The reduction of plutonium and neptunium ions by acetaldoxime in nitric acid
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V. S. Koltunov
The rate equations for the reduction of Np(V), Np(VI) and Pu(IV) ions by acetaldoxime in nitric acid have been determined as:
-d[Np(V)]/dt = k26[Np(V)][CH3CHNOH][HNO3]1.2
- d[Np(VI)/dt = k19 [Np(VI)][CH3CHNOH]/[HNO3]
- d[Pu(IV)/dt = k6 [Pu(IV)]2[CH3CHNOH]1.1/[Pu(III)][HNO3]2.2
where respectively: k26 = (9.2±0.2)×10-4 l2.2mol-2.2min-1 at 60° C; k19 = 254±10 min-1 at 26.0° C; k6 = 25.3±1.9 mol1.1 l-1.1min-1 at 19.5°C. The activation energies were found to be: E19 = 62.6±2.6 kJmol-1 and E26 = 87.7±9.8 kJmol-1. Np(V) was generally found to be stable for long periods in nearly all the kinetic experiments and the reduction of Np(V) to Np(IV) could only be studied at elevated temperatures and reactant concentrations.
Possible reaction mechanisms for the reduction of Np(VI) and Pu(IV) have been suggested; proceeding, in both cases, via the hydrolysis product and an intermediate CH3CHN¤O radical. Simple solvent extraction experiments have shown that Np(VI) and Pu(IV) can be reductively stripped from 30% TBP/n-dodecane in the presence of U(VI).
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Artikel in diesem Heft
- Formation of americium(III) complexes with aqueous silicic acid
- The reduction of plutonium and neptunium ions by acetaldoxime in nitric acid
- Complex formation of U(VI) with Bacillus-isolates from a uranium mining waste pile
- Longterm leaching of natural radionuclides from uranium mill tailings material: comparison of indoor and outdoor column experiments
- Enrichment analysis of uranium in uranium oxide by gamma-ray spectrometry without using calibration standards
- Gas phase chemistry of technetium and rhenium oxychlorides
- Synthesis and chromatographic characterization of [Tc-99m]technetium-humic acid species
- Retention of some hazardous radionuclides from nitric acid solution using tin(IV) antimonate as a cation exchanger
- Study of adsorption of zinc ions on hydrous zirconium oxide surface
- Radiometric analysis of the spent fuel pool water and reactor coolant of ET-RR.1
- Separation of carrier-free cerium radionuclides from different target matrix produced by heavy ion beams
