Preparation and characterization of PVA‐g‐GO / PVA / PAN composite membrane for pervaporation desalination

Abstract

Abstract Graphene oxide (GO) has extensive applications in membrane‐based separations, but its dispersion in the membrane has always been a problem due to the presence of π–π interactions in GO nanosheets. In this study, a grafting reaction was designed by using poly (vinyl alcohol) (PVA) for GO grafting modification and poly (vinyl alcohol)‐g‐graphene oxide (PVA‐g‐GO) nanocomposites were synthesized. The grafting material to GO was the same as the basic separation polymer material. PVA‐g‐GO showed better dispersibility and hydrophilicity than GO, and a series of composite membranes were prepared using a polyacrylonitrile (PAN) ultrafiltration (UF) membrane as a substrate. PVA‐g‐GO nanocomposites and membranes were characterized by using X‐ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier‐transform infrared spectroscopy (FTIR), water contact angle, scanning electron microscopy (SEM), etc. The addition of PVA‐g‐GO improved both the separation performance and anti‐swelling property of the composite membrane, and the PVA‐g‐GO/PVA/PAN composite membrane loaded with 2 wt.% PVA‐g‐GO obtained a high flux of 4.46 kg/m 2 · h and a high rejection of 99.99% when dehydrating 3.5 wt.% NaCl solution at 30°C by pervaporation.