Phosphate adsorption from aqueous solutions by Zirconium (IV) loaded cross-linked chitosan particles

In this work, Zirconium (IV) loaded cross-linked chitosan (CCP-Zr) was prepared by membrane-forming and cross-linking, and characterized by FTIR, XRD, SEM and EDX. Batch of experiments were performed to investigate the effects of various factors on the adsorption of phosphate onto CCP-Zr, including adsorbent dosage, initial phosphate concentration, pH value and the presence of co-ions. The experimental data were analyzed by the different adsorption kinetic and isotherm models. The results showed that the kinetic data were well fitted to the pseudo second-order model, and only 20 min was enough to reach adsorption equilibrium. The isotherm data were best described by the Langmuir isotherm model with the maximum monolayer adsorption capacity of 71.68 mg/g at pH 3 and 303 K. The adsorption mechanism was possibly attributed to the electrostatic attraction and ion exchange reaction between CCP-Zr and phosphate ions. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.