Kinetic Mismatch Drives Tetrachloroethene (PCE) Rebound in Fe(II)/Persulfate In Situ Chemical Oxidation

IF 10.6 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Journal of Hazardous Materials Pub Date : 2026-09-30 DOI:10.1016/j.jhazmat.2026.143793

Sulin Wang, Jian Xu, Fei Wang

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引用次数: 0

Abstract

Ferrous iron-activated persulfate (Fe(II)/PDS) is widely used for in situ chemical oxidation (ISCO) of chlorinated solvents, yet aqueous rebound complicates treatment evaluation. Phase-resolved mass balances were combined with electron paramagnetic resonance (EPR) and surface characterization to examine tetrachloroethene (PCE) redistribution and removal. In homogeneous aqueous systems, PCE removal was rapid within 2h, with rapid dissolved Fe(II) consumption. Among evaluated Fe(II):PDS ratios, 1:1 yielded the highest removal, with >30% PDS persisting beyond the initial stage. Following Fe(II)/PDS addition to pre-equilibrated soil–water systems, aqueous PCE increased while soil-associated PCE decreased and total PCE mass declined monotonically. SEM–EDS, FTIR, and XRD indicated Fe-rich surface deposition and altered organic functional groups, supporting interfacial changes that weaken PCE retention. Soil addition attenuated EPR spin-adduct responses. In pre-equilibrated systems, the fitted sulfate-adduct response in soil extracts exhibited negligible variation between 10 and 120min, consistent with continued soil-associated activation as intensive aqueous oxidation subsided. These observations support a kinetic mismatch between declining effective oxidative capacity and continued soil-to-water PCE release, allowing aqueous accumulation despite net removal. The findings provide a mechanistic basis for coordinating reagent transport and local activation with delayed contaminant release through alternating PDS and Fe(II) injection in groundwater circulation well (GCW) systems.

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动力学失配驱动四氯乙烯（PCE）在Fe(II)/过硫酸盐原位化学氧化中的回弹

亚铁活化过硫酸盐（Fe(II)/PDS）广泛用于氯化溶剂的原位化学氧化（ISCO），但水回弹使处理评价复杂化。相分辨质量天平结合电子顺磁共振（EPR）和表面表征来检测四氯乙烯（PCE）的再分布和去除。在均相水体系中，PCE在2h内去除迅速，溶解的Fe（II）消耗迅速。在评估的Fe(II):PDS比例中，1:1的去除率最高，30%的PDS持续到初始阶段之后。在预平衡土壤-水系统中添加Fe(II)/PDS后，水中PCE增加，与土壤相关的PCE减少，总PCE质量单调下降。SEM-EDS、FTIR和XRD显示富铁表面沉积和有机官能团改变，支持界面改变，削弱PCE保留。土壤添加减弱了EPR自旋加合反应。在预平衡系统中，土壤提取物中硫酸盐加合物的响应在10到120分钟之间表现出可以忽略不计的变化，这与随着强烈的水氧化消退而持续的土壤相关激活相一致。这些观察结果支持了有效氧化能力下降和持续的土壤-水PCE释放之间的动力学不匹配，尽管净去除，但仍允许水积累。研究结果为通过地下水循环井（GCW）系统中交替注入PDS和Fe（II）来协调试剂运输和局部活化以及延迟污染物释放提供了机制基础。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Hazardous Materials 工程技术-工程：环境

CiteScore

25.40

自引率

5.90%

发文量

3059

审稿时长

58 days

期刊介绍： The Journal of Hazardous Materials serves as a global platform for promoting cutting-edge research in the field of Environmental Science and Engineering. Our publication features a wide range of articles, including full-length research papers, review articles, and perspectives, with the aim of enhancing our understanding of the dangers and risks associated with various materials concerning public health and the environment. It is important to note that the term "environmental contaminants" refers specifically to substances that pose hazardous effects through contamination, while excluding those that do not have such impacts on the environment or human health. Moreover, we emphasize the distinction between wastes and hazardous materials in order to provide further clarity on the scope of the journal. We have a keen interest in exploring specific compounds and microbial agents that have adverse effects on the environment.