Sorption Properties of Ion-imprinted Seaweed-Chitosan Composite Adsorbents for Nickel Ions

Abstract

A granulated biosorbent-Ni-SC (Ni2+ ions imprinted seaweed-chitosan) was made by seaweed powder encapsulated with cross-linked chitosan and ion-imprint technology in this study. Ni-SC and granulated SC biosorbent (without ion-imprint technology) were investigated for nickel ions removal. The maximum nickel adsorption capacity of Ni-SC and SC were both achieved at pH 7.0 and the capacity of Ni-SC was higher than that of SC. The diffusion-controlled model and pseudo-second-order model were used to fit the adsorption kinetics data. The adsorption capacity of Ni-SC was higher than that of SC during the whole kinetics process. Also the adsorption isotherm study showed that the maximum adsorption capacity of Ni-SC (0.99 mmol•g-1) was higher than that of SC (0.41 mmol•g-1). The Thomas model can well describe the dynamic adsorption observations and the maximum column adsorption capacity qmax was 0.24 mmol•g-1.