Synthesis, characterization, and performance evaluation of UV light-driven Co-TiO₂@SiO₂ based photocatalytic nanohybrid polysulfone membrane for effective treatment of petroleum refinery wastewater

This study investigates the effects of cobalt (Co) doped TiO₂ @SiO₂ photocatalyst in the polysulfone (PSf) membrane that performed a combined membrane filtration and photocatalytic process under UV light irradiation for petroleum refinery wastewater (PRW) treatment. The photocatalyst composites were synthesized using the sol-gel method, and the membranes were prepared using the phase inversion technique. Characterization results showed that the Co doping in TiO₂ successfully improved the photo-sensitivity and photocatalytic activity of the composite, suggesting the reduction of the bandgap energy from 3.10 eV to 3.00 eV, which promoted the photocatalytic activity improvement. The addition of Co-TiO₂ @SiO₂ photocatalyst improved the membrane's porosity, hydrophilicity, water uptake ability, affinity towards water molecules, and mechanical strength. Furthermore, the PSf/Co-TiO₂ @SiO₂ membrane also exhibited enhanced performance on permeate flux, pollutant rejection, stability, recyclability, and durability. The fabricated photocatalytic membranes also exhibited superior antifouling performance and flux recovery ability when they performed under UV light irradiation.