Sulfidation of Zero-Valent Iron by Direct Reaction with Elemental Sulfur in Water: Efficiencies, Mechanism, and Dechlorination of Trichloroethylene

Shichao Cai, Bo Chen, Xiaojiang Qiu, Jiamei Li, Paul G. Tratnyek, Feng He

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Sulfidation can enhance both the reactivity and selectivity (i.e., electron efficiency, ϵe) of zero-valent iron (ZVI) in contaminant removal, which may make this technology cost-effective for a wider range of water treatment applications. However, current sulfidation methods involve either hazardous or unstable sulfidation agents (e.g., Na2S, Na2S2O3, and Na2S2O4) or energy-intensive preparations (e.g., mechanochemical sulfidation with elemental sulfur). In this study, we demonstrate that very efficient sulfidation of microscale ZVI (mZVI) can be achieved at all S/Fe molar ratios (μ100% sulfidation efficiency, ϵs) simply by direct reaction between elemental sulfur (S0) and ZVI in an aqueous suspension at ambient temperature. In comparison, the ϵs values obtained using Na2S, Na2S2O3, or Na2S2O4 as the sulfidation agents were only μ23, μ75, and μ38%, respectively. The sulfidated mZVI produced using the new method reacts with trichloroethylene (TCE) with very high rates and electron efficiencies: rate constants and electron efficiencies were 800- and 79-fold higher than those of the unsulfidated mZVI. The enhanced performance of this material, together with the operational advantages of S0 for sulfidation (including safety, stability, and cost), may make it a desirable product for full-scale engineering applications.

Original languageEnglish (US)
Pages (from-to)645-654
Number of pages10
JournalEnvironmental Science and Technology
Volume55
Issue number1
DOIs
StatePublished - Jan 5 2021

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

Fingerprint

Dive into the research topics of 'Sulfidation of Zero-Valent Iron by Direct Reaction with Elemental Sulfur in Water: Efficiencies, Mechanism, and Dechlorination of Trichloroethylene'. Together they form a unique fingerprint.

Cite this