Adsorption of copper on chitin-based materials: Kinetic and thermodynamic studies

ARTICLE IN PRESS

JID: JTICE

[m5G;May 30, 2016;16:56]

Journal of the Taiwan Institute of Chemical Engineers 0 0 0 (2016) 1–9

Contents lists available at ScienceDirect

Journal of the Taiwan Institute of Chemical Engineers journal homepage: www.elsevier.com/locate/jtice

Adsorption of copper on chitin-based materials: Kinetic and thermodynamic studies Abdelkader Labidi a,b, Asier M. Salaberria c, Susana C.M. Fernandes c, Jalel Labidi c,∗, Manef Abderrabba a a

Laboratory of Materials, Molecules and Applications, IPEST, Preparatory Institute of Scientific and Technical Studies of Tunis, University of Carthage, Sidi Bou Said road, B.P. 51 2070, La Marsa, Tunisia Chemistry Department, El Manar University, University of Sciences of Tunis, B.P: 248, El Manar II, 2092 Tunis, Tunisia c Biorefinery Processes Research Group, Department of Chemical and Environmental Engineering, University of the Basque Country (UPV/EHU), Plza. Europa1, 20018 Donostia-San Sebastian, Spain b

a r t i c l e

i n f o

Article history: Received 11 January 2016 Revised 28 March 2016 Accepted 24 April 2016 Available online xxx Keywords: Chitin Chitosan Chitosan-EDTA Copper Adsorption capacity

a b s t r a c t Copper (Cu (II)) is one of the most toxic heavy metals usually found in the environment. Thus its removal from aqueous waste streams is an important issue in nowadays. The present work focuses on the comparison of the copper adsorption on chitin-based adsorbents, i.e. chitin (CH), chitosan (CS) and chitosan- ethylenediaminetetra-acetic acid (CS-EDTA). Chitin derivatives are carbohydrate materials well known to remove heavy metal ions from aqueous solutions. The effects of contact time, initial concentration, the temperature, pH, and mass of the adsorbent in the adsorption process were studied. The adsorption isotherms were well simulated by Langmuir and Freundlich models. The maximum adsorption capacity of CH, CS and CS-EDTA at 25 °C, pH 7.0 was found to be 58, 67 and 110 mg g−1 , respectively. Thermodynamic parameters of adsorption processes such as Gibb’s free energy (G0 ), standard enthalpy (H◦ ) and entropy (S0 ) were also calculated. The results showed that the studied materials could be used as effective adsorbents for removal of copper from water. © 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

1. Introduction The waste water contamination by heavy metals is a worldwide environmental and social problem. Some metals like copper, chromium, mercury and lead are classified as toxic due to their non-biodegradability and bioaccumulation in living organisms [1]. Metals such as copper play important roles in certain industries. Copper is often used in the drive moving parts, brake linings, metal plating, pulp and paper industry, fertilizer mills, fungicides, insecticides, etc. [2]. Copper is considered a trace element at low doses due to the fact that human body can regulate the trace level haemostatically but it can be toxic at high concentration because of their tendency to accumulate in the vital organs [3] and their harmful impact on the environment due to the fact that they are non-biodegradable causing many diseases and disorders [4]. With bends its dangers, the presence of copper ions in water must be controlled. The maximum contamination level for Cu (II) ions in the industrial effluent required by United States Environmental Protection Agency (USEPA) is 1.3 mg L−1 [5]. Several

∗

Corresponding author. Tel.: +34 943017178. E-mail address: [email protected] (J. Labidi).

methods, namely chemical precipitation [6], ion exchange [7], and biological treatment [8], membrane filtration [9] and adsorption [10] were currently used to remove Cu (II) from aqueous solutions. Adsorption processes have been considered effective and efficient methods to remove Cu (II) from aqueous solutions, using a wide variety of adsorbents such as rice husks [11], carbon nanotubes [12] and lignin [13]. The use of biopolymers for removal of heavy metals from water treatment plants is one of the emerging adsorption approaches because of their good ability and affinity towards these compounds in aqueous solution. Moreover, biopolymers are from renewable resources, biodegradable and have an excellent capacity to associate with a wide variety of molecules by physical and chemical interactions [14]. Among the biopolymers, chitin that is the second most abundant natural polymer in earth after cellulose (one of the main components of crustacean shells [15]), and its main derivative, chitosan, present hydroxyl group (OH) and an amino group (NH2 ) in their backbone. The presence of these two different functional groups, which are good and valid chelating groups for the coordination of metal ions in aqueous solutions such as Cu (II), Cd (II) and U (VI) [16,17], reinforce their use in adsorption studies. Recently, chitin- and chitosan-based adsorbents in different physical forms (e.g. gel beads, membranes, sponge, fibres or hollow fibres, etc.) have been used for removal of varieties of heavy

http://dx.doi.org/10.1016/j.jtice.2016.04.030 1876-1070/© 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Please cite this article as: A. Labidi et al., Adsorption of copper on chitin-based materials: Kinetic and thermodynamic studies, Journal of the Taiwan Institute of Chemical Engineers (2016), http://dx.doi.org/10.1016/j.jtice.2016.04.030

ARTICLE IN PRESS

JID: JTICE 2

[m5G;May 30, 2016;16:56]

A. Labidi et al. / Journal of the Taiwan Institute of Chemical Engineers 000 (2016) 1–9

Abbreviations CH CS CS-EDTA C0 Ce qe qt K1 K2 H qe,

cal

qe,

exp

Kf 1 n

Rl Kl qm T Ca Kc G 0 H 0 S 0 kp C

Chitin Chitosan Chitosan-ethylenediaminetetra-acetic acid Initial copper concentration (mg L−1 ) Concentration of copper solution at equilibrium (mg L−1 ) Amount of copper adsorbed at equilibrium (mg g−1 ) Amount of copper adsorbed at time (t) (mg g−1 ) The constant adsorption pseudo-first-order model (min−1 ). The constant adsorption pseudo-second- order model (g mg−1 min−1 ) The initial absorption rate (mg g−1 min−1 ) Amount of copper calculated at equilibrium (mg g−1 ) Amount of copper of the experimental at equilibrium (mg g−1 ) Freundlich adsorption isotherm constant (mg g−1 ) Freundlich adsorption isotherm constant Dimensionless separation constant Langmuir isotherm constant related to the energy of adsorbent (L mg−1 ) The maximum adsorption capacity (mg g−1 ) Temperature (°C, K) The adsorbent phase concentration at equilibrium (mg L−1 ) The equilibrium constant Standard free energy (kJ mol−1 ) Standard enthalpy change (KJ mol−1 ) Standard entropy change (KJ mol−1 K−1 ) The constant of intraparticle diffusion model (mg g−1 min−1/2 ) The thickness of the boundary layer (mg g−1 )

