New design of graphene oxide on macroporous nylon assisted polyvinyl alcohol with Zn (II) cross-linker for pervaporation desalination

Abstract

Thin film composite membranes of macroporous nylon substrates, graphene oxide (GO) sheets, and polyvinyl alcohol (PVA) with Zn2+ (c) ions as cross-linkers have been successfully prepared. This study aims to obtain the membrane composition with the highest desalination efficiency and the best membrane permeability and stability. Membrane performance in desalination applications was evaluated by measurement of water flux and salt rejection. GO was successfully synthesized using a modified Hummers method, and the membrane was prepared by vacuum filtration with various volumes of PVAy ( y = 1 mL, 5 mL, and 10 mL). c-GO-PVA membranes were characterized by using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), water contact angle, and scanning electron microscopy (SEM). The experimental results show that adding a cross-linker increases the membrane’s stability, and adding PVA increases the hydrophilicity. The desalination test showed that pure GO membrane had high flux but the lowest salt rejection. The c-GO-PVA5 nylon membrane has a high water flux of 20.68 kg m−2 h−1 and high salt rejection (close to 100.0%), so it is recommended as a pervaporation membrane.