accepted date:

4-12-2017 17-3-2018 19-3-2018

Please cite this article as: Gharbani P, Modeling and Optimization of Reactive Yellow 145 Dye Removal Process onto Synthesized MnOX -CeO2 Using Response Surface Methodology, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2010), https://doi.org/10.1016/j.colsurfa.2018.03.046 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Modeling and Optimization of Reactive Yellow 145 Dye Removal Process onto Synthesized MnOX-CeO2 Using Response Surface Methodology

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Running title: Removal of Reactive Yellow 145 Dye by Synthesized MnOX-CeO2 Using RSM

P. Gharbani

Department of Chemistry, Ahar Branch, Islamic Azad University, Ahar, Iran Email: [email protected] ; [email protected]

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Abstract

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Graphical abstract

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In this research, MnOx- CeO2 synthesized via green method and was applied as adsorbent to remove of Reactive yellow 145 dye from aqueous solutions. Prepared MnOx- CeO2 was characterized by XRD (X-ray diffraction), XRF (X-ray fluorescence), FESEM (Field emission scanning electron microscopy), EDX (Energy-dispersive X-ray spectroscopy) and BET (Brunauer, Emmett and Teller). FESEM analysis was confirmed the nano structure of synthesized compound. Removal of Reactive yellow 145 dye experiments were designed by Response Surface Methodology (RSM) and was analyzed by ANOVA. In this research four main factors such as pH, contact time,

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initial dye concentration and dosage of adsorbent were investigated and maximum %R was obtained about 99.32%. The model predicated the interaction between initial dye concentration and adsorbent dosage was as the most effective factors. As data, removal of Reactive yellow 145 dye from aqueous solutions by synthesized MnO x/ CeO2 was obeyed Langmuir isotherm and pseudo-second order kinetic models.

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Key words: ANOVA; Isotherm; Kinetics; Reactive dye; Synthesis Introduction

Several consumable products in advanced societies are dyed in order to have a beautiful and acceptable appearance for the final consumption. Colors are different in terms of application and are classified according to chemical structure as well as method of application (dyeing of textiles, plastics etc.) (Forgacs et al. 2004). Color sources and

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pigments are used to color textiles, plastics, paper, leather, clothing, footwear, cosmetics, food processing and

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minerals. Discharge of color-producing substances into environments might create severe problems due to the

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transfer of their toxicity to aquatic life, causing damage to the environment (Raval et al. 2016). Over the past two

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decades, Environmental Protection Agency (EPA) and other national and international organizations have imposed intense regulations for the production and consumption of artificial dyes (Crini 2006). Using a variety of synthetic

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dyes in the textile factory causes the production of high volumes of toxic substances in the environment, especially in water resources. Over the last decades, the attention and consideration to eliminate these substances have

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increased. The used dyes in textile industries include types of anionic dyes (acid, direct and reactive), cationic dyes (basic dyes) and nonionic dyes (Gupta & Suha 2009). Reactive dyes with azo structure having double bond of

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nitrogen are the most commonly used dyes in the textile industry (Raval et al. 2016). With regards to the toxicity and low biodegradability of these substances, they are classified into the group of dangerous substances for environment

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and must be purified before discharge (Adeyemo et al. 2017). Reactive Yellow 145 ( RY 145) dye is one of the commonly used colors in cotton dyeing. It has sulfate groups of ethyl sulfone and monochlorotriazine, and is in the

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azo group (Khurana et al. 2017). Various physical and chemical methods such as adsorption, coagulation, filtration, electrodialysis, chemical precipitation and oxidation have been employed for the removal of colors ( Haddad et al. 2013). Among these methods, adsorption has drawn a lot of attention due to its simplicity, low cost and effectiveness in reducing azo dyes from aqueous solutions ( Haddad et al. 2013). Researchers are trying to find substances like adsorbents that are cheap and have high efficiency in eliminating pollutants. So far, in order to eliminate reactive

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pollutants from aqueous solutions, calcined bones ( Haddad et al. 2013)., composites ( Chen et al. 2016; Zheng et al. 2015), Chitosan (Esquerdo et al. 2014), activated carbon (Demirbas 2009), agricultural residues (Salleh et al. 2011) and protein nanofibers (Morshedi et al. 2013) have been used. The adsorption method is affected by different operating variables such as dosage of adsorbent, initial concentration of pollutants, pH, time and etc, that evaluating

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the effect of each one and also interaction between them require spending time and cost. Experimental design is one of the strategies that have been applied by researchers in recent years to save time and costs. Experimental design is a knowledge which influences the amount of each of the factors on the output features and can be expressed in the form of an equation. Reducing the number of tests and costs, as well as the determination of variable having the most effect on response, is the main aim of experimental design (Rao et al. 2012).

