Preparation and characterization of emulsion poly(vinyl chloride) (EPVC)/TiO₂ nanocomposite ultrafiltration membrane

Emulsion poly(vinyl chloride)/titanium dioxide (EPVC/TiO₂) nanocomposite ultrafiltration membranes were prepared using the phase inversion method with different TiO₂ contents. Pure water flux through the membranes was investigated at a operating pressure of 2bar and its antifouling properties were studied using bovine serum albumin (BSA) as a foulant. The results showed an increment in pure water flux with increasing content of TiO₂ up to 2wt%, and then it slightly decreased by addition of 4wt% TiO₂ due to agglomeration of the nanoparticles at this content. The static water contact angle test showed improvement in membrane hydrophilicity, due to hydrophilic behavior of the nanoparticles, which led to higher water flux. SEM and EDAX analyses were applied to investigate membrane morphological changes. EDAX analysis indicated that the nanoparticles are homogeneously dispersed in membrane structure at low concentrations. However, at high loading, the nanoparticles have a propensity to aggregate. SEM images showed that with TiO₂ addition, initially finger-like structures change to macro-voids and after 1wt% TiO₂ loading, they return to finger-like construction with elongated finger-like pores. TiO₂ addition also enhanced BSA rejection properties. BSA ultrafiltration experiments showed that the antifouling ability of nano-TiO₂ embedded membranes was better than the unfilled EPVC membrane.