Synthesis of modified bismuth tungstate and the photocatalytic properties on tetracycline degradation and pathways

This study adopted a solvent-thermal method with an added dispersing agent to successfully prepare modified bismuth tungstate (Bi2WO6) catalysts, which were characterized by X-ray diffraction, scanning and transmission electron microscopies, X-ray photoelectron and ultraviolet–visible diffuse reflectance spectroscopies, and photoluminescence. According to the results, the addition of a dispersing agent helped in preparing Bi2WO6 catalysts with appropriate morphology and structures, without influence on its purity, and modestly narrowed the forbidden bandwidth to 2.42 eV, effectively improving the catalysts’ visible light catalytic activity and exhibiting a 90.39% degradation of tetracycline after 60 min of irradiation. A possible pathway for TC degradation, based on its structure, was analyzed to better understand the reaction mechanisms in solution and TC found to be degraded first to some intermediate products and then the intermediate products degraded to CO2, H2O, and other small molecules. Keywords: Bismuth tungstate, Tetracycline, Visible light, Degradation products