High-valent iron-based oxidants to treat perfluorooctanesulfonate and perfluorooctanoic acid in water
Perfluoroalkyl and polyfluoroalkyl substances are occurring in consumer and industrial products. They have been found globally in the aquatic environment including drinking water sources and treated wastewater effluents, which has raised concern of potential human health effects because these substances may be bioaccumulative and extremely persistent. The saturated carbon–fluorine bonds of the substances make them resistant to degradation by physical, chemical, and biological processes. There is therefore a need for advanced remediation methods. Iron-based methods involving high-valent compounds are appealing to degrade these substances due to their high oxidation potentials and capability to generate environmentally friendly by-products. This article presents for the first time the oxidation ability of tetraoxy anions of iron(V) (FeVO4 3−, Fe(V)), and iron(IV) (FeIVO4 4−, Fe(IV)), commonly called ferrates, in neutral and alkaline solutions. Solid compounds of Fe(V) (K3FeO4) and Fe(IV) (Na4FeO4) were added directly into buffered solution containing perfluorooctansulfonate and perfluorooctanoic acid at pH 7.0 and 9.0, and mixed solutions were subjected to analysis for remaining fluoro compounds after 5 days. The analysis was performed by liquid chromatography–mass spectrometry/mass spectrometry technique. Fe(IV) showed the highest ability to oxidize the studied contaminants; the maximum removals were 34 % for perfluorooctansulfonate and 23 % for perfluorooctanoic acid. Both Fe(V) and Fe(IV) had slightly higher tendency to oxidize contaminants at alkaline pH than at neutral pH. Results were described by invoking reactions involved in oxidation of perfluorooctansulfonate and perfluorooctanoic acid by ferrates in aqueous solution. The results demonstrated potentials of Fe(V) and Fe(IV) to degrade perfluoroalkyl substances in contaminated water.
KeywordsFerrate Oxidation Degradation Perfluoroalkyl compounds Fe(V) Fe(IV)
B.J. Yates and R. Darlington acknowledge support from Battelle’s Internal Research and Development funds. V. K. Sharma thanks United States National Science Foundation (CBET 1236331) for supporting ferrate research. The authors also acknowledge the support by the Operational Program Research and Development for Innovations–European Regional Development Fund (CZ.1.05/2.1.00/03.0058) and by Technological Agency of the Czech Republic—the project Environmental Friendly Nanotechnologies and Biotechnologies in Water and Soil Treatment (TE01020218).
- Butler EC, Chen L, Darlington R (2013) Transformation of trichloroethylene to predominantly non-regulated products under stimulated sulfate reducing conditions. Groundw Monit Remediat 33(3):52–60Google Scholar
- Dedushenko SK, Perfilev YD, Tcheboukov DE, Pankratov DA, Kiselev YM (1999) A Mossbauer study of pentavalent iron in a vanadium(V) oxide matrix. Mendeleev Commun 5:171–172Google Scholar
- Filip J, Yngard RA, Siskova K, Marusak Z, Ettler V, Sajdl P, Sharma VK, Zboril R (2011) Mechanisms and efficiency of the simultaneous removal of metals and cyanides by using ferrate(VI): crucial roles of nanocrystalline iron(III) oxyhydroxides and metal carbonates. Chem Eur J 17(36):10097–10105CrossRefGoogle Scholar
- Knepper TP, Lange FT (2012) Polyfluorinated chemicals and transformation productsGoogle Scholar
- Luo Z, Strouse M, Jiang JQ, Sharma VK (2011) Methodologies for the analytical determination of ferrate(VI): a review. J Environ Sci Health, Part A Toxic/Hazard Subst Environ Eng 46(5):453–460Google Scholar
- Prucek R, Tuček J, Kolařík J, Filip J, Marušák Z, Sharma VK, Zbořil R (2013) Ferrate(VI)-induced arsenite and arsenate removal by in situ structural incorporation into magnetic iron(III) oxide nanoparticles. Environ Sci Technol 43(7):3283–3292Google Scholar
- Sharma VK, O’Connor DB, Cabelli DE (2001) Sequential one-electron reductions of Fe(V) to Fe(III) in alkaline solution. J Phys Chem B 105:11529–11532Google Scholar
- Sharma VK, Dutta PK, Ray AK (2007) Review of kinetics of chemical and photocatalytical oxidation of arsenic(III) as influenced by pH. J Environ Sci Health Part A Toxic/Hazard Subst Environ Eng 42(7):997–1004Google Scholar
- United Nations Educational, Scientific, and Cultural Organization (2003) Water for people, water for life—the United Nations World Water Development Report, Edition 1 World Water Assessment Programme (WWAP)Google Scholar