Preparation of a Copper Ion Selective Membrane by Surface-Modified Molecular Imprinting

A novel copper ion-selective membrane was prepared by pressure-driven depositing poly(ethyleneimine) (PEI) onto the surface of a polyacrylonitrile (PAN) ultrafiltration (UF) membrane and was subsequently modified with molecular imprinting technique. Examination by infrared spectroscopy and scanning electron microscopy (SEM) confirmed PEI was successfully introduced onto the surface of a hydrolyzed PAN UF membrane. The increase of the pH of copper ion solution was beneficial to the template ion adsorption on the PEI deposited PAN (PEI-PAN) membrane. In ion imprinting, with the cross-linking time prolonged, the adsorption selectivity of the ion imprinted membrane (IIM) increased. The results of binding experiment fitted well with the Langmuir model and showed that the Cu2+ imprinted membrane has the ability of specificity and recognition toward the imprinted copper ion. The imprinting factor calculated from the separation factor was 2.25, indicating that the surface imprinting process facilitated the perm-selectivity of the membrane.