Biosorption of malachite green dye from aqueous solution by calcium alginate nanoparticles: Equilibrium study

Journal of Molecular Liquids 212 (2015) 723–730

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Biosorption of malachite green dye from aqueous solution by calcium alginate nanoparticles: Equilibrium study P. Geetha a, M.S. Latha b,d,⁎, Mathew Koshy c a

Department of Chemistry, D.B. Pampa College, Parumala, Mannar, Kerala, India Department of Chemistry, S.N. College, Chengannur, Kerala, India Department of Chemistry, Bishop Moore College, Mavelikara, Kerala, India d Department of Chemistry, S.N. College, Kollam, Kerala, India b c

a r t i c l e

i n f o

Article history: Received 6 July 2015 Received in revised form 11 October 2015 Accepted 17 October 2015 Available online xxxx Keywords: Calcium alginate nanoparticles Malachite green dye Biosorption Isotherm analysis Kinetic studies Intra particle diffusion Thermodynamic parameters

a b s t r a c t Alginates, in the form of beads and hydrogels have been widely investigated for their effectiveness in pollutant removal from aqueous solution. Nanoparticles with the advantage of greater surface area and ease of mixing with contaminated water are more effective in water purification and are not much investigated. Here the dye removal potential of calcium cross-linked alginate nanoparticles, prepared by green method, is investigated in batch adsorption technique. Effect of system variables such as pH, initial dye concentration, contact time, temperature and adsorbent dose on sorption process was studied. The synthesized nanoparticles exhibited a maximum dye removal efficiency of 98.5% at 60 °C and at pH 10 in 5 min contact time. The experimental data fitted well with Langmuir model indicating monolayer adsorption mechanism and the sorption process obeyed pseudo second order kinetics. The rate-limiting mechanism in the biosorption of the dye involves a combination of intraparticle diffusion and surface adsorption. The investigation of thermodynamic parameters such as ΔG0, ΔH0 and ΔS0 confirmed the spontaneity, randomness and endothermic nature of the biosorption process. This study demonstrates that calcium alginate nanoparticles are promising biosorbent for the removal of dyes from aqueous solution as exemplified by malachite green. © 2015 Elsevier B.V. All rights reserved.

1. Introduction Rapid growth of industrialization and human urge for colour leads to an increase in the usage of dyestuff in many countries [1]. Out of the world wide annual production of 7 × 105 tones of dye, two third belongs to the textile industry alone and 10 to 15% of this used dyes is discharged directly to water generating a lot of wastewater rich in dye content [2–6]. This wastewater mixes up with surface-ground water causing pollution of water bodies. These toxic, carcinogenic dyes instigate major hazards to the environment and drinking water causing skin irritations and allergies to humans and adverse effects to microbial populations which in turn affect the natural food chain [7–9]. The presence of dyes, less than 1 ppm, produce perceptible coloration to dye bearing wastewater, inhibits sunlight penetration, reduces photosynthetic activity and hence has to be removed before discharging into rivers [10–13]. Malachite green (MG), a triphenylmethane dye is used for dyeing polyacrylonitrile, nylon, wool, silk and cotton in the textile industry and as a colouring substance in the paper and leather industry [14]. It ⁎ Corresponding author at: Department of Chemistry, S.N. College, Chengannur, Kerala, India. E-mail addresses: [email protected] (P. Geetha), [email protected] (M.S. Latha), [email protected] (M. Koshy).

http://dx.doi.org/10.1016/j.molliq.2015.10.035 0167-7322/© 2015 Elsevier B.V. All rights reserved.

is an antifungal, anti-bacterial and anti-parasitical therapeutic agent in aquacultures and in animal husbandry. However above the permissible level, it has detrimental effects on liver, gill, kidney, intestine and gonads of aquatic organisms [15]. In humans it act as a multi-organ toxin and respiratory enzyme poison damaging liver, spleen, kidney and heart and is carcinogenic [16]. Being non-biodegradable, conventional treatment technologies such as coagulation/flocculation, chemical oxidation, froth flotation, ion-exchange, membrane filtration, electrodialysis, irradiation, precipitation etc. are incompetent for the removal of colour from dye-bearing wastewater [17,18]. Adsorption using calcium alginate is an efficient method for the removal of pollutants from contaminated water due to its low cost, non-toxicity, biodegradability, simplicity of design and ease of operation [19,20]. Alginate/ polyaspartate composite gel beads were efficiently employed for the removal of basic dyes like malachite green and methylene blue from aqueous solutions [21]. Compared to beads, nanoparticles have the advantage of better efficiency due to increased surface area and hence reduce the amount of biosorbent required for the removal of contaminants. Removal of MG dye using super paramagnetic Fe3O4 nanoparticles coated with sodium alginate has also been reported in literature [22]. There is a possibility of iron contamination in using these nanoparticles for water purification. In this study calcium alginate nanoparticles were synthesized by an eco-friendly green method which involves the use of water as the

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Fig. 1. Characterization images of the biosorbent (a) SEM (b) TEM and (c) AFM images of the biosorbent; SEM of Nanoalginate (d) before and (e) after adsorption of MG dye.

medium and honey as the stabilizer. Highly stable non-aggregatory nanoparticles were prepared by the method described here. Since alginate is a highly stable polymer and no other toxic compounds are used for the preparation, the nanoparticles reported in this article forms a superior matrix for water purification compared to other reported materials.

