Separation of Toluene-Methanol Mixtures by Pervaporation Using Semi-IPN Polymer Membranes

Polyvinyl alcohol (PVOH) has been chemically modified by polymerizing hydroxyethylmethacrylate (HEMA) in aqueous solution of PVOH and finally crosslinking PVOH with glutaraldehyde to produce a semi-interpenetrating network (SIPN) membrane. Accordingly, three such SIPN membranes, namely SIPNI, SIPNII, and SIPNIII were synthesized with different weight ratio of PVOH: HEMA i.e., 1:0.25 (SIPNI), 1:0.50 (SIPNII), and 1:0.75 (SIPNIII). These SIPN membranes were used for pervaporative separation of methanol from its mixtures with toluene. The flux and methanol selectivity of these SIPN membranes were found to be much higher than conventional PVOH membrane crosslinked with glutaraldehyde. Among the three membranes, SIPNIII with 75 wt% HEMA incorporation shows optimum performance in terms of flux and methanol selectivity. The permeability of the membranes was also found to increase with increase in HEMA content in PVOH matrix. The novelty of the work lies in synthesis and characterization of a new kind of membrane and its potential for selective removal of methanol from its mixtures with toluene.