Reductive defluorination of perfluorooctane sulfonate
Valeria Ochoa-Herrera1, Reyes Sierra-Alvarez, Arpad Somogyi
1Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, USA.
Environmental Science & Technology
|June 5, 2008
Summary
This study shows that vitamin B12 can catalyze the reductive dehalogenation of perfluorooctane sulfonate (PFOS) compounds. Branched PFOS isomers degraded, while linear PFOS remained stable, offering a potential method for PFOS remediation.
Area of Science:
- Environmental Chemistry
- Biocatalysis
Background:
- Perfluorooctane sulfonate (PFOS) is a persistent environmental pollutant with global distribution and bioaccumulation potential.
- Concerns over PFOS contamination necessitate the development of effective degradation strategies.
Purpose of the Study:
- To evaluate the reductive dehalogenation of PFOS and its isomers using vitamin B12 as a catalyst.
- To investigate the efficacy of vitamin B12-mediated degradation for environmental remediation of PFOS.
Main Methods:
- Reductive dehalogenation experiments were conducted in anoxic aqueous solution at 70°C and pH 9.
- Vitamin B12 (260 μM) served as the catalyst with Ti(III)-citrate (36 mM) as the bulk reductant.
- Defluorination was quantified, and PFOS degradation was monitored using ion chromatography, LC-MS/MS, and 19F NMR.
Main Results:
- Significant defluorination was observed: 18% for technical PFOS (3 mol F-/mol PFOS) and 71% for PFOS branched isomers (12 mol F-/mol PFOS).
- Branched PFOS isomers were degraded, indicated by the disappearance of corresponding chromatographic peaks.
- Linear PFOS showed stability under the tested reductive conditions.
Conclusions:
- Vitamin B12 can catalyze the reductive dehalogenation of PFOS, with branched isomers being more susceptible than linear PFOS.
- This study presents the first report of biomolecule-catalyzed reductive dehalogenation of PFOS, suggesting a novel approach for PFOS remediation.
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