Novel Plasma Functionalized Graphene Nanoplatelets (GNPs) incorporated in forward osmosis substrate with improved performance and tensile strength

Abstract

In this study, a novel thin-film nanocomposite forward osmosis (FO) membrane incorporated with plasma functionalized graphene nanoplatelets (GNPs) was developed. The well distributed GNPs in the polyethersulfone (PES) support increased the substrate porosity by 8%, and significantly improved the substrate tensile modulus even at a higher loading of GNPs. Unlike graphene oxide (GO), the linear increase in tensile strength with increasing the GNPs loading is due to the good dispersion properties of GNPs. The results indicated that in terms of water flux improvement, the optimal amount of GNPs incorporation is 0.3 wt%, while in terms of tensile strength, adding higher amounts of GNPs does not decrease the membrane stiffness even at 1 wt% of loading. The GNPs addition also significantly reduced the membrane structural parameter from 1323 µm with 0 wt% to 449 µm with 0.5 wt% loadings. Under the FO mode, water flux of 28.1 LMH was obtained for the membrane with the 0.5 wt% GNPs loading using 2 M NaCl as draw solution and DI water as feed. Overall, this study recommends that applying GNPs for the FO membrane development may be promising considering all types of FO applications where different membranes with different properties are required.