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

Abstract

Immobilization of TiO2 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 100W for 120s followed by liquid grafting with 70% aqueous AA at 60°C for 2h maximized the number of TiO2 binding sites. Membrane hydrophilicity was tremendously enhanced by the self-assembly of TiO2, following a direct proportionality to TiO2 loading. The membrane with 0.5% TiO2 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% TiO2 and 30min cumulative irradiation were necessary to completely recover the membrane's original performance. The TiO2-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.