Contribution to the prediction of americium, plutonium and neptunium behaviour in the geosphere: chemical data
Description
An exhaustive bibliographic review on hydrolysis of americium gives the stability constants, at zero ionic strength. No evidence of Am(OH)4- formation was found by solubility studies up to pH < 13. The solubility of solid Am2 (CO3)3 characterised by its X-ray diffraction pattern is studied at a high ionic strength. All the published results on Am in carbonate media are reinterpreted using these stability constants (Am-OH-CO3 complexes are not needed). No evidence of Am(CO3)45- formation was found by spectrophotometry up to 3M. Literature results are used to determine the formal redox potentials at pH = 9.4 and to calculate the formation constants, at zero ionic strength. The formation of complexes between americium and humic materials (purified fulvic and humic acids) has been studied by a spectrophotometric technique. The results are interpreted by the formation of a 1:1 complexe. Solubility of the solid PuO2(CO3) is measured in bicarbonate media at high ionic strength, to obtain the solubility product and formation constants of the PuO2(CO3)i2-2i complexes
Availability note (English)
MF available from INIS under the Report Number.Abstract (French)
Une revue bibliographique exhaustive de l'hydrolyse de l'americium fournit les constantes de stabilite, a force ionique nulle. La formation de Am(OH)4- n'a pas ete mise en evidence par les etudes de solubilite jusqu'a pH > 13. La solubilite du solide Am2 (CO3)3, caracterise par son spectre de diffraction de rayons X, est mesuree a force ionique elevee. Les constantes de stabilite sont suffisantes pour rendre compte des resultats publies sur l'Am en milieu carbonate (donc sans faire appel a des complexes mixtes Am-OH-CO3). La formation de Am(CO3)45- n'a pas ete mise en evidence par spectrophotometrie jusqu'a 3M. Des resultats de Bourges sont utilises pour determiner les potentiels redox normaux apparents a pH = 9,4 et pour calculer les constantes de formation a force ionique nulle. La formation de complexes entre l'americium et les matieres humiques (acides humique et fulvique purifies) a ete etudiee par spectrophotometrie. Les resultats sont interpretes par la formation d'un complexe 1:1. la solubilite du solide PuO2 (CO3) est mesuree en milieu bicarbonate a force ionique elevee (I = 3M, NaClO4) on en deduit le produit de solubilite et les constantes de formation des complexes PuO2 (CO3)i2-2iFiles
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Additional details
Additional titles
- Original title (French)
- Contribution a la prevision du comportement de l'americium, du plutonium et du neptunium dans la geosphere: donnees chimiques
Publishing Information
- Imprint Pagination
- 216 p.
- Report number
- CEA-R--5473
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 20068073
- Subject category
- S54: ENVIRONMENTAL SCIENCES;
- Resource subtype / Literary indicator
- Numerical Data, Thesis
- Descriptors DEI
- AMERICIUM COMPLEXES; AMERICIUM COMPOUNDS; AQUEOUS SOLUTIONS; CARBONATES; COMPILED DATA; EXPERIMENTAL DATA; FULVIC ACIDS; GROUND WATER; HUMIC ACIDS; HYDROLYSIS; NEPTUNIUM COMPOUNDS; PLUTONIUM COMPOUNDS; PLUTONYL COMPLEXES; RADIONUCLIDE MIGRATION; REDOX POTENTIAL; SOLUBILITY; THERMODYNAMIC ACTIVITY
- Descriptors DEC
- ACTINIDE COMPLEXES; ACTINIDE COMPOUNDS; CARBON COMPOUNDS; CHEMICAL REACTIONS; COMPLEXES; DATA; DECOMPOSITION; DISPERSIONS; ENVIRONMENTAL TRANSPORT; HOMOGENEOUS MIXTURES; HYDROGEN COMPOUNDS; INFORMATION; MASS TRANSFER; MIXTURES; NUMERICAL DATA; ORGANIC ACIDS; ORGANIC COMPOUNDS; OXYGEN COMPOUNDS; PLUTONIUM COMPLEXES; POLAR SOLVENTS; SOLUTIONS; SOLVENTS; SOLVOLYSIS; TRANSPLUTONIUM COMPOUNDS; TRANSURANIUM COMPLEXES; TRANSURANIUM COMPOUNDS; WATER