Transformation of mackinawite to greigite by trichloroethylene and tetrachloroethylene. Issue 10 (29th September 2016)

• Record Type: Journal Article
• Authors: Lan, Ying; Elwood Madden, Andrew S.; Butler, Elizabeth C.
• Is Part Of: Environmental science. Volume 18:Issue 10(2016)
• Page Start: 1266
• Page End: 1273
• Publication Date: 2016-09-29
• Subjects: Environmental monitoring -- Periodicals; Biological monitoring -- Periodicals; Environmental chemistry -- Periodicals; 363.7363
• DOI: 10.1039/c6em00461j
• Languages: English
• ISSNs: 2050-7887

Abstract

Abstract : Trichloroethylene and tetrachloroethylene transform mackinawite to greigite. Abstract : Trichloroethylene (TCE) and tetrachloroethylene (PCE) are common ground water contaminants susceptible to reductive dechlorination by FeS (mackinawite) in anaerobic environments. The objective of this study was to characterize the mineral-associated products that form when mackinawite reacts with TCE and PCE. The dissolved products of the reaction included Cl − and Fe 2+, and trace amounts of cis 1, 2-dichloroethylene (for TCE) and TCE (for PCE). Selected area electron diffraction (SAED) analysis identified greigite as a mackinawite oxidation product formed after reaction between TCE or PCE and FeS over seven weeks. Release of Fe 2+ is consistent with the solid state transformation of mackinawite to greigite, resulting in depletion of the solid with Fe. X-ray photoelectron spectroscopy of the sulfur 2p peak showed a shift to a higher binding energy after FeS reacted with TCE or PCE, also observed in other studies of mackinawite oxidation to greigite. The results may help efforts to maintain the reactivity of FeS generated to remediate chlorinated aliphatic contaminants in ground water.