Pervaporation performance of quaternized poly(vinyl alcohol) and its crosslinked membranes for the dehydration of ethanol

Quaternized poly(vinyl alcohol) (q-PVA) was synthesized, and crosslinked by glutaraldehyde to reduce the swelling of the q-PVA in an aqueous solution. The structure of the q-PVA and its crosslinked membranes was characterized by scanning electron microscopy, X-ray powder diffraction, and water contact angle measurements. Pervaporation performance of the membranes was studied by the dehydration of 85 wt% ethanol solution at 50 °C. The introduction of quaternary ammonium groups enhanced the hydrophilicity and water permselectivity. The water permeability and permselectivity of the q-PVA membranes increased simultaneously with increasing degree of quaternization (DQ). The crosslinking caused a decrease in swelling and an increase in water permselectivity of the q-PVA membranes. The q-PVA membrane with DQ of 4.035% has a highest water permeability of 12.628 g μm m−2 h−1 kPa−1, and the crosslinked q-PVA membrane with degree of crosslinking of 3.92% has a highest water permselectivity of 75.