metals and dyes. For instance, chitosan membranes crosslinked with glutaraldehyde and epichlorohydrin are used for adsorption of copper [18–21]. Chitosan amino and hydroxyl groups can act as chelation sites for different metals, but can also be functionalized in order to improve this property [22]. Ethylendiaminetetraacetic acid (EDTA) is known to forms stable chelates with metal ions and has been used to functionalize CS to improve its chelation capacity and used as removal absorbent of toxic metals such as Co (II) and Ni (II) [23]. In this previous work, the authors compared the affinities of metals to CS-EDTA by a kinetic study, adsorption isotherm as evaluation tool between experimental and theoretical values. This work showed that the CS-EDTA had much better affinity for Ni (II) than for Co (II) suggesting that Ni (II) could be adsorbed selectively from the contaminated water in the presence of Co (II). EDTA was also used to in other study in the development of chitosan–silica hybrid materials for the adsorption of Co (II), Ni (II), Cd (II) and Pb (II) for water treatment [24]. In this context, the aim of this study was to synthesise chitosan-ethylenediaminetetraacetic acid (CS-EDTA) derivative and compared its Cu (II) removal capacity with those of chitin and unmodified chitosan powder. The Cu (II) adsorption properties by chitin, chitosan and chitosanEDTA were evaluated in terms of adsorption kinetics, adsorption isotherms, thermodynamic study and the adsorption mechanism. This study leads to a comparative study between a natural polymers and grafted chitosan showing the effect of chelating moiety

on the adsorption capacity due to the presence of amide and carboxylic groups on CS-EDTA.

2. Experimental 2.1. Materials Chitosan powder (CS, degree of deacetylation of 98% and viscosity-average molecular weight of 50 0,0 0 0) was supplied by Mahtani Chitosan PVT. Ltd., India. CS was purified before use by a precipitation method [25]. Briefly, CS was dissolved in 1% (v/v) aqueous acetic acid solution, filtered, and precipitated by neutralization with sodium hydroxide up to a pH = 8.5. The ensuing precipitate sample was washed with distilled water until a neutral pH and air-dried. Chitin (CH) powder was extracted in our laboratory from yellow lobster wastes (kindly supplied by Antartic Seafood S.A., Chile) based on procedures previously described in references [26–29]. The degree of deacetylation was found to be 4% by 13 C NMR. Ethylenediaminetetra-acetic acid (EDTA, ACS reagent, 99.4%), acetic anhydride (ACS reagent, > 98%), pyridine (ACS reagent, > 99%), methanol (HPLC, > 99%), ethanol (ACS reagent > 98%), diethyl ether (ACS reagent > 99%), Copper (II) nitrate-trihydrate (Cu(NO3 )2 .3H2 O, > 99%), hydrochloric acid (HCl, ACS reagent, 37%), and sodium hydroxide (NaOH, reagent grade, ≥ 98%, pellets (anhydrous)) were all purchased from Sigma–Aldrich and used as received without further purification. 2.2. Preparation and characterization of chitosan-EDTA derivative The preparation of the adsorbent chitosan-ethylenediaminetetra-acetic (CS-EDTA) was done in two steps: (A) synthesis of EDTA anhydride, and (B) polycondensation (Fig. 1). 2.2.1. Preparation of EDTA anhydride 10.0 g of EDTA (34 mmol) was suspended in 16 mL of pyridine under a nitrogen atmosphere. Subsequently, 14.0 g of acetic anhydride (0.14 mmol) was added and the mixture was stirred at 65 °C for 24 h. The final product (Fig. 1A) was then washed with an excess of acetic anhydride and diethyl ether and dried in vacuum for 24 h [30]. The chemical modification was confirmed by ATR-FTIR spectra (data not shown). Comparing with the unmodified EDTA ATR-FTIR spectrum, the EDTA anhydride spectrum clearly shows two asymmetric bands at 1804 and 1747 cm−1 , attributed to the two C=O groups of the anhydride function [31]. 2.2.2. Preparation of CS-EDTA Chitosan was chemically modified with EDTA anhydride according to the reaction shown in Fig. 1B. A total of 1 g chitosan (6 mmol) of glucosamine units was dissolved in 100 mL (10% vol. acetic acid), subsequently, the chitosan solution was diluted five times with methanol. A total of 6 g EDTA anhydride (0.0234 mol) were suspended in 100 mL of methanol and added to the solution of chitosan. The mixture was then stirred for 24 h at room temperature. After filtration, the precipitate (CS-EDTA) was first washed with ethanol and stirred for 12 h. After further filtration, the precipitate was dispersed in diluted 0.5 M NaOH solution (50 mL for 12 h to remove unreacted EDTA anhydride. Finally, the precipitate was washed several times with distilled water [32,33]. The solution was then neutralized with hydrochloric acid (0.1 M) and the obtained gel was dried for 24 h at 40 °C. The ensuing CS-EDTA (1.9 g) derivative was characterized in terms of chemical structure (ATRFTIR and 13 C solid-state NMR).

Please cite this article as: A. Labidi et al., Adsorption of copper on chitin-based materials: Kinetic and thermodynamic studies, Journal of the Taiwan Institute of Chemical Engineers (2016), http://dx.doi.org/10.1016/j.jtice.2016.04.030

JID: JTICE

ARTICLE IN PRESS

[m5G;May 30, 2016;16:56]

A. Labidi et al. / Journal of the Taiwan Institute of Chemical Engineers 000 (2016) 1–9

A

3

B

Fig. 1. Synthesis of EDTA anhydride (A) and CS-EDTA (B).

2.3. Characterization of the materials ATR-FTIR spectra (United States) were recorded on a Nicolet Nexus 670 equipped with a KRS-5 crystal of refractive index 2.4 and using an incidence angle of 45°. The spectra were taken in a transmittance mode in the wavenumber range of 750–40 0 0 cm−1 , with resolution of 4 cm−1 and after 128 scan accumulations. 13 C solid-state NMR spectra were obtained using a Bruker 400 WB Plus spectrometer. Spectra were collected by using a 4 mm CPMAS probe with a sample spinning rate of 10,0 0 0 Hz. 13 C CP-MAS spectra at 100.6 MHz of the solid samples were obtained using 12 h spectral accumulation time, a time domain of 2 K points, a spectral width of 29 kHz, a contact time of 1.5 ms and an interpulse delay of 5 s. Visible ultraviolet spectrophotometer (Jasco V-630 instrument) was used to measure the residual Cu (II) concentration.

tion capacity of Cu (II) at equilibrium was calculated as follows (Eq. 1) while the metal removal efficiency R was calculated from (Eq. 2).

