Photocatalytic antifouling nanohybrid polysulfone membrane using the synergetic effect of graphene oxide and SiO2 for effective treatment of natural rubber-laden wastewater

Abstract

This study investigates the effects of graphene oxide (GO) and SiO2 composite as nano-photocatalysts in the polysulfone (PSf) membrane to treat natural rubber-laden wastewater (NRW) treatment under UV irradiation. The membranes were fabricated using the phase inversion process. Characterization results showed that the incorporation of GO and SiO2 nanoparticles as a composite successfully changed the properties of the membranes. Optical analysis tests revealed that the composite enhanced the photocatalytic activity and possessed bandgap energy of 3.25 eV, which made the SiO2 more active under UV light exposure after incorporating the GO. The addition of GO/SiO2 to the membrane resulted in more hydrophilic properties with contact angle of 60.34 degrees and water uptake ability of 52.78%. Conducting filtration under UV irradiation using PSf/GO/SiO2 membrane exhibited a remarkable improvement in permeate flux by 129% from 9.85 L m(-2) h(-1) to 22.55 L m(-2) h(-1) and maintained 85.4% of permeate flux stability. With respect to removal performance, under the photo-filtration process, chemical oxygen demand (COD) removal increased from 73 to 84%, and ammonia-nitrogen (NH3-N) removal improved from 78 to 92%. The photocatalytic kinetic evaluation suggested that the pseudo-first order kinetic model had a better fit than the zero-order kinetic. Regeneration tests showed that the PSf/GO/SiO2 membrane has outstanding durability. The resistance during filtration and antifouling potential evaluations revealed that the GO/SiO2 composite under UV light irradiation during filtration remarkably reduced the fouling formation and generated a high flux recovery ratio. This implies that this PSf/GO/SiO2 membrane is promising for advanced treatment of NRW.