polyvinyl alcohol adsorptive membrane

Carbohydrate Polymers 210 (2019) 264–273

Contents lists available at ScienceDirect

Carbohydrate Polymers journal homepage: www.elsevier.com/locate/carbpol

Removal of Cu2+, Cd2+ and Ni2+ ions from aqueous solution using a novel chitosan/polyvinyl alcohol adsorptive membrane

T

⁎

Nadia Sahebjameea, Mohammad Soltaniehb, , Seyed Mahmoud Mousavic, Amir Heydarinasaba a

Department of Petroleum and Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran c Chemical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran b

A R T I C LE I N FO

A B S T R A C T

Keywords: Adsorptive membrane Heavy metal ions Chitosan/poly vinyl alcohol Polyethyleneimine Adsorption thermodynamics Kinetics

The chitosan/poly vinyl alcohol membrane was modified by addition of some amine group to the membrane structure utilizing polyethyleneimine (PEI) in order to increase ionic metals adsorbent properties of the membrane. The removal percentage of the modified membranes was compared with the pristine membrane and activated carbon as common adsorbents. The membranes were characterized by FTIR, SEM, swelling degree and porosity measurement. The removal percentage of the membrane containing 0.5 wt.% PEI was more than 60% higher than the activated carbon and more than 40% higher than the pristine membrane. The modified membrane showed excellent adsorption capacity of 112.13, 86.08, and 75.5 mg/g for Cd2+, Cu2+and Ni2+, respectively at 25 °C and pH 6. Adsorption kinetics and equilibrium adsorption isotherm fitted pseudo-secondorder kinetic model and Langmuir isotherm model well, respectively. The membrane could be regenerated successfully in Na2EDTA aqueous solution with no significant reduction in its adsorption efficiency.

1. Introduction Removal of heavy metal ions from wastewaters is always an issue as they are highly toxic even at low concentrations and can not be decomposed or biodegraded (Habiba, Afifi, Salleh, & Ang, 2017). Heavy metals come into the environment through various sources such as combustion, discharge of wastewater and production sites (Järup, 2003). Heavy metals accumulate in the human environment and lead to various diseases and disorders (Ahmaruzzaman & Gupta, 2011). Heavy metal ions are soluble in water and can be adsorbed quickly (Barakat, 2011). They are also nonbiodegradable and have many environmental, economic and public health effects (Min et al., 2012). In the last few decades, some processes such as biological treatments, membrane separation, advanced oxidation processes, adsorption and electrodeposition have been used to remove heavy metal ions from wastewaters (Xuefen Wang et al., 2011). The development of more effective adsorbents, such as minerals (Zarabi & Jalali, 2018), biological materials (Crini, Lichtfouse, Wilson, & Morin-Crini, 2018), zeolites (Kuang et al., 2018), polymers (Zhao et al., 2018), waste materials (Vinod Kumar Gupta, Nayak, Agarwal, & Tyagi, 2014), metal-organic framework material (MOFs) (Li et al., 2018) and layered double hydroxides (LDHs) (Gu et al., 2018) have been considered recently. Among the different adsorbents, one of the new technologies which

⁎

has attracted attention is membrane adsorption (Salehi & Madaeni, 2014; Vatanpour, Salehi, Sahebjamee, & Ashrafi, 2018).This technology is considered to be an effective and economic method for the removal of toxic heavy metal ions from aqueous solution (Vinod K Gupta, Agarwal, & Saleh, 2011). The main characteristic of the membrane adsorbents is the presence of reactive functional groups on their surfaces (C. Liu & Bai, 2006; Min et al., 2012; Neghlani, Rafizadeh, & Taromi, 2011). Functional groups such as -NH2 can easily adsorb heavy metal ions (Neghlani et al., 2011). In addition, affinity membranes are very thin so the flow path is much shorter than that in other conventional processes, which causes lower pressure drop (B. Han et al., 2006; Vatanpour et al., 2018) and increases the flux. Other benefits of adsorbent membrane include acceptable efficiency and reusability, rapid kinetics and favorable removal rates even at low concentrations (Roper & Lightfoot, 1995). Taking these considerations into account, it seems that adsorptive membranes may offer significant improvements over other conventional techniques. One of the useful and applicable polymers in highly effective metalaffinity membranes is chitosan (CS) which is a natural biopolymer with a high content of amine functional group responsible for metal ions binding (X. Liu, Cheng, & Ma, 2009). To improve thermal, mechanical and chemical stability of CS, different polymers such as poly vinyl alcohol (PVA) are used (Salehi et al., 2013).

Corresponding author. E-mail address: [email protected] (M. Soltanieh).

https://doi.org/10.1016/j.carbpol.2019.01.074 Received 24 November 2018; Received in revised form 17 January 2019; Accepted 21 January 2019 Available online 23 January 2019 0144-8617/ © 2019 Published by Elsevier Ltd.

Carbohydrate Polymers 210 (2019) 264–273

N. Sahebjamee et al.

carbon (mesh 4 × 8, from 2.4 to 4.8 mm, walnut-shell) was gifted by Part Chemical Co., Iran.

It has been proven that most of the adsorbents developed for the adsorption of metal ions and dyes, are based on the functional groups on the surfaces of the adsorbents. Functional groups such as amino groups on the surface of the adsorbents provide a selective and effective adsorption (Min et al., 2012). Adsorbents with amine groups have special properties that enable them to adsorb compounds with cationic or anionic charges at different pH values (Lin, Chen, Chien, Chiou, & Liu, 2011). Polyethyleneimine (PEI) is a cationic polymer that is used successfully in cell and tissue studies as a non-viral carrier (Nam & Nah, 2016) and in radionuclides extraction (Huang et al., 2018). Moreover, due to its amine functional groups, PEI has a high affinity for various metal ions and can be used as a chelating agent to remove heavy metal cations in aqueous solutions (Xuefen Wang et al., 2011). For this reason, PEIbased materials have been extensively investigated and so far many metal ions including Cu2 +, Ni2+, Fe2+, Co2+, Zn2+, Cd2+, Pb2+, Cr2+, and Hg2+ have been removed from sewage by these materials (Lindén et al., 2015; Xuefen Wang et al., 2011). PEI is available in both linear and branched forms (Lungu, Diudea, Putz, & Grudziński, 2016). The binding of metal ions to the branched PEI is stronger than its linear type, and the branched type contains primary, secondary and tertiaryamine groups with a 1: 1: 0.7 ratio (Lindén, Larsson, Coad, Skinner, & Nydén, 2014). PEI has good hydrophilicity, fast kinetics and high adsorption capacity (Lindén et al., 2015). Furthermore, it was shown that alkali or alkaline earth metals could not be retained by PEI at any pH; so as a huge advantage in treatment of water consisting high salt content, such as sea water, PEI just adsorbs heavy metal ions (Ghoul, Bacquet, & Morcellet, 2003; Lindén et al., 2015). (Bessbousse, Rhlalou, Verchère, & Lebrun, 2008) developed a new membrane consisting of a polymeric network of crosslinked PVA as a matrix and PEI as a complex polymer to remove heavy metal ions such as lead (II), cadmium (II), and copper (II) from aqueous solutions. In other work done by (Inphonlek, Pimpha, & Sunintaboon, 2010), the core-shell nanoparticles were synthesized containing polymethyl methacrylate (PMMA) as core with CS, PEI, and mixed CS/PEI as shells. (Jing, Gao, & Yang, 2016) modified the surface of chitosan microspheres with PEI to produce effective adsorbents for the removal of methyl orange from aqueous solutions. In this study, the adsorption capabilities and mechanism of the CS/ PVA affinity membranes modified with PEI for the first time and the removal of heavy metal ions (Cd2+, Cu2+and Ni2+) from aqueous solutions by the synthesized membrane were investigated. The novelty of the work is using PEI with great amounts of amine groups in a membrane mixture and comparing it as an adsorptive membrane with the neat CS/PVA membrane (without PEI) and activated carbon and the usual adsorbents. FTIR, SEM, BET, swelling and the point of zero charge (pHpzc) tests were performed to characterize the membranes. In addition, the adsorption isotherms have been analyzed with respect to two different models. Furthermore, the thermodynamic parameters were determined and the adsorption kinetics was also investigated. Moreover, reusability of the prepared membranes was examined using Na2EDTA.

