Immobilization of Bi 2 WO 6 on Polymer Membranes for Photocatalytic Removal of Micropollutants from Water - A Stable and Visible Light Active Alternative.

In this work, bismuth tungstate Bi 2 WO 6 is immobilized on polymer membranes to photocatalytically remove micropollutants from water as an alternative to titanium dioxide TiO 2 . A synthesis method for Bi 2 WO 6 preparation and its immobilization on a polymer membrane is developed. Bi 2 WO 6 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 2 and Bi 2 WO 6 , 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 Bi 2 WO 6 crystallinity. Under UV light at pH 7 and 11, the Bi 2 WO 6 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 Bi 2 WO 6 membrane demonstrates superior stability compared to a TiO 2 membrane during a 7-day exposure to UV light as Bi 2 WO 6 does not generate OH • radicals. The Bi 2 WO 6 membrane is an alternative for water pollutant degradation due to its visible light activity and long-term stability.