Enhanced redox degradation of chlorinated hydrocarbons by the Fe(II)-catalyzed calcium peroxide system in the presence of formic acid and citric acid

Wenchao Jiang, Ping Tang, Shuguang Lyu, Mark L. Brusseau, Yunfei Xue, Xiang Zhang, Zhaofu Qiu, Qian Sui

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5 Scopus citations


Two carboxylic acids (formic acid (FA) and citric acid (CIT)) enhanced the Fenton process using Fe(II)-activated calcium peroxide (CP) to develop a hydroxyl (HO[rad]) and carbon dioxide radical (CO2[rad]) coexistence process for the simultaneous redox-based degradation of three chlorinated hydrocarbons (CHs), namely carbon tetrachloride (CT), tetrachloroethene (PCE), and trichloroethene (TCE), was investigated. The experimental results showed that CT removal was increased while PCE and TCE degradation were decreased with the addition of FA to the Fe(II)/CP system. However, addition of CIT to the Fe(II)/CP/FA system enhanced the removal efficiency of all three contaminants. For example, 81.7%, 79.4%, and 96.1% of CT, PCE, and TCE, respectively, were removed simultaneously under the optimal molar ratio of 12/12/12/12/1 of CIT/CP/Fe(II)/FA/CHs. Mechanism study confirmed the specific roles of HO[rad] and secondarily generated CO2[rad] radical. PCE and TCE were degraded oxidatively by HO[rad] while CT was degraded via reductive dechlorination by CO2[rad]. Carbonate reduced PCE and TCE degradation in actual groundwater as it consumed reactive oxygen species, whereas humic acid and neutral pH had minimal impact on contaminant removal. These results can help us better understand the synergistic effects of carboxylic acids in the modified Fenton process for the redox degradation of refractory chlorinated hydrocarbons.

Original languageEnglish (US)
Pages (from-to)506-513
Number of pages8
JournalJournal of Hazardous Materials
StatePublished - Apr 15 2019



  • Calcium peroxide
  • Citric acid
  • Formic acid
  • Groundwater remediation
  • Selective redox degradation

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

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