2.2. Membrane preparation The modified CS thin membranes were prepared using the method introduced in the literature (X. Zeng & Ruckenstein, 1996). First, 2 g CS powder was dissolved in 100 ml of 2% acetic acid for 24 h to prepare a homogeneous solution. Then, 10 g PVA was dissolved in 100 ml deionized water by heating the solution at 70 °C under constant stirring for 24 h. PEI solution was diluted to 10 wt%. Next, all the above three solutions were mixed together by mechanical stirring in the way that the percentage of CS and PVA was maintained constant in the final solution (1 wt% of CS and 2.5 wt% of PVA) but the amount of PEI was varied (0, 0.5 and 1 wt%). The resultant homogeneous membrane casting solution was left in the beaker without stirring at 50 °C for 48 h to sufficiently free the air bubbles and for thermal cross-linking. Afterwards, the prepared solutions were casted on glass plates with the specified thickness using an applicator and dried at room temperature. The dried membranes were immersed in 1 M NaOH solution to neutralize the excess acid (Salehi et al., 2013). Then, the membranes were washed exhaustively with distilled water until all alkali was removed. Lastly, the membrane was dried at room temperature and stored. CS/ PVA/PEI membranes containing 0, 0.5, and 1 wt% of PEI, are designated as P0, P0.5, and P1, respectively. 2.3. Membrane characterization 2.3.1. SEM The morphology of the membrane surface and its cross-section was observed by LEO 1450 V P scanning electron microscope (SEM), Germany. The membrane was cut into small pieces for surface scanning, and fractured in liquid nitrogen for cross-section scanning. The specimens were sputtered by Au–Pd sputter coater before the SEM characterization. 2.3.2. FTIR FTIR spectral analysis was performed to investigate the functional groups of the membranes. A Perkin Elmer FTIR spectrometer (Spectrum 100 Series) was employed for this purpose. 2.3.3. Brunauer–Emmett–Teller (BET) surface analysis A BET analyzer (Quantachrome Autosorb I) was used to determine the specific surface area of the membranes. The samples were degassed at 50 °C for 16 h. The surface areas of all samples were characterized by nitrogen adsorption/desorption technique. 2.3.4. Swelling degree and porosity A known weight of the membrane sample was kept in distilled water for 24 h at ambient temperature. Thereafter, the excess surface water of the membrane was removed with filter paper and the wet membrane was weighed. The swelling degree of the membrane was calculated from the following Eq. (1) (Salehi et al., 2012):

2. Experimental

Swelling degree (%) = 2.1. Materials

ws − wd × 100 wd

(1)

where ws and wd are the mass of wet and dry membrane, respectively. The porosity of the membrane was determined using Eq. (2) (Xiaomin Wang, Li, Li, & Yang, 2016):

Chitosan powder with 90% deacetylation degree (CS, Mw = 100,000–300,000) was purchased from Acros, USA. Poly(vinyl) alcohol, fully hydrolyzed (PVA, Mw = 60,000) was supplied by Merck, Germany. Polyethyleneimine (PEI, branched, average Mw = 25,000) was obtained from Aldrich, USA. Ni(NO3)2.3H2O, CdN2O6.4H2O,CuSO4.5H2O, NaOH, HCl, NaCl and sodium ethylenediaminetetraacetic acid (Na2EDTA) were purchased from Merck, Germany. All the chemicals used in the experiments were of analytical grade. All the solutions were prepared with deionized water. Activated

Porosity (%) =

ws − wd × 100 ρw × V

(2)

where ρw and V represent the density of distilled water and the volume of the wet membrane, respectively. In order to determine the value of V, a certain volume of distilled water was put in the cylinder and then a piece of wet membrane was immersed in the water. Changes in the 265

Carbohydrate Polymers 210 (2019) 264–273

N. Sahebjamee et al.

where b and m are the Freundlich isotherm constants. Temkin isotherm is used to evaluate the reduction in the adsorption heat. The model assumes that the absorption heat of all molecules in a layer would decrease linearly (Pandiarajan, Kamaraj, Vasudevan, & Vasudevan, 2018). The Temkin isotherm is expressed as (Dashtian, Porhemat, Rezvani, Ghaedi, & Sabzehmeidani, 2018):

water volume shows the volume of the wet membrane (Xiaomin Wang et al., 2016). All tests were replicated three times and the mean values were determined. 2.3.5. The point of zero charge In order to determine the point of zero charge (pHpzc), NaCl was used as the electrolyte. 0.01 g of the modified membrane was added into 50 ml of 0.01 M NaCl solution. The initial pH (pHi) values of the NaCl solutions were adjusted from 2 to 10 by 0.1 M HCl or 0.1 M NaOH (Melo et al., 2018). The solution mixtures were allowed to be equilibrated for 48 h under agitation at room temperature. The final pH (pHf) values were measured and the difference between the initial and final pH values (ΔpH = pHf - pHi) was plotted versus the pHi. The pHpzc was then determined from the plot where ΔpH = 0.

Qe = B ln(KT Ce )

where B (J/mol) is related to the heat of adsorption and KT (l/g) is the Temkin constant at optimum binding energy. From the plot of Qe versus ln Ce, the values of B and KT can be found. Using Dubinin-Radushkevich isotherm, the nature of adsorption (chemisorption or physisorption) could be understood (Pandiarajan et al., 2018). This isotherm is considered as follows (Pandiarajan et al., 2018):

2.4. Static adsorption experiments

Qe = Qs exp(−βε 2)

To measure the adsorption capacity of prepared membranes, certain amount of adsorptive membrane (0.01 g) was placed in 50 ml of each aqueous solution (Cd2+, Cu2+, and Ni2+) with different concentrations of the metal ion and was agitated at a constant stirring speed of 120 rpm for 24 h. A thermostatic shaker-incubator (DK-S1060, Daikiscience Co.) was used for this purpose. The initial pH for adsorption of the metal ions on the membranes was set at 6. The test was carried out at 25 °C. The concentration of metal ion in the final solution was determined using a flame atomic absorption spectrophotometer (Z-2000 polarized Zeeman atomic absorption spectrophotometer, Hitachi, Japan). The adsorption amount of the membrane and the removal percentage of the heavy metal ions were determined by Eqs. (3) and (4), respectively (Daneshyar, Ghaedi, & Sabzehmeidani, 2017):

V Qe = (C0 − Ce ) m

(3)

C − Ce Removal % = 0 × 100 C0

(4)

ε= RT ln(1 +

1 ) Ce

(9)

R is the gas constant (8.314 J/mol K) and T is absolute temperature in K. The average energy of adsorption (E) for each molecule of adsorbate can be estimated by the following equation (Pandiarajan et al., 2018):

E=

1 −2β

(10)

