Abstract
The complexation of Np(V) with phosphate at elevated temperatures was studied by a synergistic extraction method. A mixed buffer solution of TRIS and MES was used to maintain an appropriate pH value during the distribution experiments. The distribution ratio of Np(V) between the organic and aqueous phases was found to decrease as the concentrations of phosphate were increased. Stability constants of the 1:1 and 1:2 Np(V)-HPO4 2− complexes, dominant in the aqueous phase under the experimental conditions, were calculated from the effect of [HPO4 2−] on the distribution ratio. The thermodynamic parameters including enthalpy and entropy of complexation between Np(V) and HPO4 2− at 25 °C–55 °C were calculated by the temperature coefficient method.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
U.S. Department of Energy Office of Civilian Radioactive Waste Management, Yucca Mountain Science and Engineering Report Rev. I, U.S. Department of Energy, North Las Vegas, NV, 2002.
T. J. Wolery, C. F. Jove-Colon, Qualification of Thermodynamic Data for Geochemical Modeling of Mineral-Water Interactions in Dilute Systems, Rev 00, Argonne National Laboratory, Argonne, IL, 2004.
R. J. Lemire, J. Fuger, H. Nitsche, P. Potter, M. H. Rand, J. Rydberg, K. Spahiu, J. C. Sullivan, W. J. Ullman, P. Vitorge, H. Wanner, Chemical Thermodynamics of Neptunium and Plutonium, Elsevier, New York, 2001, p. 198.
A. Morgenstern, J. I. Kim, Radiochim. Acta, 72 (1996) 73.
A. I. Moskvin, V. F. Peretrukhin, Sov. Radiochim, 6 (1964) 198.
T. F. Rees, S. R. Daniel, Polyhedron, 3 (1984) 667.
Y. Inoue, O. Tochiyama, Bull. Chem. Soc. Japan, 58 (1985) 2228.
A. I. Moskvin, V. F. Peretrukhin, Sov. Radiochim., 6 (1964) 198.
G. R. Choppin, H. N. Erten, Y. Xia, Radiochim. Acta, 74 (1996) 123.
Y. Xia, L. Rao, D. Rai, A. R. Felmy, Radiochim. Acta, 86 (1999) 33.
Y. Xia, J. I. Friese, D. A. Moore, L. Rao, J. Radioanal. Nucl. Chem., 268 (2006) 445.
L. Rao, G. R. Choppin, Inorg. Chem., 23 (1984) 2351.
H. M. Irving, M. G. Miles, L. D. Pettit, Anal. Chim. Acta, 38 (1967) 475.
A. E. Martell, R. M. Smith, Critical Selected Stability Constants of Metal Complexes Database, NIST Standard Reference Database, 46, Version 7.0, 2003.
J. I. Partanen, A. K. Covington, J. Chem. Eng. Data, 50 (2005) 2065.
L. P. Nims, J. Am. Chem. Soc., 56 (1934) 1110.
I. Grenthe, J. Fuger, R. J. M. Konings, R. J. Lemire, A. B. Muller, C. N. Cregu, H. Wanner, Chemical Thermodynamics of Uranium, Elsevier, North-Holland, Amsterdam, 1992.
L. Rao, Private Communication, 2008.
G. Scatchard, Chem. Rev., 19 (1936) 309.
L. Rao, T. G. Srinivasan, A. Y. Garnov, P. Zanonato, P. Di Bernardo, A. Bismondo, Geochim. Cosmochim. Acta, 68 (2004) 4821.
Y. Xia, J. I. Friese, D. A. Moore, L. Rao, Proc. of 2006 Int. High-Level Radioactive Waste Management Conf., The American Nuclear Society, La Grange Park, IL, 2006, p. 716.
R. G. Pearson, J. Chem. Educ., 45 (1968) 58.
R. G. Pearson, J. Chem. Educ., 45 (1968) 643.
S. Ahrland, Coord. Chem. Rev., 8 (1972) 21.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Xia, Y., Friese, J.I., Bachelor, P.P. et al. Thermodynamics of neptunium(V) complexes with phosphate at elevated temperatures. J Radioanal Nucl Chem 280, 599–605 (2009). https://doi.org/10.1007/s10967-009-7476-8
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10967-009-7476-8