C0 − Ce ∗V M

(1)

C0 − Ce ∗ 100 C0

(2)

qe = R=

Where: qe is the amount of copper adsorbed on chitin, chitosan and chitosan-EDTA at equilibrium (mg g−1 ), C0 and Ce is the initial and the equilibrium concentration of copper in the solution, respectively (mg L−1 ), M is the weight of adsorbents (g) and V (L) volume of solution. 3. Results and discussion 3.1. Characterization of CS-EDTA

2.4. Adsorption experiments The batch adsorption experiments were performed in triplicate. Before the adsorption tests, appropriate solutions of different Cu (II) concentrations (150, 200, 250 and 300 mgL−1 ) were prepared from Cu (NO3 )2 .3H2 O. The effect of contact time from 1 to 90 min on the absorption chitin, chitosan and CS-EDTA sorption capacity was studied at fixed temperature and pH (25 °C, pH 7.0). The pH of the different solutions was adjusted by adding different concentrations of HCl (0.1 N) or NaOH (0.1 N). Adsorption experiments were performed by stirring 0.2 g of each material, i.e. chitin, chitosan and chitosan-EDTA at 300 rpm in 100 mL of the above Cu (II) solutions. At the determinate contact time, the supernatant was removed and filtered. The residual Cu (II) concentration was measured by a visible ultraviolet spectrophotometer at 810 nm that correspond to the maximum absorbance for copper. The thermodynamic parameters of the adsorption were established by studying adsorption of copper at different temperatures (from 25 to 45 °C). The absorp-

The chemical modification of chitosan was confirmed by ATRFTIR (Fig. 2A) and 13 C solid-state NMR (Fig. 2B). The presence of bands associated with amide and carboxylic groups, and the decrease of intensity of the bands between 30 0 0 and 340 0 cm−1 assigned to OH and NH2 groups, in the CS-EDTA spectrum on Fig. 2A, confirms the functionalization of chitosan with EDTA anhydride. The spectrum of the CS-EDTA shows: (i) a band at 1727 cm−1 attributed to the carbonyl group of the carboxylic acid function (COOH); (ii) a strong band at 1624 cm−1 assigned to the carbonyl group of the amide function; (iii) a band at 1540 cm−1 assigned to the vibration (NH) of the secondary amide; (iv) the presence of an intense band at 1383 cm−1 attributed to the (C=O) (COOH); and (v) a band at 1311 cm−1 assigned vibration (OCN) [34]. Fig. 2B shows the solid-state 13 C NMR spectra of CS and CSEDTA. CS spectra showed the typical peaks of chitosan at 57.53, 61.47, 75.8, 83.21, 86.08 and 105.27 ppm characteristic to oligosaccharides carbons [35]. The most significant peaks of CS-EDTA

Please cite this article as: A. Labidi et al., Adsorption of copper on chitin-based materials: Kinetic and thermodynamic studies, Journal of the Taiwan Institute of Chemical Engineers (2016), http://dx.doi.org/10.1016/j.jtice.2016.04.030

ARTICLE IN PRESS

JID: JTICE 4

[m5G;May 30, 2016;16:56]

A. Labidi et al. / Journal of the Taiwan Institute of Chemical Engineers 000 (2016) 1–9

A

B

Fig. 2. ATR-FTIR spectra of CS and CS-EDTA (A),

13

C NMR spectra of CS and CS-EDTA (B).

Fig. 3. Effect of contact time on the adsorption of Cu (II) onto CH, CS and CS-EDTA at different concentrations of Cu (II) (150, 200, 250 and 300 mgL− 1 ) at 25 °C and pH = 7 using 0.2 g of adsorbent.

appeared at 168.34 and 174.40 ppm corresponding to the carbonyl of amide group and carboxylic acid, respectively. The signal at 59.35 ppm was attributed to the CH2 of EDTA; both signals at 55.55 and 52.94 ppm were assigned to the CH2 groups of the ethyl group of EDTA on the functionalized chitosan [36]. 3.2. Adsorption kinetics 3.2.1. Effect of contact time on the adsorption of Cu (II) by CH, CS and CS-EDTA Fig. 3A, B, C shows the sorption capacity as a function of time (from 1 to 90 min) of CH, CS and CS-EDTA powders in 100 mL of

each different copper concentration solution. Fig. 4 shows the general aspect and the colors of the materials before and after the absorption tests. The three materials showed almost the same behavior regarding the removal of Cu (II) ions in the different solutions, increasing up to 30 min and then were maintained almost constant. In other words, the copper adsorption occurred in two steps: an initial fast step up to 30 min followed by a second phase in which no important variation on the adsorption capacity was observed. This observation is due to the fact that the adsorption sites are available at the beginning of the experiments followed by a saturation of the metal on the surface of the adsorbent materials. Moreover, Fig. 3 also shows that the rate of removal of

Please cite this article as: A. Labidi et al., Adsorption of copper on chitin-based materials: Kinetic and thermodynamic studies, Journal of the Taiwan Institute of Chemical Engineers (2016), http://dx.doi.org/10.1016/j.jtice.2016.04.030

JID: JTICE

ARTICLE IN PRESS

[m5G;May 30, 2016;16:56]

A. Labidi et al. / Journal of the Taiwan Institute of Chemical Engineers 000 (2016) 1–9

5

Fig. 4. General aspect of CH, CS and CS-EDTA before and after copper adsorption.

Cu (II) ions was dependent on the initial concentration (c0 ) of Cu (II) ions as observed in previous study [30]. Promoting an increase in the adsorption capacity of all materials at different contact time. This observation is due to the fact that the mass transfer effects and the driving force of the concentration gradient being directly proportional to the initial concentrations [37]. Thus, the amide and carboxylic groups are present simultaneously in a polymer backbone (CS-EDTA) leads to the increase of adsorption capacity [38,39]. For instance, for the same initial concentration of 300 mg.L−1 , the absorption capacity of CS-EDTA (110 mg.g−1 ) was superior to CS (67 mg.g−1 ) and then CH (58 mg.g−1 ). 3.2.2. Simulation modeling of adsorption data The modeling of the adsorption kinetic was performed using the pseudo-first-order model and pseudo-second-order (Lagergren). These originally empirical models have been widely used to describe the kinetic of adsorption. The kinetic of Cu (II) adsorption on the (CH, CS, CS-EDTA) was investigated in relation to the pseudo-first-order kinetic model (Eq. 2) and the pseudo secondorder kinetic model (Eqs. 3 and 4) respectively: The pseudo-first-order kinetic model rate equation is given by Lagergren [40]:

dq = K1 ( qe − qt ) dt

(3)

qe and qt are the adsorption capacity of Cu (II) (mg.g−1 ) at equilibrium and at time (t) respectively, K1 (min−1 ) is the constant adsorption of the pseudo-first-order kinetic model. The linear variation of the curve log(qe − qt ) versus time (t) was used to calculate the values of the constant (K1 ) for the adsorption of Cu (II) by the CH, CS and CS-EDTA. The equation of the pseudo-second-order kinetic model is as follows [41]:

dq = K2 (qe − qt )2 dt H=

K2 q2e

(4) (5)

