Activation of Persulfate by Quinones: Free Radical Reactions and Implication for the Degradation of PCBs

• Published in: Environmental science & technology Vol. 47; no. 9; pp. 4605 - 4611
• Main Authors: Fang, Guodong, Gao, Juan, Dionysiou, Dionysios D, Liu, Cun, Zhou, Dongmei
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 07-05-2013
• Subjects: Applied sciences; Biodegradation; Chemical reactions; Decontamination. Miscellaneous; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Feasibility Studies; Free Radicals; Groundwaters; Natural water pollution; Organic contaminants; Oxidation; PCB; Pollution; Pollution, environment geology; Polychlorinated biphenyls; Polychlorinated Biphenyls - chemistry; Quinones - chemistry; Soil and sediments pollution; Sulfates - chemistry; Water treatment and pollution; In situ; Quinone; Polychlorobiphenyls; Soil pollution; Sediments; Organic chlorine compounds; Free radical reaction; Organic halogen compounds; Persistent organic pollutant; Chemical activation; Halogenated hydrocarbon; Decontamination; Chlorocarbon; Aromatic compound; Oxidation; Water pollution; Organic compounds; Ground water; Inorganic radical anion
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es400262n

There has been considerable interest in the use of persulfate for in situ chemical oxidation of organic contaminants in soils, sediments, and groundwater. Since humic acid (HA) exists ubiquitously in these environmental compartments, its redox active functional moieties, such as quinones, may play an important role in the oxidation processes of persulfate treatments. Understanding the effects of HA, especially the quinone functional groups on the degradation of pollutants by persulfate and the production of sulfate radicals (SO4 •‑) from persulfate, is beneficial for devising effective and economically feasible remediation strategies. In this study, the effects of model quinone compounds and HA on the degradation of 2,4,4′-trichlorobiphenyl (PCB28) by persulfate and the production of SO4 •‑ from persulfate were investigated. It was found that quinones and HA can efficiently activate persulfate for the degradation of PCB28. The mechanism of persulfate activation was elucidated by quenching and electron paramagnetic resonance (EPR) studies. The results indicated that production of SO4 •‑ from persulfate and quinones was semiquinone radical-dependent. The effects of quinone concentrations were also studied. The findings of this study elucidated a new pathway of persulfate activation, which could degrade environmental contaminants efficiently and provide useful information for the remediation of contaminated soil and water by persulfate.