微波辅助Bi_2WO_6光催化降解四氯酚研究

采用水热法制备了纳米Bi2WO6,并用X射线衍射仪XRD、透射电镜TEM和比表面积分析仪BET表征其晶相结构、形貌及比表面积;然后以2,3,4,6-四氯酚(TeCP)为目标物考察了Bi2WO6在微波场中的光催化活性;最后探讨了TeCP在微波光催化反应体系中的降解机理。结果表明,微波辅助Bi2WO6光催化能够有效降解TeCP,反应20minTeCP(30mg/L)的去除率为94%,相应的动力学常数为0.191min-1;用GC/MS分析检测了此反应中TeCP的7种降解中间产物:2,3,4-三氯酚、2,3,5-三氯酚、2,3,6-三氯酚、2,4,5-三氯酚、2,4,6-三氯酚、3,4,5-三氯酚和2,3,5,6-四氯酚;推断在微波辅助Bi2WO6光催化反应体系TeCP的降解机理为TeCP异构化、脱氯、三氯酚异构化和矿化。

Microwave-assisted Photocatalytic Degradation of Tetrachlorophenol in Aqueous Bi2WO6 Suspensions

Bi2WO6 was successfully synthesized by a facile hydrothermal method,and characterized by X -ray diffraction (XRD),transmission electron microscopy (TEM)and Brunauer-Emmett-Teller (BET). Then the photocatalytic activity of Bi2WO6 on the degradation of 2,3,4,6-tetrachlorophenol (TeCP)in microwave-assisted photocatalytic degradation system (MPC)was investigated. The degradation mechanism of TeCP in MPC was discussed. Results illustrated that TeCP(30mg/L) was degraded effectively and removal efficiency was about 94% in 20min,with corresponding reaction rate constant 0.191min-1. Seven degradation intermediates of TeCP in MPC were identified by GC/MS,including 2,3,4-trichlorophenol,2,3,5 trichloropheno l,2,3,6-trichlorophenol,2,4,5-trichlorophenol,2,4,6-trichlorophenol,3,4,5-trichlorophenol and 2,3, 5,6 -trichlorophenol. The possible degradation mechanism of TeCP in MPC included four processes including TeCP isomerization,dechlorination, trichlorophenol isomerization and mineralization,which coexisted in microwave -assisted photocatalytic system.