Adsorption of Au(III) ions on xanthated crosslinked chitosan resin in hydrochloric acid medium

Xanthated crosslinked chitosan (XCCS) resin prepared under microwave irradiation were used for adsorbing Au(III) ions in hydrochloric acid medium. The influence of pH and temperature on the adsorption capacity of XCCS was investigated. The original XCCS and the loaded XCCS were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The results indicate that the XCCS has ability to adsorb Au(III) ions and the maximum adsorption capacity of Au(III) ions on XCCS is observed at pH 1 and 20 °C. The data of batch adsorption tests are fitted to kinetic models and isotherm models, respectively. The kinetics of adsorption process is found to follow pseudo-second-order kinetic rate model, and equilibrium data agree very well with the Langmuir model. Thermodynamic calculation of the Au(III) ions adsorption process indicates that the adsorption process is spontaneous and endothermic.