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

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 100 W for 120 s followed by liquid grafting with 70% aqueous AA at 60 degrees C for 2 h 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 30 min cumulative irradiation were necessary to completely recover the membrane's original performance. The TiO2-modified membranes removed 30-42% of 50 mg/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. (c) 2012 Elsevier B.V. All rights reserved.