环境化学
禾志强,刘启旺.Fe3+催化氧化S(Ⅳ)反应机理初探[J].环境科学学报,2006,26(10):1701-1706
Fe3+催化氧化S(Ⅳ)反应机理初探
- The initially explores of the machanism of Fe3+ catalyzed oxidation of S(Ⅳ)
- 基金项目：国家自然科学基金项目(No.20267001)
- 作者
- 单位
- 禾志强
- 内蒙古电力科学研究院, 呼和浩特 010020
- 刘启旺
- 内蒙古工业大学电力学院, 呼和浩特 010080
- 摘要：通过分析酸性条件下(pH为1～3),Fe3+催化氧化S(Ⅳ)过程中溶液吸光度变化的趋势,对Fe3+催化氧化S(Ⅳ)的反应机理进行了初步推导.实验证明,液相中该反应机理主要是催化氧化与自由基反应相结合,O2的存在对于反应有重要作用,O2-·的生成是S(Ⅳ)被氧化的关键;当水中溶解氧接近耗尽时,反应进程发生改变.当Fe3+、S(Ⅳ)浓度增加,自由基生成量增加时,有利于反应进行;作为反应产物,Fe2+、S(Ⅵ)浓度增加,反应推动力减小,反应速率降低;同时Fe2+、SO42-可以与溶液中的其它物质形成配合物,影响了Fe3+—S(Ⅳ)配合物的生成与分解,不利于S(Ⅵ)的氧化.
- Abstract：The mechanism of the catalyzed oxidation reaction of S(Ⅳ) with Fe3+ was studied by analyzing variation trend of the absorbance of the mixed solution under acidic condition (pH=1～3). It was found that the mechanism of the reaction in aqueous solution was the combination of catalyzed oxidation and radical reaction, and the O2- produced from the oxygen in solution played a very important role for the oxidation of S(Ⅳ). As a result, when the oxygen in solution was approached exhausted, the reaction path was changed as well. The studies also showed that the increase of the concentration of Fe3+ and S(Ⅳ) was beneficial to the reaction due to the increase amount of radical; however, the increase of the concentration of Fe2+ and S(VI) results in the reduced reaction rate due to the chemical equilibrium and the complexes formation of Fe2+ and SO42- with other spices in the solution, which impede the formation and decomposition of Fe3+-S(Ⅳ) complexes.
- Key words：catalyzed oxidation mechanism transition metal
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