H (mg g−1 min−1 ) is the initial absorption rate, and the constant K2 (g mg−1 min−1 ) is the pseudo-second order kinetic model. The plot of the change in ( qt ) versus (t) allows determining the t values of K2 , H and qe . The correlation coefficient (R2 ) of the pseudo-first-order model for CH, CS and CS-EDTA (Table 1) is in the range of 90% and the values calculated qe,cal and experimental qe,exp are so far, this kinetic model is not valid. However the pseudo- second-order model,

the correlation coefficient (R2 ) exceeds 99% and the values of qe,cal calculated and qe,exp of the experimental are nearly coincident, these results demonstrate the validity of the kinetic pseudosecond-order, is valid for biopolymer as an adsorbent of metals citing chitosan modified by H2 SO4 [42], chitosan grafted with MNPS and amended by α -ketoglutarique acid [43]. 3.3. Adsorption isotherm Adsorption isotherm model is used to quantify the sorption capacity of CH, CS and CS-EDTA for the copper removal. Here, two isotherms, namely Langmuir and Freundlich models were applied (Eqs. 5–7). 3.3.1. Langmuir isotherm When adsorption occurs in a single layer in the adsorption sites energetically equivalent that can contain only one molecule per site and there no interactions between the adsorbed molecules. The Langmuir model equation is as follows:

qe =

qm 1 + Kl qm

(6)

qe (mg g−1 ) is the adsorption capacity at equilibrium, qm (mg g−1 ) is the maximum adsorption capacity, ce it is concentration of copper at equilibrium (mg L−1 ). Plotting the curve Cqee versus ce to cal-

culate the values of the affinity constant Kl (L mg−1 ) and qm [44]. To determine whether the adsorption is favorable, known as separation factor (Rl ) which are represented as:

Rl =

1 1 + Kl C0

(7)

(0 1) unfavorable Rl (= 1), linear (Rl = 0): irreversible, where C0 is the initial concentration of Cu (II) ions; Kl is the Langmuir constant. 3.3.2. Freundlich isotherm This empirical model can be applied to multilayer gas adsorption or liquid–solid adsorption with non-uniform distribution of adsorption energy and affinities onto a heterogeneous surface. The Freundlich model equation is as follows: 1

qe = Kf Ce n

(8)

where, Kf (mg g−1 ) and n are the Freundlich parameters related to adsorption capacity and adsorption intensity, respectively 1n represents the affinity of Cu (II) to the surface, 1n is greater than unity, it means that the S-type is isothermal and the adsorption of Cu (II)

Please cite this article as: A. Labidi et al., Adsorption of copper on chitin-based materials: Kinetic and thermodynamic studies, Journal of the Taiwan Institute of Chemical Engineers (2016), http://dx.doi.org/10.1016/j.jtice.2016.04.030

ARTICLE IN PRESS

JID: JTICE 6

[m5G;May 30, 2016;16:56]

A. Labidi et al. / Journal of the Taiwan Institute of Chemical Engineers 000 (2016) 1–9 Table 1 Parameters of kinetic model for the Cu (II) adsorption onto CH, CS and CS-EDTA. Material

Kinetic model

Parameters

150 mgL−1

200 mgL−1

250 mgL−1

300 mgL−1

CH

Pseudo-first-order

qe cal (mg g−1 ) K1 (min−1 ) R2 qe cal (mg g−1 ) K2 (g mg−1 min−1 ) H (mg g−1 min−1 ) R2 qe,exp (mg g−1 )

18.23 0.044 0.95 31.74 0.005 5.57 0.99 30.55

23.38 0 .036 0.92 39 .06 0.003 5.20 0.98 37.00

24.89 0.040 0.93 41.66 0.004 7.40 0.99 39.50

31.04 0.067 0.86 51.28 0.004 12.62 0.99 50.14

qe cal (mg g−1 ) K1 (min−1 ) R2 qe cal (mg g−1 ) K2 (g mg−1 min−1 ) H (mg g−1 min−1 ) R2 qe,exp (mg g−1 )

19.48 0.015 0.95 30 .75 0.007 7 .78 0.99 32.25

19.62 0.012 0.94 35.75 0 .008 12.39 0.99 37.17

18.45 0.010 0 .93 48.75 0.008 22.27 0.99 51 .81

24.51 0 .012 0 .91 60.75 0 .006 26 .88 0.99 62.50

qe cal (mg g−1 ) K1 (min−1 ) R2 qe cal (mg g−1 ) K2 (g mg−1 min−1 ) H (mg g−1 min−1 ) R2 qe,exp (mg g−1 )

20.41 0.038 0.97 75 .75 0.006 40 .16 0.99 75.00

28.84 0.044 0.94 91.74 0 .003 33.55 0.99 89.50

40.73 0.048 0 .96 100 0.003 34.96 0.99 98.00

39.81 0 .047 0 .98 111.11 0 .003 45 .66 0.99 109.00

Pseudo -second-order

CS

Pseudo-first-order

Pseudo-second-order

CS-EDTA

Pseudo-first-order

Pseudo -second-order

Table 2 Langmuir and Freundlich isotherm parameters for Cu (II) adsorption onto CH, CS and CS-EDTA at 25 °C. Materials

CH CS CS-EDTA

Langmuir

Freundlich

qm (mg.g−1 )

Rl

Kl (L.mg−1 )

R2

Kf (mg.g−1 )

1/n

R2

58 67 110

0.19a, 0.15b,0.12c 0.1d 0.11a, 0.08b, 0.07c 0 .06d 0.021a, 0.016b 0.013c, 0.01d

0.028 0.052 0.302

0.96 0.99 0.99

14.56 16.28 69.32

0.23 0.25 0.093

0.98 0.98 0.95

ions onto biopolymers is heterogeneous [45]. The Freundlich constants can be obtained from the plot of the change in logqe versus logce . Adsorption parameters using equations of Langmuir and Freundlich are summarized in Table 2. There are numerous studies and experimental models [46] showing that the adsorption performance of the metals by chitosan is dependent of the metal. Most studies using copper, have reported that the Langmuir model is the best to describe this adsorption. In a previous study showing the ability of the shrimp shell for the retention of copper [47], Langmuir model was adopted because of the competition between the proton and copper for binding sites on shrimp shell. In our study, the adsorption of Cu (II) onto chitin, chitosan, chitosan-EDTA was well performed by Langmuir isotherm showing high (R2 ) (from 0.96 to 0.99). These results may be due to a homogeneous distribution of active sites on the surface of these materials. The constant values (Rl ) are in the favorable boundary (between 0 and 1), and the Freundlich constant ( 1n ) is less than one, which also indicates a favorable process. The adsorption capacity of other chitin and chitosan derivatives tested for the removal of Cu (II) in previous studies is listed in Table 3. It is clear that CS-EDTA has a good adsorption capacity (qm = 110 mg g−1 ) compared to the other adsorbents [48–53]. 3.4. Thermodynamic studies The adsorption capacities of CH and CS decreased with increasing the temperature. This indicates that the adsorption of copper is favored at the lower temperatures but was favored at higher tem-

Table 3 Comparison of the maximum adsorption capacity (mg g−1 ) of Cu (II) on different chitin and chitosan derivatives (including CS-EDTA). Adsorbent material

Adsorption capacity (mg g−1 )

Polyaniline graft chitosan Chitosan nano-hydroxyapatite composite Epichlorohydrin cross-linked xanthate chitosan Chitosan membrane Chitosan-g-PEI Chitosan-g-BPMAMF Chitosan-EDTA powder

83.30 4.80 30.21 25.64 84.00 109 110

Refs.

