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Towards Use of Persulfate Electrogenerated at Boron Doped Diamond Electrodes as Ex-Situ Oxidation Approach - Storage and Service-Life Solution Parameters

MetadataDetails
Publication Date2022-03-01
JournalJournal of The Electrochemical Society
AuthorsKarla Caroline de Freitas Araújo, Karyn Nathallye de Oliveira Silva, Mayra Kerolly Sales Monteiro, Djalma Ribeiro da Silva, Marco A. Quiróz
InstitutionsUniversidade Federal do Rio Grande do Norte, Johannes Gutenberg University Mainz
Citations16

To date, a wide range of synthetic and real effluents have been treated using in situ electrochemically driven BDD-SO 4 2− /SO 4 ·− /S 2 O 8 2− systems to eliminate persistent organic pollutants and microorganisms. Although reactive sulfate-based species are electrochemically generated in situ with free heterogenous · OH radicals, SO 4 2− /SO 4 ·− /S 2 O 8 2− species have a half-life greater than that of the · OH radicals. However, no information has been published regarding the properties of the oxidant solution after its electrochemical synthesis. Here, an electrochemical BDD-SO 4 2− /SO 4 ·− /S 2 O 8 2− system was evaluated in terms of solution oxidation power as a function of storage temperature, storage time, and ex situ applicability. Results clearly show that storage temperature has an influence on the storage and service-life of the solutions called fresh -persulfate (25 °C) or cold -persulfate (10 °C). Greater stability in the cold -persulfate solution was observed, as a function of time, and it was effective in degrading organic pollutants as an ex situ oxidation approach, eliminating 80.73%, 79.25%, and 63.25% after 120 min for methyl orange dye, 1,4-benzoquinone (1,4-BQ), and caffeine, respectively. Cold -persulfate solution also proved to be a feasible off-grid technology after 14 days storage. These results contribute to understanding of the fundamentals of sulfate aqueous solutions as precursors of sulfate-based oxidizing solutions and their applications.