Novel dense poly(vinyl alcohol)–TiO2 mixed matrix membranes for pervaporation separation of water–isopropanol mixtures at 30 °C

Novel poly(vinyl alcohol)–titanium dioxide (PVA–TiO2) mixed matrix membranes have been prepared by incorporating nano-sized titanium dioxide (21 nm) and titanium dioxide surface modified with polyaniline (PANI) into PVA and crosslinked with glutaraldehyde. The developed membranes have been assessed for intermolecular interactions using Fourier transform infrared (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) techniques to understand their morphological and thermal properties. Suitability of these membranes to dehydrate isopropanol by pervaporation (PV) has been demonstrated. The effect of feed composition as well as extent of filler loading on the PV separation performance of these membranes has been evaluated. Sorption studies have been carried out to evaluate the extent of interaction and degree of swelling of the membranes in pure liquids as well as feed mixtures of water and isopropanol. Addition of small amount of nano-sized filler particles into the crosslinked PVA membrane matrix has been instrumental in increasing the membrane selectivity to infinity values. The uncrosslinked mixed matrix PVA membranes have yielded higher swelling properties than those of the crosslinked ones. However, swelling results of the crosslinked (unfilled) PVA membranes are higher than all the mixed matrix membranes. The addition of filler particles has decreased the extent of swelling and the flux properties, giving an increase in selectivity.