617 nm) in 1000 mL water. This was further diluted with deionized water to desired concentration. The pH was adjusted by adding 0.1 M HCl or 0.1 M NaOH. All reagents used in the experiments were of analytical grade obtained from Merck, Mumbai, India.

2. Materials and methods 2.1. Preparation of calcium alginate nanoparticles Alginic acid sodium salt (1 g) was added to 100 mL deionized water containing 1% honey and magnetically stirred till complete dissolution. CaCl2 solution (20 mL, 1 M) was then added drop wise to the alginate solution and the resulting mixture was stirred magnetically for four hours. After this, the nanoparticles were centrifuged, washed with plenty of deionized water and air-dried. 2.2. Characterization of nanoparticles The surface structure of the synthesized alginate nanoparticles (both solid and liquid form) was examined using Philips XL 30 CP Scanning Electron Microscope. In the case of liquid sample, a drop of the nanoparticle dispersed in water was placed on the mount and after drying, it was sputter coated with a conductive material like gold for 2 min at an electron acceleration voltage of 20 kV. The topography of the sample was studied by the TEM (JEOL model 1200EX instrument) operated at 80 kV voltage, after ultrasonicating the colloidal solution in triple distilled water for 15 min. AFM images were recorded using a NTEGRA (NT-MDT) at a resonance frequency of 299 kHz and a spring constant of 20–80 Nm−1. The nature of interaction and the functional groups was studied by FTIR (Instrument Model: SPECTRUM 400) within the range 400–4000 cm−1, using KBr as back ground material. 2.3. Adsorbate Stock solution of the dye was prepared by dissolving 1000 mg of MG dye (malachite green oxalate, C.I. Basic Green 4, C.I. Classification Number 42,000, chemical formula C52H54N4O12, MW = 927.00, λmax =

Fig. 2. FTIR Spectrum of the biosorbent (a) before and (b) after dye adsorption.

P. Geetha et al. / Journal of Molecular Liquids 212 (2015) 723–730

725

Fig. 3. Influence of operational parameters on biosorption (a) pH (b) initial dye concentration (c) contact time and (d) biosorbent dose.

2.4. Method 2.4.1. Adsorption experiments The adsorption experiments were carried out in batch mode. A known weight of the adsorbent was shaken with 75 mL of

aqueous dye solution of varying initial concentration (20 mg L− 1, 50 mg L− 1, 100 mg L− 1 and 200 mg L− 1) at 30 °C. The contents were then filtered at different time intervals and the residual dye concentration was measured using UV–Visible Spectrophotometer (Systronics UV–Visible Double Beam Spectrophotometer

Fig. 4. Adsorption isotherm models.

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2201) at 617 nm wavelength. Experiment was repeated at 40, 50 and 60 °C. Removal of dye from solutionð%Þ ¼

C 0 −C e  100 C0

ð1Þ

Amount of dye adsorption, qe (mgg−1) C 0 −C e  V→ qe ¼ w

ð2Þ

where C0 and Ce are the initial and final concentrations (mgL−1), respectively, V is the volume in litres of the solution and w (g) is the mass of dry sorbent used. 2.4.2. Kinetics and thermodynamics of adsorption 2.4.2.1. Adsorption isotherm models. The data obtained has been fitted to the three widely accepted surface adsorption isotherms, Langmuir [23], Freundlich [24] and Temkin [25] models. The linearised form of Langmuir Isotherm model is Ce ¼ qe

1 Ce þ → Q mb Q m

ð3Þ

where Qm (mgg−1) and b (Lmg−1) are Langmuir constants determined from the slope and intercept of the plot of Ce/qe versus Ce {Eq. (3)}, Ce (mgL− 1) and qe (mgg− 1) are the concentration and the amount of dye adsorbed respectively. The dimensionless constant separation factor RL [26] determine the ease of adsorption RL ¼ 1=1 þ bCo →

ð4Þ

1 ln C e → n

Sl No.

Adsorption isotherms

Isotherm parameters

1.

Langmuir model

2.

