Iron-Mediated Oxidation of Antimony(III) by Oxygen and Hydrogen Peroxide Compared to Arsenic(III) Oxidation
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- 作者：Ann-Kathrin Leuz ; Stephan J. Hug ; Bernhard Wehrli ; and C. Annette Johnson
- 刊名：Environmental Science & Technology
- 出版年：2006
- 出版时间：April 15, 2006
- 年：2006
- 卷：40
- 期：8
- 页码：2565 - 2571
- 全文大小：1196K
- 年卷期：v.40,no.8(April 15, 2006)
- ISSN：1520-5851
文摘
Antimony is used in large quantities in a variety ofproducts, though it has been declared as a pollutant ofpriority interest by the Environmental Protection Agency ofthe United States (USEPA). Oxidation processes criticallyaffect the mobility of antimony in the environment since Sb(V) has a greater solubility than Sb(III). In this study, the co-oxidation reactions of Sb(III) with Fe(II) and both O2and H2O2 were investigated and compared to those of As(III). With increasing pH, the oxidation rate coefficientsof Sb(III) in the presence of Fe(II) and O2 increased andfollowed a similar pH trend as the Fe(II) oxidation by O2. Half-lives of Sb(III) were 35 and 1.4 h at pH 5.0 and pH 6.2,respectively. The co-oxidation with Fe(II) and H2O2 is about7000 and 20 times faster than with Fe(II) and O2 at pH 3and pH 7, respectively. For both systems, 
OH radicals appearto be the predominant oxidant below approximately pH4, while at more neutral pH values, other unknownintermediates become important. The oxidation of As(III)follows a similar pH trend as the Sb(III) oxidation; however,As(III) oxidation was roughly 10 times slower and onlypartly oxidized in most of the experiments. This study showsthat the Fe(II)-mediated oxidation of Sb(III) can be animportant oxidation pathway at neutral pH values.
OH radicals appearto be the predominant oxidant below approximately pH4, while at more neutral pH values, other unknownintermediates become important. The oxidation of As(III)follows a similar pH trend as the Sb(III) oxidation; however,As(III) oxidation was roughly 10 times slower and onlypartly oxidized in most of the experiments. This study showsthat the Fe(II)-mediated oxidation of Sb(III) can be animportant oxidation pathway at neutral pH values.