A Novel Method for Tracer Concentration Plutonium(V) Solution Preparation

Preparation of relatively pure low concentration Pu(V) solutions for environmental studies is nontrivial due to the complex redox chemistry of Pu. Ozone gas generated by an inexpensive unit designed for household-use was used to oxidize a 2 × 10(-8) M Pu(IV) solution to predominantly Pu(VI) with some Pu(V) present. Over several days, the Pu(VI) in the solution reduced to Pu(V) without further reducing to Pu(IV). The reduction from Pu(VI) to Pu(V) could be accelerated by raising the pH of the solution, which led to an immediate conversion without substantial conversion to Pu(IV). The aqueous Pu was found to be stable as predominately Pu(V) for greater than one month from pH 3-7; however, at circumneutral pH, a sizable fraction of Pu was lost from solution by either precipitation or sorption to the vial walls. This method provides a fast means of preparing Pu(V) solutions for tracer concentration studies without numerous extraction or cleanup steps.