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Response Surface Methodology (RSM) is one the most important testing design methods including a set of statistical techniques, and can be applied in the optimization of processes that affect the considered response by a number of

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variables. RSM not only determines the optimized conditions, but also recommends an appropriate regression model (CCD) among

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(Ahmadi et al. 2014). RSM includes Box-Behnken design (BBD) and Central composite design

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which, the central composite design is one of the most used designs in RSM (Sawale & Lele 2009). In this study, initially, nanoparticles of MnOx/CeO2 were synthesized. Thereafter, by considering four factors (time,

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the dosage of adsorbent, initial dye concentration and pH) according to CCD using RSM, the optimal modeling for

Materials and Methods

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the removal of RY 145 dye by mineral nano MnOx/CeO2 was investigated.

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Mn(NO3)2.6H2O (251.01 g/mol), (NH4)2Ce(NO3)6 (548.22 g/mol) and KOH were purchased from the Daejeon

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Company of Korea. RY 145 dye was obtained from Iran Golden trade Aretha Company, while sodium hydroxide (NaOH) and hydrochloric acid (HCI) were prepared from Merck. Chemical structure of RY 145 dye is shown in

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Fig. 1.

Synthesis of MnOx/CeO2 To synthesize MnOx/CeO2, Mn(NO3)2.6H2O and (NH4)2Ce(NO3)6 were provided in an Erlenmeyer in the ratio of 1:1 and was stirred . Subsequently, 2 M KOH solution was added to the above solution drop by drop, until the pH of the solution was reached to 10. Following the adjustment of pH, the stirring of solution stopped. A brown colored precipitate was formed that was held in a temperature of 50°C for 2 h. The solution was filtrated and washed with

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distilled water. Thereafter, a brown-colored precipitate was kept in an oven at 110°C for 12 h for drying. The dried powder was calcined at 500°C for 6 h (Tang et al. 2006). Design of Experiments The RSM method is widely applied in chemical engineering for optimizing the adsorption process. Central

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composite design (CCD) has been widely employed for quadratic model fitness and it requires the least amount of conducted experiments. The total amount of conducted experiments in this type of design is usually in the form of a set of2n testing, 2n pivotal trials and nc central tests (Tang et al. 2006). n is the number of independent variables of the process. The mathematical relationship between response and variables can be expressed in an equation (1) and in the form of a second-order polynomial: k

i 1

i 1

k

k

(1)

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i 1 j 1

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k

y  0   i xi   ii xi2   ij xi x j  

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where, y represents the predicted response for the elimination efficiency, β0 is constant factor, βi is coefficient of

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linear effects, βii is coefficient square effects, βij is factor interactions, while xi and xj are variables. ε is the random

Response surface methodology

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error or uncertainty between predicted and measured values ( Allahveran & Mehriza 2017).

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To obtain the main effects and interaction of independent variables affecting response, the statistical method of RSM was applied in the adsorption of RY 145 dye using MnOx/CeO2 as adsorbent. The entire experiments were carried

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out based on RSM experiment design with five levels and four variables. That type of design was in the form of Central Composite Design and second-order design. In this method, the effect of independent variables i.e., RY 145

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dye initial concentration, adsorbent dosage, contact time and pH on the response were examined. Ranges and levels of these factors are presented in Table 1.