[48] [49] [50] [51] [52] [53] Present study

peratures for CS-EDTA. The decrease of the adsorption at higher temperature for CH and CS indicates the exothermic nature of the adsorption process. To evaluate the effect of temperature on the adsorption of copper in the aqueous solution, the values of (G0 ), (H◦ ) and (S0 ) were determined as follows (Eqs. 8–11):

Ca Ce

(9)

G0 = −RT LnKc

(10)

Kc =

LnKc =

S ◦ R

−

H ◦ RT

G 0 = H 0 − T S 0

(11) (12)

Please cite this article as: A. Labidi et al., Adsorption of copper on chitin-based materials: Kinetic and thermodynamic studies, Journal of the Taiwan Institute of Chemical Engineers (2016), http://dx.doi.org/10.1016/j.jtice.2016.04.030

ARTICLE IN PRESS

JID: JTICE

[m5G;May 30, 2016;16:56]

A. Labidi et al. / Journal of the Taiwan Institute of Chemical Engineers 000 (2016) 1–9 Table 4 The thermodynamic parameters for the adsorption of Cu (II) onto CH, CS and CSEDTA. Material

H◦ (KJ mol−1 )

S◦ (KJ mol−1 K−1 )

࢞G° (KJ mol−1 )

T

CH

−33.65

−0.11

−0.87 0.23 1.33

25 35 45

CS

−31.91

−0.10

−2 .11 −1 .11 −0.11

25 35 45

CS-EDTA

5.32

0.025

−2 .13

25

Kc is the equilibrium constant, Ca is the adsorbent phase concentration at equilibrium (mg L−1 ) and Ce is the equilibrium concentration in solution (mg L−1 ). (G0 ), (H◦ ) and (S0 ) were from the linear variation of LnKc versus T1 (R2 > 0.99). The thermodynamic parameters for copper adsorption onto CH, CS and CSEDTA are shown in Table 4. In general, the change in free energy (Gibbs) for the physisorption is between −20 and 0 kJ mol−1 , but chemisorption is from −80 to −400 kJ mol−1 . The negative values of the standard enthalpy (− 31.91 kJ mol−1 , −33.65 kJ mol−1 to chitin and chitosan, respectively) shows that the adsorption is physical in nature involving low Wander Waals attraction forces type, and is also exothermic, the negative values of entropy (−0.10 KJ mol−1 , −0.11 KJ mol−1 for the chitin and chitosan, respectively) corresponds to a decrease in degree of freedom of the adsorbed species [54]. The values of (G0 ) at 25–45 °C are negative for the adsorption of copper onto chitosan indicates spontaneity is favored at these temperatures, against chitin, at 25 °C the value of G0 ) is negative indicates that the adsorption is possible, but at 35 °C and 45 °C, positive values indicate that spontaneity is not favored at these temperatures. The thermodynamic parameters of adsorption of copper onto CS-EDTA ((H◦ ) and (࢞S° )) were found to be 5.32 KJmol−1 and 0.025 KJ mol−1 K−1 respectively, the values of (G0 ) are −2.13, −2.38, −2.63 KJ mol−1 at the adsorption temperature of 25–45 ◦ C respectively (Table 4). Negative values of (G0 ) at different temperatures indicated the feasibility and spontaneous nature of the Cu (II) adsorption process. The positive value of (H◦ ) reflected an endothermic nature of adsorption, which was supported by the increased adsorption capacity of Cu (II) onto CSEDTA. The positive value of (S0 ) shows the increased randomness in the solid/solution interface during the sorption of Cu (II) ions by the adsorbent, on increasing the heterogeneity of the surface of the adsorbent [55]. 3.7. Mechanism of copper adsorption onto CH, CS and CS-EDTA 3.7.1. Interaction of Cu (II) with CH, CS and CS-EDTA adsorbents Chitin carries an amide group per glucose unit; this amide group is an electron pair available for coordination and behaves like a Lewis base. These mechanisms are generally complicated because they require the presence of different interactions like ion exchange, training complex coordination/chelation, electrostatic interactions, acid–base interactions, hydrogen bonds [56]. Chelation is the mechanism most appropriate to describe the adsorption binding of transition metal per chitosan. During the chelating nitrogen atoms in the amine groups of chitosan may create dative covalent bonds with the copper ions. Chelation of metal ions by chitosan is being classified as the “bridge model” or “pendant model,” according to the nature of the bonding pattern. In the “bridge model”, the metal ions are bound to two amine groups of the same channel or different channels, via intra or intermolecular complexation, in contrast to “bridge model”, the metal ion is bound to a single amine group in a suspend mode, and hydroxyl groups and pairs of oxygen atoms in the water molecules

7

Table 5 Parameters of intraparticle diffusion model for Cu (II) adsorption. Materials

C0

k p1

k p2

c1

c2

R1 2

R2 2

CH

a b c d

3.22 2.47 3.86 7.45

1.25 2.35 1.80 1.62

8.61 13.15 12.89 11.65

18.86 15.61 23.84 34.55

0.93 0.96 0.92 0.98

0.83 0.92 0.83 0.98

CS

a b c d

5.16 3.55 4.75 8.45

0.77 0.59 1.02 0.7

5.00 15.00 24.29 20.91

23.65 30.75 41.33 54.17

0.98 0.93 0.99 0.96

0.92 0.71 0.72 0.83

CS-EDTA

a b c d

5.16 7.60 7.42 8.31

1.47 1.33 2.37 1.91

45.75 46.99 50.58 58.30

61.29 76.83 76.31 91.32

0.98 0.92 0.95 0.89

0.97 0.94 0.91 0.96

a:150 mgL−1 , b: 200 mgL−1 , c: 250 mgL−1 , d: 300 mgL−1

may be involved in coordinating [57] that converts color powder of chitin and chitosan. CS-EDTA forms very stable chelates with metals. In addition, over the presence of carboxyl groups in the CS-EDTA structure makes it more stable. In most studies, EDTA chelates with divalent metals are reported as quinquedentate where a carboxyl group is free and a water molecule is coordinated to the metal center. Sexidentate structures may be important to the high ionic strength, Cu (II) have high stability constant EDTA chelate could explain a high adsorption capacity obtained for Cu (II) that was also observed by Nowack and Sigg [58]. 3.7.2. Intraparticle diffusion model The intraparticle diffusion model is also applied to analyze the distribution mechanism and rate controlling steps that affects the kinetics of adsorption. It can be expressed in the following form:

