Advanced Oxidation Kinetics and Mechanism of Preservative Propylparaben Degradation in Aqueous Suspension of TiO2 and Risk Assessment of Its Degradation Products

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• 作者：Hansun Fang ; Yanpeng Gao ; Guiying Li ; Jibin An ; Po-Keung Wong ; Haiying Fu ; Side Yao ; Xiangping Nie ; Taicheng An
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：March 19, 2013
• 年：2013
• 卷：47
• 期：6
• 页码：2704-2712
• 全文大小：421K
• 年卷期：v.47,no.6(March 19, 2013)
• ISSN：1520-5851

文摘

The absolute kinetic rate constants of propylparaben (PPB) in water with different free radicals were investigated, and it was found that both hydroxyl radicals (HO^{鈥?/sup>) and hydrated electrons could rapidly react with PPB. The advanced oxidation kinetics and mechanisms of PPB were investigated using photocatalytic process as a model technology, and the degradation was found to be a pseudo-first-order model. Oxidative species, particularly HO鈥?/sup>, were the most important reactive oxygen species mediating photocatalytic degradation of PPB, and PPB degradation was found to be significantly affected by pH because it was controlled by the radical reaction mechanism and was postulated to occur primarily via HO鈥?/sup>-addition or H-abstraction reactions on the basis of pulse radiolysis measurements and observed reaction products. To investigate potential risk of PPB to humans and aqueous organisms, the estrogenic assays and bioassays were performed using 100 渭M PPB solution degraded by photocatalysis at specific intervals. The estrogenic activity decreased as PPB was degraded, while the acute toxicity at three trophic levels first increased slowly and then decreased rapidly as the total organic carbon decreased during photocatalytic degradation.}