Structure of Biogenic Uraninite Produced by Shewanella oneidensis Strain MR-1

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• 作者：Eleanor J. Schofield ; Harish Veeramani ; Jonathan O. Sharp ; Elena Suvorova ; Rizlan Bernier-Latmani ; Apurva Mehta ; Jonathan Stahlman ; Samuel M. Webb ; David L. Clark ; Steven D. Conradson ; Eugene S. Ilton
• 刊名：Environmental Science & Technology
• 出版年：2008
• 出版时间：November 1, 2008
• 年：2008
• 卷：42
• 期：21
• 页码：7898-7904
• 全文大小：273K
• 年卷期：v.42,no.21(November 1, 2008)
• ISSN：1520-5851

文摘

The stability of biogenic uraninite with respect to oxidation is seminal to the success of in situ bioreduction strategies for remediation of subsurface U(VI) contamination. The properties and hence stability of uraninite are dependent on its size, structure, and composition. In this study, the local-, intermediate-, and long-range molecular-scale structure of nanoscale uraninite produced by Shewanella oneidensis strain MR-1 was investigated using EXAFS, SR-based powder diffraction and TEM. The uraninite products were found to be structurally homologous with stoichiometric UO₂ under all conditions considered. Significantly, there was no evidence for lattice strain of the biogenic uraninite nanoparticles. The fresh nanoparticles were found to exhibit a well-ordered interior core of diameter ca. 1.3 nm and an outer region of thickness ca ∼0.6 nm in which the structure is locally distorted. The lack of nanoparticle strain and structural homology with stoichiometric UO₂ suggests that established thermodynamic parameters for the latter material are an appropriate starting point to model the behavior of nanobiogenic uraninite. The detailed structural analysis in this study provides an essential foundation for subsequent investigations of environmental samples.