Improved visible light-responsive bisphenol A photodegradation utilizing TiO2/WS2 photocatalytic membranes with energy storage ability

Abstract

Membrane separation and photocatalytic degradation are essential technologies for wastewater purification, but they encounter challenges like membrane fouling and low photocatalytic efficiency. The integration of photocatalysis and membrane technology, along with the creation of a heterojunction photocatalyst, proves to be a promising solution by enhancing the efficiency of charge carrier transport. Titanium dioxide (TiO2) and tungsten disulfide (WS2) are key components, each offering unique benefits such as TiO2 stability and WS2 strong adsorption of visible light. TiO2/WS2 is synthesized through a one-step hydrothermal method at distinct hydrothermal times. A TiO2/WS2 photocatalytic membrane is constructed using the co-extrusion technique, with varying ratios of TiO2/WS2. The membrane undergoes characterization for both morphology and properties, as well as photocatalytic testing. TiO2/WS2 synthesized over a 20 h hydrothermal period is selected for deposition into the polyvinylidene fluoride (PVDF) membrane matrix. The resulting 0.5 wt% TiO2/WS2 photocatalytic membrane exhibits improved wettability, high porosity, and favorable water flux, demonstrating outstanding photocatalytic activity with an 85.3% degradation of bisphenol A (BPA) under visible light. The membrane also shows an 80.4% rejection of 1 mg/L BPA in dark conditions. In terms of energy storage, the 0.5 wt% TiO2/WS2 photocatalytic membrane exhibits a BPA photocatalytic performance resulting in 51.0% photodegradation, while the rejection rate reaches 27.4% for BPA removal after 120 min. In conclusion, the TiO2/WS2 photocatalytic membrane serves as a versatile solution, enhancing both photocatalytic degradation and rejection capabilities, with potential for energy storage in removing BPA from aquatic environments, regardless of light presence.