Oxidation of Organic Compounds in Water by Unactivated Peroxymonosulfate
Oxidation of Organic Compounds in Water by Unactivated Peroxymonosulfate
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DOI：
10.1021/acs.est.8b00735
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发表时间：
2018-05-15
影响因子：
11.4
通讯作者：
Pignatello, Joseph J.
中科院分区：
文献类型：
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作者：
Yang, Yi;Banerjee, Gourab;Pignatello, Joseph J.
过一硫酸盐（HSO5- 和 PMS）是高级氧化工艺 (AOP) 中用于处理废水的可选大量氧化剂。通常，PMS 通过输入能量或还原剂来激活，以产生硫酸根或羟基自由基或两者。这项研究表明，未经显式激活的 PMS 可以与多种化合物直接反应，包括抗生素、药物、酚类和常用的单线态氧 (O-1(2)) 陷阱和猝灭剂，特别是糠醇 (FFA)、叠氮化物和组氨酸。在 pH 9 下，反应时间从几分钟到几小时不等。通过使用具有中间反应性 (FFA) 的测试化合物，电子顺磁共振 (EPR) 和清除实验排除了硫酸根和羟基自由基。尽管 O-1(2) 是通过 EPR 检测到的，并且是通过 PMS 自分解按化学计量产生的，但 (1)O(2) 由于其被水有效猝灭而仅发挥次要作用，这一点通过操纵 O-1(2) 形成速率（添加 H2O2）或寿命（氘溶剂同位素效应）的实验证实。与 PMS 的直接反应对 pH 值和离子强度高度敏感，并且可以通过非自由基途径被碳酸（氢）盐、硼酸盐和焦磷酸盐（尽管不是磷酸盐）加速。研究结果表明，与 PMS 的直接反应可能会引导降解途径，因此在 AOP 和其他应用中必须予以考虑。它们还提醒研究人员在选择缓冲液以及 O-1(2) 陷阱和猝灭剂时要小心。
Peroxymonosulfate (HSO5- and PMS) is an optional bulk oxidant in advanced oxidation processes (AOPs) for treating wastewaters. Normally, PMS is activated by the input of energy or reducing agent to generate sulfate or hydroxyl radicals or both. This study shows that PMS without explicit activation undergoes direct reaction with a variety of compounds, including antibiotics, pharmaceuticals, phenolics, and commonly used singlet-oxygen (O-1(2)) traps and quenchers, specifically furfuryl alcohol (FFA), azide, and histidine. Reaction time frames varied from minutes to a few hours at pH 9. With the use of a test compound with intermediate reactivity (FFA), electron paramagnetic resonance (EPR) and scavenging experiments ruled out sulfate and hydroxyl radicals. Although O-1(2) was detected by EPR and is produced stoichiometrically through PMS self-decomposition, (1)O(2)plays only a minor role due to its efficient quenching by water, as confirmed by experiments manipulating the O-1(2) formation rate (addition of H2O2) or lifetime (deuterium solvent isotope effect). Direct reactions with PMS are highly pH- and ionic-strength sensitive and can be accelerated by (bi)carbonate, borate, and pyrophosphate (although not phosphate) via non-radical pathways. The findings indicate that direct reaction with PMS may steer degradation pathways and must be considered in AOPs and other applications. They also signal caution to researchers when choosing buffers as well as O-1(2) traps and quenchers.