Dehydration of isopropanol by poly(vinyl alcohol) hybrid membrane containing oxygen-plasma treated graphene oxide in pervaporation process

Poly(vinyl alcohol) (PVA)/polyethersulfone (PES) composite membranes were fabricated using two PVA polymers with molecular weights of 50,000 and 15,000 and different crosslinker agents. The membrane with the top layer consisting PVA 50,000 and formaldehyde as the crosslinker were found to have a better separation factor than the others for pervaporative dehydration of isopropanol. While adding 1.0 wt% graphene oxide could represent a better pervaporation separation factor, 248.7% higher than that of the unfilled membrane, treating the graphene oxide nanosheets using cold plasma irradiation under oxygen atmosphere could yield 47.5% higher separation factor compared to the membrane containing untreated nanosheets owing to higher functional groups on the treated nanosheets that enhance the crosslinking density of the membrane. The best plasma treatment conditions in the selected range were found as 60 s irradiation under 0.3 mbar pressure and device power of 25 watts. The superior performance of the optimal membrane fabricated in the present study was confirmed by comparing the values of normalized pervaporation water index with those in previous studies.