Perfluorooctanoic acid degradation in the presence of Fe(III) under natural sunlight.
Perfluorooctanoic acid degradation in the presence of Fe(III) under natural sunlight.
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DOI：
10.1016/j.jhazmat.2013.09.001
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发表时间：
2013-11
影响因子：
13.6
通讯作者：
Dandan Liu;Zong-ming Xiu;Fei Liu;Gang Wu;D. Adamson;C. Newell;P. Vikesland;A. Tsai;P. Alvarez
中科院分区：
文献类型：
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作者：
Dandan Liu;Zong-ming Xiu;Fei Liu;Gang Wu;D. Adamson;C. Newell;P. Vikesland;A. Tsai;P. Alvarez
全氟辛酸(PFOA)是一种难降解污染物，其单键F键具有较高的键离解能(BDE)(116千卡/摩尔)。在此，我们展示了一种在阳光和铁(III)存在下分解全氟辛酸的新方法。在此条件下，50μM全氟辛酸中97.8%±1.7%在28天内分解为短链中间体和氟化物(F-−)，总体脱氟程度为12.7%±0.05%。在可见光下没有去除全氟辛酸，表明全氟辛酸的分解需要紫外线辐射。光谱分析表明，该分解反应可能是由全氟辛酸向Fe(III)的电子转移引发的，生成了Fe(II)和不稳定的有机羧基。通过电子顺磁共振(EPR)检测，这种有机自由基的另一种形成机制涉及羟基自由基。在太阳辐射下，全氟辛酸可以被Fe(III)降解，这一观察结果提供了对可能被忽视的自然衰减过程的机械洞察。由于Fe(III)在天然水中含量丰富，而阳光基本上是免费的，这项工作代表着朝着开发简单且廉价的全氟辛烷磺酸污染水修复策略迈出的重要一步。
Due to the high bond dissociation energy (BDE) of Csingle bondF bonds (116 kcal/mol), perfluorooctanoic acid (PFOA) is a highly recalcitrant pollutant. Herein, we demonstrate a novel method to decompose PFOA in the presence of sunlight and ferric iron (Fe(III)). Under such conditions, 97.8 ± 1.7% of 50 μM PFOA decomposed within 28 days into shorter-chain intermediates and fluoride (F−), with an overall defluorination extent of 12.7 ± 0.5%. No PFOA was removed under visible light, indicating that UV radiation is required for PFOA decomposition. Spectroscopic analysis indicates that the decomposition reaction is likely initiated by electron-transfer from PFOA to Fe(III), forming Fe(II) and an unstable organic carboxyl radical. An alternative mechanism for the formation of this organic radical involves hydroxyl radicals, detected by electron paramagnetic resonance (EPR). The observation that PFOA can be degraded by Fe(III) under solar irradiation provides mechanistic insight into a possibly overlooked natural attenuation process. Because Fe(III) is abundant in natural waters and sunlight is essentially free, this work represents a potentially important step toward the development of simple and inexpensive remediation strategies for PFOA-contaminated water.