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Title: U(VI) Reduction by Biogenic and Abiotic Hydroxycarbonate Green Rusts: Impacts on U(IV) Speciation and Stability Over Time

Green rusts (GRs) are redox active Fe II-Fe III minerals that form in the environment via various biotic and abiotic processes. Although both biogenic (BioGR) and abiotic (ChemGR) GRs have been shown to reduce U VI, the dynamics of the transformations and the speciation and stability of the resulting U IV phases are poorly understood. We used carbonate extraction and XAFS spectroscopy to investigate the products of U VI reduction by BioGR and ChemGR. The results show that both GRs can rapidly remove U VI from synthetic groundwater via reduction to U IV. The initial products in the ChemGR system are solids-associated U IV-carbonate complexes that gradually transform to nanocrystalline uraninite over time, leading to a decrease in the proportion of carbonate-extractable U from ~95% to ~10%. In contrast, solid-phase U IV atoms in the BioGR system remain relatively extractable, non-uraninite U IV species over the same reaction period. The presence of calcium and carbonate in groundwater significantly increase the extractability of U IV in the BioGR system. Furthermore, these data provide new insights into the transformations of U under anoxic conditions in groundwater that contains calcium and carbonate, and have major implications for predicting uranium stability within redox dynamicmore » environments and designing approaches for the remediation of uranium-contaminated groundwater.« less
Authors:
 [1] ; ORCiD logo [2] ;  [3] ;  [4] ; ORCiD logo [4]
  1. China Univ. of Geosciences, Wuhan (China); Argonne National Lab. (ANL), Argonne, IL (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States); Bulgarian Academy of Sciences, Sofia (Bulgaria)
  3. Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of Leeds, Leeds (United Kingdom)
  4. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Environmental Science and Technology
Additional Journal Information:
Journal Volume: 52; Journal Issue: 8; Journal ID: ISSN 0013-936X
Publisher:
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1437378

Yan, Sen, Boyanov, Maxim I., Mishra, Bhoopesh, Kemner, Kenneth M., and O'Loughlin, Edward J.. U(VI) Reduction by Biogenic and Abiotic Hydroxycarbonate Green Rusts: Impacts on U(IV) Speciation and Stability Over Time. United States: N. p., Web. doi:10.1021/acs.est.7b06405.
Yan, Sen, Boyanov, Maxim I., Mishra, Bhoopesh, Kemner, Kenneth M., & O'Loughlin, Edward J.. U(VI) Reduction by Biogenic and Abiotic Hydroxycarbonate Green Rusts: Impacts on U(IV) Speciation and Stability Over Time. United States. doi:10.1021/acs.est.7b06405.
Yan, Sen, Boyanov, Maxim I., Mishra, Bhoopesh, Kemner, Kenneth M., and O'Loughlin, Edward J.. 2018. "U(VI) Reduction by Biogenic and Abiotic Hydroxycarbonate Green Rusts: Impacts on U(IV) Speciation and Stability Over Time". United States. doi:10.1021/acs.est.7b06405.
@article{osti_1437378,
title = {U(VI) Reduction by Biogenic and Abiotic Hydroxycarbonate Green Rusts: Impacts on U(IV) Speciation and Stability Over Time},
author = {Yan, Sen and Boyanov, Maxim I. and Mishra, Bhoopesh and Kemner, Kenneth M. and O'Loughlin, Edward J.},
abstractNote = {Green rusts (GRs) are redox active FeII-FeIII minerals that form in the environment via various biotic and abiotic processes. Although both biogenic (BioGR) and abiotic (ChemGR) GRs have been shown to reduce UVI, the dynamics of the transformations and the speciation and stability of the resulting UIV phases are poorly understood. We used carbonate extraction and XAFS spectroscopy to investigate the products of UVI reduction by BioGR and ChemGR. The results show that both GRs can rapidly remove UVI from synthetic groundwater via reduction to UIV. The initial products in the ChemGR system are solids-associated UIV-carbonate complexes that gradually transform to nanocrystalline uraninite over time, leading to a decrease in the proportion of carbonate-extractable U from ~95% to ~10%. In contrast, solid-phase UIV atoms in the BioGR system remain relatively extractable, non-uraninite UIV species over the same reaction period. The presence of calcium and carbonate in groundwater significantly increase the extractability of UIV in the BioGR system. Furthermore, these data provide new insights into the transformations of U under anoxic conditions in groundwater that contains calcium and carbonate, and have major implications for predicting uranium stability within redox dynamic environments and designing approaches for the remediation of uranium-contaminated groundwater.},
doi = {10.1021/acs.est.7b06405},
journal = {Environmental Science and Technology},
number = 8,
volume = 52,
place = {United States},
year = {2018},
month = {4}
}