Understanding the stability of plutonium (Pu) adsorbed to mineral surfaces is key to understanding the environmental tranport of Pu. Previously, hydrogen peroxide (H2O2) has been shown to alter the redox state of arsenic adsorbed to mineral surfaces, thus affecting its sorption behavior. Here we demonstrate that environmental concentrations of H2O2 can affect the stability of Pu adsorbed to goethite, montmorillonite and quartz across a wide range of pH values. In batch experiments where Pu(IV) was adsorbed to goethite for 21 days at pH 4, 6, and 8, the addition of 5 � 500 �M H2O2 resulted in significant Pu desorption. At pH 6 and 8 this desorption was transient, with re-adsorption of the Pu to goethite within 30 days. At pH 4, no Pu re-adsorption was observed. Experiments with both quartz and montmorillonite at 5 �M H2O2 desorbed far less Pu than the goethite experiments, highlighting the contribution of Fe redox couples in controlling Pu desorption at low H2O2 concentrations. Plutonium(IV) adsorbed to quartz, and subsequently spiked with 500 �M H2O2 also resulted in significant desorption of Pu, demonstrating the complexity of the desorption process. Our results provide the first evidence of H2O2 catalyzed desorption of Pu(IV) from mineral surfaces. We suggest this reaction pathway coupled with environmental levels of hydrogen peroxide may contribute to Pu mobility in the environment.This work was funded by U. S. DOE Office of Biological & Environmental Sciences, Subsurface Biogeochemistry 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.

H<sub>2</sub>O<sub>2</sub> catalyzed desorption of plutonium from mineral surfaces

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

H2O2 catalyzed desorption of plutonium from mineral surfaces

H₂O₂ catalyzed desorption of plutonium from mineral surfaces