Photocatalytic Fe-doped TiO2/PSF composite UF membranes: Characterization and performance on BPA removal under visible-light irradiation

The visible-light responsive photocatalyst was blended into the polysulfone (PSF) membrane casting solution to prepare photocatalytic Fe-doped TiO2/PSF composite ultrafiltration (UF) membranes by phase inversion method, while the photocatalyst was synthesized by hydrothermal method. Bisphenol A (BPA, at a concentration of 10 mg·L−1) was adopted to test the photocatalytic performance of catalysts and composite membranes. Different parameters that affected BPA removal were discussed, including metal variety, metal proportion, hydrothermal reaction time, temperature and catalyst ratio. The morphologies, photophysical and photochemical properties of catalysts and composite membranes were investigated using various microscopic and spectroscopic techniques. UV–Vis spectra displayed that the absorption of Fe-doped TiO2 (Fe-TiO2) extended into the visible region compared to TiO2, which was in accordance with its high BPA degradation rate of 92.30% within 180 min under visible-light irradiation. SEM images showed significant changes in cross-section morphologies of the composite membranes. The addition of photocatalyst enabled the composite membrane to possess visible-light photocatalysis and ultrafiltration simultaneously. The resulted composite membrane exhibited BPA removal rate of 90.78% within 180 min under visible-light irradiation, enhanced mechanical capacity and self-cleaning ability. Furthermore, the possible removal mechanism of BPA by photocatalytic composite membrane was proposed.