Investigation of the Iron-Peroxo Complex in the Fenton Reaction: Kinetic Indication, Decay Kinetics, and Hydroxyl Radical Yields.
Investigation of the Iron-Peroxo Complex in the Fenton Reaction: Kinetic Indication, Decay Kinetics, and Hydroxyl Radical Yields.
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DOI：
10.1021/acs.est.7b03706
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发表时间：
2017-12
影响因子：
11.4
通讯作者：
H. L. Wiegand;Christian Timon Orths;K. Kerpen;H. Lutze;T. Schmidt
中科院分区：
文献类型：
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作者：
H. L. Wiegand;Christian Timon Orths;K. Kerpen;H. Lutze;T. Schmidt
芬顿反应描述了 Fe(II) 与过氧化氢的反应。几位研究人员提出了中间铁-过氧复合物的形成，但仍然缺乏其存在的实验证据。本研究调查了这种中间体在不同条件下的形成和寿命，例如不同的 Fe(II) 浓度、羟基自由基清除剂（二甲基亚砜，DMSO）的存在与否以及不同的 pH 值。获得的结果表明在所有实验条件下都形成了铁-过氧配合物。根据这些数据，可以检查铁-过氧复合物的稳定性。在 pH 3 下，无论是否存在 DMSO，铁-过氧复合物的 [Fe(II)]0 衰减率均约为 50 s-1。在没有 DMSO 和 [Fe(II)]0 = 300 μM 的情况下，pH 1 和 2 时的衰减率约为 70 s-1，pH 3 和 4 时的衰减率约为 50 s-1。因此，随着 pH 值的增加，铁-过氧复合物变得更加稳定。此外，确定了 pH 依赖性羟基自由基产率，以研究中间复合物稳定性的增加是否可能表明铁-过氧复合物的不同反应，可能产生 Fe(IV) 而不是文献中建议的羟基自由基形成。然而，发现羟基自由基的产生与 Fe(II) 浓度成正比。
The Fenton reaction describes the reaction of Fe(II) with hydrogen peroxide. Several researchers proposed the formation of an intermediate iron-peroxo complex but experimental evidence for its existence is still missing. The present study investigates formation and lifetime of this intermediate at various conditions such as different Fe(II)-concentrations, absence vs presence of a hydroxyl radical scavenger (dimethyl sulfoxide, DMSO), and different pH values. Obtained results indicate that the iron-peroxo complex is formed under all experimental conditions. Based on these data, stability of the iron-peroxo complex could be examined. At pH 3 regardless of [Fe(II)]0 decay rates for the iron-peroxo complex of about 50 s-1 were determined in absence and presence of DMSO. Without DMSO and [Fe(II)]0 = 300 μM variation of pH yielded decay rates of about 70 s-1 for pH 1 and 2 and of about 50 s-1 at pH 3 and 4. Hence, the iron-peroxo complex becomes more stable with increasing pH. Furthermore, pH-dependent hydroxyl radical yields were determined to investigate whether the increasing stability of the intermediate complex may indicate a different reaction of the iron-peroxo complex which might yield Fe(IV) instead of hydroxyl radical formation as suggested in literature. However, it was found that hydroxyl radicals were produced proportionally to the Fe(II)-concentration.