Influence of Glyoxal on the Catalytic Oxidation of S(IV) in Acidic Aqueous Media
Influence of Glyoxal on the Catalytic Oxidation of S(IV) in Acidic Aqueous Media
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DOI：
10.1021/acsearthspacechem.8b00168
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发表时间：
2019-01-01
影响因子：
3.4
通讯作者：
Grassian, Vicki H.
中科院分区：
文献类型：
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作者：
Coddens, Ellen M.;Huang, Liubin;Grassian, Vicki H.
在不同的实验条件下，研究了乙二醛在酸性水溶液中以Fe ~（3+）水溶液和固体氧化铁形式存在的铁催化氧化5（IV）反应中的作用.结果表明，乙二醛存在时，Fe ~（3+）（aq）离子催化S（IV）氧化的速率降低。质谱分析和红外光谱分析结果表明，SO 4-自由基的捕获，以及glycoprotein-S（IV）加合物的形成，是负责这种抑制作用。有趣的是，虽然硫氧化在乙二醛存在下被动力学抑制，但亚硫酸盐形式的S（IV）随着时间的推移完全转化为硫酸盐。此外，乙二醛的抑制作用也可以观察到在S（IV）的反应中由氧化铁颗粒催化，虽然小于溶解的Fe 3+（aq）催化。所观察到的抑制效果的氧化铁颗粒被认为是由于竞争性的表面吸附在氧化铁颗粒表面。总体而言，这些发现表明，乙二醛对S（IV）的催化氧化的影响高度依赖于机制，铁的形式（溶解与固体），以及环境条件，包括pH值和浓度。
The role of glyoxal in 5(IV) oxidation in acidic aqueous solutions catalyzed by iron in the form of aqueous Fe3+ ions and solid iron oxide was investigated under different experimental conditions. It is found that the rate of Fe3+(aqueous (aq)) ion-catalyzed S(IV) oxidation decreases in the presence of glyoxal. The results of mass spectral analysis and infrared spectra suggest that the trapping of SO4- radicals, as well as the formation of glyoxal-S(IV) adducts, are responsible for this inhibition effect. Interestingly, although sulfur oxidation is kinetically inhibited in the presence of glyoxal, S(IV) in the form of sulfite is over time completely converted to sulfate. Additionally, the inhibition effects of glyoxal can also be observed in the reaction of S(IV) catalyzed by iron oxide particles, albeit less than that catalyzed by dissolved Fe3+(aq). The observed inhibition effect for the iron oxide particles is proposed to be attributed to competitive surface adsorption on the iron oxide particle surface. Overall, these findings suggest that the effects of glyoxal on the catalytic oxidation of S(IV) are highly dependent on the mechanism, form of iron (dissolved vs solid), and the ambient conditions including pH and concentration.