The study of copper adsorption from aqueous solution using crosslinked chitosan immobilized on bentonite

Batch experiments were performed to investigate the adsorption of Cu(II) from aqueous solution using noncrosslinked and crosslinked chitosan immobilized on bentonite (CIB). Crosslinking agents such as epichlorohydrin (ECH), glutaraldehyde (GLA), and ethylene glycol diglycidyl ether (EDGE) were utilized to improve the chemical and mechanical properties of the adsorbent. The effect of contact time, pH, and initial concentration on the adsorption capacity was determined. The adsorption capacities of the adsorbents are arranged in the following order: CIB-EDGE > CIB-ECH > CIB >> CIB-GLA. Langmuir and Freundlich equations were used to analyze the isotherm data. Equilibrium studies showed that CIB, CIB-EDGE, and CIB-ECH correlated well with the Langmuir model while CIB-GLA fits well with the Freundlich model. Kinetics of Cu(II) adsorption was best described by the pseudosecond-order equation, which indicates that chemisorption is the rate-limiting step. In the desorption study, more than 92 and 75% of Cu(II) could be recovered from CIB-EDGE and CIB-ECH beads using HCl solution (pH 1) agitated for 120 min. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012