If E < 8)kJ/mol(the adsorption would performed through weak Van der Waals interactions and it would have a physical adsorption nature, and if 8 < E < 16 (kJ/mol), the adsorption would performed through ion-exchange mechanism and for values greater than 16 kJ/ mol the adsorption process is considered to be controlled by a particle diffusion mechanism (Mittal, Mittal, Malviya, Gupta, & Science, 2010; Pandiarajan et al., 2018). 2.4.2. Adsorption thermodynamics In order to calculate the thermodynamic parameters, the static adsorption experiments were performed at temperatures of 298, 308, and 318 K for aqueous solutions of Cd2+, Cu2+, and Ni2+ with C0 = 30 mg/ l and pH = 6. The thermodynamic parameters reflect the feasibility and spontaneity of the processes, the exothermicity or endothermicity of the reaction, and the entropy changes during the adsorption process (Debnath, Maity, & Pillay, 2014; Jing et al., 2016). Thermodynamic parameters include Gibbs free energy changes (ΔG°), enthalpy (ΔH°) and entropy (ΔS°), which are the most important properties of the adsorption process for practical applications (Dawood & Sen, 2012). The following equation is used to determine Gibbs free energy change (Debnath et al., 2014):

2.4.1. Adsorption isotherms For isothermal studies, first 50 ml solutions of the metal with initial concentration C0 from 5 to 30 mg/l at temperature of 25 °C and pH = 6 were prepared. Then 0.01 g dry membrane was put into each solution under constant stirring for 24 h. Different isotherm models (Langmuir, Freundlich, Temkin, and Dubinin–Redushkevich) were applied to investigate the adsorption process. In the Langmuir adsorption isotherm, because the adsorption is limited to only a monolayer on the surface, there will be the same energy and enthalpy for all ions of a solution in the adsorption process (Özcan, Özcan, Tunali, Akar, & Kiran, 2005; Xiaomin Wang et al., 2016). The mathematical equation of this model can be expressed using the following Eq. (5) (Özcan et al., 2005):

bCe 1 + bCe

(8)

where Qs is the maximum adsorbed amount at optimal experimental conditions, β is the Dubinin-Radushkevich constant which can be calculated by plotting ln Qe versus ε2, and ε is the adsorption potential that can be obtained by the following equation (Dashtian et al., 2018):

where C0 and Ce are the initial and final concentrations of metal ion (mg/l) in the solution, respectively, V is the volume of the solution (l), m is the mass of the adsorptive membrane (g), and Qe is the equilibrium adsorbed amount of metal ion on the membrane (mg/g).

Qe = a

(7)

ΔG° = −RT lnK

(5) 2

(11)

In this equation, Ce (mg/l) and Qe (mg/cm ) are the equilibrium ion concentration and equilibrium adsorption of the ion on the membrane, respectively. Moreover, a and b are the equilibrium constants of the isotherm. The empirical relation of Freundlich is based on the multilayer adsorption on heterogeneous surfaces and the heterogeneous distribution of energy on active adsorbent sites (R. Han et al., 2009). The main relationship is shown by Eq. (6) (R. Han et al., 2009):

where R is the universal gas constant (8.314 J/mol K), T is the absolute temperature (K), and K is the equilibrium adsorption constant. The latter is the ratio of heavy metal adsorbed on the adsorbent surface (mg/g) to the heavy metal available in solution (mg/l) at a constant temperature (Qe/Ce). The changes of enthalpy (ΔH°) and entropy (ΔS°) were calculated using van’t Hoff (Eq. (12))(Özcan et al., 2005):

Qe = b Cem

lnK =

(6) 266

ΔS o ΔH o − R RT

(12)

Carbohydrate Polymers 210 (2019) 264–273

N. Sahebjamee et al.

Fig. 1. FTIR spectra for the membranes: (A) P0, (B) P0.5 and (C) P1 spectra.

2.5. Regeneration of the membranes

2.4.3. Adsorption kinetics The adsorption kinetics, adsorption rate and mechanisms were studied according to the following experiments. First, a number of flasks, each one contained 50 ml of metal solutions with initial concentration of 30 mg/l at pH 6 were prepared. Then 0.01 g of sample membranes was put into each solution under constant stirring at 25 °C for 24 h using the shaker-incubator. In order to investigate the adsorption mechanism, the adsorption constants can be calculated using the Lagergren equation as the pseudofirst order mechanism, the Ho equation as the pseudo-second order mechanism, and the intraparticle diffusion model which are the most commonly used ones for the adsorption of metal ions (Cheng, Liu, Han, & Ma, 2010; Xiaomin Wang et al., 2016). The general form of the first and second order models are as follows, respectively (Xiaomin Wang et al., 2016):

Q = Qe (1 − exp(−k1 t )) Q=

Qe 2k2 t 1 + Qe k2 t

The recovery of the membrane after the stabilization of heavy metal ions is an important feature in order to investigate the possibility of industrial applications of the membrane. To test reusability of the membranes, the adsorption/desorption cycles of membrane were performed. Metal ion desorption is usually carried out in concentrated nitric acid or hydrochloric acid (Bessbousse et al., 2008; C. Liu & Bai, 2006; Shen et al., 2009). However, because acid is an oxidizing agent and may result in degradation of the membrane, some researchers prefer EDTA, a potent complexing agent, for discharging metal ions (Bessbousse et al., 2008; C. Liu & Bai, 2006; Salehi et al., 2012; Shen et al., 2009; Urbina et al., 2018; Wu et al., 2017). Therefore, the desorption of heavy metals including cadmium, copper, and nickel from membranes was performed using 0.05 M Na2EDTA solution and membrane P0.5 was selected for regeneration tests. 0.01 g of membrane was incubated in 50 ml of metal ion solution with initial concentration of 30 ppm at 25 °C and pH = 6 for 24 h. After calculating the amount of metal ion adsorption, the saturated membrane was first washed with deionized water to remove the non-adsorbed metal ions, and then was immersed in 50 ml of 0.05 M Na2EDTA solution with stirring for 2 h. The membrane was washed again with distilled water. Then the regenerated membrane was used for the next cycle in the same manner. This adsorption/desorption cycle was repeated four times.

(13)

(14)

where Qe (mg/g) and Q (mg/g) are the adsorption capacity at equilibrium and at time t (h) and k1 (1/h) and k2 (g/mg.h) represent the rate constant of pseudo-first and second order models, respectively. In adsorption studies, the importance of intraparticle model is due to determining the rate limiting step of the adsorption process (Kaur, Kaur, Umar, Anderson, & Kansal, 2019). Weber and Morris (Weber & Morris, 1963) showed that if the intraparticle diffusion is the rate controlling step, the adsorption capacity would change with the square root of the time. The internal particle diffusion equation was described using the following equation (Weber & Morris, 1963):

Q= kWM t 1/2 + C

3. Results and discussion 3.1. Investigation of the membranes chemical structure The FTIR spectra of the CS/PVA and modified CS/PVA membranes are shown in Fig. 1. Spectrum A for CS/PVA membrane shows an almost wide band around 3200-3500 cm−1 which is assigned to the stretching vibrations of the NeH groups and/or the OeH groups (Habiba et al., 2017). The presence of saccharide which is a repeating

(15)

where the kWM (mg/g. h1/2) represents the intraparticle diffusion rate constant, and C is the intercept which is calculated from the plotting Q vs t1/2 (Jamshidi, Ghaedi, Sabzehmeidani, & Bagheri, 2018). 267

