Development of anti-foulant ultraviolet-assisted polyvinyl alcohol layer on the polysulfone-based nanohybrid membrane for industrial rubber wastewater decontamination

Introduction: Membrane fouling has been reported to be one of the bottlenecks of membrane technologies for wastewater treatment. To mitigate its negative impacts, we fabricated polysulfone membrane (PSf) composites made of silica (SiO2) and graphene oxide (GO) nanoparticles that modified with ultraviolet (UV)-assisted polyvinyl alcohol layer on the membrane surface.

Methods: The membrane composite was synthesized using non-solvent induced phase separation (NIPS) method. The membrane was further treated by UV irradiation and cross-linked with PVA coating to cope with the fouling problem. The modified membrane was applied for industrial rubber wastewater decontamination.

Results: The UV irradiation and cross-linked PVA coating to the PSf/GO-SiO2 membrane improved the pseudo-steady state permeate flux by 60.15% from 20.05 to 50.32 L/m2hr and maintained the permeate flux up to 82.33%. About 85% of total dissolved solids (TDS), 81% of chemical oxygen demand (COD), and 84% of ammonia compound (NH3) with initial concentrations of 335.76, 242.55, 175.19 mg/L, respectively, could be removed after 8 h of membrane treatment. The modified membrane also exhibited an excellent flux recovery ratio of up to 83%.

Discussion: The modified membrane changed the fouling mechanism from pore blockage to cake filtration, which signifies the capability of the membrane to tackle severe fouling tendency. The cross-linked UV/PVA coating reduced fouling formation by reducing the adsorptive interactions between the foulant molecules and the membrane surface by enhancing membrane surface hydrophilicity. This implies that incorporating GO/SiO2 nanoparticles with UV irradiation and PVA coating substantially enhanced the physicochemical properties of the PSf membrane.