Preparation of Surface Ion-Imprinted Materials Based on Modified Chitosan for Highly Selective Recognition and Adsorption of Nickel Ions in Aqueous Solutions

Nickel with good corrosion resistance is usually used for electroplating. However, the human health and live environment will be in danger if the discharge of nickel wastewater exceeds certain levels. Nickel pollutants are derived mainly from mining, smelting, electroplating, and other industries. Thus, it is very important to separate them from wastewater. One way is via surface imprinting. Here, chitosan, nickel nitrate, and epichlorohydrin were used as the substrate, template ion, and cross-linking agent, respectively, to synthesize a novel imprinted material for selective nickel adsorption. The adsorption kinetics study indicated that equilibrium was reached within 200 min, and the adsorption behavior was in good agreement with a pseudo-second-order nonlinear model. The adsorption capacity approached 20.0 mg·g–1, and the selectivity to Ni2+ was 56.9, 55.2, and 49.2 in the presence of cobalt, calcium, and manganese ions, respectively. In addition, the adsorption capacity remained at 96.1% after the polymer was reused five times. Overall, the imprinted polymer was a highly selective adsorbent for efficiently sequestering Ni and removing it from water.