Photocatalytic PVDF ultrafiltration membrane blended with visible-light responsive Fe(III)-TiO2 catalyst: Degradation kinetics, catalytic performance and reusability

Abstract

• The visible-light responsive Fe(III)-TiO 2 /PVDF composite membranes were prepared. • The composite membrane exhibited abilities of both filtration and photocatalysis. • Reactive radicals and degradation intermediates during reaction were identified. • The anti-fouling and mechanical properties of the membrane were enhanced. • The composite membrane showed an excellent reusability for 9 cycles. A novel Fe(III)-TiO 2 /polyvinylidene fluoride (PVDF) composite ultrafiltration (UF) membrane was prepared by using phase inversion method. The structural characteristics, as well as the photocatalytic, antifouling and reusability properties, of composite membranes were investigated. Our results showed that the reaction of bisphenol-A (BPA) degradation fitted the pseudo-second-order kinetics models. The Fe-TiO 2 /PVDF-0.10 composite membrane achieved a higher BPA degradation efficiency (69.9%) within reaction time of 180 min than pristine PVDF membrane 45.1%. The quenching tests and ESR results confirmed the dominant role of hole (h + ) and O 2 − as active species responsible for BPA degradation in the photocatalytic system. Combing pathway of photocatalytic degradation of BPA and quantitative structure activity relationship (QSAR) analysis indicated decline in toxicity of most intermediates compared with BPA. Additionally, the composite membrane also exhibited a higher permeation flux (585 L·m −2 ·h −1 ) and water flux recovery rate (>70%) under simulated visible-light irradiation, indicating better antifouling property of the membrane. Moreover, excellent durability and reusability were demonstrated by a insignificant loss of photocatalytic efficiency losses (4%) after 9-cycle operation. The incorporation of Fe(III)-TiO 2 could improve physical and chemical properties of UF membrane in terms of hydrophilicity, mechanical properties and thus photocatalytic anti-fouling performance, which broadens the application field of membrane filtration technology.