Freundlich model

Qm (mgg−1) b (Lmg−1) kf (mgg−1) (Lmg−1)1/n n 1/n A (Lg−1) BT (J mol−1) bT

3.

Temkin model

R2 277.78 0.1915 81.45 3.664 0.2729 7.072 40.99 61.46

0.998

0. 935

0.911

2.4.2.3. Intraparticle diffusion model. To study the mechanism of biosorption experimental data was fitted in an intraparticle diffusion plot between qt and t1/2 based on Weber and Morris theory [30]. qt ¼ ki t 1=2 þ C→

ð9Þ

Where ki is the intraparticle diffusion rate constant (mgg−1 min1/2), calculated from the slope and the intercept C reflects the boundary layer effect. The value of C gives an idea of the contribution of surface sorption in the rate determining step [31]. 2.4.2.4. Thermodynamic studies. Thermodynamic feasibility and the spontaneity of the process were investigated by calculating the Gibbs free energy change (ΔG0), enthalpy change (ΔH0) and entropy change (ΔS0) by the van't Hoff equation [32,33]. ln K c ¼

ΔS0 ΔH 0 − → R RT

ð10Þ

e e where K c ¼ C oC−C =1− C oC−C o o

The linear form of Freundlich equation is lnqe ¼ ln k f þ

Table 1 The isotherm constants and regression data for Langmuir, Freundlich and Temkin adsorption isotherm models for adsorption of MG dye on CANPs.

e here C oC−C is the fraction adsorbed at equilibrium at temperature T deo

ð5Þ

where kf indicates the adsorption capacity of the biosorbent and 1/n indicates the intensity of adsorption, which can be calculated from the plot of ln (qe) versus ln(Ce).Value of n greater than 1 favour the adsorption process. Temkin isotherm (Eq. (6) has been tested by plotting qe vs ln Ce.

gree K. The values of Δ H0 and Δ S0 can be computed from the slope and intercept of the plot of ln Kc versus 1/T. The Gibbs free energy change (ΔG0) can be calculated from the equation [34] ΔGo ¼ −RT lnK c →

ð11Þ

The energy of activation Ea can be computed from the equation Ea ¼ ΔH0 þ RT→

qe ¼ BT ln AT þ BT ln C e →

ð6Þ

where BT = RT/bT. Here BT is the Temkin constant and is related to heat of sorption, R is the gas constant (8.314 Jmol−1 K) and T the absolute temperature (K) whereas AT (Lg−1) is the equilibrium binding constant corresponding to the maximum binding energy [27]. 2.4.2.2. Kinetic models. For kinetic studies, data was fitted to Lagergren's pseudo-first order model {Eq. (7)} [28] and pseudo-second order model {Eq. (8)} [29] which are represented by logðqe −qt Þ ¼ logqe −

k1 t→ 2:303

The value of Ea below 42 K J mol−1 indicates diffusion controlled process while higher values indicate chemical reaction processes [35]. 2.4.3. Desorption studies Desorption was studied using water, acetic acid and dilute hydrochloric acid. 2.5. Statistical analysis Statistical analysis was conducted using one-way analysis of variance (ANOVA) and Duncan's multiple range tests to determine the

ð7Þ

t 1 t ¼ þ qt K 2 qe 2 qe

ð8Þ −1

ð12Þ

−1

Where qe (mgg ) and qt (mgg ) are the amount of dye adsorbed at equilibrium and at time t, respectively, k1 (min−1) and k2 (gmg−1 min−1) are the pseudo-first order and pseudo-second order adsorption rate constants, respectively.

Table 2 Values of the dimensionless equilibrium parameter for varying concentrations of MG dye. Concentration of MG (mgL−1)

RL values

20 50 100 200

0.7267 0.5155 0.3472 0.2101

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Fig. 5. (a) Pseudo-first order and (b) pseudo-second order kinetics; (c) intraparticle diffusion model and (d) thermodynamic study.

significant differences between the variables and all the values were expressed as mean value ± SD (n = 3). 3. Results and discussion 3.1. Characterization of the biosorbent 3.1.1. Microscopic characterization The SEM, TEM and AFM images of CANPs shown in Fig. 1(a), (b) and (c) indicates the formation of spherical alginate nanoparticles. SEM images of the biosorbent before and after dye adsorption is shown in Fig. 1(d) and (e) respectively. Unlike the SEM of particles dispersed in water [Fig. 1(a)], the particles in the dried form shown in Fig. 1(d) and (e) appears to be sticky and aggregated, due to the adhesive nature of surfactant used. However, it could be easily redispersed on mild sonication. A rough surface was seen for biosorbent in SEM [Fig. 1(d)]. After the adsorption process a smooth surface was observed [Fig. 1(e)]. Similar effect was reported in literature for various materials [36,37]. 3.1.2. Spectroscopic characterization (FTIR) FTIR spectrum of CANPs before adsorption shows major peaks at 3343 cm−1, 1598 cm−1, 1426 cm−1, 1078 cm−1,1023 cm−1 characteristic of [υ(O–H)], [υ(C = O)], [υ(C–OH)] and [υ(OC–OH) respectively. This indicates the presence of both carboxyl and hydroxyl groups in the

