Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) are groundwater contaminants of emerging concern due to their toxicity and persistence. Currently, there are limited destructive treatment options for this type of water. One promising approach is electrochemical oxidation (EO) using a boron-doped diamond (BDD) anode. However, during EO treatment, chloride in water is readily converted to perchlorate (ClO₄^–), which is an endocrine disruptor. This is a common dilemma for EO techniques: anodes with higher EO activity tend to produce more ClO₄^–. In this study, we used the BDD anode as a model anode to treat PFOA and PFOS in a chloride-bearing electrolyte. We found that the formation of ClO₄^– can be largely inhibited without compromising the efficiency of PFOA and PFOS destruction by adding hydrogen peroxide (≥50 mM H₂O₂). Experimental approaches and computational kinetic modeling indicate that H₂O₂ inhibits ClO₄^– formation by quenching chlorine and hydroxyl radicals and the oxidation of PFOA and PFOS is primarily determined by direct electron transfer oxidation, regardless of the dominant radical species. This facile strategy suppressed 88% of ClO₄^– formation during EO treatment of groundwater spiked with PFOA and PFOS.

中文翻译：

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地下水中全氟烷基酸电化学氧化过程中高氯酸盐的形成抑制

全氟辛酸（PFOA）和全氟辛烷磺酸盐（PFOS）由于其毒性和持久性而成为人们关注的地下水污染物。当前，这种水的破坏性处理方法有限。一种有前途的方法是使用掺硼金刚石（BDD）阳极的电化学氧化（EO）。但是，在EO处理过程中，水中的氯化物很容易转化为高氯酸盐（ClO ₄ ^–），而高氯酸盐是内分泌干扰物。这是EO技术的共同困境：具有较高的EO活性阳极倾向于产生更CLO ₄ ^- 。在这项研究中，我们将BDD阳极用作模型阳极，以处理含氯电解质中的PFOA和PFOS。我们发现ClO ₄的形成^–通过添加过氧化氢（≥50 mM H ₂ O ₂），可以在不损害PFOA和PFOS破坏效率的情况下，显着抑制二氧化硫的生成。实验方法和计算动力学模型表明ħ ₂ ö ₂抑制CLO ₄ ^-的形成通过淬火氯和羟基自由基和PFOA和全氟辛烷磺酸的氧化主要通过直接电子转移的氧化来确定，而不管主导自由基物种。此容易策略抑制CLO的88％₄ ^-形成EO治疗地下水与PFOA和PFOS掺入的期间。