Roles of hydroxyl and sulfate radicals in degradation of trichloroethene by persulfate activated with Fe2+ and zero-valent iron: Insights from carbon isotope fractionation
Roles of hydroxyl and sulfate radicals in degradation of trichloroethene by persulfate activated with Fe2+ and zero-valent iron: Insights from carbon isotope fractionation
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羟基和硫酸根在 Fe2 和零价铁活化的过硫酸盐降解三氯乙烯中的作用：来自碳同位素分馏的见解
DOI：
10.1016/j.jhazmat.2017.09.048
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发表时间：
2018-02-15
影响因子：
13.6
通讯作者：
Li, Xiaoqian
中科院分区：
文献类型：
--
作者：
Liu, Yunde;Zhou, Aiguo;Li, Xiaoqian
在基于过硫酸盐的原位化学氧化(ISCO)过程中，包括羟基(HO中心点)和硫酸根(SO4中心点-)在内的活性物种在污染物降解过程中起着重要作用。活性物种的产生和贡献是关键的，可以使用化合物特定同位素分析(CSIA)进行评估。然而，需要对单个活性物种降解的污染物的稳定同位素分馏(或同位素富集度S值)进行评估，但缺乏这种评估。本研究首次用化学探针法测定了三氯乙烯(TCE)在SO4中心点法降解过程中的碳同位素分馏，得到了-6.4+/-0.7到-6.9+/-0.5‰的值。HO中心点对TCE降解的a值与文献报道的结果有显著差异，可用来识别HO中心点和SO4中心点对TCE的竞争降解。根据观测到的a值和扩展的Rayleigh方程，评价了Fe-0或Fe(II)活化的Per硫酸盐中SO4中心点和Ho中心点对TCE降解的贡献。这项研究为确定单个活性物种降解污染物的稳定同位素分馏提供了一个启发性的思路，这对CSIA在相关环境中的应用是至关重要的。(C)2017爱思唯尔B.V.保留所有权利。
Active species including hydroxyl (HO center dot) and sulfate radicals (SO4 center dot-) play important roles in contaminant degradation during the persulfate based in-situ chemical oxidation (ISCO) process. The generation and contribution of active species are critical and can potentially be evaluated using compound specific isotope analysis (CSIA). However, the evaluation of stable isotope fractionation (or isotope enrichment factor s values) for contaminants degraded by individual active species of concern is required but lacking. This study firstly determined the carbon isotope fractionation of trichloroethene (TCE) degradation by SO4 center dot- with chemical probe methods to obtain a values from -6.4 +/- 0.7 to -6.9 +/- 0.5 parts per thousand. The a values were significantly different from those reported for TCE degradation by HO center dot, which could be used to identify the competing TCE degradation by HO center dot and SO4 center dot-. Relying on the observed a values and the extended Rayleigh-type equation, the contributions of SO4 center dot- and HO center dot to TCE degradation were evaluated in per sulfate activated by Fe-0 or Fe(II). This study provides an illuminating idea to determine stable isotope fractionation for contaminant degradation by individual active species, which is crucial for the application of CSIA in relevant environments. (C) 2017 Elsevier B.V. All rights reserved.