Development of chitosan-based hydrogel beads for heavy metals removal from aqueous solutions

Abstract

Chitosan and its modified forms have received great attention as potential adsorbents due to its outstanding adsorption characteristics toward removal of vaious toxic heavy metal ions from aqueous solutions. In this work, a porous chitosan hydrogel beads (CHB) and CHB cross-linked with glutaraldehyde (GLA) and citric acid (CA) were synthesized and used for investigation of its adsorption performances toward the removal of Pb(II), Cu(II), Zn(II), Cd(II) and Cr(VI) ions from water in batch and dynamic systems. Maximum removal was achieved in the pH ranges of 4.0 - 6.5 and 2.0 - 3.5 for divalent cations and Cr(VI) oxyanion, respectively. The equilibrium adsorption data were best fitted by the Langmuir isotherm model. Based on the optimal conditions, the fixed-bed breakthrough curves for the removal of the studied metal ions from the aqueous solutions using fixedbed columns were experimentally evaluated, as well as theoretically predicted using COMSOL Multiphysics software.