Fabrication of electrically conductive TiO2/PANI/PVDF composite membranes for simultaneous photoelectrocatalysis and microfiltration of azo dye from wastewater

Membrane microfiltration (MF) is widely used in modern water treatment industry although membrane fouling is a problematic challenge. Strategically coupling MF with semiconductor photocatalysis has been reported to enable retarding the cake layer formation, but the efficiency remains to be further improved. Here we report a novel conductive membrane of ternary polyvinylidene fluoride (PVDF)–polyaniline (PANI)–TiO2 composite synthesized by a phase inversion method with the mediation of sodium dodecyl sulfate (SDS) surfactant. The resultant hybrid TiO2/PANI/PVDF membrane features a high porosity, fair mechanical stability with TiO2 nanoparticles firmly grafting on the membrane surface, and an average resistivity as low as ~4.74 Ω·m, exhibiting remarkable photoelectrocatalytic activity in azo dyes decolorization under both stationary and continuous cross-flow modes, superior to those by photocatalysis and electrocatalysis. The successful combination of MF technology and solar photoelectrocatalysis with the assist of sunlight irradiation and bias potential applied on the TiO2/PANI/PVDF membrane dramatically improves the azo dye decolorization efficiency and water flux concurrently, offering a feasible solution to improve the self-cleaning properties of polymeric membrane.