- Title
- Reduced uranium phases produced from anaerobic reaction with nanoscale zerovalent iron
- Creator
- Tsarev, Sergey; Collins, Richard N.; Fahy, Adam; Waite, T. David
- Relation
- Environmental Science & Technology Vol. 50, Issue 5, p. 2595-2601
- Publisher Link
- http://dx.doi.org/10.1021/acs.est.5b06160
- Publisher
- American Chemical Society
- Resource Type
- journal article
- Date
- 2016
- Description
- Nanoscale zerovalent iron (nZVI) has shown potential to be an effective remediation agent for uranium-contaminated subsurface environments, however, the nature of the reaction products and their formation kinetics have not been fully elucidated over a range of environmentally relevant conditions. In this study, the oxygen-free reaction of U(VI) with varying quantities of nZVI was examined at pH 7 in the presence of both calcium and carbonate using a combination of X-ray absorption spectroscopy, X-ray diffraction and transmission electron microscopy. It was observed that the structure of the reduced U solid phases was time dependent and largely influenced by the ratio of nZVI to U in the system. At the highest U:Fe molar ratio examined (1:4), nanoscale uraninite (UO₂) was predominantly formed within 1 day of reaction. At lower U:Fe molar ratios (1:21), evidence was obtained for the formation of sorbed U(IV) and U(V) surface complexes which slowly transformed to UO₂ nanoparticles that were stable for up to 1 year of anaerobic incubation. After 8 days of reaction at the lowest U:Fe molar ratio examined (1:110), sorbed U(IV) was still the major form of U associated with the solid phase. Regardless of the U:Fe molar ratio, the anaerobic corrosion of nZVI resulted in the slow formation of micron-sized fibrous chukanovite (Fe₂(OH)₂CO₃) particles.
- Subject
- Nanoscale zerovalent iron (nZVI); X-ray absorption spectroscopy; nanoscale uraninite (UO₂); uranium
- Identifier
- http://hdl.handle.net/1959.13/1325223
- Identifier
- uon:25215
- Identifier
- ISSN:0013-936X
- Language
- eng
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