DIFFERENTIAL REDOX AND SORPTION OF CR(III/VI) ON NATURAL SILICATE AND OXIDE MINERALS: EXAFS AND XANES RESULTS
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dc.contributor.author | Peterson M.L. | |
dc.contributor.author | Brown G.E. | |
dc.contributor.author | Parks G.A. | |
dc.contributor.author | Stein C.L. | |
dc.date.accessioned | 2020-12-16T02:21:33Z | |
dc.date.available | 2020-12-16T02:21:33Z | |
dc.date.issued | 1997 | |
dc.identifier | https://elibrary.ru/item.asp?id=273737 | |
dc.identifier.citation | Geochimica et Cosmochimica Acta, 1997, , 16, 3399-3412 | |
dc.identifier.issn | 0016-7037 | |
dc.identifier.uri | https://repository.geologyscience.ru/handle/123456789/20873 | |
dc.description.abstract | Synchrotron-based X-ray absorption fine structure (XAFS) spectroscopy was used to investigate the reduction of aqueous Cr(VI) to Cr(III) in magnetite-bearing soils from Cr-contaminated sites. Soils from two field sites were examined, showing that mixed-valence Cr(III/VI) effluent is reduced to Cr(III) when associated with the magnetite fraction of the soil, whereas the Cr effluent associated with non-Fe(II)-bearing minerals results in mixed Cr(III/VI) adsorbates or precipitated phases. The Fe2+ in magnetite, Fe2+Fe3+2O4, may act as an electron source for heterogeneous Cr(VI)-to-Cr(III) reduction, converting magnetite topotactically to maghemite, γ-Fe3+2O3. The ratio of Cr(VI)/total Cr was determined by the height of the Cr(VI) XAFS pre-edge feature, which is due to a 1s to 3d electronic transition. This pre-edge feature was calibrated as a function of Cr(VI)/Cr(III) using mixtures of Cr(III) and Cr(VI) model compounds. Environmental remediation of Cr-contaminated sites requires knowledge of chromium oxidation and speciation, and XAFS spectroscopy may be used to supply both types of information with minimal sample processing or data analysis. | |
dc.title | DIFFERENTIAL REDOX AND SORPTION OF CR(III/VI) ON NATURAL SILICATE AND OXIDE MINERALS: EXAFS AND XANES RESULTS | |
dc.type | Статья |
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