nanoparticles [38]. After dye adsorption [Fig. 2] peaks are seen at 3253 cm−1,2967 cm−1,1737 cm−1 and 1537 cm−1,1366 cm−1,1216 cm−1 and 1029 cm− 1 and 1020 cm− 1. The new peaks at 2967 cm− 1, 1737 cm− 1 and 1216 cm− 1 are due to the presence of aromatic chromophore group (~ 3030 cm− 1), substituted benzenes (region 2000–1670 cm− 1)and C–N vibrations of the dye (range 1220–1020 cm−1) [39]. The shifts in peak values after adsorption is due to chemical interaction between the functional groups present in CANPs and MG [40]. The broadening of –OH peak at 3253 cm−1 and carbonyl group peak at 1537 cm−1 indicates the involvement of hydroxyl and carbonyl groups in the biosorption of MG dye onto CANPs [41].

3.2. Factors affecting the adsorption process 3.2.1. Effect of solution pH pH plays a significant role in dye adsorption. It affects the adsorption capacity and cause changes in the structural stability and colour intensity of the dye molecules [42,43]. Fig. 3(a) shows the effect of solution pH on the adsorption process. The percentage removal of MG was found to increase with increasing pH of the dye solution in the range studied (4–10) and the maximum adsorption was observed at pH 10. At lower acidic pH, the carboxyl groups of MG get protonated. The competition between the cationic dye and H+ ions and their electrostatic repulsion lead to a decrease in adsorption at lower pH [44]. On the contrary, at

Table 3 Regression coefficients and equilibrium parameters of kinetic study. MG concentration

First order kinetics

(mgL 20 50 100 200

−1

)

(min

Second order kinetics R2

k1 −1

(mgg 0.5755 0.8464 0.9598 0.9791

R2

k2 −1

)

0.02096 0.1967 0.2070 0.5807

qe

1.11 39.23 160.18 53.11

)

(gmg

−1

min

0.0116 0.0108 0.00401 0.00263

−1

qe

qe (calculated) −1

)

(mgg 0.999 0.999 0.999 0.999

65.36 153.85 263.16 270.27

)

(mgg1) 72.77 150.08 257.80 265.40

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Table 4 Rate constants and regression coefficients of intraparticle diffusion model. Initial MG concentration

Intraparticle diffusion rate constant

Boundary layer effect

(mg L−1)

(ki) (mgg−1 min1/2)

(C)

20 50 100 200

0.876 3.136 7.509 3.91

74.74 133.75 211. 60 228.39

R2

0.941 0.914 0.663 0.869

higher pH the surface of the adsorbent become negatively charged due to accumulation of OH− which enhances electrostatic interaction with positively charged dye molecules resulting in increased adsorption [45]. 3.2.2. Effect of initial dye concentration and contact time The percentage of biosorption was found to decrease with increase in initial dye concentration (20, 50,100 and 200 mg L−1). This is due to the decreased availability of free adsorption sites on the surface of the adsorbent with increase in the concentration of dye [Fig. 3(b)]. Actual amount of dye adsorbed per unit mass of the adsorbent (q mgg−1) was increased with increase in initial dye concentration. Effect of contact time on adsorption is shown in Fig. 3(c). Equilibrium was established in 5 min for low concentration (20 mg L− 1) of dye while it take relatively longer contact time at higher initial concentrations due to the higher amount of dye molecules [46,47].The extent of adsorption is rapid in the initial stages due to the availability of a large number of surface sites and becomes slow in later stages till saturation is attained. This is due to the difficulty involved in occupying the remaining surface sites due to repulsion between solute molecules of the solid and bulk phases. A rapid uptake of dye and establishment of equilibrium in a short period signifies the efficiency of the biosorbent for its use in wastewater treatment. 3.2.3. Effect of adsorbent mass Adsorbent mass also affect the adsorption process at a constant initial concentration of the dye solution. Fig. 3(d) shows an increase in percentage removal from 95.8 to 98.5 with increase in biosorbent mass from 0.02–0.08 mgL− 1. This is due to the increase in sorption sites with the increase in the amount of the adsorbent. 3.3. Isotherm analysis Out of the three isotherm models, Langmuir, Freundlich and Temkin shown in Fig. 4(a), (b) and (c) respectively, the data fitted well with Langmuir model with a high value for correlation coefficient R2 (0.998). The isotherm constants and regression data for all the three adsorption isotherms for adsorption of MG dye on CANPs are shown in Table 1. The maximum biosorption capacity of nanoalginate obtained from Langmuir model was 277.78 mgg−1. The value of Freundlich constant kf representing sorption capacity is 81.45 and that of the slope 1/n which is a measure of adsorption intensity is 0.2729 with an R2 value of 0.935. This result indicated the best fit of the data with both Langmuir and Freundlich isotherms, slightly better described by Langmuir model. This suggests the monolayer coverage of MG dye on the surface of the nanobiosorbent [22]. Table 5 Thermodynamic parameters of malachite green dye adsorption onto CANPs. Temp