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Reactive Yellow 145 dye absorption experiments All of experiments were carried out in a batch system. The stock solution of RY 145 dye with the concentration of 1000 mg/L was provided. All adsorption experiments were performed on the stirrer by adding 50 ml of RY 145 dye solutions in the 100 ml Erlenmeyer. In this research, various conditions and factors affecting the adsorption process include; the initial RY 145 dye concentration (20 - 100 mg/L), pH (2-10), the dosage of adsorbent (0.05 – 0.25g/50

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ml) and contact time (20-100 min.). After the desired time, a sample was taken from the solution and after filtration, UV-Vis spectrophotometer was used to determine the concentration of dye. The percent of dye removal onto the MnOx/CeO2 (mg/g) at any time (qt) and at equilibrium (qe), were calculated

(C0 -Ct ) ×100 C0

(C 0C t ) V M

q e=

(C 0  C e ) V M

(3)

(4)

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qt=

(2)

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%Removal=

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from the following Eqs ( 2-4)., respectively :

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where C0, Ct and Ce are the initial, at any time and equilibrium dye concentration (mg/L), respectively. V is the

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solution volume (L) and M is the adsorbent mass (g) ( Mehrizad et al. 2012) . Results and Discussion

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Characterization of synthesized MnOx/CeO2

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X-ray diffraction pattern of synthesized MnOx/CeO2 nanoparticles is presented in Fig. 2. The observed diffraction peaks at 2θ =29°, 32.48°, 48.14°, 57.04° are related to XRD spectrum of MnO x/CeO2. In

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line with the reported researches, for mixed oxides of calcined MnO x/CeO2 at temperatures lower than773°K, the X-

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ray diffraction pattern will not show any diffraction of manganese calcinations. Moreover, only wide peaks related to CeO2 structure in the form of cubic fluorite structure will be observed (Tang et al. 2006). In this study, given that the mixture of MnOx/CeO2 has been calcined at a temperature of 773°K, any spectrum of MnOx will not be observed in

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the pattern of XRD. On the other hand, the combination of mixed phase of manganese and cerium oxide oxides is intensely dependent on manganese and cerium oxide molar ratios (Machida et al. 2000). For the ratio of 0.5, only the wide peaks of CeO2 will be observed i.e., the result of the formation of solid solution between CeO2 and Mn2O3. Furthermore, for the ratio of

= 0.5, the possibility that solid

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solution will be formed during the process of calcinations is very high which is exactly in line with the work carried out in this research (Tang et al. 2006).

The Fig. 3 shows the surface morphology of MnOx/CeO2 in the 200 nm scale by FESEM and EDX results. As

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shown, the morphology of metal oxide mixtures is uniform and homogeneous, and the diameter of the obtained particles is in the nanometer range (~50 nm). The results of EDX (Fig. 3) reveal that synthesized MnOx/CeO2 consist of Mn, Ce and O.

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The results of Particle-size distribution (PSD) revealed that the average size of the Synthesized nanoparticles are 37.75 nm and the obtained single peak indicated that the quality of the synthesized MnOx/CeO2nano particles is good (Fig. 4).

The results of BET and XRF analysis is shown in Table 2 & 3, respectively. As the diameter of pores is about 6.79

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Also, Table 3 confirmed the purity of prepared MnOx/CeO2.

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nm (between 2 to 50 nm), then it can be concluded that the provided MnOx/CeO2 is a type of mesoporous material.

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Optimization of parameters affecting elimination process using RSM The effect of various parameters on the removal of the RY 145 dye using the prepared MnOx/CeO2 was examined

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are summarized in Table 4.

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and the details of the designed tests with the results of tests (experimental) as well as the predicted results (theory)

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To investigate the correctness of the model, analysis of variance (ANOVA) was conducted and its results are presented in Table 5.

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According to Table 5, it was observed that for the represented model, the level of P is less than 0.0001 which is indicative of high degree of confidence of models (Kalavathy et al. 2009). The results of ANOVA show that the

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influence of interactions between variables on removal procedure is far better than individual variable. In addition, according to the results, it was observed that the influence of response (percentage removal) by the linear variables of A and B (the dye concentration and the absorbent dosage) is more than that of other variables. This is due to the low value of P and high value of F (Kalavathy et al. 2009).

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ANOVA results suggest that the model is significant (Model F-value= 261.64 and Model p-value<0.0001) which confirms the proximity of experimental and predicted data (Table 4). On the other hand, the value of predicted R 2 and R2adj are in agreement with each other, which confirms the fitness of the model. According to the obtained results, the experimental relation between response R (%) and independent variables (A, B, C, D) in adsorption of

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the yellow dye 145 by MnOx/CeO2 is according to following: Removal % = 3.93 A + 3.72B + 1.73C + 1.03D -7.64AB - 6.92AC + 2.57 AD - 4.25BC + 0.66BD + 5.04CD (5)

To study the effect of parameters regarding the removal of RY145 dye using MnOX/CeO2, three-dimensional Figs were provided, and the optimum conditions of maximum removal of dye were obtained.

