Immobilization of BiWO on Polymer Membranes for Photocatalytic Removal of Micropollutants from Water - A Stable and Visible Light Active Alternative.

In this work, bismuth tungstate BiWO is immobilized on polymer membranes to photocatalytically remove micropollutants from water as an alternative to titanium dioxide TiO. A synthesis method for BiWO preparation and its immobilization on a polymer membrane is developed. BiWO is characterized using X-ray diffraction and UV-vis reflectance spectroscopy, while the membrane undergoes analysis through scanning electron microscopy, X-ray photoelectron spectroscopy, and degradation experiments. The density of states calculations for TiO and BiWO, along with PVDF reactions with potential reactive species, are investigated by density functional theory. The generation of hydroxyl radicals OH is investigated via the reaction of coumarin to umbelliferone via fluorescence probe detection and electron paramagnetic resonance. Increasing reactant concentration enhances BiWO crystallinity. Under UV light at pH 7 and 11, the BiWO membrane completely degrades propranolol in 3 and 1 h, respectively, remaining stable and reusable for over 10 cycles (30 h). Active under visible light with a bandgap of 2.91 eV, the BiWO membrane demonstrates superior stability compared to a TiO membrane during a 7-day exposure to UV light as BiWO does not generate OH radicals. The BiWO membrane is an alternative for water pollutant degradation due to its visible light activity and long-term stability.