LAUSR

Abstract Minute amount of poly(vinyl alcohol) (PVA) was used to cross-link graphene oxide (GO) nanosheets to prepare composite graphene oxide-framework (GOF) membranes with a nacre-like structure. The PVA provided additional increase in viscosity of GO suspension which made the solution casting of a large-area composite GOF membrane possible. The membranes were applied to separate an acetic acid-water mixture through pervaporation. The ATR-FTIR and XPS analyses confirmed the covalent bonding between GO and PVA as ether bonds were formed. This influenced the changes in water contact angle where it increased from 40.8° (pristine GO) to 62.7° (GO-PVA 8wt% ). X-ray diffraction showed that d -spacing of GOF was higher than GO due to the intercalation of PVA. The d -spacing of GO layer from dry to wet state has a difference of 2.59 A but addition of PVA lowered the difference to 0.38 A. The newly formed covalent bonds between GO and PVA might suppressed the stretching of d -spacing. It shows that the swelling was prevented and the interlayer spacing can be tuned. The composite GO-PVA 8wt% membrane has a short d -spacing and provided an outstanding pervaporation performance at 80 °C with a permeation flux of 463.9 g m −2  h −1 and water concentration in permeate of 97.7%.