Journal article
Identification of the reactive oxygen species responsible for carbon tetrachloride degradation in modified Fenton's systems
Environmental science & technology, Vol.38(20), pp.5465-5469
10/15/2004
Handle:
https://hdl.handle.net/2376/112589
PMID: 15543752
Abstract
The reactive oxygen species responsible for the transformation of carbon tetrachloride (tetrachloromethane, CT) by modified Fenton's reagent using hydrogen peroxide (H2O2) concentrations >0.1 M was investigated. Addition of the hydroxyl radical scavenger 2-propanol to modified Fenton's reactions did not significantly lower CT transformation rates. Scavenging by 2-propanol not only confirmed that hydroxyl radicals are not responsible for CT destruction, but also suggested that a major product of an iron (III)-driven initiation reaction, superoxide radical anion (O2-), is the species responsible for CT transformation. To investigate this hypothesis, CT degradation was studied in aqueous KO2 reactions. Minimal CT degradation was found in CT-KO2 reactions; however, when H2O2 was added to the KO2 reactions at concentrations similar to those in the modified Fenton's reactions (0.1, 0.5, and 1 M), CT degradation increased significantly. Similar results were obtained when 1 M concentrations of other solvents were added to aqueous KO2 reactions, and the observed first-order rate constant for CT degradation correlated strongly (R2 = 0.986) with the empirical solvent polarity (E(T)N) of the added solvents. The results indicate that even dilute concentrations of solvents, including H202, can increase the reactivity of O2- in water, probably by changing its solvation sphere. The higher reactivity of O2- generated in modified Fenton's reagent, which has a less polar nature due to the presence of H2O2, may result in a wider range of contaminant degradation than previously thought possible.
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Details
- Title
- Identification of the reactive oxygen species responsible for carbon tetrachloride degradation in modified Fenton's systems
- Creators
- Brant A Smith - Department of Civil and Environmental Engineering, Washington State University, Pullman, Washington 99164-2910, USAAmy L TeelRichard J Watts
- Publication Details
- Environmental science & technology, Vol.38(20), pp.5465-5469
- Academic Unit
- Civil and Environmental Engineering, Department of
- Publisher
- United States
- Identifiers
- 99900547746201842
- Language
- English
- Resource Type
- Journal article