Removal of persistent organic contaminants by electrochemically activated sulfate
Article
Article Title | Removal of persistent organic contaminants by electrochemically activated sulfate |
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ERA Journal ID | 4674 |
Article Category | Article |
Authors | Farhat, Ali (Author), Keller, Jurg (Author), Tait, Stephan (Author) and Radjenovic, Jelena (Author) |
Journal Title | Environmental Science and Technology |
Journal Citation | 49 (24), pp. 14326-14333 |
Number of Pages | 8 |
Year | 2015 |
Publisher | American Chemical Society |
Place of Publication | Washington, United States |
ISSN | 0013-936X |
1520-5851 | |
Digital Object Identifier (DOI) | https://doi.org/10.1021/acs.est.5b02705 |
Web Address (URL) | https://pubs.acs.org/doi/pdf/10.1021/acs.est.5b02705 |
Abstract | Solutions of sulfate have often been used as background electrolytes in the electrochemical degradation of contaminants and have been generally considered inert even when high-oxidation-power anodes such as boron-doped diamond (BDD) were employed. This study examines the role of sulfate by comparing electro-oxidation rates for seven persistent organic contaminants at BDD anodes in sulfate and inert nitrate anolytes. Sulfate yielded electro-oxidation rates 10–15 times higher for all target contaminants compared to the rates of nitrate anolyte. This electrochemical activation of sulfate was also observed at concentrations as low as 1.6 mM, which is relevant for many wastewaters. Electrolysis of diatrizoate in the presence of specific radical quenchers (tert-butanol and methanol) had a similar effect on electro-oxidation rates, illustrating a possible role of the hydroxyl radical (•OH) in the anodic formation of sulfate radical (SO4•–) species. The addition of 0.55 mM persulfate increased the electro-oxidation rate of diatrizoate in nitrate from 0.94 to 9.97 h–1, suggesting a nonradical activation of persulfate. Overall findings indicate the formation of strong sulfate-derived oxidant species at BDD anodes when polarized at high potentials. This may have positive implications in the electro-oxidation of wastewaters containing sulfate. For example, the energy required for the 10-fold removal of diatrizoate was decreased from 45.6 to 2.44 kWh m–3 by switching from nitrate to sulfate anolyte. |
Keywords | activated sulfate, electro-oxidation |
ANZSRC Field of Research 2020 | 401102. Environmentally sustainable engineering |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions |
Byline Affiliations | University of Queensland |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q52v1/removal-of-persistent-organic-contaminants-by-electrochemically-activated-sulfate
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