Carbohydrate Polymers 210 (2019) 264–273

N. Sahebjamee et al.

Fig. 2. SEM images of the membranes with different PEI amounts: surface of (a) P0, (b) P0.5, and (c) P1 membranes and cross section of (d) P0, (e) P0.5, and (f) P1 membranes.

unit of CS was confirmed by the absorption bands observed at 850, 1139 cm−1(de Souza Costa-Júnior, Pereira, & Mansur, 2009; Kumar et al., 2010). Absorption bands at 1590 and 1655 cm−1 indicated the presence of amide I and II peaks, respectively (de Souza Costa-Júnior et al., 2009; Srinivasa, Ramesh, Kumar, & Tharanathan, 2003). The sharp peaks at 1375 and 1421 cm−1 were attributed to the CH3 symmetrical deformation mode (de Souza Costa-Júnior et al., 2009). All of the above peaks are reported as characteristic of CS/PVA blend in the literature (Cheng et al., 2010; de Souza Costa-Júnior et al., 2009; Jing et al., 2016; Kumar et al., 2010; Pimpha, Sunintaboon, Inphonlek, &

Table 1 Swelling degree, porosity and surface area analysis data of the membranes. Membrane

Swelling degree%

Porosity%

Specific surface area (m2/g)

P0 P0.5 P1

473.58 560.79 569.93

38.76 55.03 48.84

0.4 0.95 0.7

268

Carbohydrate Polymers 210 (2019) 264–273

N. Sahebjamee et al.

ions. Therefore, it seems that the modified CS/PVA/PEI membrane was successfully synthesized. 3.2. Morphology of the membranes In general, due to the long evaporation step, CS membranes which are produced by casting evapoaration method have a dense structure (Sun et al., 2011). Fig. 2a and d show the surface and cross section of the membrane P0, respectively. According to the figure, no porosity at the membrane surface can be observed, which is related to almost dense structure of the CS/PVA membrane (Salehi et al., 2013; Shafiq et al., 2017). Because the addition of hydrophilic PEI (Ghoul et al., 2003; Lindén et al., 2015; Yang et al., 2016) to the casting solution can increase the hydrophilicity of the composite, NaOH attack was performed faster (Salehi et al., 2012). Consequently, the membrane surface became less dense in the P0.5 and P1. For the membrane with 1% PEI, although there were more void at the surface, the rise in the polymer content and the viscosity of the solution caused the porosity of the sublayer to decrease and the membrane became denser than P0.5 membrane (compare Fig. 2e with f) (Salehi et al., 2012). Moreover, the figure depicts that, the membrane thickness also increased by augmenting the amount of PEI, which is mainly due to increase in the polymer content.

Fig. 3. Comparing the removal percentage of the affinity membranes (P0, P0.5, P1) with activated carbon (C2, C5) (T = 25 °C, C0 = 30 mg/l and pH = 6). Table 2 Isotherm and thermodynamic parameters for the adsorption of heavy metal ions (Cd2+, Cu2+, Ni2+) onto P0.5 membranes. Isotherm

Parameters

Cd2+

Cu2+

Ni2+

Langmuir

a (mg/g) b (l/mg) R2 m b (mg/g) R2 B (J/mol) KT (l/g) R2 Qs (mg/g) β E (kJ/mol) R2 298 K 308 K 318 K – –

131.579 0.528 0.9979 0.388 48.014 0.9468 29.097 4.906 0.977 105.278 −3 × 10-7 1.291 0.9396 6.051 5.984 318 K −7.313 −4.259

116.279 0.228 0.9955 0.4948 26.272 0.9684 27.774 1.854 0.9903 81.39 −8 × 10-7 0.791 0.9536 5.817 5.809 5.794 −6.15 −1.11

96.150 0.237 0.9982 0.4499 23.625 0.9826 22.027 2.106 0.995 68.91 −7 × 10-7 0.845 0.9274 5.818 5.581 5.535 −10.07 −14.86

Freundlich

Temkin

Dubinin–Radushkevich

-ΔG° (kJ/mol)

ΔH° (kJ/mol) ΔS° (J/mol K)

3.3. BET analysis The results of the BET surface area analysis of the membranes are summarized in Table 1. It was observed that the P0.5 membrane exhibited higher surface area rather than P0 and P1. It should be mentioned that our goal of adding PEI to the CS/PVA mixture has been to increase the functional groups rather than augment the porosity. 3.4. Porosity and swelling degree of the membranes The porosity and swelling degree were determined through the measurement of water uptake of the membranes. The results show that porosity was increased with adding 0.5% PEI to the casting solution, but higher amount of PEI led to lower porosity. The results are in agreement with the result of the SEM images discussion. Due to hydrophilic functional groups of PEI, by adding the PEI to CS/PVA blend, the degree of swelling of the membrane increases. Hydroxyl and amino groups of the polymers can offer considerable hydrogen bonds with water molecules (Zhu, Shentu, Liu, & Weng, 2006). The degree of swelling was determined to be 560.79% for P0.5 membrane.

Table 3 Kinetic parameters for metal ions (Cd2+, Cu2+, Ni2+) adsorption by P0.5 membrane (T = 25 °C, C0 = 30 mg/l and pH = 6). Kinetic Model

Parameters

Cd2+

Cu2+

Ni2+

Pseudo-first-order model

k1 (1/h) Qe,cal (mg/g) R2 k2 (g/mg.h) Qe,cal (mg/g) R2 kWM (mg/g min1/2) C (mg/g) R2 kWM (mg/g min1/2) C (mg/g) R2

0.4991 46.30 0.9398 0.039 113.636 0.9999 54.627 23.802 0.8822 2.3499 104.16 0.9592

0.5074 32.36 0.9502 0.057 87.719 1.000 30.468 34.561 0.8416 1.5537 80.873 0.9237

0.5414 33.01 0.9544 0.040 78.125 0.9997 32.133 21.45 0.9492 1.5755 70.429 0.8511

Pseudo-second-order mode

Intra-particle diffusion (first step) Intra-particle diffusion (second step)

3.5. pH determination at the point of zero charge (pHPZC) The point of zero charge (pHpzc) for the P0.5 membrane, which was determined from the plot, was about 7.75. It means that the membrane has positively charged sites when pH is lower than 7.75 (Mohammadi, Khani, Gupta, Amereh, & Agarwal, 2011). Amino groups are responsible for the uptake of Cd2+, Cu2+, and Ni2+as follows (Ghaee, Shariaty-Niassar, Barzin, & Zarghan, 2012): -NH3+ + M2+ -NH2M2+ + H+ (M2+ is a metal ion such as Cd2+, 2+ Cu , and Ni2+.) Therefore, efficient adsorption of metal ion would be performed at pH < 7.75.

