Preparation and hydrophobicity modification of poly(vinylidene fluoride-co-hexafluoropropylene) membranes for pervaporation separation of volatile organic compound from water

In this study, novel nanocomposite membranes were fabricated for the removal of isopropyl benzene, a volatile organic compound (VOC), from water via pervaporation (PV). The membranes were made of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) copolymer. In order to improve the hydrophobic properties of the membranes, hydrophobic silica nanoparticles that had been surface modified by hexamethyldisilazane were used as the nanofiller in the PV membranes, for the first time. Incorporating hydrophobic silica nanoparticles into PVDF-HFP and increasing its concentration up to 9 wt% enhanced membrane hydrophobicity. Evaluation of membrane performance in VOC separation from water showed that the membrane containing 9 wt% of silica had the highest VOC separation factor, so that the values of total flux, separation factor, and PV separation index (PSI) were 3.77 g/m(2)/h; 42,483.81; and 158,788.50 g/m(2)/h for this membrane, respectively. The separation factor and PSI value of the mentioned membrane were almost 204 and 5 times higher than that of the neat PVDF-HFP membrane.