Permselectivity of Liquid–Polymer Hybrid Membrane Composed of Carbon Tetrachloride and 2-Hydroxyethyl Acrylate– Acrylonitrile Graft Copolymer for Ethanol–Water Mixture

Abstract

A membrane with selective permeability for ethanol was designed for the separation of ethanol from its aqueous solution by pervaporation on the basis of the difference in solubility between two components of the membrane. A liquid membrane was introduced to extend this difference and ethanol in the liquid membrane was isolated by the polymer membrane; that is, a liquid–polymer hybrid membrane was formed. Carbon tetrachloride was used as a liquid membrane, and 2-hydroxyethyl acrylate (HEA) (branch)–acrylonitrile (AN) (backbone) graft copolymer membrane was used as a polymer membrane. The effect of the microphase separated structure of the graft copolymer membrane on permselectivity was studied. The microdomain of the AN moiety displayed more dispersion and a smaller microdomain with decreasing chain length of the backbone polymer. It was found that the plasticizing effect was suppressed effectively by the microphase separated structure and the permselectivity of the graft copolymer membrane for ethanol was higher. When pervaporation of the ethanol–water mixture was carried out using the liquid–polymer hybrid membrane, ethanol completely permeated the liquid–polymer hybrid membrane.