Degradation and mineralization of bisphenol A by mesoporous Bi2WO6 under simulated solar light irradiation

Bismuth tungstate (Bi2WO6) catalysts of different morphology were synthesized with a hydrothermal method by controlling the pH of the reaction solution. The properties of the synthesized catalysts were characterized and all catalysts presented high photoabsorption capacity in the range of UV light to visible light around 450 nm. The surface area of the catalysts decreased but the crystallinity increased with the pH of the hydrothermal reaction solution in the range of 4-11. It was found that the crystallinity of the catalysts played an important role on their degradation capacity to Bisphenol A (BPA). Bi2WO6 catalyst prepared at pH 11 displayed a mesoporous structure and it showed the highest photocatalytic activity to degrade BPA under simulated solar light irradiation. Nearly 100% of BPA with original concentration at 20 ppm was removed after 30 min irradiation in a solution with pH 10 and Bi2WO6 amount of 1.0 g L(-1). Furthermore, 86.6 and 99.1% of the total organic carbon was eliminated after 60 and 120 min irradiation, respectively. Only one intermediate at m/z 133 was observed by LC/MS and a simple pathway of BPA degradation by Bi2WO6 was proposed.