A novel PES-TiO2 hollow fiber hybrid membrane prepared via sol-gel process assisted reverse thermally induced phase separation (RTIPS) method

A new attempt to prepare polyethersulfone (PES)-Titania (TiO2) organic-inorganic hollow fiber hybrid membranes were investigated by sol-gel process assisted reverse thermally induced phase separation (RTIPS) method. The membrane formation mechanism underwent NIPS (coagulation temperature lower than cloud point) or RTIPS (coagulation temperature higher than cloud point) process. Properties of hollow fiber hybrid membranes, which varied with TiO2 sol addition and coagulation temperature, were investigated by SEM, EDX, AFM, TGA, XPS and contact angle. SEM results showed that the dense skin layer was produced in the hybrid membranes via NIPS process, while porous skin layer and sponge-like structures emerged in the hybrid membranes via RTIPS process. As a result, pure water flux, BSA rejection, mechanical properties of hybrid membranes by RTIPS were higher than that via NIPS. EDX mapping spectra proved that the dispersion uniformity of TiO2 particles through sol-gel process on the top surface of 1 wt% TiO2 embedded PES membrane, which prepared in 60 degrees C coagulation bath. XPS data revealed the element distribution in the hybrid membranes. AFM and TGA revealed increased surface roughness and thermal stability of the hybrid membranes by the addition of TiO2 sol, respectively. The organic-inorganic hybrid membranes prepared with 1 wt% TiO2 sol content by RTIPS method exhibited decent performance, which reached maximum pure water flux of 1046 L/(m(2)h) and BSA rejection of 75%.