Conceptual and numerical model of uranium(VI) reductive immobilization in fractured subsurface sediments

Geomicrobiological factors that control uranium mobility in the environment: Update on recent advances in the bioremediation of uranium-contaminated sites

“…This is a critical first step in identifying key factors that control the rate and extent of the redox reactions of radionuclides under conditions relevant to subsurface settings where nuclear waste will potentially be disposed of. In terms of the next step, a conceptual and numerical model must be developed to accommodate those geomicrobiological and hydrological parameters that have a strong influence on the transport and fate of radionuclides in subsurface settings (Roden and Scheibe, 2005).…”

Iron Reduction and Radionuclide Immobilization: Kinetic, Thermodynamic and Hydrologic controls & Reaction-Based Modeling - Final Report

“…We have obtained kinetic parameters for reduction of soluble U(VI)-carbonate complexes by G. sulfurreducens and S. putrefaciens (Roden and Scheibe, 2003;. We examined the potential for bioreduction of U(VI) by Geobacter sulfurreducens in the presence of synthetic Fe(III) oxides and natural Fe(III) oxide-containing solids (Jeon et al, 2004a, b) in which more than 95% of added U(VI) was sorbed to mineral surfaces.…”

“…We have demonstrated the use of a reaction-based reactive transport model (HYDROGEOCHEM) for the simulation of biological iron reduction in natural sediment columns (Burgos and Yeh, unpublished results). Finally, we have developed a preliminary reaction-based model of coupled Fe(III) oxide/U(VI) reduction that has been employed in numerical simulations of U(VI) bioreduction in bench-scale (Roden, 2003d) and field-scale (Roden and Scheibe, 2003;Roden, 2003c) systems. This progress gives us confidence that these models can be successfully applied to field conditions that required large reaction networks and physical heterogeneity.…”

Basic Research Needs for Geosciences: Facilitating 21st Century Energy Systems

“…The fate and transport of radionuclides and metals (Charlet and Polya 2006;Kretschmar and Schaefer 2005;Lloyd and Oremland 2006;Roden and Scheibe 2005;Steefel et al 2005), the corrosion of nuclear waste forms and packages (Bruno and Ewing 2006;Burns and Klingensmith 2006;Ewing 2006;Grambow 2006), the performance of engineered barrier systems, the storage of CO 2 in deep aquifers (Bachu et al 1994;Bruant et al 2002;Elliott et al 2001;Gaus et al 2005;Gunter et al 1993;Johnson et al 2004;Rochelle et al 2004), and the global elemental and nutrient cycles (Berner 1995;Berner et al 1983;Van Cappellen and Gaillard 1996) are all influenced by biogeochemical processes. In many cases, the rates of these processes are directly mediated by microbial activity.…”