Tabata, 2010). Spectrum B and C depict the FTIR spectra related to the modified membranes with different PEI contents. It can be seen from the figure that all peaks in spectrum A are also present in spectra B and C, just some of them are intensified. Existence of a very broad peak in the frequency range of 3200–3600 evidences a rise in amino groups content which are introduced to the CS/PVA blend by addition of PEI (Pimpha et al., 2010). The more PEI percentage, the wider peak was seen. These changes confirmed that PEI increased the amino groups content of the CS/PVA blend, which are responsible for the chelation of heavy metal

3.6. Static adsorption behavior of the membranes 3.6.1. Removal percentage of heavy metal ions Fig. 3 shows the removal percentage of the membranes with different PEI loadings for heavy metal ions of Ni2+, Cu2+, and Cd2+. Moreover, the adsorption of these affinity membranes was compared with activated carbon, which is one of the most popular and common 269

Carbohydrate Polymers 210 (2019) 264–273

N. Sahebjamee et al.

Fig. 4. (a) Effect of contact time (b) pseudo first order (c) pseudo second order (d) intra-particle-diffusion plot for the adsorption of the metal ions on P0.5 membrane (T = 25 °C, C0 = 30 mg/l and pH = 6). Table 4 The metal ion properties (Tan et al., 2016; Tansel, 2012). Metal ion

Ionic radius (nm)

Hydrated radius(nm)

Electronegativity

Hydration free energy (KJ/mol)

Ni2+ Cu2+ Cd2+

0.069 0.070 0.095

0.404 0.419 0.426

1.91 1.9 1.69

−2106 −2160 −1979

Table 5 Comparison of Cu2+, Ni2+, and Cd2+ adsorption capacities by some different chitosan-based adsorbents. Ions 2+

Cu

Ni2+

Cd2+

Adsorbent

Q (mg/g)

pH

T(℃)

Dose (g)

Reference

Chitosan/ silica chitosan/cellulose acetate Chitosan/rectorie Chitosan magnetic cellulose − chitosan chitosan/PVA/MWCNT-NH2/PEG Chitosan/PVA/PEI magnetic chitosan-isatin Chitosan/ silica chitosan/iron oxide Chitosan/rectorie Chitosan/PVA/PEI chitosan Chitosan/rectorie chitosan/vermiculite Chitosan Activated fly ash /chitosan Chitosan/PVA/PEI

19.87 48.2 20.49 72 65.8 35 86.08 40.15 5.21 58 13.32 75.5 94 16.53 58.48 19 87.72 112.13

5 5. 6 6 5 6 6 5 5 3 6 6 6 6 4 6.5 8 6

20 25 25 25 room temperature 40 25 28 20 25 25 25 25 25 30 room temperature 25 25

0.5 1.1 0.04 0.02 0.05 0.02 0.01 – 0.5 0.05 0.04 0.01 – 0.04 0.04 – 0.1 0.01

Ghaee et al. (2012) C. Liu and Bai (2006) L. Zeng et al. (2015) Cao, Li, Liang, Wang, and Wu, (2016) Peng, Meng, Ouyang, and Chang, (2014) Salehi et al. (2013) This work Monier, Ayad, Wei, and Sarhan, (2010) Ghaee et al. (2012) Keshvardoostchokami, Babaei, Zamani, Parizanganeh, and Piri, (2017) L. Zeng et al. (2015) This work &Zielińska, Chostenko and Truszkowski (2010) L. Zeng et al. (2015) Chen et al. (2018) Unagolla and Adikary (2015) Pandey and Tiwari (2015) This work

repeated with higher dosage of the adsorbent (C5). Therefore, in general the static adsorption tests for P0, P0.5, P1, and C2 were performed with 0.02 g adsorbent but for C5 with 0.05 g adsorbent. Fig. 3 shows the distinct and noticeable difference between the removal percentage of affinity membranes and activated carbon in adsorption of metal ions with low concentration. Even much more amount of activated carbon (C5) could not compensate this gap. Furthermore, as can be seen from the figure, P0.5 has the most amount of removal and the removal percentage of heavy metal ions for

adsorbents. Similar static adsorption experiments were performed with activated carbon. Specific amount of affinity membranes (P0, P0.5, and P1) were added separately to 50 ml of metal solutions at a specified temperature and pH, and after 24 h of agitation, the amount of adsorption was obtained from Eq. (3). Similar static adsorption experiment was performed for activated carbon at the same operating conditions (C2). In order to better compare the ability of the affinity membrane and the activated carbon, the static adsorption test for activated carbon were 270

Carbohydrate Polymers 210 (2019) 264–273

N. Sahebjamee et al.

Fitting results for the kinetic models are given in Table 3. According to these results, the adsorption process of heavy metals by the membrane is in good agreement with the pseudo-second-order model, which is consistent with the reported results in the literature for solutions with low concentrations (Azizian, 2004; Ho, 2006). In fact, the existence of amine functional groups cause the adsorption process of heavy metal ions on the membrane to be carried out through chelating ion exchange process (Cheng et al., 2010; Salehi et al., 2012). It was found that the affinity of the membrane on the basis of mmol metal ions/g adsorbent is in the order of Cu2+ > Ni2+ > Cd2+(1.355, 1.286, and 0.998 mmol/g for Cu2+, Ni2+, and Cd2+, respectively). A number of characteristic properties of Cu2+, Cd2+ and Ni2+, such as the ionic radius, hydrated radius, electronegativity, and hydration free energy are listed in Table 4. According to this table the ionic and hydrated radii of Cu2+ and Ni2+ are smaller than those of Cd2+, so the smaller the ion’s hydration, the closer and stronger it is for the adsorbing surface (Ko, Cheung, Choy, Porter, & McKay, 2004). Cu2+ and Ni2+ also have higher electronegativity than that of Cd2+ (Tan, Hu, & Bi, 2016). Therefore, there was stronger affinity for Cu2+ and Ni2+ than Cd2+. It can be seen from the table that Cu2+ has larger radius than Ni2+ while their electronegativity are almost the same, but due to lower hydration free energy, there would be stronger attraction between the Cu2+ and the membrane surface (Tansel, 2012). It has been proven that the hydrated radius is not the only parameter for prediction of cation-exchange selectivity (Tansel, 2012). Lower hydration free energy is the main reason for the ions to create a soft hydration shell which could be rearranged or lose the water molecules more easily than the other ions (Tansel, 2012). Similar results have been reported based on Jahn-Teller effect which is a predominant reason for copper complexes selectivity (Marcus, 1988; Zhou, Wang, Liu, & Huang, 2009). Some related adsorbents were compared with the present adsorbent (P0.5) and the results were summarized in a tabular form (Table 5).

Fig. 5. Adsorption performance of membrane P0.5 for heavy metal ions during the different cycles (T = 25 °C, C0 = 30 mg/l and pH = 6).

the membrane with the highest amount of PEI (P1) is less than that for P0.5 due to different values of PEI and porosity of the membranes. As P0.5 showed higher efficiency for adsorption based on the aforementioned batch adsorption results, further analysis for investigation of the static adsorption behavior was done for this membrane in the following sections. 3.6.2. Isothermal studies Isotherms fitting results for Langmuir, Freundlich, Temkin, and Dubinin–Redushkevich models are listed in Table 2. It can be seen that Langmuir equation gives a relatively better fit to the equilibrium data. The low values for E (below 8 kJ/mol) in Dubinin–Radushkevich isotherm suggested the physical adsorption nature of the adsorption processes. 3.6.3. Thermodynamic studies The thermodynamic parameters were estimated to evaluate the feasibility and nature of the adsorption reaction (Salehi et al., 2012). With regard to the results obtained in Table 2 and the negative values of ΔG° for metal ions of Ni2+, Cu2+, and Cd2+, it is clear that the adsorption of the metal ions onto CS/PVA/PEI membrane was spontaneous and thermodynamically favorable. In addition, the decrease in ΔG° values with increasing the temperature indicates a reduction in the rate of the adsorption favorability by higher temperatures. The negative ΔH° values suggest that the adsorption process on CS/PVA/PEI membranes has an exothermic nature. With respect to Table 3, entropy changes in the adsorption process are negative, which reflects the fact that the degree of freedom at the solid-liquid interface is reduced during adsorption (Jing et al., 2016; Salehi et al., 2012).

