The sluggish reduction of Fe(III) to Fe(II) restricts the decontamination efficiency of Fenton reactions. New strategy development toward enhancing Fe(II) regeneration and decontamination efficiency relies primarily on the well-established inorganic Fenton chemistry, yet the involvement of organic contaminants and its potential role in the Fenton reactions have been insufficiently concerned. Here, using 2,5-thiophene carboxylic acid (TDA) as a representative sulfur-containing heterocyclic contaminant and atrazine as a coexisting contaminant, we uncovered the promoting effect of thiophene derivatives on Fenton oxidation. The degradation of TDA and coexisting refractory contaminants was highly efficient in the sluggish Fe(III)/HO oxidation process with autocatalytic features. Spin trapping and chemical scavenging results underpinned the crucial contribution of hydroxyl radicals (HO) to organic oxidation. Analysis of iron cycling combined with theoretical calculations revealed that the enhancement of TDA on Fenton oxidation originated from the rapid reduction of Fe(III) by the primary radicals generated from addition of HO to the thiophene ring.

中文翻译：

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芬顿反应中噻吩衍生物的自催化氧化和难降解污染物的共降解


Fe(III) 向 Fe(II) 的缓慢还原限制了芬顿反应的去污效率。提高 Fe(II) 再生和净化效率的新策略开发主要依赖于完善的无机芬顿化学，但有机污染物的参与及其在芬顿反应中的潜在作用尚未得到充分关注。在这里，我们使用2,5-噻吩甲酸（TDA）作为代表性的含硫杂环污染物和莠去津作为共存污染物，揭示了噻吩衍生物对芬顿氧化的促进作用。在具有自催化功能的缓慢 Fe(III)/H2O 氧化过程中，TDA 和共存的难熔污染物的降解非常有效。自旋捕获和化学清除结果支撑了羟基自由基（H2O）对有机氧化的重要贡献。铁循环分析结合理论计算表明，TDA对芬顿氧化的增强源自于噻吩环上H2O加成产生的初级自由基对Fe(III)的快速还原。