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首页> 外文期刊>Environmental Science & Technology >Mechanisms on the Impacts of Alkalinity, pH, and Chloride on Persulfate-Based Groundwater Remediation
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Mechanisms on the Impacts of Alkalinity, pH, and Chloride on Persulfate-Based Groundwater Remediation

机译：碱度，pH和氯化物对过硫酸盐基地下水修复的影响机理

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摘要

Persulfate (S_2O_8~(2-))-based in situ chemical oxidation (ISCO) has gained more attention in recent years due to the generation of highly reactive and selective sulfate radical (S0_4~(˙-)). This study examined the effects of important groundwater chemical parameters, i.e., alkalinity, pH, and chloride on benzene degradation via heterogeneous persulfate activation by three Fe(lII)- and Mn(IV)-containing aquifer minerals: ferrihydrite, goethite, and pyrolusite. A comprehensive kinetic model was established to elucidate the mechanisms of radical generation and mineral surface complexation. Results showed that an increase of alkalinity up to 10 meq/L decreased the rates of persulfate decomposition and benzene degradation, which was associated with the formation of unreactive surface carbonato complexes. An increase in pH generally accelerated persulfate decomposition due to enhanced formation of reactive surface hydroxo complexation. A change in the chloride level up to 5 mM had a negligibly effect on the reaction kinetics. Kinetics modeling also suggested that S0_4~(˙-) was transformed to hydroxyl radical (HO*) and carbonate radical (CO_3~(˙-)) at higher pHs. Furthermore, the yields of two major products of benzene oxidation, i.e., phenol and aldehyde, were positively correlated with the branching ratio of S0_4~(˙-) reacting with benzene, but inversely correlated with that of HO~˙ or CO_3~(˙-), indicating that S0_4~(˙-) preferentially oxidized benzene via pathways involving fewer hydroxylation steps compared to HO* or CO_3~(˙-).
机译：近年来，过硫酸盐（S_2O_8〜（2-））基原位化学氧化（ISCO）由于产生了高反应性和选择性的硫酸根（S0_4〜（˙-））而备受关注。这项研究研究了重要的地下水化学参数（即碱度，pH和氯化物）对苯的降解的影响，该苯降解是通过三种含Fe（II）和Mn（IV）的含水层矿物（三水铁矿，针铁矿和软锰矿）通过过硫酸盐活化而进行的。建立了一个综合动力学模型来阐明自由基产生和矿物表面络合的机理。结果表明，提高碱度至10 meq / L会降低过硫酸盐分解和苯降解的速率，这与无反应性表面碳酸盐配合物的形成有关。由于反应性表面羟基络合物形成的增加，pH值的升高通常会加速过硫酸盐的分解。氯化物含量变化至5 mM对反应动力学的影响可忽略不计。动力学建模还表明，在较高的pH值下，SO_4〜（˙-）被转化为羟基自由基（HO *）和碳酸盐自由基（CO_3〜（˙-））。此外，苯氧化的两种主要产物酚和醛的产率与S0_4〜（˙-）与苯反应的支化比正相关，而与HO〜˙或CO_3〜（˙ -），表明S0_4〜（˙-）与HO *或CO_3〜（˙-）相比，通过涉及更少羟基化步骤的途径优先氧化了苯。

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  • 来源
    《Environmental Science & Technology》 |2017年第7期|3948-3959|共12页
  • 作者

    Wei Li; Ruben Orozco; Natalia Camargos; Haizhou Liu;

  • 作者单位

    Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, United States,Program of Environmental Toxicology, University of California, Riverside, California 92521, United States;

    Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, United States;

    Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, United States;

    Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, United States,Program of Environmental Toxicology, University of California, Riverside, California 92521, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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