kc

Ea

(Kelvin)

(K J mol

303 313 323 333

29.82 29.90 29.99 30.07

−1

)

ΔG0 (K J mol

24.35 33.59 44.23 65.89

−8.04 −9.10 −10.10 −11.60

ΔH0 −1

)

(K J mol

27.30

ΔS0 −1

)

(J K−1 mol−1)

116.48

From the plot of qe versus ln Ce, the values of the Temkin isotherm constant AT (Lg− 1) and BT related to heat of sorption (J mol− 1) are determined. The value of the regression coefficient 0.911 shows the poorest fit of the experimental data in this model. Thus it can be concluded that the Langmuir monolayer adsorption model was more suitable for the adsorption of MG dye on CANPs. The values of the equilibrium parameter RL for varying concentrations of MG dye are given in Table 2. Since the value of RL lies between 0 and 1, the adsorption of MG dye onto CANPs is a favourable one. 3.4. Adsorption kinetics Using Eq. (7), ln (qe − qt) versus t was plotted at different MG concentrations and is shown in Fig. 5(a). The Lagergren first order rate constant (k1) and qe determined from the model are presented in Table 3 along with the corresponding correlation coefficients. The low values of the correlation coefficient show that the adsorption of MG by nanoalginate does not obey first order kinetics. Therefore, the experimental kinetic data was further analysed using the pseudo second order model by plotting t/qt against t [Fig. 5(b)].The higher values of R2 for all the varying initial concentrations of MG indicate the better fit of pseudo second order kinetic model. The decrease in the rate of MG removal with increasing initial dye concentration is evident from the decreasing values of k2 with increase in dye concentration. At higher concentrations the dye diffusivity decreases due to the association of MG molecules forming bulky aggregates [48]. The value of qe obtained from the slope of the plot of second order kinetics is in close agreement with that of the experimental value. 3.5. Intraparticle diffusion mechanism To analyse the mechanism of adsorption the experimental data was fitted into intra particle diffusion model. For this the amount of dye adsorbed at different time t (qt) was plotted against square root of time (t1/2) [Fig. 5(c)]. Graph passing through the origin indicate intraparticle diffusion mechanism. The deviation of the plots from the origin and the higher values of intercept C (boundary layer effect) seen in this study indicate a combination of intraparticle diffusion and surface adsorption as the rate-limiting mechanism [49]. The rate constants and regression coefficients of intraparticle diffusion model is included in Table 4.

3.6. Thermodynamic studies The thermodynamic parameters for the biosorption of MG onto nanoalginate at various temperatures were computed by plotting ln kc vs 1/T [Fig. 5(d)] and the values are listed in Table 5. ΔH0 and ΔS0 have been computed from the slope and the intercept of the plot while the Gibbs free energy change ΔG0 was calculated using Eq. (11). The positive value of ΔH0 indicates the endothermic nature [50] while that of ΔS0 confirms the irreversible nature, sorption stability [51] as well as increasing randomness at the solid/liquid interface during adsorption. As the dye molecules get attached to the biosorbent, the previously bound water molecules on the dye get released as free molecules and disbursed to the solution causing an increase in entropy [52].The positive value of ΔS0 indicates high affinity of the dye towards the biosorbent as well as the structural change taking place in the adsorbent and adsorbate [53–55]. The negative values of ΔG0 indicate the spontaneity of adsorption process and its decrease with increase in temperature indicates more favourable adsorption at higher temperatures [56]. The positive value of Ea indicates that increase in temperature favours the biosorption process which is endothermic in nature.

