High flux composite PTMSP-silica nanohybrid membranes for the pervaporation of ethanol/water mixtures

Silica-filled poly(1-trimethylsilyl-1-propyne) (PTMSP) layers were successfully applied for the first time on top of ultrafiltration support membranes and applied in the pervaporative separation of ethanol/water mixtures. Reduction of the thickness of the separating PTMSP top layer and addition of hydrophobic silica particles resulted in a clear flux increase as compared to dense PTMSP membranes. With ethanol/water separation factors up to 12 and fluxes up to 3.5 kg m−2 h−1, the prepared supported PTMSP-silica nanohybrid membranes performed significantly better than the best commercially available organophilic pervaporation membranes. Characterization of a polyvinylidene fluoride (PVDF) and a polyacrylonitrile (PAN) support membrane revealed a more open, irregular and hydrophobic surface structure for the former membrane, thus explaining the higher fluxes of the PTMSP/PVDF composite membrane. Because of their promising flux-selectivity combination, the prepared membranes exhibit great potential in the removal of alcohols from aqueous mixtures.