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Czechoslovak Journal of Physics

, Volume 49, Supplement 1, pp 603–609 | Cite as

Redox potentials of M(VI)/M(V) limiting carbonate complexes (M=U or Pu) at different ionic strengths and temperatures. Entropy and heat capacity

  • H. Capdevila
  • P. Vitorge
Chemistry of Actinide and Trans-actinide Elements

Abstract

For waste disposal programs, actinide aqua ions and limiting complexes had been studied by cyclic voltametry. Measured redox potentials in non complexing media were modelled by using SIT and Taylor’s series expansions to the second order for ionic strength I, and temperature T, influences. These data treatments give standard values for redox potential Eo, corresponding ΔSo, ΔHo and ΔCp o of reactions, and excess values (variations of E’o, ΔS, ΔH and ΔCp with I) that can be deduced by using T influence on fitted SIT coefficients Δε. This methodology is used here at 5 to 70°C in 0.3 to 1.5 M Na2CO3 media (I=0.9 to 4.5M). Eo=0.191±0.015 (−0.779±0.010) V/SHE, ΔSo=−178±37 (−174±5) J. K−1. mol−1, ΔCp o=−516±744 (−414±176) J. K−1.mol−1 and Δε=−0.175±0.04+(2.1±2.0) 10−3 ΔT-(2.4±7.7) 10−5 (ΔT)2/2 (−0.91±0.10+(7.0±1.9)10−3 ΔT-(5.8±0.11) 10−5 (ΔT)2/2) kg.mol−1 are obtained at 25°C and I=0 for the MO2(CO3)3 4−+e→MO2(CO3)3 5− reaction where M=Pu (and U respectively), lg(β3 Vo3 VIo)= −12.6±0.3 (−14.65±0.17) is deduced. lgβ3 V = 3.1±1.4 (6.95±0.18) is proposed using published β3 VI values.

Keywords

Uranium Redox Potential Plutonium Activity Coefficient Redox Couple 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. [1]
    Gorgeon L.: These Université Paris 6 25/11/1994.Google Scholar
  2. [2]
    André A.: These Institut National Polytechnique de Lorraine, Nancy 15/09/1997.Google Scholar
  3. [3]
    Vitorge P. and Capdevila H.: CEA-R-5793 (1998).Google Scholar
  4. [4]
    Lemire R. et al.: Chemical Thermodynamics of Neptunium and Plutonium Paris OECD NEA (to be published).Google Scholar
  5. [5]
    Capdevila H. and Vitorge P.: Radiochim. Acta 68 (1995) 51.Google Scholar
  6. [6]
    Capdevila H. and Vitorge P.: J. Radioanal. Nucl. Chem. 143 (1990) 403.CrossRefGoogle Scholar
  7. [7]
    Capdevila H.: These Université d’Orsay (Paris 11) (5 June 1992).Google Scholar
  8. [8]
    Silva R. J. et al.: Chemical thermodynamics of Americium Elsevier. Amsterdam (1995).Google Scholar
  9. [9]
    Grenthe I., et al.: Chemical thermodynamics of Uranium Elsevier, Amsterdam (1992).Google Scholar
  10. [10]
    Grenthe I., et al.: Modelling in Aquatic Chemistry. OECD-NEA Paris (1997).Google Scholar
  11. [11]
    Giffaut E., Vitorge P and Capdevila H.: J. Alloys Compounds 213/214 (1995) 278.CrossRefGoogle Scholar
  12. [12]
    Robouch P., Vitorge P.: Inorg. Chim. Acta 140 (1987) 239.CrossRefGoogle Scholar
  13. [13]
    Offerlé S., Capdevila H. and Vitorge P.: CEA-N-2785 (1995).Google Scholar
  14. [14]
    Simakin G.: Radiokhimiya 19 (4) (1977) 518 (Sov. Radiochem. 424).Google Scholar
  15. [15]
    Riglet C.: These Université Paris 6 17/3/1989 (CEA-R-5535 (1990)).Google Scholar
  16. [16]
    Capdevila H., Giffaut E., Vitorge P. and Delmau L.: Radiochim. Acta 74 (1996) 93.Google Scholar
  17. [17]
    Simakin G. et al.: Radiokhim., 16 (6) (1974) 859 (Sov. Radiochem., 838).Google Scholar
  18. [18]
    Wester D. and Sullivan J.: Radiochem. Radioanal. 57 (1983) 35.Google Scholar

Copyright information

© Institute of Physics, Acad. Sci. CR 1999

Authors and Affiliations

  • H. Capdevila
    • 1
  • P. Vitorge
    • 1
  1. 1.CEA DCC/DESD/SESDSaclayFrance

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