Actions for Uranium(IV) adsorption by natural organic matter in anoxic sediments [electronic resource].

Email RIS file
Bookmark
Report an Issue

Uranium(IV) adsorption by natural organic matter in anoxic sediments [electronic resource].

Published
Washington, D.C. : United States. Dept. of Energy, 2017.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
Physical Description
pages 711-716 : digital, PDF file
Additional Creators
Pacific Northwest National Laboratory (U.S.), United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
Access Online

Availability

I Want It
I Want It

Finding items...

Restrictions on Access
Free-to-read Unrestricted online access
Summary
Uranium is an important fuel source and a global environmental contaminant. It accumulates in the tetravalent state, U(IV), in anoxic sediments, including ore deposits, marine basins, and contaminated aquifers. However, very little is known about the speciation of U(IV) in low temperature geochemical environments, inhibiting the development of a conceptual model of U behavior. Until recently, U(IV) was assumed to exist predominantly as the sparingly soluble mineral uraninite (UO2) in anoxic sediments; yet studies now show that UO2 is not often dominant in these environments. However, a model of U(IV) speciation under environmentally relevant conditions has not yet been developed. Here we show that complexes of U(IV) adsorb on organic carbon and organic carbon-coated clays in an organic-rich natural substrate under field-relevant conditions. Whereas previous research assumed that the U(IV) product depended on the reduction pathway, our results demonstrate that UO2 formation can be inhibited simply by decreasing the U:solid ratio. Thus, it is the number and type of surface ligands that controls U(IV) speciation subsequent to U(VI) reduction. Projections of U transport and bioavailability, and thus its threat to human and ecosystem health, must consider retention of U(IV) ions within the local sediment environment.
Report Numbers
E 1.99:pnnl-sa--119314
pnnl-sa--119314
Subject(s)
Other Subject(s)
Note
Published through SciTech Connect.
01/09/2017.
"pnnl-sa--119314"
"48570"
"KP1704020"
Proceedings of the National Academy of Sciences of the United States of America 114 4 ISSN 0027-8424 AM
Bone, Sharon; Dynes, James; Cliff, John; Bargar, John.
Funding Information
AC05-76RL01830
View MARC record | catkey: 24044038