Incorporating Mesoporous Anatase TiO₂ Spheres to Conductive Carbon Black Filled PVDF Membrane for Self-Cleaning Photo(electro)catalytic Filtration

Abstract

Polyvinylidene fluoride (PVDF) membranes have been widely used for micro/ultrafiltration. However, their hydrophobicity leads to serious membrane fouling over time during the process of dye decolorization, which limits their practical application. Herein, PVDF, mesoporous TiO2 spheres (MTS, ∼460 nm), and carbon black (CB) are strategically hybridized via a polyvinylpyrrolidone (PVP)-assisted phase inversion method. The fabricated PVDF/CB/TiO2 conductive membrane prepared by optimal low-molecular-weight PVP (10 kDa) shows a highly porous structure with macro-voids, and MTS are firmly incorporated into the PVDF/CB membrane matrix with a morphologically intact structure, rendering the ternary and conductive membranes with excellent PEC properties. The decolorization rate of 0.50 mg/L methylene blue (MB) reaches 98.6% under the condition of 1.0 V bias potential and simulated solar light irradiation in a continuous cross-flow filtration process. The •O2 – and •OH radicals and photogenerated holes (h+) are mainly responsible for MB decolorization in the PEC system. Our work provided a sustainable and efficient method for dye decolorization by combining the PEC system and membrane technology.