qt = k pt 1/2 + C g−1

(13)

min−1/2 )

k p (mg is the constant of intraparticle diffusion model and C (mg g−1 ) is a constant which is related to the thickness of the boundary layer. The variation of the curve of qt = f(t 1/2 ) at various concentrations of Cu (II) allows the determination of the controlled adsorption process parameters. To follow the pattern of intraparticle diffusion, the data points are connected by two straights. The first portion is assigned to the diffusion of the adsorbate in the solution to the outer surface of the adsorbent (external diffusion) and the second part describes the step of gradual adsorption, which corresponds to the diffusion of the adsorbate inside the adsorbent (intraparticle diffusion) [59]. Table 5 gives the model parameters corresponding to both parties according to Eq. (13). For all initial concentrations, k p1 was higher than, k p1 , and C2 was larger than C2 . This indicates that the metal removal rate is higher in the beginning due to the large surface area of the adsorbent available for adsorption of metal ions. After the material formed a thick adsorbed layer (caused by inter-ionic attraction and molecular association) of the adsorbent and decreases the rate of absorption is controlled by the rate at which the adsorbate was transported from the outside to the sites within the adsorbent particles. The intraparticle diffusion is part of the adsorption step, but not the only speed control. Other mechanisms such as complex or ion exchange can also control the rate of adsorption [60]. 3.7.3. Effect of pH on Cu (II) adsorption The pH value of the solution of Cu (NO3 )2 plays an important role in the whole of the adsorption process and especially the amount of copper adsorbed [61]. The Fig. 5A shows the effect of pH on the removal of copper (II) by CH, CS and CS-EDTA. The maximum adsorption of copper occurs at pH 4.0 as expected,

Please cite this article as: A. Labidi et al., Adsorption of copper on chitin-based materials: Kinetic and thermodynamic studies, Journal of the Taiwan Institute of Chemical Engineers (2016), http://dx.doi.org/10.1016/j.jtice.2016.04.030

ARTICLE IN PRESS

JID: JTICE 8

[m5G;May 30, 2016;16:56]

A. Labidi et al. / Journal of the Taiwan Institute of Chemical Engineers 000 (2016) 1–9

A

B

Fig. 5. Effect of adsorbent dosage on copper removal by CH, CS and CS-EDTA (pH 6.0, c0 = 300 mg L−1 and T = 25 °C (A), Effect of pH on Cu (II) adsorption using CH, CS and CS-EDTA adsorbents(B).

when the pH is slightly acidic, the adsorption process is more efficient. It reaches a adsorption capacity equal to 53, 77 and 123 mg g−1 for CH, CS and CS-EDTA respectively .Moreover, increasing the pH above 6.0 promotes the precipitation of copper hydroxide (Cu (OH)2 ) insoluble causing a decrease of removal of Cu (II) ions [62]. 3.7.4. Effect of adsorbent dose copper removal The effect of the dose of CH, CS and CS-EDTA introduced into the adsorption process of Cu2+ is shown in Fig. 5B as expected; clearly, the removal of Cu (II) onto the three materials steeply increased along with increasing amount of adsorbent, which is due to the increase of the surface area of the adsorbent for copper removal. After (0.6 g) dose of adsorbent the copper removal remains unchanged since the adsorption equilibrium is reached although the number of binding sites available for adsorption increases with increasing the adsorbent dose. 3.7.5. Desorption experiments Regeneration of the used adsorbent Chitin, chitosan and Chitosan-EDTA is important for understanding adsorption mechanism in addition to metal ions recovery and adsorbent. The re-use of the adsorbent, helps minimize the cost of the entire process. Cu (II) adsorbed on the surface of adsorbents can be recovered by desorption with adequate eluents. The desorption efficiencies of copper with initial concentration of 300 mg L−1 were 89.0, 87.5 and 91.0% for chitin, chitosan and chitosan-EDTA, respectively; using HCl (0.5 M) as eluent is an effective method of desorbing copper loaded adsorbents (CH, CS, CS-EDTA). After desorption the used adsorbents washed with distilled water and can be used for other cycle of adsorption/desorption to copper removal. 4. Conclusion In this study, chitin, chitosan and chitosan-EDTA were used for copper (II) removal in aqueous solution and compared. The results obtained from the adsorption isotherms with different values of initial concentrations of copper (II) indicates that the adsorption equilibrium data fitted well to Langmuir isotherm and maximum monolayer adsorption capacity for Cu (II) was (110 mg g−1 ) for CS-EDTA higher than chitosan (67 mg g−1 ) and chitin (58 mg g−1 ) under the same conditions (25 °C and pH 7.0). This fact could be explained by the more favorable interaction between CS-EDTA with copper, due to the immobilisation of EDTA groups on chitosan chains. Chitosan showed better results than chitin, because of the presence of more amino groups in chitosan. The values of the thermodynamic parameters have shown that the adsorption

