Crean, D.E., Stennett, M.C. orcid.org/0000-0002-8363-9103, Livens, F.R. et al. (3 more authors) (2020) Multimodal x-ray microanalysis of a UFeO4 : evidence for the environmental stability of ternary U(v) oxides from depleted uranium munitions testing. Environmental Science: Processes & Impacts, 22 (7). pp. 1577-1585. ISSN 2050-7887
Abstract
An environmentally aged radioactive particle of UFeO4 recovered from soil contaminated with munitions depleted uranium (DU) was characterised by microbeam synchrotron X-ray analysis. Imaging of uranium speciation by spatially resolved X-ray diffraction (μ-XRD) and X-ray absorption spectroscopy (μ-XAS) was used to localise UFeO4 in the particle, which was coincident with a distribution of U(V). The U oxidation state was confirmed using X-ray Absorption Near Edge Structure (μ-XANES) spectroscopy as +4.9 ± 0.15. Le-Bail fitting of the particle powder XRD pattern confirmed the presence of UFeO4 and a minor alteration product identified as chernikovite (H3O)(UO2)(PO4)·3H2O. Refined unit cell parameters for UFeO4 were in good agreement with previously published values. Uranium–oxygen interatomic distances in the first co-ordination sphere were determined by fitting of Extended X-ray Absorption Fine Structure (μ-EXAFS) spectroscopy. The average first shell U–O distance was 2.148 ± 0.012 Å, corresponding to a U valence of +4.96 ± 0.13 using bond valence sum analysis. Using bond distances from the published structure of UFeO4, U and Fe bond valence sums were calculated as +5.00 and +2.83 respectively, supporting the spectroscopic analysis and confirming the presence of a U(V)/Fe(III) pair. Overall this investigation provides important evidence for the stability of U(V) ternary oxides, in oxic, variably moist surface environment conditions for at least 25 years.
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Copyright, Publisher and Additional Information: | © 2020 The Royal Society of Chemistry. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (http://creativecommons.org/licenses/by/3.0/). | ||||
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Institution: | The University of Sheffield | ||||
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) | ||||
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Depositing User: | Symplectic Sheffield | ||||
Date Deposited: | 06 Aug 2020 12:19 | ||||
Last Modified: | 06 Oct 2020 12:53 | ||||
Status: | Published | ||||
Publisher: | Royal Society of Chemistry (RSC) | ||||
Refereed: | Yes | ||||
Identification Number: | https://doi.org/10.1039/d0em00243g | ||||
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