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According to Fig. 5 (a), (d), (e), increasing the dosage of absorbent has a direct effect on the RY145 dye removal and

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by increasing the dosage of absorbent from 0.05 to 0.25 g, the removal of dye will increase. This procedure can be due to increase of the surface area of adsorbent. Although by increasing the dosage of absorbent, the rate of

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adsorption in the unit mass of adsorbent (adsorption capacity) will decrease owing to the saturation of some sites on

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the surface of the adsorbent (Ong et al. 2007). According to Fig. 5 (a), (b), and (c), by increasing dye concentration from 20 to 100 mg/L, removal will increase. This phenomenon is due to the increasing number of collisions of dye

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and absorbent molecules and so, more molecules are removed from the solution (Kumar et al. 2008).

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According to Fig. 5 (b), (d),and (f), the maximum removal of dye was obtained in low pHs. In acidic pH, H

+

ion

concentration increases and the surface of MnOx/CeO2 is positively charged by absorbing these protons. On the other

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hand, the RY145 dye is an ionic composite; thus, the force of electrostatic attraction between absorbent and RY145 dye is the main reason for the increase of adsorption in acidic conditions. In high pHs, the adsorption operation is not

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desirable as a result of electrostatic repulse between anionic dye molecules and the negatively charged sites on the absorbent surface. In alkaline pHs, production of hydroxyl groups in the solution will increase leading to negative

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electric charge on the surface of the adsorbent. Consequently, the repulsion between the dye and the absorbent surface will result in the reduction of adsorption (Lima et al. 2008 & Crini 2006). According to Fig. 5 (c), (e), and (f), it was observed that by increasing time from 20 to 100 min, the percentage of removal will increase. It shows that increasing the contact time between absorbent and the absorbed will be far better (Crini 2006).

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Results revealed that, under optimum conditions (initial dye concentration of 50 mg/L, MnOx/CeO2 dosage of 0.13 g/ 50mL, pH of 6 and contact time of 55 min), the removal percent was 96.41%. This was verified experimentally (93.43%), that confirmed the success of the model. Comparisons of various adsorbents for the adsorption of RY145 dye is presented in Table 6. The results indicated that MnOx/CeO2 has a high capacity to remove of RY145 dye

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from aqueous solutions.

Adsorption isotherms

Adsorption isotherms are mathematical equations that indicate the value of the absorbed substance on the surface of the absorbent in low temperature ( Haddad et al. 2013). Isothermal studies were carried out in various concentrations of the RY145 dye solution. Non-Linear Langmuir (Langmuir 1916), Freundlich (Freundlich 1906) and Temkin

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(Temkin & Pyzhev 1939) isotherm models (equations 6, 7, 8, respectively) were employed to evaluate the fitness of

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q m K L Ce 1+K L Ce

(6)

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qe =

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adsorption equilibrium data.

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q e = K F Cen

(8)

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qe =B ln(KT Ce )

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(7)

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In the above-mentioned equations, qe is the amount of absorption per unit mass of adsorbent at equilibrium (mg/g), Ce and qm, respectively, are solution equilibrium concentration (mg/L) and the amount of absorption per unit mass

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of adsorbent for complete coverage or a single layer of absorbent absorption capacity (mg/g) (Langmuir 1916). KL is the adsorption equilibrium constant (L/mg) of Langmuir (Langmuir 1916). KF and 1/n are Freundlich isotherm 1/2

and n shows tendency to

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constants (Freundlich 1906). KF reveals the adsorption capacity by (mg/g) (Lmg)

adsorption (Freundlich 1906). B is a constant that depends on the heat of adsorption and KT is the equilibrium link constant or fixed isotherms compliance (L/g) (Temkin & Pyzhev 1939). In Fig. 6, the curves obtained by drawing three isotherms are presented. As shown, the RY145 dye adsorption on the surface of MnOx/CeO2 follows the Langmuir isotherm. Therefore, according to the theory of Langmuir, it can be concluded that the adsorption of RY145 dye on the MnOx/CeO2 is done in a monolayer form (Langmuir 1916).