of Cu (II) onto CS-EDTA was spontaneous and endothermic, spontaneous and exothermic for chitosan, in contrast in chitin, if the temperatures increase beyond 25 °C the adsorption does not become spontaneous. Adsorption kinetics follows the kinetic pseudosecond-order model. Thus, the pH values play a very important role in the adsorption process, according to the results of the effect of pH achieved maximum adsorption capacities for all adsorbents at pH 4.0. The results of this research indicate that CH and CS have a great potential to be used as an economical, rapid and efficient adsorbents to adsorb Cu (II) from effluents. Also the modified CS-EDTA which has more binding sites caused by the presence of more chelating groups is good idea to develop other modified materiel based chitin for heavy metals adsorption. Acknowledgments The authors are thankful for the financial support of the Department of Education, Universities and Investigation of the Basque Government (IT672-13) and the Ministry of higher Education and scientific research of Tunisia (mobility grant of Mr. Abdelkader Labidi). References [1] Arain MB, Kazi TG, Jamali MK, Jalbani N, Fridi HI, Shah A. Total dissolved and bioavailable elements in water and sediment samples and their accumulation in Oreochromis mossambicus of polluted Manchar Lake. Chemosphere 2008;70:1845–56. [2] Volesky B, Holan ZR. Biosorption of heavy metals. Biotechnol Prog 1995;11:235–50. [3] Francisco CF, Barros FCF, Sousa FW, Cavalcante RM, Carvalho TV, Dias FS, et al. Removal of copper, nickel and zinc ions from aqueous solution by chitosan-8-hydroxyquinoline beads. Clean 2008;36:292–8. [4] Crini G. Recent developments in polysaccharide-based materials used as adsorbents in waste water treatment. Prog Polym Sci 2005;30:38–70. [5] Hasan S, Ghosha TK, Viswanath DS, Boddub VM. Dispersion of chitosan on perlite for enhancement of copper (II) adsorption capacity. J Hazard Mater 2008;152:826–37. [6] Dermentzis K, Davidis A, Papadopoulou D, Christoforidis A, Ouzounis K. Copper removal from industrial wastewaters by means of electrostatic shielding driven electrodeionization. J Eng Sci Technol 2009;2:131–6. [7] Huang SH, Chen DH. Rapid removal of heavy metal cations and anions from aqueous solutions by an amino-functionalized magnetic nano-adsorbent. J Hazard Mater 2009;163:174–9. [8] Chen H, Dai GL, Zhao J, Zhong AG, Wu JY, Yan H. Removal of Cu(II) ions by biosorbent–Cinnamomum camphora leaves powder. J Hazard Mater 2010;177:228–36. [9] Ghaeea A, Shariaty-Niassar M, Barzin J, Zarghan A. Adsorption of copper and nickel ions on macroporous chitosan membrane: equilibrium study. Appl Surf Sci 2012;258:7732–43. [10] Bhatnagar A, Minocha AK. Conventional and non-conventional adsorbent for the removal of pollutants from water. J Indian Chem Technol 2006;13:203–17. [11] Aydın H, Bulut Y, Yerlikaya C. Removal of copper (II) from aqueous solution by adsorption onto low-cost adsorbents. J Environ Manag 2008;87:37–45.

Please cite this article as: A. Labidi et al., Adsorption of copper on chitin-based materials: Kinetic and thermodynamic studies, Journal of the Taiwan Institute of Chemical Engineers (2016), http://dx.doi.org/10.1016/j.jtice.2016.04.030

JID: JTICE

ARTICLE IN PRESS

[m5G;May 30, 2016;16:56]

A. Labidi et al. / Journal of the Taiwan Institute of Chemical Engineers 000 (2016) 1–9 [12] Li YH, Ding J, Luan ZK, Di ZC, Zhu YF, Xu CL, et al. Competitive adsorption of Pb2+ , Cu2+ and Cd2+ ions from aqueous solutions by multiwalled carbon nanotubes. Carbon 2003;41:2787–92. [13] Mohan D, Pittman CU Jr, Steele PH. Single, binary and multi-component adsorption of copper and cadmium from aqueous solutions on Kraft lignin-a biosorbent. J Colloid Interface Sci 2006;297:489–504. [14] Li YJ, Xiang B, Ni YM. Removal of Cu (II) from aqueous solutions by chelating starch derivatives. J Appl Polym Sci 2004;92:3881–5. [15] Beaney P, Mendoza JL, Healy M. Comparison of chitins produced by chemical and bioprocessing methods. J Chem Technol Biotechnol 2005;80:145–50. [16] Johanna RE, William GD, Jean DM, Aria A. Kinetics of cadmium uptake by chitosan-based crab shells. Water Res 2002;36:3219–26. [17] Bassi R, Prasher SO, Simpson BK. Removal of selected metal ions from aqueous solutions using chitosan flakes. Sep Sci Technol 20 0 0;35:547–602. [18] Beppu MM, Vieira RS, Aimoli CG, Santana CC. Crosslinking of chitosan membranes using glutaraldehyde: effect on ion permeability and water absorption. J Membr Sci 2007;301:126–34. [19] Mirmohseni A, Seyed Dorraji MS, Figoli A, Tasselli F. Chitosan hollow fibers as effective biosorbent toward dye: preparation and modelling. Bioresour Technol 2012;121:212–20. [20] Zhang L, Guo J, Du Y. Morphology and proprerties of cellulose/ chitin blends membranes from NaOH/thiourea solution. J Appl Polym Sci 2002;86:2025–32. [21] Sun X, Peng Q, Jing B, Chen YJ, Li DQ. Chitosan (chitin)/cellulose composite biosorbents prepared using ionic liquid for heavy metal ions adsorption. Separations 2009;55:2062–9. [22] Stefancich S, Delben F, Muzzarelli RAA. Interaction of soluble chitosan with dyes in water. I. Optical evidence. Charbohydr Polym 1994;24:17–23. [23] Repo E, Warchol JK, Kurniawan TA, Sillanpää MET. Adsorption of Co(II) and Ni(II) by EDTA- and/or DTPA-modified chitosan: kinetic and equilibrium modelling. Chem Eng J 2010;161:73–82. [24] Repo E, Warchoł JK, Bhatnagar A, Sillanpää M. Heavy metals adsorption by novel EDTA-modified chitosan–silica hybrid materials. J Colloid Interface 2011;358:261–7. [25] Cunha AG, Fernandes SCM, Freire CSR, Silvestre AJD, Pascoal Neto C, Gandini A. Fabrication and characterization of light-responsive multilayer films of Chitosan and Azopolymer. Biomacromolecules 2008;9:610–14. [26] Salaberria AM, Fernandes SCM, Diaz RH, Labidi J. Processing of α -chitin nanofibers by dynamic high pressure homogenization: charcterization and antifungal activity against A. Niger Carbohydr Polym 2015;116:286–91. [27] Salaberria AM, Labidi J, Fernandes SCM. Chitin nanocrystals and nanofibers as nano-sized fillers into thermoplastic starch-based biocomposites processed by melt-mixing. Chem Eng J 2014;256:356–642. [28] Salaberria AM, Diaz RH, Labidi J, Fernandes SCM. Role of chitin nanocrystals and nanofibers on physical, mechanical and functional properties in thermoplastic starch films. Food Hydrocolloids 2015;46:93–102. [29] Salaberria AM, Diaz RH, Labidi J, Fernandes SCM. Preparing valuable renewable nanocomposite films based exclusively on oceanic biomass-chitin nanofillers and chitosan. React Funct Polym 2015;89:31–9. [30] Nagib S, Inoue K, Yamaguchi T, Tamaru T. Recovery of Ni from a large excess of Al generated from spent hydrodesulphurization catalyst using picolylamine type chelating resin and complexane types of chemically modified chitosan. Hydrometallurgy 1999;51:73–85. [31] Pereira FV, Gurgel LVA, Gil LF. Removal of Zn2+ from aqueous single metal solutions and electroplating wastewater with wood sawdust and sugarcane bagasse modified with EDTA dianhydride (EDTAD). J Hazard Mater 2010;176:856–63. [32] Tulu M, Geckeler KE. Synthesis and properties of hydrophilic polymers. Part7. Preparation, characterization and metal complexation of carboxy-functional polyesters based on poly(ethylene glycol). Polym Int 1999;48:909–14. [33] Kumar R, Barakat MA, Daza YA, Woodcock HL, Kuhn JN. EDTA functionalized silica for removal of Cu (II), Zn (II) and Ni (II) from aqueous solution. J Colloid Interface Sci 2013;408:200–5. [34] Inoue K, Ohto K, Yoshizuka K, Yamaguchi T, Tanaka T. Adsorption of lead (II) ion on complexane types of chemically modified chitosan. Bull Chem Soc Jpn 1997;70:2443–7. [35] Huang R, Mendis E, Rajapakse N, Kim SK. Strong electronic charge as an important factor for anticancer activity of chitooligosaccharides (COS). Life Sci 2006;78:2399–408. [36] Saitô H, Tabeta R, Ogawa K. High-resolution solid-state 13C NMR study of chitosan and its salts with acids: conformational characterization of polymorphe and helical structures as viewed from the conformation-dependent 13 C chemical shifts. Macromolecules 1987;20:2424–30.

