Application of surface molecular imprinting adsorbent in expanded bed for the adsorption of Ni2+ and adsorption model

A new surface molecular imprinting adsorbent (SMIA) was used in an expanded bed. The expansion ratio and adsorption performance were studied at different volumetric rates, inlet concentrations, and pH values. A model based on the Adams–Bohart adsorption model of breakthrough curves was established. The predicted curves had good agreement with the experimental curves. The breakthrough time (T1/2) decreased with increasing inlet concentration when the outlet concentration was half the initial concentration (C/C0=0.5). The inlet concentration had little effect on the adsorption rate constant (k1) value when the initial concentration (C0) was above 150 mg/L. However, T1/2 values increased with increasing initial pH of the inlet solution, and the k1 value decreased due to the competition between H+ and Ni2+.