Mechanism of carbon tetrachloride reduction in ferrous ion activated calcium peroxide system in the presence of methanol

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

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

This study investigated the reductive initiation for the depletion of highly oxidized/perhalogenated pollutants, specifically the degradation of carbon tetrachloride (CT) was induced by adding methanol (MeOH) into a ferrous ion (Fe(II)) activated calcium peroxide (CaO2) system. The results indicated that CT could be completely degraded within 20 min at CaO2/Fe(II)/MeOH/CT molar ratio of 30/40/10/1 in this system. Scavenging tests suggested that both superoxide radical anion (O2[rad]−) and carbon dioxide radical anion (CO2[rad]−) were predominant reactive species responsible for CT destruction. Hydroxymethyl radicals ([rad]CH2OH), an intermediate in the transformation of MeOH, could also initiate CT degradation by reducing C–Cl bond. GC/MS analysis identified CHCl3, C2Cl4, and C2Cl6 as the intermediates accompanied by CT destruction, and a reduction mechanism for CT degradation was proposed accordingly. In addition, the impact of solution matrix and initial solution pH were evaluated, and the results showed that Cl, NO3, and HCO3 had adverse effects on CT degradation. Moreover, the alkaline condition was unfavorable to CT depletion. In conclusion, the results obtained in the actual groundwater tests encouragingly demonstrated that the CaO2/Fe(II)/MeOH process is a highly promising technique for the remediation of CT-contaminated groundwater.

Original languageEnglish (US)
Pages (from-to)243-250
Number of pages8
JournalChemical Engineering Journal
Volume362
DOIs
StatePublished - Apr 15 2019

Keywords

  • Calcium peroxide
  • Carbon tetrachloride
  • Groundwater remediation
  • Methanol
  • Reductive radicals

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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