9

[37] Wan MW, Kan CC, Rogel DB, Dalida PML. Adsorption of copper (II) and lead (II) ions from aqueous solution on chitosan-coated sand. Carbohydr Polym 2010;80:891–9. [38] Mishra DK, Tripathy J, Behari K. Synthesis and characterization of Chitosan-g-Methacrylic acid and studies of its additional physicochemical properties, such as swelling, metal-ion sorption, and flocculation behavior. Carbohydr Polym 2008;71:524–34. [39] Kolya H, Tripathy T. Metal complexation studies of amylopectin– graft-poly[(N,Ndimethylacrylamide)-co-(acrylic acid)]: a biodegradable synthetic graft copolymer. Int J Biol Macromol 2013;62:557–64. [40] Lagergren S. Zur theorie der sogenannten adsorption geloster stoffe, Kungliga Svenska Vetenskapsakademiens. Handlingar 1898;24:1–39. [41] Ho Y, Mckay G. Pseudo-second order model sorption processes. Process Biochem 1999;34:451–65. [42] Kamari A, Ngah WSW. Isotherm, Kinetic and thermodynamic studies of lead and copper uptake by H2 SO4 modified chitosan. Colloids Surf B Biointerfaces 2009;73:257–66. [43] Zhou YT, Branford-White C, Nie HL, Zhu LM. Adsorption mechanism of Cu2+ from aqueuos solution by chitosan-coated magnetic nanoparticles modified with ketoglutaric acid. Colloids Surf B Biointerfaces 2009;74: 244–252. [44] Boddu VM, Abburi K, Talbott JL, Smith ED. Removal of hexavalent chromium from wastewater using a new composite chitosan biosorbent. Environ Sci Technol 2003;37:4449–56. [45] Freundlich HMF. Uber die adsorption in losungen Zeitschrift fur physikalische chemie. Leipzig 1906;57:385–470. [46] Findon A, McKay G, Blair HS. Transport studies for the sorption of copper ions by chitosan. J Environ Sci Health 1993;28:173–85. [47] Petrisor G, Komnitsas K, Lazar I, Voicu A, Dobrota S, Stefanescu M. Biosorption of heavy metals from leachates generated at mine waste disposal sites. J Eur Miner Process Environ Prot 2002;2:158–67. [48] Igberase E, Osifo P, Ofomaja A. The adsorption of copper (II) ions by polyaniline graft chitosan beads from aqueous solution: equilibrium, kinetic and desorption studies. Chem Eng J 2014;2:362–9. [49] Gandhia MR, Kousalya GN, Meenakshia S. Removal of copper (II) using chitin/chitosan nano-hydroxyapatite composite. Int J Biol Macromol 2011;48:119–24. [50] Kannamba B, Reddy KL, Apparao BV. Removal of Cu (II) from aqueous solutions using chemically modified chitosan. J Hazard Mater 2010;175: 939–948. [51] Ghaeea A, Niassar MS, Barzinc J, Zarghan A. Adsorption of copper and nickel ions on macroporous chitosan membrane: equilibrium study. Appl Surf Sci 2012;258:7732–43. [52] Ng JCY, Cheung WH, McKay G. Equilibrium studies of the sorption of Cu (II) ions onto chitosan. J Colloid Interface Sci 2002;255:64–74. [53] Justi KC, Favere VT, Laranjeira MCM, Neves A, Peralta RA. Kinetics and equilibrium adsorption of Cu(II), Cd(II), and Ni(II) ions by chitosan functionalized with 2[-bis-(pyridylmethyl)aminomethyl]-4-methyl-6-formylphenol. J Colloid Interface Sci 2005;291:369–74. [54] Jaycock MJ, Parfitt GD. Chemistry of Inerfaces, Ltd. Chichester: Ellis Horwood; 1981. [55] Kyzas GZ, Kostoglou M, Lazaridis NK. Copper and chromium (VI) removal by chitosan derivatives-Equilibrium and kinetic studies. Chem Eng J 2009;152:440–8. [56] Debbaudt AL, Ferreira ML, Gschaider ME. Theoretical and experimental study of M2+ adsorption on biopolymers III, Comparative kinetic pattern of Pb, Hg and Cd. Carbohydr Polym 2004;56:321–32. [57] Nieto JM, Peniche-Covas C, Del Bosque J. Prepartion and characterization of a chitosan-Fe(II) complex. Carbohydr Polym 1992;18:221–4. [58] Nowack B, Sigg L. Adsorption of EDTA and metal-EDTA complexes onto goethite. J Colloid Interface Sci 1996;177:106–21. [59] Weber TW, Chakkravorti RK. Pore and solid diffusion models for fixed bed adsorbers. Am Inst Chem Eng J 1974;20:228–38. [60] Cheung WH, Szeto YS, McKay G. Intraparticle diffusion processes during acid dye adsorption onto chitosan. Bioresour Technol 2007;98:2897–904. [61] Liu D, Dezhi S, Yangqing L. Removal of Cu(II) and Cd(II) from aqueous solutions by polyaniline on sawdust. J Sep Sci Technol 2011;46:321–9. [62] Wan Ngah WS, Fatinathan S. Adsorption characterization of Pb(II) and Cu(II) ions onto chitosan–tripolyphosphate beads: kinetic, equilibrium and thermodynamic studies. J Environ Manag 2010;91:958–69.

Please cite this article as: A. Labidi et al., Adsorption of copper on chitin-based materials: Kinetic and thermodynamic studies, Journal of the Taiwan Institute of Chemical Engineers (2016), http://dx.doi.org/10.1016/j.jtice.2016.04.030