A major challenge in predicting the mobility and transport of plutonium (Pu) is determining the dominant geochemical processes that control its behavior in the subsurface. An improved understanding of coupled processes, from the mineral surface to the field scale, under relevant environmental conditions is essential for significant breakthroughs in Pu transport conceptual model. However, systematic studies under relevant environmental conditions are lacking.<br/><br/>In this presentation, we show integrated results of isotherms of Pu(IV) and Pu(V) on goethite over a ten order of magnitude concentration range and goethite surface characterization. Techniques used include accelerator mass spectrometry (AMS) and NuPlasma HR MC-ICP-MS for ultra-low level Pu analysis; TEM and NanoSIMS for characterizing Pu nano-particles’ morphology, crystal structures and distribution on goethite. Although the ultimate isotherms for Pu(IV) and Pu(V) solutions /goethite systems converge, distinctly different sorption kinetics and morphology of Pu nano-particles on goethite reveal sorption mechanisms.<br/><br/>This work was funded by Office of Science, Biological & Environmental Research Program, and performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Security, LLC under Contract DE-AC52-07NA27344.

Plutonium sorption to goethite at sub-femtomolar to micromolar concentrations: Redox transformations and surface precipitation

251st National Meeting (2016)

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