3.7. Reusability of the membranes The reusability of the membrane P0.5 is shown in Fig. 5. Desorption resulted in a slight loss of membrane adsorption ability. Generally, the metal adsorption capacity on the membrane was decreased with increasing the number of reuse cycle due to the loss of active sites during repeated adsorption/desorption processes. The adsorption capacity of the membrane was decreased by only less than 5% after four adsorption/desorption cycles, which indicated the potential for reusability and stability of the membrane for heavy metals adsorption. 4. Conclusion In this work, adding a third polymer (PEI), which contains a large number of amine functional groups, to the CS/PVA blend led to a rise in adsorption sites and thus increased the adsorption capacity of the membrane. However, adding too much PEI decreased the membrane porosity and had an inverse effect on the membrane efficiency. Comparison of the adsorbent membranes with activated carbon showed that their removal efficiency for metal ions of Ni2+, Cu2+, and Cd2+ was more than activated carbon. The adsorption process was fitted well by Langmuir isotherm model and the pseudo-second order kinetic equation. The negative values of ΔG and ΔH showed that the adsorption is spontaneous and exothermic. The membranes could be regenerated successfully in EDTA aqueous solution. With respect to the results of the present study, the addition of PEI to the CS/PVA structure resulted in a remarkable increase in removal of heavy metal ions from aqueous solution.

3.6.4. Kinetic studies Fig. 4a shows the adsorption of metal ions (Cd2+, Cu2+, Ni2+) on the P0.5 membrane versus time. This figure revealed that during the first five hours the adsorption had a faster rate which is due to the abundant free adsorption sites on the surface with easy access for the metal ions (Jing et al., 2016). Then adsorption rate slows down and gradually reaches to the equilibrium. Figs. 4b and 4c represent the linear plot of pseudo first and second order model, respectively. The values of k1, k2, and Qe were calculated from the slope and intercept of the respective linear plots. In Fig. 4d, there are two separate regions, which show that the internal particle diffusion is not the only rate controlling stage and there are two processes involved. The first linear section, with a sharper slope, describes the rapid adsorption step at the outer surface of the membrane, which can be eliminated by increasing the stirring rate. The second linear part describes the gradual and slow adsorption step, where the intraparticle diffusion is the rate controller stage. Similar results have been reported (Dotto & Pinto, 2011).

Acknowledgements

for 271

The first author is grateful to the Islamic Azad University of Quchan supporting scholarship. The authors also appreciate the

Carbohydrate Polymers 210 (2019) 264–273

N. Sahebjamee et al.

experimental facilities provided by this university to carry out this research.

167–182. Jing, Y., Gao, H., & Yang, C. Y. (2016). Chitosan microspheres modified with poly (ethylenimine) enhance the adsorption of methyl orange from aqueous solutions. Asia-Pacific Journal of Chemical Engineering, 11(3), 428–436. Kaur, R., Kaur, A., Umar, A., Anderson, W. A., & Kansal, S. K. (2019). Metal organic framework (MOF) porous octahedral nanocrystals of Cu-BTC: Synthesis, properties and enhanced adsorption properties. Materials Research Bulletin, 109, 124–133. Keshvardoostchokami, M., Babaei, L., Zamani, A., Parizanganeh, A., & Piri, F. (2017). Synthesized chitosan/iron oxide nanocomposite and shrimp shell in removal of nickel, cadmium and lead from aqueous solution. Global Journal of Environmental Science Management, 3(3), 267–278. Ko, D. C., Cheung, C. W., Choy, K. K., Porter, J. F., & McKay, G. (2004). Sorption equilibria of metal ions on bone char. Chemosphere, 54(3), 273–281. Kuang, P., Chen, N., Feng, C., Li, M., Dong, S., Lv, L., et al. (2018). Construction and optimization of an iron particle–zeolite packing electrochemical–adsorption system for the simultaneous removal of nitrate and by-products. Journal of the Taiwan Institute of Chemical Engineers, 86, 101–112. Kumar, H. N., Prabhakar, M., Prasad, C. V., Rao, K. M., Reddy, T. A. K., Rao, K. C., et al. (2010). Compatibility studies of chitosan/PVA blend in 2% aqueous acetic acid solution at 30 C. Carbohydrate Polymers, 82(2), 251–255. Li, J., Wang, X., Zhao, G., Chen, C., Chai, Z., Alsaedi, A., et al. (2018). Metal–organic framework-based materials: superior adsorbents for the capture of toxic and radioactive metal ions. Chemical Society Reviews, 47(7), 2322–2356. Lin, Y.-F., Chen, H.-W., Chien, P.-S., Chiou, C.-S., & Liu, C.-C. (2011). Application of bifunctional magnetic adsorbent to adsorb metal cations and anionic dyes in aqueous solution. Journal of Hazardous Materials, 185(2-3), 1124–1130. Lindén, J. B., Larsson, M., Coad, B. R., Skinner, W. M., & Nydén, M. (2014). Polyethyleneimine for copper absorption: Kinetics, selectivity and efficiency in artificial seawater. RSC Advances, 4(48), 25063–25066. Lindén, J. B., Larsson, M., Kaur, S., Skinner, W. M., Miklavcic, S. J., Nann, T., et al. (2015). Polyethyleneimine for copper absorption II: Kinetics, selectivity and efficiency from seawater. RSC Advances, 5(64), 51883–51890. Liu, C., & Bai, R. (2006). Adsorptive removal of copper ions with highly porous chitosan/ cellulose acetate blend hollow fiber membranes. Journal of Membrane Science, 284(12), 313–322. Liu, X., Cheng, Z., & Ma, W. (2009). Removal of copper by modified chitosan adsorptive membrane. Frontiers of Chemical Engineering in China, 3(1), 102–106. Lungu, C. N., Diudea, M. V., Putz, M. V., & Grudziński, I. P. (2016). Linear and Branched PEIs (Polyethylenimines) and Their Property Space. International Journal of Molecular Sciences, 17(4), 555. Marcus, Y. (1988). Ionic radii in aqueous solutions. Chemical Reviews, 88(8), 1475–1498. Melo, B. C., Paulino, F. A., Cardoso, V. A., Pereira, A. G., Fajardo, A. R., & Rodrigues, F. H. (2018). Cellulose nanowhiskers improve the methylene blue adsorption capacity of chitosan-g-poly (acrylic acid) hydrogel. Carbohydrate Polymers, 181, 358–367. Min, M., Shen, L., Hong, G., Zhu, M., Zhang, Y., Wang, X., et al. (2012). Micro-nano structure poly (ether sulfones)/poly (ethyleneimine) nanofibrous affinity membranes for adsorption of anionic dyes and heavy metal ions in aqueous solution. Chemical Engineering Journal, 197, 88–100. Mittal, A., Mittal, J., Malviya, A., Gupta, V., & Science, I. (2010). Removal and recovery of Chrysoidine Y from aqueous solutions by waste materials. Journal of Colloid and Interface Science, 344(2), 497–507. Mohammadi, N., Khani, H., Gupta, V. K., Amereh, E., & Agarwal, S. (2011). Adsorption process of methyl orange dye onto mesoporous carbon material–kinetic and thermodynamic studies. Journal of Colloid and Interface Science, 362(2), 457–462. Monier, M., Ayad, D., Wei, Y., & Sarhan, A. (2010). Adsorption of Cu (II), Co (II), and Ni (II) ions by modified magnetic chitosan chelating resin. Journal of Hazardous Materials, 177(1-3), 962–970. Nam, J.-P., & Nah, J.-W. (2016). Target gene delivery from targeting ligand conjugated chitosan–PEI copolymer for cancer therapy. Carbohydrate Polymers, 135, 153–161. Neghlani, P. K., Rafizadeh, M., & Taromi, F. A. (2011). Preparation of aminated-polyacrylonitrile nanofiber membranes for the adsorption of metal ions: Comparison with microfibers. Journal of Hazardous Materials, 186(1), 182–189. Özcan, A., Özcan, A. S., Tunali, S., Akar, T., & Kiran, I. (2005). Determination of the equilibrium, kinetic and thermodynamic parameters of adsorption of copper (II) ions onto seeds of Capsicum annuum. Journal of Hazardous Materials, 124(1-3), 200–208. Pandey, S., & Tiwari, S. (2015). Facile approach to synthesize chitosan based composite—Characterization and cadmium (II) ion adsorption studies. Carbohydrate Polymers, 134, 646–656. Pandiarajan, A., Kamaraj, R., Vasudevan, S., & Vasudevan, S. (2018). OPAC (orange peel activated carbon) derived from waste orange peel for the adsorption of chlorophenoxyacetic acid herbicides from water: Adsorption isotherm, kinetic modelling and thermodynamic studies. Bioresource Technology, 261, 329–341. Peng, S., Meng, H., Ouyang, Y., & Chang, J. (2014). Nanoporous magnetic cellulose–Chitosan composite microspheres: Preparation, characterization, and application for Cu (II) adsorption. Industrial & Engineering Chemistry Research, 53(6), 2106–2113. Pimpha, N., Sunintaboon, P., Inphonlek, S., & Tabata, Y. (2010). Gene delivery efficacy of polyethyleneimine-introduced chitosan shell/poly (methyl methacrylate) core nanoparticles for rat mesenchymal stem cells. Journal of Biomaterials Science Polymer Edition, 21(2), 205–223. Roper, D. K., & Lightfoot, E. N. (1995). Separation of biomolecules using adsorptive membranes. Journal of Chromatography A, 702(1-2), 3–26. Salehi, E., & Madaeni, S. (2014). Influence of poly (ethylene glycol) as pore-generator on morphology and performance of chitosan/poly (vinyl alcohol) membrane adsorbents. Applied Surface Science, 288, 537–541. Salehi, E., Madaeni, S., Rajabi, L., Derakhshan, A., Daraei, S., & Vatanpour, V. (2013).

