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Title: Trace Uranium Partitioning in a Multiphase Nano-FeOOH System

Abstract

The characterization of trace elements in minerals using extended X-ray absorption fine structure (EXAFS) spectroscopy constitutes a first step toward understanding how impurities and contaminants interact with the host phase and the environment. However, limitations to EXAFS interpretation complicate the analysis of trace concentrations of impurities that are distributed across multiple phases in a heterogeneous system. Ab initio molecular dynamics (AIMD)-informed EXAFS analysis was employed to investigate the immobilization of trace uranium associated with nanophase iron (oxyhydr)oxides, a model system for the geochemical sequestration of radiotoxic actinides. The reductive transformation of ferrihydrite [Fe(OH)3] to nanoparticulate iron oxyhydroxide minerals in the presence of uranyl (UO 2) 2+(aq) resulted in the preferential incorporation of U into goethite (α-FeOOH) over lepidocrocite (γ-FeOOH), even though reaction conditions favored the formation of excess lepidocrocite. This unexpected result is supported by atomically resolved transmission electron microscopy. We demonstrate how AIMD-informed EXAFS analysis lifts the strict statistical limitations and uncertainty of traditional shell-by-shell EXAFS fitting, enabling the detailed characterization of the local bonding environment, charge compensation mechanisms, and oxidation states of polyvalent impurities in complex multiphase mineral systems.

Authors:
ORCiD logo; ; ORCiD logo; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1355047
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science and Technology; Journal Volume: 51; Journal Issue: 9
Country of Publication:
United States
Language:
ENGLISH
Subject:
54 ENVIRONMENTAL SCIENCES

Citation Formats

McBriarty, Martin E., Soltis, Jennifer A., Kerisit, Sebastien, Qafoku, Odeta, Bowden, Mark E., Bylaska, Eric J., De Yoreo, James J., and Ilton, Eugene S.. Trace Uranium Partitioning in a Multiphase Nano-FeOOH System. United States: N. p., 2017. Web. doi:10.1021/acs.est.7b00432.
McBriarty, Martin E., Soltis, Jennifer A., Kerisit, Sebastien, Qafoku, Odeta, Bowden, Mark E., Bylaska, Eric J., De Yoreo, James J., & Ilton, Eugene S.. Trace Uranium Partitioning in a Multiphase Nano-FeOOH System. United States. doi:10.1021/acs.est.7b00432.
McBriarty, Martin E., Soltis, Jennifer A., Kerisit, Sebastien, Qafoku, Odeta, Bowden, Mark E., Bylaska, Eric J., De Yoreo, James J., and Ilton, Eugene S.. Tue . "Trace Uranium Partitioning in a Multiphase Nano-FeOOH System". United States. doi:10.1021/acs.est.7b00432.
@article{osti_1355047,
title = {Trace Uranium Partitioning in a Multiphase Nano-FeOOH System},
author = {McBriarty, Martin E. and Soltis, Jennifer A. and Kerisit, Sebastien and Qafoku, Odeta and Bowden, Mark E. and Bylaska, Eric J. and De Yoreo, James J. and Ilton, Eugene S.},
abstractNote = {The characterization of trace elements in minerals using extended X-ray absorption fine structure (EXAFS) spectroscopy constitutes a first step toward understanding how impurities and contaminants interact with the host phase and the environment. However, limitations to EXAFS interpretation complicate the analysis of trace concentrations of impurities that are distributed across multiple phases in a heterogeneous system. Ab initio molecular dynamics (AIMD)-informed EXAFS analysis was employed to investigate the immobilization of trace uranium associated with nanophase iron (oxyhydr)oxides, a model system for the geochemical sequestration of radiotoxic actinides. The reductive transformation of ferrihydrite [Fe(OH)3] to nanoparticulate iron oxyhydroxide minerals in the presence of uranyl (UO2)2+(aq) resulted in the preferential incorporation of U into goethite (α-FeOOH) over lepidocrocite (γ-FeOOH), even though reaction conditions favored the formation of excess lepidocrocite. This unexpected result is supported by atomically resolved transmission electron microscopy. We demonstrate how AIMD-informed EXAFS analysis lifts the strict statistical limitations and uncertainty of traditional shell-by-shell EXAFS fitting, enabling the detailed characterization of the local bonding environment, charge compensation mechanisms, and oxidation states of polyvalent impurities in complex multiphase mineral systems.},
doi = {10.1021/acs.est.7b00432},
journal = {Environmental Science and Technology},
number = 9,
volume = 51,
place = {United States},
year = {Tue Apr 11 00:00:00 EDT 2017},
month = {Tue Apr 11 00:00:00 EDT 2017}
}