Influence of manganese dioxide on the oxidation states of plutonium

When manganese dioxide impregnated filters have been used to concentrate plutonium from water solutions some anomalies were detected, which were ascribed to the probable existence of plutonium in two different oxidation states. The results of this paper seem to confirm this assumption that the Pu in the solution is a mixture of Pu(III) and Pu(IV). After contact with MnO₂, plutonium in the solution consists of only Pu(IV).