Doping polysulfone ultrafiltration membrane with TiO2-PDA nanohybrid for simultaneous self-cleaning and self-protection

To prepare an ultrafiltration membrane with simultaneous self-cleaning and self-protection abilities, TiO 2 -polydopamine (PDA) nanohybrid are facilely prepared and used to functionalize polysulfone (PSf) membrane matrix. In the TiO 2 -PDA nanohybrid , PDA spheres acts as an adhesive substrate to hold densely covered photocatalytic TiO 2 nanoparticles , and also serves as a free-radical scavenger to protect PSf membrane against the damage by free radicals produced by TiO 2 during UV exposure treatment. The spherical-shaped TiO 2 -PDA can be easily doped into PSf membrane via phase inversion method, which allows the hydrophilic TiO 2 -PDA spheres migrating to the hydrophobic PSf surface and benefiting the antifouling ability. As a result, the TiO 2 -PDA/PSf hybrid membrane exhibits excellent overall performances in separation efficiency, remarkable self-cleaning property and performance stability under UV irradiation, in comparison with PSf and TiO 2 /PSf membrane. The influence of TiO 2 -PDA content on the membrane properties is also investigated, and it is found the hybrid membrane with 0.8   wt% TiO 2 -PDA possesses the optimal performance.