Heterogeneous reduction of 239PuO2 by aqueous Fe(II) in the presence of hematite
-
A. R. Felmy
,
D. A. Moore
Abstract
The reduction of PuO2(am) by Fe(II) in the presence and absence of hematite was studied over a range of pH values and oxidation/reduction potentials. In contrast to thermodynamic predictions, the presence of hematite did not have a major effect on the overall reduction of PuO2(am) to aqueous Pu(III). Instead the aqueous Pu(III) concentrations at longer time frames were accurately predicted using the measured Fe(II) concentration and existing thermodynamic data for the reaction: H2O + H++ Fe2++ PuO2(am) ⇌ Pu3++ Fe(OH)3(am) with log K =− 0.6. The accuracy of this approach in all solutions containing aqueous Fe(II), coupled with the apparent lack of oxidation of Fe(II) by O2(g), suggests that the Fe(OH)3(am) is formed by the oxidation of Fe(II) to Fe(III) by radiolysis. The continued generation of reactive amorphous iron hydroxide by radiolysis prevents thermodynamic equilibrium from being reached with more stable ferric oxide compounds, except possibly under acidic conditions where amorphous ferric hydroxide is soluble. The use of measured pe values, instead of aqueous Fe(II) measurements, also yields reasonable predictions of the final Pu(III) concentrations although the predictions are more uncertain.
© 2013 by Walter de Gruyter Berlin Boston
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Articles in the same Issue
- Masthead
- Masthead
- MicroSISAK: continuous liquid–liquid extractions of radionuclides at 0.2 mL/min
- Crystal structure and spectral properties of complexes of tetravalent Th, U, Np and Pu nitrates with trimethyl phosphate and dimethyl phosphate
- Heterogeneous reduction of 239PuO2 by aqueous Fe(II) in the presence of hematite
- New alkyl-pyridinedicarboxyamides as extractants for separationof trivalent minor actinides from fission products by extraction chromatography
- Liquid–liquid extraction of Np4+ and Pu4+ using several tetra-alkyl substituted diglycolamides
- Ion-imprinted polymeric nanoparticles as a novel sorbent to separate radioyttrium from Sr target
- Effect of a spacer moiety on radiometal labelled Neurotensin derivatives
- Investigaton of Kpong carbonatite as a potential source for rare earth elements (REEs) using instrumental neutron activation analysis (INAA)
- Precise age determination of a single plutonium particle using inductively coupled plasma mass spectrometer
