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Title: Aqueous Complexation Reactions Governing the Rate and Extent of Biogeochemical U(VI) Reduction

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN; Pacific Northwest National Laboratory (PNNL), Richland, WA; Argonne National Laboratory (ANL), Argonne, IL
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
894286
Report Number(s):
CONF-ERSP2006-11
Resource Type:
Conference
Resource Relation:
Conference: Annual Environmental Remediation Sciences Program PI Meeting, April 3-5, 2006, Warrenton, VA
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 54 ENVIRONMENTAL SCIENCES

Citation Formats

Brooks, Scott C., Dong, Wenming, Carroll, Sue, Fredrickson, James K., Kemner, Kenneth M., and Kelly, Shelly. Aqueous Complexation Reactions Governing the Rate and Extent of Biogeochemical U(VI) Reduction. United States: N. p., 2006. Web.
Brooks, Scott C., Dong, Wenming, Carroll, Sue, Fredrickson, James K., Kemner, Kenneth M., & Kelly, Shelly. Aqueous Complexation Reactions Governing the Rate and Extent of Biogeochemical U(VI) Reduction. United States.
Brooks, Scott C., Dong, Wenming, Carroll, Sue, Fredrickson, James K., Kemner, Kenneth M., and Kelly, Shelly. Wed . "Aqueous Complexation Reactions Governing the Rate and Extent of Biogeochemical U(VI) Reduction". United States. doi:. https://www.osti.gov/servlets/purl/894286.
@article{osti_894286,
title = {Aqueous Complexation Reactions Governing the Rate and Extent of Biogeochemical U(VI) Reduction},
author = {Brooks, Scott C. and Dong, Wenming and Carroll, Sue and Fredrickson, James K. and Kemner, Kenneth M. and Kelly, Shelly},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Apr 05 00:00:00 EDT 2006},
month = {Wed Apr 05 00:00:00 EDT 2006}
}

Conference:
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  • The proposed research will elucidate the principal biogeochemical reactions that govern the concentration, chemical speciation, and reactivity of the redox-sensitive contaminant uranium. The results will provide an improved understanding and predictive capability of the mechanisms that govern the biogeochemical reduction of uranium in subsurface environments. In addition, the work plan is designed to: (1) Generate fundamental scientific understanding on the relationship between U(VI) chemical speciation and its susceptibility to biogeochemical reduction reactions. ? Elucidate the controls on the rate and extent of contaminant reactivity. (2) Provide new insights into the aqueous and solid speciation of U(VI)/U(IV) under representative groundwater conditions.
  • The proposed research will elucidate the principal biogeochemical reactions that govern the concentration, chemical speciation, and reactivity of the redox-sensitive contaminant uranium. The results will provide an improved understanding and predictive capability of the mechanisms that govern the biogeochemical reduction of uranium in subsurface environments. In addition, the work plan is designed to: (1) Generate fundamental scientific understanding on the relationship between U(VI) chemical speciation and its susceptibility to biogeochemical reduction reactions. (2) Elucidate the controls on the rate and extent of contaminant reactivity. (3) Provide new insights into the aqueous and solid speciation of U(VI)/U(IV) under representative groundwater conditions.
  • The proposed research will elucidate the principal biogeochemical reactions that govern the concentration, chemical speciation, and reactivity of the redox-sensitive contaminant uranium. The results will provide an improved understanding and predictive capability of the mechanisms that govern the biogeochemical reduction of uranium in subsurface environments.
  • In-situ reductive biotransformation of subsurface U(VI) to U(IV) (as ?UO2?) has been proposed as a bioremediation method to immobilize uranium at contaminated DOE sites. The chemical stability of bacteriogenic ?UO2? is the seminal issue governing its success as an in-situ waste form in the subsurface. The structure and properties of chemically synthesized UO2+x have been investigated in great detail. It has been found to exhibit complex structural disorder, with nonstoichiometry being common, hence the designation ?UO2+x?, where 0 < x < 0.25. Little is known about the structures and properties of the important bacteriogenic analogs, which are believed to occurmore » as nanoparticles in the environment. Chemically synthesized UO2+x exhibits an open fluorite structure and is known to accommodate significant doping of divalent cations. The extent to which bacteriogenic UO2+x incorporates common ground water cations (e.g., Ca2+) has not been investigated, and little is known about nonstoichiometry and structure defects in the bacteriogenic material. Particle size, nonstoichiometry, and doping may significantly alter the reactivity, and hence stability, of bacteriogenic UO2+x in the subsurface. The presence of associated sulfide minerals, and solid phase oxidants such as bacteriogenic Mn oxides may also affect the longevity of bacteriogenic UO2 in the subsurface.« less