Separation of isopropyl alcohol–water mixtures by pervaporation using crosslink IPN membranes

Polyvinyl alcohol (PVOH) has been chemically modified by crosslink copolymerization of acrylic acid (AA) and hydroxyethylmethacrylate (HEMA) in aqueous solution of PVOH and finally crosslinking PVOH to produce a full interpenetrating network (IPN) membrane termed as PVAH. Accordingly, three such full crosslink IPNs, i.e. PVAHI, PVAHII and PVAHIII containing varied weight ratio of PVOH and copolymer along with crosslink PVOH (which has not been modified by copolymerization) have been synthesized and used for pervaporative separation of isopropanol (IPA)–water mixtures. Permeability and water selectivity of these membranes were found to increase with increasing amount of copolymer in PVOH matrix. However, among the three membranes, PVAHIII were found to show highest flux but lower selectivity while PVAHI membrane showed optimum performance in terms of both flux and selectivity.