Enhanced Oxidation of Organic Contaminants by Iron(II)-Activated Periodate: The Significance of High-Valent Iron-Oxo Species.
Enhanced Oxidation of Organic Contaminants by Iron(II)-Activated Periodate: The Significance of High-Valent Iron-Oxo Species.
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铁 (II) 激活的高碘酸盐增强有机污染物的氧化：高价铁氧物种的意义。
DOI：
10.1021/acs.est.1c00375
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发表时间：
2021-03
影响因子：
11.4
通讯作者：
Y. Zong;Yufei Shao;Yunqiao Zeng;Binbin Shao;Longqian Xu;Zhenyu Zhao;Wen Liu;Deli Wu
中科院分区：
文献类型：
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作者：
Y. Zong;Yufei Shao;Yunqiao Zeng;Binbin Shao;Longqian Xu;Zhenyu Zhao;Wen Liu;Deli Wu
高碘酸钾（PI、KIO4）在酸性条件下很容易被 Fe(II) 激活，从而在 2 min 内增强了有机污染物的去除效果，所选污染物的衰减率甚至超过了相同条件下 Fe(II)/过二硫酸盐和 Fe(II)/过二硫酸盐工艺的衰减率。以甲基苯基亚砜（PMSO）为底物的 18O 同位素标记技术和 X 射线吸收近边结构光谱为 Fe(II)/PI 过程中高价铁氧物种 (Fe(IV)) 的生成提供了确凿的证据。密度泛函理论计算确定，Fe(II)与PI的反应遵循Fe(H2O)62+和IO4(H2O)-之间形成氢键配合物、配体交换和氧原子转移，从而生成Fe(IV)物质。更有趣的是，意外检测到18O标记的羟基化PMSO不仅有利于同时生成·OH，而且证明·OH是通过Fe(IV)自衰变形成H2O2以及随后的芬顿反应间接产生的。此外，IO4- 并未转化为不需要的碘物质（即 HOI、I2 和 I3-），而是转化为无毒的碘酸盐 (IO3-)。该研究提出了一种高效且环境友好的方法来快速去除新出现的污染物，并丰富了对Fe(IV)介导过程中·OH演化机制的理解。
Potassium periodate (PI, KIO4) was readily activated by Fe(II) under acidic conditions, resulting in the enhanced abatement of organic contaminants in 2 min, with the decay ratios of the selected pollutants even outnumbered those in the Fe(II)/peroxymonosulfate and Fe(II)/peroxydisulfate processes under identical conditions. Both 18O isotope labeling techniques using methyl phenyl sulfoxide (PMSO) as the substrate and X-ray absorption near-edge structure spectroscopy provided conclusive evidences for the generation of high-valent iron-oxo species (Fe(IV)) in the Fe(II)/PI process. Density functional theory calculations determined that the reaction of Fe(II) with PI followed the formation of a hydrogen bonding complex between Fe(H2O)62+ and IO4(H2O)-, ligand exchange, and oxygen atom transfer, consequently generating Fe(IV) species. More interestingly, the unexpected detection of 18O-labeled hydroxylated PMSO not only favored the simultaneous generation of ·OH but also demonstrated that ·OH was indirectly produced through the self-decay of Fe(IV) to form H2O2 and the subsequent Fenton reaction. In addition, IO4- was not transformed into the undesired iodine species (i.e., HOI, I2, and I3-) but was converted to nontoxic iodate (IO3-). This study proposed an efficient and environmental friendly process for the rapid removal of emerging contaminants and enriched the understandings on the evolution mechanism of ·OH in Fe(IV)-mediated processes.