A novel super-hydrophilic PSf/HAO nanocomposite ultrafiltration membrane for efficient separation of oil/water emulsion

•Novel PSf/HAO nanocomposite was prepared for effective oil/water emulsion separation.•The nanocomposite preparation process is simple, low-cost and applicable.•The optimized nanocomposite has super-hydrophilic characteristic (contact angle=8°).•Permeate flux was increased from 150.8 for PSf to1194L/m2hbar for PSf/HAO-2.•PSf/HAO-2 exhibited excellent oil rejection using the 1g/L oil–water emulsion as feed. In this work, flat sheet polysulfone (PSf)-based membranes modified with inorganic hydrous aluminum oxide (HAO) nanoparticles were used as antifouling ultrafiltration membranes for removing oil molecules from oily solution. SEM, AFM and FTIR analyses were performed on the fabricated membranes to study the effect of HAO nanoparticles loading on the membrane properties. The membrane hydrophilicity and separation performance were determined through contact angle measurement and cross-flow ultrafiltration of oily solution, respectively. Results showed that the hydrophilicity of HAO-modified membrane was increased remarkably upon addition of the highest weight ratio of HAO nanoparticles to PSf (i.e. 2:1), which led to a significant rise in permeate flux, achieving 1194L/m2hbar in comparison to 151L/m2hbar shown by the plain PSf membrane. With respect to oil removal efficiency, the modified membrane was found to exhibit almost complete elimination of oil molecules with flux recovery ratio of around 67% after a simple water washing process. The promising results achieved by the modified PSf membrane could be mainly due to the presence of hydroxyl functional groups on the membrane surface upon addition of highly hydrophilic HAO nanoparticles, which improved not only membrane water permeability but also its antifouling ability.