Oxidative and Reductive Pathways in Iron-Ethylenediaminetetraacetic Acid–Activated Persulfate Systems
- 1 April 2012
- journal article
- Published by American Society of Civil Engineers (ASCE) in Journal of Environmental Engineering
- Vol. 138 (4), 411-418
- https://doi.org/10.1061/(asce)ee.1943-7870.0000496
Abstract
The iron (II)-ethylenediaminetetraacetic acid (EDTA) and iron (III)-EDTA activation of persulfate was compared using reactant-specific probe compounds: the combined sulfate radical and hydroxyl radical probe anisole, the hydroxyl radical probe nitrobenzene, and the reductant/nucleophile probe hexachloroethane. Iron (II)-EDTA and iron (III)-EDTA were equally effective for activating persulfate decomposition and for generating reductants/nucleophiles at pH 5, while iron (III)-EDTA was a more effective activator than iron (II)-EDTA for generating oxidants. Use of the combined sulfate radical and hydroxyl radical scavenger isopropanol and the hydroxyl radical scavenger tert-butanol demonstrated that approximately 86 and 73% of the oxidation activity in iron (II)-EDTA and iron (III)-EDTA-activated persulfate systems, respectively, was attributable to hydroxyl radical activity. The generation of hydroxyl radical in iron-EDTA-activated persulfate systems at pH 5 was confirmed using electron spin resonance spectroscopy. The results of these pathway analyses, in conjunction with confirmation of the results using the common groundwater contaminant trichloroethylene (TCE), show that iron (II)-EDTA and iron (III)-EDTA-activated persulfate may be an effective system for the in situ remediation of contaminated groundwater.Keywords
This publication has 16 references indexed in Scilit:
- Mechanism of Base Activation of PersulfateEnvironmental Science & Technology, 2010
- Identification of Sulfate and Hydroxyl Radicals in Thermally Activated PersulfateIndustrial & Engineering Chemistry Research, 2009
- Enhanced Reactivity of Superoxide in Water−Solid MatricesEnvironmental Science & Technology, 2009
- Persulfate oxidation of trichloroethylene with and without iron activation in porous mediaChemosphere, 2008
- Influence of pH on persulfate oxidation of TCE at ambient temperaturesChemosphere, 2007
- Rate constants for reactions of SO4˙− radicals in acetonitrileInternational Journal of Chemical Kinetics, 1993
- Rate constants for hydrogen abstraction reactions of the sulfate radical, SO4−. AlcoholsInternational Journal of Chemical Kinetics, 1989
- Critical Review of rate constants for reactions of hydrated electrons, hydrogen atoms and hydroxyl radicals (⋅OH/⋅O− in Aqueous SolutionJournal of Physical and Chemical Reference Data, 1988
- Spin trapping with 5,5-dimethylpyrroline-N-oxide in aqueous solution.CHEMICAL & PHARMACEUTICAL BULLETIN, 1981
- Rate constants and mechanism of reaction of sulfate radical anion with aromatic compoundsJournal of the American Chemical Society, 1977