Complexation of Uranium(VI) and Samarium(III) with Oxydiacetic Acid: Temperature Effect and Coordination Modes (Articolo in rivista)

Type
Label
  • Complexation of Uranium(VI) and Samarium(III) with Oxydiacetic Acid: Temperature Effect and Coordination Modes (Articolo in rivista) (literal)
Anno
  • 2003-01-01T00:00:00+01:00 (literal)
Alternative label
  • Rao L. 1, Garnov A.Y. 1, Jiang J. 1, Di Bernardo P. 3, Zanonato P. 3, Bismondo A. 2 (2003)
    Complexation of Uranium(VI) and Samarium(III) with Oxydiacetic Acid: Temperature Effect and Coordination Modes
    in Inorganic chemistry
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Rao L. 1, Garnov A.Y. 1, Jiang J. 1, Di Bernardo P. 3, Zanonato P. 3, Bismondo A. 2 (literal)
Pagina inizio
  • 3685 (literal)
Pagina fine
  • 3692 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 42 (literal)
Rivista
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#descrizioneSinteticaDelProdotto
  • Recently there has been significant interest in the effect of temperature on the coordination of actinides in solution, due to the demands for scientific information to aid the safe management of nuclear wastes.It is known that the temperature of nuclear wastes in the storage tanks is significantly above the ambient temperature and can be up to 90 C. However, the majority of the thermodynamic data on actinide coordination are for 25 C.5 The lack of data on actinide coordination at variable temperatures makes it difficult to predict the behavior of actinides in the waste processing and disposal where elevated temperatures are expected. Therefore, the trends in thermodynamic parameters over a wide range of temperature could provide insight into the nature of the actinide complex and the solvent effect. (literal)
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • 2. ICIS-CNR; 1. - Berkeley; 3. UNI-PD; (literal)
Titolo
  • Complexation of Uranium(VI) and Samarium(III) with Oxydiacetic Acid: Temperature Effect and Coordination Modes (literal)
Abstract
  • The complexation of uranium(VI) and samarium(III) with oxydiacetate (ODA) in 1.05 mol kg-1 NaClO4 is studied at variable temperatures (25-70 C). Three U(VI)/ODA complexes (UO2L, UO2L22-, and UO2HL2-) and three Sm(III)/ODA complexes (SmLj(3-2j)+ with j = 1, 2, 3) are identified in this temperature range. The formation constants and the molar enthalpies of complexation are determined by potentiometry and calorimetry. The complexation of uranium(VI) and samarium(III) with oxydiacetate becomes more endothermic at higher temperatures. However, the complexes become stronger due to increasingly more positive entropy of complexation at higher temperatures that exceeds the increase in the enthalpy of complexation. The values of the heat capacity of complexation (Cp in J K-1 mol-1) are 95 ± 6, 297 ± 14, and 162 ± 19 for UO2L, UO2L22-, and UO2HL2-, and 142 ± 6, 198 ± 14, and 157 ± 19 for SmL+, SmL2-, and SmL33-, respectively. The thermodynamic parameters, in conjunction with the structural information from spectroscopy, help to identify the coordination modes in the uranium oxydiacetate complexes. The effect of temperature on the thermodynamics of the complexation is discussed in terms of the electrostatic model and the change in the solvent structure. (literal)
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