P. Geetha et al. / Journal of Molecular Liquids 212 (2015) 723–730

3.7. Desorption studies Desorption studies reveal the nature of adsorption and the possibility of reuse of the adsorbent. Weakly bound dye can be easily desorbed by water at neutral pH. Dye attachment by ion exchange mechanism necessitates highly alkaline or acidic environment for desorption. i.e. if strong acids like HCl can desorb the dye, the attachment of the dye onto the adsorbent is by ion exchange or electrostatic attraction [57]. In our system more than 90% of the adsorbed dye was removed using HCl which confirmed the electrostatic nature of binding of MG dye to the nanosorbent [58]. 4. Conclusions In the present study nanoalginate produced by green technology was used for the removal of MG dye from aqueous solution. Reaction parameters such as contact time, initial dye concentration, pH, adsorbent dose, temperature etc. had a marked influence on the dye removal. A maximum of 98.5% of the dye was removed at an alkaline pH of 10, at 60 °C and at 5 min contact time. The equilibrium data fitted well with Langmuir adsorption model, obeying monolayer adsorption. The adsorption kinetics followed pseudo second order with combined influence of intraparticle diffusion and surface adsorption mechanisms in the rate determining step. The positive values of ΔH0 and ΔS0 indicate the endothermic nature and increasing randomness of the adsorption process while the negative value of ΔG0 confirmed the spontaneity of MG adsorption by nanoalginate. The activation energy of adsorption of MG dye was found to be lower than 42 KJ mol−1 indicative of diffusion controlled process. Ease of removal of dye in presence of acid after adsorption provides the possibility of reusing both dye and the biosorbent. This is very important in reducing waste material and controlling pollution of surface water in industrial area. Nanoparticles were synthesized by a green method and the use of organic reagents and solvents were avoided. The present study demonstrates the potential of using nanoalginate prepared by a green method for the effective removal of MG dye from industrial effluents. Acknowledgements Geetha P is thankful to the University Grants Commission, SWRO (No.F.FIP./XIth plan/KLMG047TF03 dtd 30/08/2011) for providing financial support for the conduct of the research work under the Faculty Improvement Programme during XIth plan period. References [1] S.V. Mohan, N.C. Rao, S. Srinivas, K.K. Prasad, J. Karthikeyan, Treatment of simulated reactive yellow 22 (Azo) dye effluents using Spirogyra species, Waste Manag. 22 (2002) 575–582. [2] M. Mohamed, Acid dye removal: comparison of surfactant–modified mesoporous FSM — 16 with activated carbon derived from rice husk, J. Colloid Interface Sci. 272 (2004) 28–34. [3] G. Parshetti, S. Kalme, G. Saratale, S. Govindwar, Biodegradation of Malachite Green by Kocuria rosea MTCC 1532, Acta Chim. Slov. 53 (2006) 492–498. [4] K. Vijayaraghavan, Y.S. Yun, Biosorption of C.I. Reactive Black 5 from aqueous solution using acid-treated biomass of brown seaweed Laminaria sp, Dyes Pigments 76 (2008) 726–732. [5] P. Monash, G. Pugazhenthi, Adsorption of crystal violet dye from aqueous solution using mesoporous materials synthesized at room temperature, Adsorption 15 (2009) 390–405. [6] R. Dod, G. Banerjee, S. Saini, Adsorption of methylene blue using green pea peels (Pisum sativum): a cost-effective option for dye-based waste water treatment, Biotechnol. Bioprocess Eng. 17 (2012) 862–874. [7] R. Gong, Y. Ding, M. Li, C. Yang, H. Liu, Y. Sun, Utilization of powdered peanut hull as biosorbent for removal of anionic dye from aqueous solution, Dyes Pigments 64 (2005) 187–192. [8] T. Akar, A.S. Ozcan, S. Tunali, A. Ozcan, Biosorption of a textile dye (Acid Blue 40) by cone biomass of Thuja orientalis: estimation of equilibrium, thermodynamic and kinetic parameters, Bioresour. Technol. 99 (2008) 3057–3065.

