Evaluation of the antifouling and photocatalytic properties of poly(vinylidene fluoride) plasma-grafted poly(acrylic acid) membrane with self-assembled TiO2.

Immobilization of TiO(2) is a promising approach that produces antifouling and photocatalytic membranes that could help advance wastewater treatment and re-use processes. In this study, poly(acrylic acid) (PAA) was plasma-grafted on commercial poly(vinylidene fluoride) (PVDF) to introduce functional groups on the membrane surface that can support the nanoparticles. It was found that plasma treatment at 100 W for 120 s followed by liquid grafting with 70% aqueous AA at 60°C for 2h maximized the number of TiO(2) binding sites. Membrane hydrophilicity was tremendously enhanced by the self-assembly of TiO(2), following a direct proportionality to TiO(2) loading. The membrane with 0.5% TiO(2) loading maintained the highest pure water flux and the best protein antifouling property. UV irradiation triggered the photodegradation of strongly bound foulants, but at least 1.5% TiO(2) and 30 min cumulative irradiation were necessary to completely recover the membrane's original performance. The TiO(2)-modified membranes removed 30-42% of 50mg/l aqueous Reactive Black 5 (RB5) dye. The fabricated membranes demonstrate huge potential for use in membrane reactors with high hydrophilicity, fouling mitigation, and photocatalytic capability.