Enhanced degradation of halogenated aliphatics by zero-valent iron
- Univ. of Waterloo, Ontario (Canada). Waterloo Centre for Groundwater Research
Laboratory tests were conducted to examine zero-valent iron as an enhancing agent in the dehalogenation of 14 chlorinated methanes, ethanes, and ethenes. All compounds were tested by batch procedures in which 10 g of 100-mesh electrolytic iron was added to 40 ml hypovials. Aqueous solutions of the respective compounds were added to the hypovials, and the decline in concentration was monitored over time. Substantial rates of degradation were observed for all compounds tested with the exception of dichloromethane. The degradation process appeared to be pseudo first-order with respect to the organic compound, with the rate constant appearing to be directly proportional to the surface area to volume ratio and increasing with increasing degree of chlorination. Column tests showed the process to proceed under flow conditions with degradation rates independent of velocity and consistent with those measured in the batch tests. When normalized to 1 m[sup 2]/ml, the t[sub 50] values ranged from 0.013 to 20 hr, and were about 5 to 15 orders of magnitude lower than values reported for natural rates of abiotic degradation. The results indicate abiotic reductive dechlorination, with iron serving as the source of electrons; the mechanism is, however, uncertain. Based on the rapid rates of degradation, both in situ and aboveground applications for remediation of contaminated ground water are proposed.
- OSTI ID:
- 7069335
- Journal Information:
- Ground Water; (United States), Journal Name: Ground Water; (United States) Vol. 32:6; ISSN GRWAAP; ISSN 0017-467X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
CHEMICAL REACTIONS
CHLORINATED ALIPHATIC HYDROCARBONS
CLEANING
DECONTAMINATION
DEHALOGENATION
GROUND WATER
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROGEN COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN COMPOUNDS
REMEDIAL ACTION
TECHNOLOGY ASSESSMENT
WATER