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Temperature effects on the interaction mechanisms between U(VI) and Eu(III) and ZrP2O7: experiment and modelling

Authors :
Florence Mercier-Bion
H. Catalette
G. Lagarde
Romuald Drot
N. Finck
Eric Simoni
Institut de Physique Nucléaire d'Orsay (IPNO)
Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
Source :
Radiochimica Acta, Radiochimica Acta, Oldenbourg Wissenschaftsverlag, 2008, 96, pp.11-21. ⟨10.1524/ract.2008.1459⟩
Publication Year :
2008
Publisher :
HAL CCSD, 2008.

Abstract

In the field of nuclear waste management, prediction of the radionuclides migration through the geosphere has to take into account the effects of temperature. The chosen substrate, zirconium diphosphate, was previously described concerning its surface acidity properties for several temperatures (25 °C, 50 °C, 75 °C, 90 °C). Edges for uranyl sorption were obtained in NaClO4medium, and the europium(III) sorption edges were realized in KNO3medium to evaluate the influence of the complexing nitrate ions. Influence of the temperature, the nature of the cation and the nature of the substrate were pointed out by comparing the edges for the different systems. A structural investigation (TRLFS) was carried out to define experimentally, at the microscopic level, the sorption equilibria. Only UO22+and Eu3+were sorbed on both ZrP2O7surface sites (≡Zr–O and ≡P–O), the nitrate medium having no influence on the sorbed species. Furthermore, temperature did not change the sorption mechanisms. The surface complexation modelling of both investigated systems was realized using i) the constant capacitance model ii) the results of the substrate characterizations iii) uranyl sorbed complex determinations. The formation of bidentate surface complexes onto the ≡Zr–O site is not accompanied by a proton release, whereas the formation of bidentate surface complexes onto the ≡P–O site is followed by a release of 2 protons, for both cations and at all temperatures studied. The determined sorption constants increase with temperature, as was expected from the analysis of the sorption edge positions.

Details

Language :
English
ISSN :
00338230 and 21933405
Database :
OpenAIRE
Journal :
Radiochimica Acta, Radiochimica Acta, Oldenbourg Wissenschaftsverlag, 2008, 96, pp.11-21. ⟨10.1524/ract.2008.1459⟩
Accession number :
edsair.doi.dedup.....366bb1707ca590c65868c326b4b2b031
Full Text :
https://doi.org/10.1524/ract.2008.1459⟩