Adsorption of uranium (VI) from aqueous solution onto cross-linked chitosan

Cross-linked chitosan (CCTS) was synthesized by the reaction of chitosan with epichlorohydrin under alkaline conditions. Adsorption of uranium (VI) from aqueous solution onto cross-linked chitosan was investigated in a batch system. Adsorption isotherm and adsorption kinetic studies of uranium (VI) onto cross-linked chitosan were carried out. The influence factors on uranium (VI) adsorption were also investigated and described in detail, such as contact time, pH value and initial uranium (I) concentration. Langmuir and Freundlich adsorption models were used for the mathematical description of the adsorption equilibrium. Equilibrium data agreed very well with the Langmuir model. Adsorption kinetics data were tested using pseudo-first-order and pseudo-second-order models. Kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate-limiting step. Results also showed that cross-linked chitosan was favourable adsorbent.