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Adsorption kinetics Adsorption kinetics is expressed as the speed of removing substance that is absorbed on the surface. Furthermore, it depends on the interaction of absorbent and absorbed as well as system conditions. Various Kinetics models have been used for the examination of kinetics data of adsorption process and determination of the speed controller.

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Among the most important models, Lagergren’s pseudo-first order kinetic model and Ho’s pseudo-second order kinetic apparent model can be mentioned (Lagergren 1898). The pseudo-first-order differential form is as follows:

qt  qe (1  e  k 1t )

(9)

In the above equation, K1 is the first-order apparent speed constant (min-1), qe and qt are the adsorption capacity in the equilibrium and t, respectively (mg g-1) (Lagergren 1898).

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(10)

qe2 k 2t 1  k 2q e t

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qt 

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The pseudo-second-order differential form is as follows:

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In the above equation, K2 is the second-order apparent speed constant (g mg-1 min-1) (Ho & Mckay 1998). In Fig. 7,

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the curve resulting from both the pseudo-first order and pseudo-second order kinetics is presented. As Fig. 7, the

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Conclusion

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adsorption of the RY145 dye on MnOx/CeO2 follows the pseudo-second order kinetic.

In this study, the synthesized MnOx/CeO2 was utilized as an absorbent for the removal of RY145 dye from the

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aqueous solutions. The results of XRD analysis confirmed the synthesis of MnOx/CeO2. Moreover, the results of FESEM and BET revealed that the particles were nano-sized and have a high surface area. Efficiency results of

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synthesized MnOx/CeO2 in removal of the RY145 dye by RSM revealed that the adsorption process depends on pH, the initial concentration of dye, absorbent dosage and the time of contact. The dosage of MnOx/CeO2 and the initial concentration of dye are the main parameters affecting this experiment. Therefore, the adsorption of RY145 dye on MnOx/CeO2 follows pseudo-second order kinetic and Langmuir isotherm.

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Figure captions Fig. 1. Chemical structure of the RY 145 dye Fig. 2. XRD patterns of the prepared MnOx/CeO2

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Fig. 3. FE-SEM image & EDX spectrum of prepared MnOx/CeO2 Fig. 4. Particle-size distribution (PSD) of the synthesized MnOx/CeO2nanoparticles.

Fig. 5. Effect of influential parameters on the removal of RY145 dye: (a) initial dye concentration and MnOx/CeO2 dosage; (b) pH and initial dye concentration; (c) time and initial dye concentration ; (d) pH and MnO x/CeO2 dosage; (e) time and MnOx/CeO2 dosage; (f) time and pH

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Fig. 6. Results of Langmuir, Freundlich and Temkin isotherms on removal of RY145 dye by MnOx/CeO2

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Fig. 7. Kinetic removal of 145 RY by MnOx/CeO2\

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NaO3S SO2CH2CH2OSO3Na

SO3Na N

H N

N N

N NaO3S

H NHCONH2

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Cl

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Fig. 1. Chemical structure of the RY 145 dye

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Fig. 2. XRD patterns of the prepared MnOx/CeO2

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Fig. 3. FE-SEM image & EDX spectrum of prepared MnOx/CeO2

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Fig. 4. Particle-size distribution (PSD) of the synthesized MnOx/CeO2nanoparticles.

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A

CC

Fig. 5: Effect of influential parameters on the removal of RY145 dye: (a) initial dye concentration and MnOx/CeO2 dosage; (b) pH and initial dye concentration; (c) time and initial dye concentration ; (d) pH and MnOx/CeO2 dosage; (e) time and MnOx/CeO2 dosage; (f) time and pH

17

40

qe

30 20

SC RI PT

10 0 0

2

4

6

8

10

12

14

Ce qe EXP.

qe langmuier

qe frundlich

qe temkin

N

U

Fig. 6: Results of Langmuir, Freundlich and Temkin isotherms on removal of RY145 dye by MnOx/CeO2

0.6

A M

0.4 0.3

Experimental

0.2

Pseudo-first-order

0.1

Psuedo-second-order

0 10

20

30

TE

0

D

qt (mg/g)

0.5

40

50

EP

t (time)

A

CC

Fig. 7: Kinetic removal of 145 RY by MnOx/CeO2

18

Table 1 Ranges and levels of the influential parameters

[RY 145]0 (mg/L) [MnOx/CeO2]0( g/50 ml) Contact Time (min.) pH

Levels -α (-2)

