Degradation of trichloroethylene in aqueous solution by persulfate activated with citric acid chelated ferrous ion

•TCE is frequently detected in groundwater with its recalcitrant characteristics.•Effective degradation of TCE is achieved by CA–chelated-Fe(II) activated PS.•SO4−, OH and O2− radicals are generated in CA–Fe(II)-activated PS system.•Cl−, HCO3− anions and HA have an inhibitive effect on TCE degradati...

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Bibliographic Details
Published in:Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2014-11, Vol.255, p.585-592
Main Authors: Wu, Xiaoliang, Gu, Xiaogang, Lu, Shuguang, Xu, Minhui, Zang, Xueke, Miao, Zhouwei, Qiu, Zhaofu, Sui, Qian
Format: Article
Language:English
Subjects:
Activated
Anions
Citric acid
Degradation
Ferrous ion
Free radicals
Groundwater remediation
Oxidation
Persulfate
Radicals
Reactive oxygen species
Trichloroethylene
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Summary:•TCE is frequently detected in groundwater with its recalcitrant characteristics.•Effective degradation of TCE is achieved by CA–chelated-Fe(II) activated PS.•SO4−, OH and O2− radicals are generated in CA–Fe(II)-activated PS system.•Cl−, HCO3− anions and HA have an inhibitive effect on TCE degradation efficiency. In this study, persulfate (PS) activated by the citric acid (CA)-chelated–ferrous ion (Fe(II)) to stimulate the oxidation of trichloroethylene (TCE) in groundwater remediation was investigated. The experimental results showed that TCE can be completely degraded over 60min with a PS/Fe(II)/CA/TCE molar ratio of 15:2:1:1, demonstrating the effectiveness of Fe(II)–CA activated PS oxidation on TCE degradation. The probe compound tests clearly identified the generation and intensity of the reactive oxygen species in PS/Fe(II)/CA system, namely sulfate radicals (SO4−), hydroxyl radicals (OH) and superoxide radical anions (O2−). Moreover, the free radical quenching studies further indicated the generation of these reactive oxygen species and OH is the predominant one in Fe(II)–CA-activated PS system. The TCE degradation rate decreased as the Cl−, HCO3− anions and HA increased over the tested range of ion strengths, owing to their significant scavenging function to OH and SO4− radicals. Briefly, Fe(II)–CA activated PS oxidation is a highly promising technique for remediation of the contaminated sites containing TCE, but more complex constituents existed in in-situ groundwater should be carefully considered for its practical application.
ISSN:1385-8947
1873-3212
DOI:10.1016/j.cej.2014.06.085