References Ahmaruzzaman, M., & Gupta, V. K. (2011). Rice husk and its ash as low-cost adsorbents in water and wastewater treatment. Industrial & Engineering Chemistry Research, 50(24), 13589–13613. Azizian, S. (2004). Kinetic models of sorption: a theoretical analysis. Journal of Colloid and Interface Science, 276(1), 47–52. Barakat, M. (2011). New trends in removing heavy metals from industrial wastewater. Arabian Journal of Chemistry, 4(4), 361–377. Bessbousse, H., Rhlalou, T., Verchère, J.-F., & Lebrun, L. (2008). Sorption and filtration of Hg (II) ions from aqueous solutions with a membrane containing poly (ethyleneimine) as a complexing polymer. Journal of Membrane Science, 325(2), 997–1006. Cao, J., Li, D., Liang, W., Wang, Y., & Wu, D. (2016). Glutaraldehyde cross-linked chitosan nanofibers: Preparation, characterization and application in adsorption of Cu (ii). Journal of Nanoscience and Nanotechnology, 16(3), 2922–2928. Chen, L., Wu, P., Chen, M., Lai, X., Ahmed, Z., Zhu, N., et al. (2018). Preparation and characterization of the eco-friendly chitosan/vermiculite biocomposite with excellent removal capacity for cadmium and lead. Applied Clay Science, 159, 74–82. Cheng, Z., Liu, X., Han, M., & Ma, W. (2010). Adsorption kinetic character of copper ions onto a modified chitosan transparent thin membrane from aqueous solution. Journal of Hazardous Materials, 182(1-3), 408–415. Crini, G., Lichtfouse, E., Wilson, L. D., & Morin-Crini, N. (2018). Conventional and nonconventional adsorbents for wastewater treatment. Environmental Chemistry Letters, 1–19. Daneshyar, A., Ghaedi, M., & Sabzehmeidani, M. (2017). H2S adsorption onto Cu-Zn–Ni nanoparticles loaded activated carbon and Ni-Co nanoparticles loaded γ-Al2O3: Optimization and adsorption isotherms. Journal of Colloid and Interface Science, 490, 553–561. Dashtian, K., Porhemat, S., Rezvani, A. R., Ghaedi, M., & Sabzehmeidani, M. M. (2018). Adsorption of semisoft pollutants onto Bi2S3/Ag2S-AC under the influence of ultrasonic waves as external filed. Journal of Industrial and Engineering Chemistry, 60, 390–400. Dawood, S., & Sen, T. K. (2012). Removal of anionic dye Congo red from aqueous solution by raw pine and acid-treated pine cone powder as adsorbent: Equilibrium, thermodynamic, kinetics, mechanism and process design. Water Research, 46(6), 1933–1946. de Souza Costa-Júnior, E., Pereira, M. M., & Mansur, H. S. (2009). Properties and biocompatibility of chitosan films modified by blending with PVA and chemically crosslinked. Journal of Materials Science Materials in Medicine, 20(2), 553–561. Debnath, S., Maity, A., & Pillay, K. (2014). Magnetic chitosan–GO nanocomposite: Synthesis, characterization and batch adsorber design for Cr (VI) removal. Journal of Environmental Chemical Engineering, 2(2), 963–973. Dotto, G., & Pinto, L. (2011). Adsorption of food dyes acid blue 9 and food yellow 3 onto chitosan: Stirring rate effect in kinetics and mechanism. Journal of Hazardous Materials, 187(1-3), 164–170. Ghaee, A., Shariaty-Niassar, M., Barzin, J., & Zarghan, A. (2012). Adsorption of copper and nickel ions on macroporous chitosan membrane: Equilibrium study. Applied Surface Science, 258(19), 7732–7743. Ghoul, M., Bacquet, M., & Morcellet, M. (2003). Uptake of heavy metals from synthetic aqueous solutions using modified PEI—silica gels. Water Research, 37(4), 729–734. Gu, P., Zhang, S., Li, X., Wang, X., Wen, T., Jehan, R., et al. (2018). Recent advances in layered double hydroxide-based nanomaterials for the removal of radionuclides from aqueous solution. Environmental Pollution, 240, 493–505. Gupta, V. K., Agarwal, S., & Saleh, T. A. (2011). Synthesis and characterization of alumina-coated carbon nanotubes and their application for lead removal. Journal of Hazardous Materials, 185(1), 17–23. Gupta, V. K., Nayak, A., Agarwal, S., & Tyagi, I. (2014). Potential of activated carbon from waste rubber tire for the adsorption of phenolics: Effect of pre-treatment conditions. Journal of Colloid and Interface Science, 417, 420–430. Habiba, U., Afifi, A. M., Salleh, A., & Ang, B. C. (2017). Chitosan/(polyvinyl alcohol)/ zeolite electrospun composite nanofibrous membrane for adsorption of Cr6+, Fe3+ and Ni2+. Journal of Hazardous Materials, 322, 182–194. Han, B., Carvalho, W., Canilha, L., Da Silva, S. S., e Silva, J. B. A., McMillan, J. D., et al. (2006). Adsorptive membranes vs. resins for acetic acid removal from biomass hydrolysates. Desalination, 193(1-3), 361–366. Han, R., Zhang, J., Han, P., Wang, Y., Zhao, Z., & Tang, M. (2009). Study of equilibrium, kinetic and thermodynamic parameters about methylene blue adsorption onto natural zeolite. Chemical Engineering Journal, 145(3), 496–504. Ho, Y.-S. (2006). Review of second-order models for adsorption systems. Journal of Hazardous Materials, 136(3), 681–689. Huang, Z.-W., Li, Z.-J., Wu, Q.-Y., Zheng, L.-R., Zhou, L.-M., Chai, Z.-F., et al. (2018). Simultaneous elimination of cationic uranium (VI) and anionic rhenium (VII) by graphene oxide–poly (ethyleneimine) macrostructures: a batch, XPS, EXAFS, and DFT combined study. Environmental Science Nano, 5(9), 2077–2087. Inphonlek, S., Pimpha, N., & Sunintaboon, P. (2010). Synthesis of poly (methyl methacrylate) core/chitosan-mixed-polyethyleneimine shell nanoparticles and their antibacterial property. Colloids and Surfaces B, Biointerfaces, 77(2), 219–226. Jamshidi, H., Ghaedi, M., Sabzehmeidani, M. M., & Bagheri, A. R. (2018). Comparative study of acid yellow 119 adsorption onto activated carbon prepared from lemon wood and ZnO nanoparticles loaded on activated carbon. Applied Organometallic Chemistry, 32(2), e4080. Järup, L. (2003). Hazards of heavy metal contamination. British Medical Bulletin, 68(1),

