Graphene oxide functionalized with zwitterionic copolymers as selective layers in hybrid membranes with high pervaporation performance

Zwitterionic copolymers, poly(glycidyl methacrylate-sulfobetaine methacrylate) [poly(GMA-SBMA)], was incorporated into graphene oxide (GO) to form a GO-poly(GMA-SBMA) framework. This compound was then deposited onto a polysulfone support through pressure-assisted filtration to fabricate hybrid membranes. Optimum fabrication conditions were determined by varying the poly(GMA-SBMA) loading. Attenuated total reflectance-Fourier transform infrared and X-ray photoelectron spectroscopy confirmed the covalent bonding between poly(GMA-SBMA) and GO. On account of loading incremental amounts of poly(GMA-SBMA), the membrane thickness was increased (illustrated by field emission scanning electron microscopic images), the interlayer spacing between GO sheets was expanded (shown by X-ray diffraction patterns), and the membrane hydrophilic properties were enhanced (indicated by water contact angle data). Relative to the pristine GO membrane, hybrid membranes fabricated at optimum conditions exhibited superior separation performance (99.60 wt% water concentration in permeate and 1102 gm(-2).h(-1) permeation flux) on dehydrating a 70 wt% aqueous isopropanol solution by pervaporation. This present study explored the potential of poly(GMA-SBMA) for developing hybrid membranes with excellent pervaporation performance.