Preparation and Characterization of Chromium(VI) Ion-Imprinted Composite Membranes with a Specifically Designed Functional Monomer

Cr(VI) anion-imprinted composite membranes (Cr(VI)-IICM1∼23) based on a designed functional monomer N,N'-(ethane-1,2-diyl)bis(2-methylacrylamide) (EBMA) were synthesized via surface-grafting. Using nylon-6 membrane for support, the main imprinting parameters, i.e., the functional monomer and crosslinker dosages, membrane soaking times, and porogen solvent ratios were optimized. The morphology and surface area of the optimum imprinted composite membrane (Cr(VI)-IICM11) were characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. The effects of the Cr(VI) anion concentration, adsorption time, temperature, and pH on adsorption were investigated. Additionally, the permeation, mass transfer, and adsorption of the Cr(VI)-IICM11 were characterized for aqueous Cr(VI) anions. The adsorption capacity and imprinting factor of the Cr(VI)-IICM11 in the imprinting solution were high, and the membrane had good permeation selectivity for Cr(VI) anions. Additionally, Cr(VI)-IICM11 efficiently adsorbed aqueous Cr(VI) anions. These results suggest that EBMA was a suitable functional monomer for Cr(VI) anions serving as the template. Therefore, Cr(VI)-IICM is a suitable material for adsorbing and separating Cr(VI) anions in complex, aqueous solutions.