Evaluation of the adsorption of nickel(II) and cadmium(II) ions in chitosan, crosslinked chitosan and crosslinked carboxymethylchitosan

Abstract

In this work, the studies of adsorption of nickel(II) and cadmium(II) ions on chitosan(Q), on chitosan crosslinked (QR) and on carboxymethyl chitosan crosslinked (CMQ-R) were performed. The adsorbents (Q, QR and CMQ-R) were characterized by Fourier Transform Infrared (FTIR), TGA analysis and Scanning Electron Microscope (SEM). The kinetics study demonstrated that the adsorption process proceeded according to the pseudo-second-order model. The equilibrium data were analyzed by Langmuir, Freundlich and Tenkim isotherms models. The maximum adsorption capacities (qmax) for nickel(II) ion in Q were 16.6 mg g-1 and for nickel(II)/cadmium(II) ion in QR and CMQ-R were 16.8/6.0 and 84.9/113.4 mg g-1, respectively. Thermodynamic parameters of sorption process such as ΔG°, ΔH°, and ΔS° were also calculated.