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Biological Reduction of a U(V)-Organic Ligand Complex

Molinas, Margaux; Faizova, Radmila; Brown, Ashley; Galanzew, Jurij; Schacherl, Bianca; Bartova, Barbora; Meibom, Karin L.; Vitova, Tonya; Mazzanti, Marinella; Bernier-Latmani, Rizlan

Abstract:
Metal-reducing microorganisms such as Shewanella oneidensis MR-1 reduce highly soluble species of hexavalent uranyl (U(VI)) to less mobile tetravalent uranium (U(IV)) compounds. The biologically mediated immobilization of U(VI) is being considered for the remediation of U contamination. However, the mechanistic underpinnings of biological U(VI) reduction remain unresolved. It has become clear that a first electron transfer occurs to form pentavalent (U(V)) intermediates, but it has not been definitively established whether a second one-electron transfer can occur or if disproportionation of U(V) is required. Here, we utilize the unusual properties of dpaea2– ((dpaeaH2═bis(pyridyl-6-methyl-2-carboxylate)-ethylamine)), a ligand forming a stable soluble aqueous complex with U(V), and investigate the reduction of U(VI)–dpaea and U(V)–dpaea by S. oneidensis MR-1. We establish U speciation through time by separating U(VI) from U(IV) by ion exchange chromatography and characterize the reaction end-products using U M4-edge high resolution X-ray absorption near-edge structure (HR-XANES) spectroscopy. We document the reduction of solid phase U(VI)–dpaea to aqueous U(V)–dpaea but, most importantly, demonstrate that of U(V)–dpaea to U(IV). ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000131425
Veröffentlicht am 16.04.2021
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Nukleare Entsorgung (INE)
Publikationstyp Zeitschriftenaufsatz
Publikationsdatum 20.04.2021
Sprache Englisch
Identifikator ISSN: 0013-936X, 1520-5851
KITopen-ID: 1000131425
HGF-Programm 32.11.01 (POF IV, LK 01) Nuclear Waste Disposal
Weitere HGF-Programme 54.11.11 (POF IV, LK 01) Accelerator Operation, Research and Development
Erschienen in Environmental Science and Technology
Verlag American Chemical Society (ACS)
Band 55
Heft 8
Seiten 4753–4761
Vorab online veröffentlicht am 11.03.2021
Nachgewiesen in Scopus
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