我们是否正确地检测和理解可能在电子偏磁共振光谱技术的先进氧化过程中产生的单片氧?
Yang Zong1,2, Long Chen3, Yunqiao Zeng1
1State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science & Engineering, Tongji University, Shanghai 200092, China.
Environmental science & technology
|June 13, 2023
概括
电子磁共振 (EPR) 在先进的氧化过程中可以错误地识别单片氧 (O2) . 这项研究揭示了常见的氧化剂,而不是O2,导致错误的EPR信号,影响过程理解.
科学领域:
- 环境化学环境化学
- 分析化学 分析化学
- 先进的氧化过程 先进的氧化过程
背景情况:
- 用阻碍胺的电子磁共振 (EPR) 光谱法是检测单片氧 (1O2) 的常用方法.
- 在水处理和污染物降解的先进氧化过程 (AOP) 中,O2至关重要.
- 之前的研究假设EPR信号与AOP中的O存在直接相关.
研究的目的:
- 调查EPR光谱在检测各种AOP中的可靠性.
- 为了确定在EPR.中观察到的假阳性O2信号的来源.
- 为了澄清与AOP中的其他氧化剂相比,O2的作用和反应性.
主要方法:
- 使用EPR光谱与固态阻碍氨基检测O2 .
- 采用9,10-二乙烯灭和近红外光学来确认O2的存在/不存在.
- 在过氧化/低化,Fe (II) /H2O,UV/H2O和酸盐 (Fe (VI)) 工艺中研究的活性物种.
- 在100K时使用EPR识别了基质中间体,并进行了理论计算.
主要成果:
- 假1O2信号被EPR检测到在1O2-缺少Fe (II) /H2O2,UV/H2O2,和Fe (VI) 的过程中.
- 这些虚假信号源于受阻胺的直接氧化,由基基 (OH) 和高价值铁物种等反应性物种产生.
- 与OH和高价值铁物种相比,O2在降解有机污染物的反应性和效率较低.
结论:
- 在AOP中,常见的氧化物种可以显著误导1O2的EPR检测.
- 通过氨基氧化形成的氧化基,而不是O2,解释了在某些AOP中观察到的EPR信号.
- 重新考虑EPR信号的解释对于准确理解AOP机制和O2的作用至关重要.
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