Remediation of groundwater contaminated by chlorinated organic compounds using alkaline-activated persulfate

Abstract This research assesses how effectively alkaline-activated persulfate removes 1,2-dichloroethane (1,2-DCA) and trichloroethylene (TCE) from groundwater, while examining the underlying mechanisms. The results show that while the degradation efficiency of 1,2-DCA (4.2 × 10-4 M) ranges from 42...

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Main Authors: Yu-Chu Feng, Yen-Ping Peng, Chia-Hsiang Lai, Chia-Hua Lin, Yi-Min Lin, Yu-Chen Chang, Ku-Fan Chen
Format: Article
Language:English
Published: BMC 2025-05-01
Series:Sustainable Environment Research
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Online Access:https://doi.org/10.1186/s42834-025-00249-x
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author Yu-Chu Feng
Yen-Ping Peng
Chia-Hsiang Lai
Chia-Hua Lin
Yi-Min Lin
Yu-Chen Chang
Ku-Fan Chen
author_facet Yu-Chu Feng
Yen-Ping Peng
Chia-Hsiang Lai
Chia-Hua Lin
Yi-Min Lin
Yu-Chen Chang
Ku-Fan Chen
author_sort Yu-Chu Feng
collection DOAJ
description Abstract This research assesses how effectively alkaline-activated persulfate removes 1,2-dichloroethane (1,2-DCA) and trichloroethylene (TCE) from groundwater, while examining the underlying mechanisms. The results show that while the degradation efficiency of 1,2-DCA (4.2 × 10-4 M) ranges from 42 to 96%, TCE (4.2 × 10-4 M) is completely degraded by persulfate (4.2 × 10-2 M) after 120 h. The alkaline conditions (pH > 11) improve the degradation of 1,2-DCA but hinder TCE breakdown, leading to the formation of vinyl chloride through dehydrochlorination of 1,2-DCA. The degradation patterns for 1,2-DCA and TCE align with pseudo-first-order kinetics. The highest rate constant for 1,2-DCA oxidation is 6.3 × 10-6 s-1 at pH 13 whereas the highest rate constant for TCE removal is 2.5 × 10-5 s-1 at pH 3. Electron paramagnetic resonance analysis reveals the presence of both SO4 -· and ·OH in the alkaline-activated persulfate system. Although alkaline persulfate generates more sulfate radicals and highly oxidative hydroxyl radicals, the elevated pH reduces oxidation reduction potential (ORP), which limits contaminant removal. For each unit increase in pH, the ORP value decreases by approximately 49.9 mV. Additionally, the presence of chloride (0.05-0.40 M) and carbonate (0.01-0.27 M) diminishes the degradation rates of both pollutants, with carbonate having a more substantial inhibitory effect under alkaline conditions. When both 1,2-DCA and TCE are present, alkaline conditions suppress TCE degradation, and acidic conditions reduce 1,2-DCA removal. This study highlights the importance of pH, ORP, and anion interactions in the effectiveness of alkaline-activated persulfate in treating chlorinated organic compounds in groundwater.
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issn 2468-2039
language English
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spelling doaj-art-13ec5b53619d4de192f2378845bcf4ed2025-08-20T02:34:19ZengBMCSustainable Environment Research2468-20392025-05-0135111310.1186/s42834-025-00249-xRemediation of groundwater contaminated by chlorinated organic compounds using alkaline-activated persulfateYu-Chu Feng0Yen-Ping Peng1Chia-Hsiang Lai2Chia-Hua Lin3Yi-Min Lin4Yu-Chen Chang5Ku-Fan Chen6Department of Civil Engineering, National Chi Nan UniversityInstitute of Environmental Engineering, National Sun Yat-sen UniversityDepartment of Biotechnology, National Formosa UniversityDepartment of Biotechnology, National Formosa UniversityDepartment of Civil Engineering, National Chi Nan UniversityDepartment of Civil Engineering, National Chi Nan UniversityDepartment of Civil Engineering, National Chi Nan UniversityAbstract This research assesses how effectively alkaline-activated persulfate removes 1,2-dichloroethane (1,2-DCA) and trichloroethylene (TCE) from groundwater, while examining the underlying mechanisms. The results show that while the degradation efficiency of 1,2-DCA (4.2 × 10-4 M) ranges from 42 to 96%, TCE (4.2 × 10-4 M) is completely degraded by persulfate (4.2 × 10-2 M) after 120 h. The alkaline conditions (pH > 11) improve the degradation of 1,2-DCA but hinder TCE breakdown, leading to the formation of vinyl chloride through dehydrochlorination of 1,2-DCA. The degradation patterns for 1,2-DCA and TCE align with pseudo-first-order kinetics. The highest rate constant for 1,2-DCA oxidation is 6.3 × 10-6 s-1 at pH 13 whereas the highest rate constant for TCE removal is 2.5 × 10-5 s-1 at pH 3. Electron paramagnetic resonance analysis reveals the presence of both SO4 -· and ·OH in the alkaline-activated persulfate system. Although alkaline persulfate generates more sulfate radicals and highly oxidative hydroxyl radicals, the elevated pH reduces oxidation reduction potential (ORP), which limits contaminant removal. For each unit increase in pH, the ORP value decreases by approximately 49.9 mV. Additionally, the presence of chloride (0.05-0.40 M) and carbonate (0.01-0.27 M) diminishes the degradation rates of both pollutants, with carbonate having a more substantial inhibitory effect under alkaline conditions. When both 1,2-DCA and TCE are present, alkaline conditions suppress TCE degradation, and acidic conditions reduce 1,2-DCA removal. This study highlights the importance of pH, ORP, and anion interactions in the effectiveness of alkaline-activated persulfate in treating chlorinated organic compounds in groundwater.https://doi.org/10.1186/s42834-025-00249-xChlorinated organic compoundIn situ chemical oxidationAlkaline-activated persulfateDehydrochlorinationAnion
spellingShingle Yu-Chu Feng
Yen-Ping Peng
Chia-Hsiang Lai
Chia-Hua Lin
Yi-Min Lin
Yu-Chen Chang
Ku-Fan Chen
Remediation of groundwater contaminated by chlorinated organic compounds using alkaline-activated persulfate
Sustainable Environment Research
Chlorinated organic compound
In situ chemical oxidation
Alkaline-activated persulfate
Dehydrochlorination
Anion
title Remediation of groundwater contaminated by chlorinated organic compounds using alkaline-activated persulfate
title_full Remediation of groundwater contaminated by chlorinated organic compounds using alkaline-activated persulfate
title_fullStr Remediation of groundwater contaminated by chlorinated organic compounds using alkaline-activated persulfate
title_full_unstemmed Remediation of groundwater contaminated by chlorinated organic compounds using alkaline-activated persulfate
title_short Remediation of groundwater contaminated by chlorinated organic compounds using alkaline-activated persulfate
title_sort remediation of groundwater contaminated by chlorinated organic compounds using alkaline activated persulfate
topic Chlorinated organic compound
In situ chemical oxidation
Alkaline-activated persulfate
Dehydrochlorination
Anion
url https://doi.org/10.1186/s42834-025-00249-x
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