Insights into carbon isotope fractionation on trichloroethene degradation in base activated persulfate process: The role of multiple reactive oxygen species.
Insights into carbon isotope fractionation on trichloroethene degradation in base activated persulfate process: The role of multiple reactive oxygen species.
复制标题
深入了解碱活化过硫酸盐工艺中三氯乙烯降解的碳同位素分馏：多种活性氧的作用。
DOI：
10.1016/j.scitotenv.2021.149371
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发表时间：
2021-07
影响因子：
9.8
通讯作者：
Li Minglu
中科院分区：
文献类型：
--
作者：
Liu Yunde;Zhang Yuanzheng;Zhou Aiguo;Li Minglu
了解活性氧（ROS）的作用是阐明原位化学氧化（ISCO）降解污染物机理的基础。采用化合物特异性同位素分析（CSIA）和自由基猝灭法研究了碱活化过硫酸盐（PS）过程中羟基自由基（HO自由基点）、硫酸根自由基（SO 4自由基点-）和超氧自由基（O2自由基点-）对三氯乙烯（TCE）降解的影响。TCE的碳同位素分馏取决于碱：PS比，在碱：PS摩尔比为0.5：1至10：1时，碳富集因子（ε值）为−9.8 ± 0.5‰至−16.7 ± 1.0‰，这归因于多种ROS对TCE的多途径降解。TCE通过O2自由基点−攻击途径降解的预期ε值（−31.6 ± 1.6‰）比通过SO 4自由基点−或HO自由基点途径降解的预期ε值更负。利用观测到的ε值估算了HO自由基dot、SO 4自由基dot−和O2自由基dot−对碱活化PS过程中TCE降解的相对贡献。在碱活化的PS中，HOradical dot和O2 radical dot−是TCE降解的主要ROS（相对贡献分别为55-69%和22- 45%）。本研究为CSIA在环境中活性氧污染物降解途径的研究提供了前景。
Understanding the role of reactive oxygen species (ROS) is essential to elucidate the mechanism of contaminants degradation in in-situ chemical oxidation (ISCO). In this study, compound specific isotope analysis (CSIA) and radicals quenching methods were integrated to investigate the roles of hydroxyl radical (HOradical dot), sulfate radical (SO4radical dot−), and superoxide radical (O2radical dot−) on trichloroethene (TCE) degradation during persulfate (PS) activated with base. The carbon isotope fractionation of TCE was found to be dependent of the base:PS ratios, yielding carbon enrichment factors (ε values) from −9.8 ± 0.5‰ to −16.7 ± 1.0‰ at base:PS molar ratios between 0.5:1 and 10:1, which was attributed to multi-pathways degradation of TCE by multiple ROS. The expected ε value (−31.6 ± 1.6‰) for TCE degradation via O2radical dot−attacking pathway, was more negative than those values via SO4radical dot−or HOradical dot pathways. The relative contributions of HOradical dot, SO4radical dot−and O2radical dot−for TCE degradation during base activated PS were estimated with observed ε values. HOradical dot and O2radical dot−were the predominant ROS for TCE degradation (with the relative contribution of 55–69% and 22–45%, respectively) in base activated PS. This work highlights the prospect of CSIA application for identifying degradation pathways of contaminants with ROS in environment.