Performance evaluation of PES-ZnO nanohybrid using a combination of UV irradiation and cross-linking for wastewater treatment of the rubber industry to clean water

Polyethersulfone (PES) membrane can be easily fouled during wastewater treatment as it is slightly hydrophobic. Consequently, several modifications are required to improve membrane surface properties to avoid membrane fouling. UV irradiation and cross-linked polyvinyl alcohol coating on nanohybrid membranes were performed in this study, and PES was combined with ZnO nanoparticles as an inorganic additive. Also, the PES-ZnO nanohybrid membrane was treated under the UV irradiation for a specific exposure time followed with membrane coating using polyvinyl alcohol (PVA) by the dip-coating method. Then, rubber wastewater filtration tests were performed using a cross-flow filtration system. The results revealed that the modifications significantly improved permeability and selectivity. As the duration of the UV irradiation increased, the higher mean flux value increased up to 14.55 L.m^-2.h^-1, but it was sacrificing the rejection efficiency. While the PVA coating decreased the water permeability up to 10.5 L.m^-2.h^-1 and increased the PVA concentration, the contaminant rejection increased up to 82%. The best membrane composition based on this study consisted of 17 wt.% of PES, 1 wt.% of ZnO nanoparticles, 5 wt.% Polyethylene glycol (PEG), 2 minutes UV irradiation, and 3% PVA coating.