University of Illinois Urbana-Champaign

The effects of bicarbonate and mineral surfaces on uranium immobilization under anaerobic conditions

Jurado, Luis A.

Content Files
Jurado_Luis.pdf

Permalink

https://hdl.handle.net/2142/26036

Description

Title
The effects of bicarbonate and mineral surfaces on uranium immobilization under anaerobic conditions
Author(s)
Jurado, Luis A.
Issue Date
2011-08-25T22:10:05Z
Director of Research (if dissertation) or Advisor (if thesis)
Werth, Charles J.
Department of Study
Civil & Environmental Eng
Discipline
Environ Engr in Civil Engr
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Date of Ingest
2011-08-25T22:10:05Z
Keyword(s)
  • uranium
  • remediation
  • uranium biogeochemistry
  • uranium remediation
Abstract
For four decades, from 1940 through 1980, the U.S. Department of Energy (DoE) extensively mined and processed uranium at various sites. As a result, widespread uranium contamination exists in subsurface sediments and aquifers. In subsurface environments, uranium primarily exists as U(VI) or U(IV), oxidized and reduced species, respectively. U(VI) is highly soluble and toxic, U(IV), while relatively toxic, is insoluble which greatly reduces its exposure pathways. We seek to examine the role of ferric iron on U(VI) reduction by adsorbing U(VI) onto ferric and non-ferric mineral surfaces in the presence of a reductant. Further, we seek to understand the role that NaHCO3, a natural groundwater buffer, has in the reductive geochemical transformations of U(VI) adsorbed on ferric and non-ferric mineral surfaces. Bench top studies were performed using 100 uM U(VI) and the reductant AHQDS, in the presence and absence of Fe-Gel (amorphous ferric oxyhydroxide) and gamma-Al2O3. In the presence of a HEPES buffer at pH 8, results demonstrate direct homogeneous reduction in several hours in the absence of Fe-Gel or gamma-Al2O3, and reduction within a 48-hour period in the presence Fe-Gel or gamma-Al2O3. While adsorbed to both ferric and non-ferric mineral surfaces, U(VI) reduction is inhibited. U(VI) reduction in the presence of NaHCO3 buffer also inhibits U(VI) reduction.
Graduation Semester
2011-08
Permalink
http://hdl.handle.net/2142/26036
Copyright and License Information
Copyright 2011 Luis A. Jurado

Owning Collections

Graduate Dissertations and Theses at Illinois PRIMARY
Graduate Theses and Dissertations at Illinois
Dissertations and Theses - Civil and Environmental Engineering