272

Carbohydrate Polymers 210 (2019) 264–273

N. Sahebjamee et al.

Preparation, characterization, and adsorption performance. Arabian Journal of Chemistry. Wang, X., Li, Y., Li, H., & Yang, C. (2016). Chitosan membrane adsorber for low concentration copper ion removal. Carbohydrate Polymers, 146, 274–281. Wang, X., Min, M., Liu, Z., Yang, Y., Zhou, Z., Zhu, M., et al. (2011). Poly (ethyleneimine) nanofibrous affinity membrane fabricated via one step wet-electrospinning from poly (vinyl alcohol)-doped poly (ethyleneimine) solution system and its application. Journal of Membrane Science, 379(1-2), 191–199. Weber, W. J., & Morris, J. C. (1963). Kinetics of adsorption on carbon from solution. Journal of the Sanitary Engineering Division, 89(2), 31–60. Wu, S., Kan, J., Dai, X., Shen, X., Zhang, K., & Zhu, M. (2017). Ternary carboxymethyl chitosan-hemicellulose-nanosized TiO 2 composite as effective adsorbent for removal of heavy metal contaminants from water. Fibers and Polymers, 18(1), 22–32. Yang, H. C., Wu, M. B., Li, Y. J., Chen, Y. F., Wan, L. S., & Xu, Z. K. (2016). Effects of polyethyleneimine molecular weight and proportion on the membrane hydrophilization by codepositing with dopamine. Journal of Applied Polymer Science, 133(32). Zarabi, M., & Jalali, M. (2018). Competitive Removal of Ammonium-Nitrogen from Aqueous Solutions by Mineral and Organic Adsorbents. Communications in Soil Science and Plant Analysis, 49(10), 1129–1143. Zeng, X., & Ruckenstein, E. (1996). Control of pore sizes in macroporous chitosan and chitin membranes. Industrial & Engineering Chemistry Research, 35(11), 4169–4175. Zeng, L., Chen, Y., Zhang, Q., Guo, X., Peng, Y., Xiao, H., et al. (2015). Adsorption of Cd (II), Cu (II) and Ni (II) ions by cross-linking chitosan/rectorite nano-hybrid composite microspheres. Carbohydrate Polymers, 130, 333–343. Zhao, G., Huang, X., Tang, Z., Huang, Q., Niu, F., & Wang, X.-K. (2018). Polymer-based nanocomposites for heavy metal ions removal from aqueous solution: a review. Polymer Chemistry, 9(26), 3562–3582. Zhou, L., Wang, Y., Liu, Z., & Huang, Q. (2009). Characteristics of equilibrium, kinetics studies for adsorption of Hg (II), Cu (II), and Ni (II) ions by thiourea-modified magnetic chitosan microspheres. Journal of Hazardous Materials, 161(2-3), 995–1002. Zhu, Q., Shentu, B., Liu, Q., & Weng, Z. (2006). Swelling behavior of polyethylenimine–cobalt complex in water. European Polymer Journal, 42(6), 1417–1422. Zielińska, K., Chostenko, A. G., & Truszkowski, S. (2010). Adsorption of cadmium ions on chitosan membranes: kinetics and equilibrium studies. Progress on Chemistry and Application of Chitin and its Derivatives, 15, 73–78.

Static and dynamic adsorption of copper ions on chitosan/polyvinyl alcohol thin adsorptive membranes: Combined effect of polyethylene glycol and aminated multiwalled carbon nanotubes. Chemical Engineering Journal, 215, 791–801. Salehi, E., Madaeni, S., Rajabi, L., Vatanpour, V., Derakhshan, A., Zinadini, S., et al. (2012). Novel chitosan/poly (vinyl) alcohol thin adsorptive membranes modified with amino functionalized multi-walled carbon nanotubes for Cu (II) removal from water: preparation, characterization, adsorption kinetics and thermodynamics. Separation and Purification Technology, 89, 309–319. Shafiq, M., Sabir, A., Islam, A., Khan, S., Hussain, S., Butt, M., et al. (2017). Development and performance characteristics of silane crosslinked poly (vinyl alcohol)/chitosan membranes for reverse osmosis. Journal of Industrial and Engineering Chemistry, 48, 99–107. Shen, W., Chen, S., Shi, S., Li, X., Zhang, X., Hu, W., et al. (2009). Adsorption of Cu (II) and Pb (II) onto diethylenetriamine-bacterial cellulose. Carbohydrate Polymers, 75(1), 110–114. Srinivasa, P., Ramesh, M., Kumar, K., & Tharanathan, R. (2003). Properties and sorption studies of chitosan–polyvinyl alcohol blend films. Carbohydrate Polymers, 53(4), 431–438. Sun, F., Cha, H.-R., Bae, K., Hong, S., Kim, J.-M., Kim, S. H., et al. (2011). Mechanical properties of multilayered chitosan/CNT nanocomposite films. Materials Science and Engineering A, 528(21), 6636–6641. Tan, P., Hu, Y., & Bi, Q. (2016). Competitive adsorption of Cu2+, Cd2+ and Ni2+ from an aqueous solution on graphene oxide membranes. Colloids and Surfaces A, Physicochemical and Engineering Aspects, 509, 56–64. Tansel, B. (2012). Significance of thermodynamic and physical characteristics on permeation of ions during membrane separation: Hydrated radius, hydration free energy and viscous effects. Separation and Purification Technology, 86, 119–126. Unagolla, J., & Adikary, S. (2015). Adsorption characteristics of cadmium and lead heavy metals into locally synthesized Chitosan Biopolymer. Tropical Agricultural Research, 26(2). Urbina, L., Guaresti, O., Requies, J., Gabilondo, N., Eceiza, A., Corcuera, M. A., et al. (2018). Design of reusable novel membranes based on bacterial cellulose and chitosan for the filtration of copper in wastewaters. Carbohydrate Polymers, 193, 362–372. Vatanpour, V., Salehi, E., Sahebjamee, N., & Ashrafi, M. (2018). Novel chitosan/polyvinyl alcohol thin membrane adsorbents modified with detonation nanodiamonds:

273