729

[9] B.H. Hameed, M.I. El-Khaiary, Malachite green adsorption by rattan sawdust: isotherm, kinetic and mechanism modeling, J. Hazard. Mater. 159 (2008) 574–579. [10] K.V. Kumar, K. Porkodi, Batch adsorber design for different solution volume/ adsorbent mass ratios using the experimental equilibrium data with fixed solution volume/adsorbent mass ratio of malachite green onto orange peel, Dyes Pigments 74 (2007) 590–594. [11] F.A. Pavan, E.C. Lima, S.L.P. Dias, A.C. Mazzocato, Methylene blue biosorption from aqueous solutions by yellow passion fruit waste, J. Hazard. Mater. 150 (2008) 703–712. [12] M. Daneshvar, A.R. Ayazloo, M. Khataee, Pourhassan, biological decolorization of dye solution containing malachite green by microalgae Cosmarium sp, Bioresour. Technol. 98 (2007) 1176–1182. [13] S. Cengiz, L. Cavas, Removal of methylene blue by invasive marine seaweed: Caulerpa racemosa var. cylindracea, Bioresour. Technol. 99 (2008) 2357–2363. [14] Z. Bekc, I.C. Özveri, Y. Seki, K. Yurdakoc, Sorption of malachite green on chitosan bead, J. Hazard. Mater. 154 (2008) 254–261. [15] S. Srivastava, R. Sinha, D. Roy, Toxicological effects of malachite green, Aquat. Toxicol. 66 (2004) 319–329. [16] V.K. Garg, R. Kumar, R. Gupta, Removal of malachite green dye from aqueous solution by adsorption using agro-industry waste: a case study of Prosopiscineraria, Dyes Pigments 62 (2004) 1–10. [17] E. Forgacs, T. Cserhatia, G. Orosl, Removal of synthetic dyes from wastewaters: a review, Environ. Int. 30 (2004) 953–971. [18] K.V. Kumar, V. Ramamurthi, S. Sivanesan, Biosorption of malachite green, a cationic dye onto Pithophora sp., a fresh water alga, Dyes Pigments 69 (2006) 102–107. [19] F. Wang, J. Zhao, F. Pan, H. Zhou, X. Yang, W. Li, H. Liu, Adsorption properties toward trivalent rare earths by alginate beads doping with silica, Ind. Eng. Chem. Res. 52 (2013) 3453–3461. [20] F. Wang, J. Zhao, X. Wei, F. Huo, W. Li, Q. Hu, H. Liu, Adsorption of rare earths (III) by calcium alginate–poly glutamic acid hybrid gels, J. Chem. Technol. Biotechnol. 89 (2014) 969–977. [21] Y.S. Jeon, J. Lei, J.H. Kim, Dye adsorption characteristics of alginate/polyaspartate hydrogels, J. Ind. Eng. Chem. 14 (2008) 726–731. [22] A. Mohammadi, H. Daemi, M. Barikani, Fast removal of malachite green dye using novel superparamagnetic sodium alginate coated Fe3O4 nanoparticles, Int. J. Biol. Macromol. 69 (2014) 447–455. [23] I. Langmuir, The constitution and fundamental properties of solids and liquids, J. Am. Chem. Soc. 38 (1916) 2221–2295. [24] H.M.F. Freundlich, Over the adsorption in solution, J. Phys. Chem. 57 (1906) 385–470. [25] M.J. Temkin, V. Pyzhev, Recent modifications to Langmuir isotherms, Acta Physiochim. URSS 12 (1940) 217–222. [26] T.W. Weber, R.K. Chakkravorti, Pore and solid diffusion models for fixed bed adsorbers, AICHE J. 20 (1974) 228–238. [27] Y. Zhang, Y. Li, L.Q. Yang, X.J. Ma, L.Y. Wang, Z.F. Ye, Characterization and adsorption mechanism of Zn2+ removal by PVA/EDTA resin in polluted water, J. Hazard. Mater. 178 (2010) 1046–1054. [28] S. Lagergren, About the theory of so-called adsorption of soluble substances, K. Sven. Vetenskapsakad. Handl. 24 (1898) 1–39. [29] Y.S. Ho, G. McKay, Sorption of dye from aqueous solution by peat, Chem. Eng. J. 70 (1998) 115–124. [30] W.J. Weber Jr., J.C. Morris, Kinetics of adsorption on carbon from solution, J. Sanit. Eng. Div. Proc. Am. Soc. Civil Eng. 89 (1963) 31–59. [31] B.R. Venkatraman, K. Hema, V. Nandhakumar, S. Arivoli, Adsorption thermodynamics of Malachite green dye onto acid activated low cost carbon, J. Chem. Pharm. Res. 3 (2011) 637–649. [32] A.E. Martell, R.M. Smith, Critical Stability Constants: Inorganic Chemistry IV, Plenum, New York, 1977. [33] J.M. Murray, J.G. Dillard, The oxidation of cobalt (II) adsorbed on manganese dioxide, Geochim. Cosmochim. Acta 43 (1979) 781–787. [34] Y.S. Ho, A.E. Ofomaja, Biosorption thermodynamics of cadmium on coconut copra meal as biosorbent, Biochem. Eng. J. 30 (2006) 117–123. [35] D.L. Sparks, Environ, Soil. Chem. Academic Press, San Diego, CA, 1995. [36] B.H. Hameed, M.I. El-Khaiary, Batch removal of malachite green from aqueous solutions by adsorption on oil palm trunk fibre: equilibrium isotherms and kinetic studies, J. Hazard. Mater. 154 (2008) 237–244. [37] T. Santhi, S. Manonmani, T. Smitha, Removal of malachite green from aqueous solution by activated carbon prepared from the epicarp of Ricinus communis by adsorption, J. Hazard. Mater. 179 (2010) 178–186. [38] M.M. EL-Tayieb, M.M. El-Shafei, M.S. Mahmoud, The role of alginate as polymeric material in treatment of tannery wastewater, Int. J. Sci. Technol. 2 (2013) 218–224. [39] J.R. Dyer, Applications of Absorption Spectroscopy of Organic Compounds, PrenticeHall, University of Michigan, 1965. [40] C.P. Sekhar, S. Kalidhasan, V. Rajesh, N. Rajesh, Bio-polymer adsorbent for the removal of malachite green from aqueous solution, Chemosphere 77 (2009) 842–847. [41] S. Qaiser, R. Anwar, Saleemi, M. Uma, Biosorption of lead (II) and chromium (VI) on groundnut hull: equilibrium, kinetics and thermodynamics study, Electron. J. Biotechnol. 12 (2009) 1–17. [42] R.C. Sun, J. Tomkinson, Fractional separation and physicochemical analysis of lignins from the black liquor of oil palm trunk fiber pulping, Sep. Purif. Technol. 24 (2001) 529–539. [43] M. Anbia, A. Ghaffari, Removal of Malachite green from dye wastewater using mesoporous carbon adsorbent, J. Iran. Chem. Soc. l (8) (2011) S67–S76. [44] K. Porkodi, K.V. Kumar, Equilibrium, kinetics and mechanism modeling and simulation of basic and acid dyes sorption onto jute fiber carbon: eosin yellow, malachite green and crystal violet single component systems, J. Hazard. Mater. 143 (2007) 311–327.

