Pervaporation studies of gaseous plasma treated PVA membrane

Nonporous polyvinyl alcohol (PVA) membrane was modified in gaseous plasma to improve the separation efficiency for water-isopropanol (IPA) mixtures. Method of pervaporation separation process was adopted to assess the permselectivity after plasma processing. Membranes were exposed to plasma of air, nitrogen and oxygen for 2–15 min, and, their performances was evaluated at 75 °C for separation of azeotropic mixture of water–IPA. The optimized treatment time thus obtained for modification of PVA membrane was specifically used to further investigate the pervaporation performance over the selected water–IPA concentration range. Separation process at this stage was carried out at 25 and at 75 °C. The modified membrane was characterized by ATR-FTIR spectrometry, thermal analyses using DSC and wide angle X-ray diffraction. It has been found that the nitrogen plasma processing induces cross-linking on membrane surface leading to effective improvement in separation performance of membrane.