A Novel Surface Ion-Imprinted Cation-Exchange Membrane for Selective Separation of Copper Ion

Ion-exchange membranes have been widely used in the separation of ionic mixtures or as a barrier in some types of chemical power source because of their selectivity to cations and anions. In this article, a novel single-ion selective ion-exchange membrane was fabricated to selectively separate copper ion from aqueous media. Polyethylenemine (PEI) was deposited onto a commercial cation-exchange membrane through an electric-field-enhanced procedure, and was subsequently modified with an ion imprinting technique. The effects of different parameters such as current density and feed composition on the deposition of PEI were studied. The copper ion imprinted membrane (Cu-IIM) showed lower resistance than the nonimprinted membrane (NIM) indicating the formation of a specific transportation path for the ions. The difference of binding isotherms for copper ion and zinc ion confirmed that the Cu-IIM had specificity to recognize copper ions. The permselectivity of the Cu-IIM was tested on an electrodialysis setup. The imprinting factor calculated from the separation factors of the imprinted and nonimprinted membrane was 1.99, demonstrating that the imprinting process enhanced the permselectivity of the membrane. The transport mechanism of ions in the Cu-IIM was also studied and analyzed.