730

P. Geetha et al. / Journal of Molecular Liquids 212 (2015) 723–730

[45] X. Pan, D. Zhang, Removal of malachite green from water by firmiana simplex wood fiber, Electron. J. Biotechnol. 12 (2009) 1–10. [46] M.N. Idris, Z.A. Ahmad, M.A. Ahmad, Adsorption equilibrium of malachite green dye onto rubber seed coat based activated carbon, Int. J. Basic Appl. Sci. 11 (2011) 38–43. [47] M.A. Shouman, S.A. Khedr, A.A. Attia, Basic dye adsorption on low cost biopolymer: kinetic and equilibrium studies, IOSR-JAC 2 (2012) 27–36. [48] T. Vckerstaff, The Physical Chemistry of Dyeing, Interscience Publishing Inc., N.Y., 1954 [49] M.M. Abd El-Latif, A.M. Ibrahim, M.F. El-Kady, Adsorption equilibrium, kinetics and thermodynamics of methylene blue from aqueous solutions using biopolymer oak sawdust composite, J. Am. Sci. 6 (2010) 267–283. [50] S. Arivoli, M. Hema, Comparative study on the adsorption kinetics and thermodynamics of dyes onto acid activated low cost carbon, Int. J. Phys. Sci. 2 (2007) 10–17. [51] R. Donat, A. Akdogan, E. Erdem, H. Cetisli, Thermodynamics of Pb2+ and Ni2+ adsorption onto natural bentonite from aqueous solutions, J. Colloid Interface Sci. 286 (2005) 43–52. [52] S. Senthilkumaar, P. Kalaamani, C.V. Subburaam, Liquid phase adsorption of crystal violet onto activated carbons derived from male flowers of coconut tree, J. Hazard. Mater. B136 (2006) 800–808.

[53] R. Patel, S. Suresh, Kinetic and equilibrium studies on the biosorption of reactive black 5 dye by Aspergillus foetidus, Bioresour. Technol. 99 (2008) 51–58. [54] Ö. Saltabaş, M. Teker, Z. Konuk, Biosorption of cationic dyes from aqueous solution by water hyacinth roots, Global NEST J. 14 (2012) 24–31. [55] V.K. Gupta, K. Vinod, Equilibrium uptake, sorption dynamics, process development, and column operations for the removal of copper and nickel from aqueous solution and wastewater using activated slag, a low-cost adsorbent, Ind. Eng. Chem. Res. (ACS) 37 (1998) 192–202. [56] A.B. Zaki, M.Y. El-Sheikh, J. Evans, S.A. El-Safty, Kinetics and mechanism of the sorption of some aromatic amines onto amberlite IRA-904 anion exchange resin, J. Colloid Interface Sci. 221 (2000) 58–63. [57] I.D. Mall, V.C. Srivastava, G.V.A. Kumar, I.M. Mishra, Characterization and utilization of mesoporous fertilizer plant waste carbon for adsorptive removal of dyes from aqueous solution, Colloids Surf. A 278 (2006) 175–187. [58] L. Wang, J. Zhang, A. Wang, Fast removal of methylene blue from aqueous solution by adsorption onto chitosan-g-poly (acrylic acid)/attapulgite composite, Desalination 266 (2011) 33–39.