Effect of Nano-TiO2 Particles on the Performance of PVDF, PVDF-g-(Maleic anhydride), and PVDF-g-Poly(acryl amide) Membranes

To study the effects of nano-TiO2 particles on membrane performance and structure and to explore possible interactions between nano-TiO2 particles and polymer, polymer/TiO2 embedded hybrid membranes and neat polymer membranes were prepared using the phase inversion method. Poly(vinylidene difluoride) (PVDF) poly(vinylidene difluoride)-g-(maleic anhydride) (PVDF-g-MA), and poly(vinylidene difluoride)-g-poly(acryl amide) (PVDF-g-PAM) were selected as the membrane materials. SEM images showed that the hybrid membranes had a thinner skin layer and a larger number of pores in the sublayer than the neat membranes, which was the main cause of the increase in water flux of the hybrid membranes. They also exhibited a better antifouling property than the neat ones in the continuous BSA solution filtration process. In the 48 h-long pure water experiment, the hybrid membranes underwent a water flux decline and an increase in contact angle. The loss of nano-TiO2 particles, revealed by EDS analysis, influenced the stability of hybrid membrane performance. The XPS analysis suggested that nano-TiO2 particles were immobilized in the membrane surface layer through the formation of a stable chemical structure resulting from its reaction with polymer and/or through intertwining with polymer chains.