Arsenite Oxidation-Enhanced Photocatalytic Degradation of Phenolic Pollutants on Platinized TiO2

详细信息    查看全文

• 作者：Jaesung Kim ; Jungwon Kim
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：November 18, 2014
• 年：2014
• 卷：48
• 期：22
• 页码：13384-13391
• 全文大小：449K
• ISSN：1520-5851

文摘

The effect of As(III) on the photocatalytic degradation of phenolic pollutants such as 4-chlorophenol (4-CP) and bisphenol A (BPA) in a suspension of platinized TiO₂ (Pt/TiO₂) was investigated. In the presence of As(III), the photocatalytic degradation of 4-CP and BPA was significantly enhanced, and the simultaneous oxidation of As(III) to As(V) was also achieved. This positive effect of As(III) on the degradation of phenolic pollutants is attributed to the adsorption of As(V) (generated from As(III) oxidation) on the surface of Pt/TiO₂, which facilitates the production of free OH radicals (^{鈥?/sup>OH_f) that are more reactive than surface-bound OH radicals (鈥?/sup>OH_s) toward phenolic pollutants. The generation of 鈥?/sup>OH_f was indirectly verified by using coumarin as an OH radical trapper and comparing the yields of coumarin鈥擮H adduct (i.e., 7-hydroxycoumarin) formed in the absence and presence of As(V). In repeated cycles of 4-CP degradation, the degradation efficiency of 4-CP gradually decreased in the absence of As(III), whereas it was mostly maintained in the presence of As(III), which was either initially present or repeatedly injected at the beginning of each cycle. The positive effect of As(III) on 4-CP degradation was observed over a wide range of As(III) concentrations (up to mM levels) with Pt/TiO₂. However, a high concentration of As(III) (hundreds of 渭M) inhibited the degradation of 4-CP with bare TiO₂. Therefore, Pt/TiO₂ can be proposed as a practical photocatalyst for the simultaneous oxidation of phenolic pollutants and As(III) in industrial wastewaters.}