INSIGHTS INTO THE MECHANISM OF Cu2+ BINDING ONTO CHITOSAN-BASED CRYOGEL COMPOSITES: EQUILIBRIUM, KINETICS AND THERMODYNAMICS STUDIES

In this study, chitosan-based cryogel composites were prepared by combining the ion-imprinting methodology with ice-templating approach and were used as sorbents for Cu2+ ions. To understand the mechanism of Cu2+ sorption onto ion-imprinted cryogel composites (II-CCs), a systematic analysis of sorption isotherms, kinetics and thermodynamics data was performed. Accordingly, the Cu2+ sorption was a spontaneous endothermic monolayer sorption with chemisorption as the rate-limiting step. A faster sorption of Cu2+ ions was observed for II-CCs (20 min) compared to the non-imprinted ones (60 min), which was most probably caused by the presence of imprinted cavities. The reusability of IICCs was also investigated and it was shown that the sorption capacity of II-CCs towards Cu2+ remained almost unchanged after five cycles of sorption/desorption.