-1

0

+1

20

40

60

80

0.05

0.1

0.15

0.2

20

40

60

2

4

6

Table 2 Results of BET Mean pore diameter 6.9722 nm

80

100

8

10

U

Vm 43.04 cm3 g-1

0.25

N

as,BET 187.33 m2 g-1

+α(+2) 100

SC RI PT

Factors

A

Table 3 Results of XRF

% Of the sample

M

Mix ingredients MgO

Manganese (II) oxide

MnO

23.91

Cerium (III) Oxide

Ce2O3

75.63

0.46

A

CC

EP

TE

D

Magnesium Oxide

19

Table 4 Designed tests by CCD along with Exp. and Predicate results

A

M

R% (Exp.) 96.21 90.33 89.73 63.84 90.08 27.19 87.18 82.41 77.03 84.8 67.21 77.78 87.81 84.9 97.18 78.64 87 48.99 89.72 92 85.6 88.83 91.51 93.97 92.78 78.6 92.71 93.37 99.32 98.5

R% (Pred.) 84.21 90.33 89.73 61.83 92.09 47.19 97.18 82.41 81.03 74.8 77.21 63.77 74.81 81.89 81.18 91.63 85 82.98 80.71 90 80.6 78.84 93.51 83.97 91.78 82.6 86.71 91.37 85.33 98.5

U

SC RI PT

D Time (min.) 40 60 60 80 60 60 60 40 80 40 60 80 60 80 60 80 80 40 40 60 20 40 40 80 60 60 100 80 60 40

N

C Dosage (g/50ml) 0.1 0.15 0.15 0.1 0.15 0.15 0.15 0.1 0.1 0.1 0.15 0.2 0.15 0.1 0.15 0.2 0.2 0.1 0.2 0.25 0.15 0.2 0.2 0.1 0.15 0.05 0.15 0.2 0.15 0.2

D

B pH 8 6 6 8 6 6 6 4 8 4 6 8 6 4 10 8 4 8 4 6 6 8 8 4 6 6 6 4 2 4

A

CC

EP

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

A Dye Conc.(mg/L) 40 100 60 80 60 20 60 80 40 40 60 80 60 80 60 40 80 80 80 60 60 80 40 40 60 60 60 40 60 40

TE

Run

20

Table 5: Analysis of variance (ANOVA) Mean Squares 330.92

F-value 261.64

p-value 0.0001

371.57

1

371.57

293.78

0.0001

B: Dosage

331.28

1

331.28

261.92

0.0001

C: pH D: Time

71.84

1

71.84

56.8

AB

25.39 934.82

1 1

25.39 934.82

20.08 739.1

AC

766.64

1

766.64

606.13

AD

105.35

1

105.35

83.29

BC BD

289.63

1

289.63

228.99

6.94 405.76

1 1

6.94 405.76

5.49 320.81

24.03 9.02 15.01 3333.26

19 14 5 29

1.26 0.64 3

0.21

U

0.0003 0.0001 0.0001 0.0001 0.0001 0.0302 0.0001 0.9897

A

CC

EP

TE

D

M

Cor Total

0.0001

N

CD Residual Lack Of Fit Pure Error

of

A

Model A: Dye conc.

Sum squares 3309.23

SC RI PT

Df 10

Source

21

Table 6 Comparison of different adsorbents for the adsorption of Reactive Yellow 145

Adsorption capacity qmax (mg/g)

Removal%

Reference

Activated carbon from the fire stick wood

-------

96.76

Rao et al. 2015

Chitosan coated magnetite nanoparticles

47.62

-------

Kalkan et al. 2012

Activated carbon from Iraqi Zahdi date seeds

100

-------

Lafta et al. 2014

activated carbon synthesized from waste biomass materials Activated carbon from Iraqi berhy dates palm seeds Activated carbon

1694.3

-------

Gupta & Suha 2009

199.4

-------

Lafta 2015

-------

90.7

Active carbon adsorbent-loaded cationic surfactant Non-activated carbon

-------

97.6

Sulaymon & Abood 2014 Mahmoud et al. 2015

190.2

-------

Mahmoud et al. 2015

Activated carbon with ZnCl2

199.4

MnOx/CeO2

-------

U

SC RI PT

Adsorbents

N

-------

This work

A

CC

EP

TE

D

M

A

98.5

Esmael et al. 2015

22