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

Abstract

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.

Impact of Natural Organic Matter on Plutonium Vadose Zone Migration from an NH4Pu(V)O2CO3(s) Source

“…Pu(V) Working Solution Preparation. A Pu(V) stock solution was prepared by ozonation according to the method used by Conroy et al 44 Briefly, an appropriate amount of 2.0 × 10 −3 M 242 Pu(IV) solution in 0.01 M HCl or 2.2 × 10 −9 M 238 Pu(IV) solution in 0.01 M HCl was pipetted into a flat-bottomed, round flask containing 75 mL of deionized water to obtain a total activity of 700 dpm/mL. The initial pH was adjusted between 3 and 4.…”

“…A Pu(V) stock solution was prepared by ozonation according to the method used by Conroy et al 44 . Briefly, the appropriate amount of a 2.0×10 Pu(III) and Pu(IV), leaving Pu(V) and Pu(VI) in the aqueous phase.…”

Membranes for the Capture and Screening of Waterborne Plutonium Based on a Novel Pu-Extractive Copolymer Additive

“…Table S2 in Supplementary Materials provides the composition of the solution. Pu oxidation states of the 238 Pu dilutions were determined through a solvent extraction method outlined by Powell et al [15].…”

Functionalized Polymer Thin Films for Plutonium Capture and Isotopic Screening from Aqueous Sources

“…To attain this objective, we prepared submicron thin polymer–ligand films that varied in thickness and evaluated them for extraction of plutonium from solutions at pH 2.3 and 6.3. For pH 6.3 the oxidation state of plutonium was adjusted to 90 ± 5% Pu­(V) using a method developed by Conroy et al Three extractive ligands were chosen based on their ability to bind to actinides from solution: thenoyltrifluoroacetone, dibenzoylmethane, and di­(2-ethylhexyl) phosphoric acid. − Distribution of the ligand within the polymer films was investigated using angle-resolved X-ray photoelectron spectroscopy (AR-XPS) to examine whether the ligand was evenly dispersed throughout the thickness of the film, or if concentration gradients formed within the films. Analysis of alpha spectroscopy pulse height spectra revealed the effects of film thickness on peak energy resolution.…”

“…The pH of the solution was adjusted to a value between 3.5 and 4.5 by adding dropwise additions of 0.1 and 0.01 M NaOH solutions. Following pH adjustment, the solution was placed in a gas scrubber and treated with O 3 gas over the course of 3 d. Periodically, the oxidation state of the solution was measured using a solvent extraction method 19 until the solution was greater than 90% Pu(V). These measurements were taken over the course of the batch uptake experiments to ensure that the Pu(V) content stayed within the range of 90 ± 5%.…”