Effect of PVP loading on pervaporation performance of poly(vinyl alcohol) membranes for THF/water mixtures

This work reports an experimental study on the pervaporative dehydration of an industrial solvent tetrahydrofuran (THF) using a blend membrane of PVA/PVP crosslinked with maleic acid. The influence of feed composition and permeate pressure on the pervaporation flux and selectivity has been investigated. The membrane was found to exhibit a water flux of 0.007 kg/m2 h with a water selectivity of infinity for dehydration of 97% THF at 30 °C. FTIR of the blend was carried out to interpret its behavior on the basis of interactions between carbonyl groups of the cationic PVP and hydroxyl groups of the neutral PVA polymer. X-ray diffraction and sorption studies were carried out to study the degree of crystallinity and polymer–liquid interactions. The variation in film morphology was examined by scanning electron microscopy (SEM). Pervaporation experiments showed that high selectivity and promising permeability were obtained with a 9:1 blending ratio of PVA/PVP membrane crosslinked with 5 wt% maleic acid.