Plutonium oxidation state distribution in natural clay and goethite

Distribution of Pu(IV) and Pu(V) oxidation states at trace initial concentrations (10^?10–10^?11 mol L^?1) was studied in a liquid- and solid-phase of natural clay and goethite systems. Experiments showed an increase in the concentration of Pu(III) up to 11% at pH 5 in solids of the natural clay ?0.1 mol L^?1 NaNO₃ system containing Pu(IV) after 7-day contact. A kinetic sorption/reduction experiment with goethite suspensions (0.01 mol L^?1 NaNO₃ containing Pu(V)) indicated the presence of Pu(III) in the solids up to 15%.