Spectroscopic Investigations of Neptunium's and Plutonium's Oxidation States in Sol-Gel Glasses as a Function of Initial Valence and Thermal History
Tóm tắt
Several oxidation states of neptunium and plutonium, Pu(III), Pu(IV), Pu(VI), Np(IV), Np(V), and Np(VI), were studied in glasses prepared by a sol-gel technology. The oxidation state of these actinides in the sol-gel product was examined by absorption spectroscopy after solidification, aging, and thermal treatment. The oxidation state of the actinides in the starting solutions was essentially maintained through the solidification process of the silica matrix. However, during densification and removal of residual solvents at elevated temperatures, both actinides converted eventually to their tetra valent states while in the different sol-gel products. This finding is in accord with reports that tetravalent states of plutonium and neptunium are acquired in glass products prepared by dissolution of the actinide in molten glasses. Comparisons between room temperature spectra obtained from neptunium and plutonium in heated sol-gel products and from molten glass products showed subtle differences that can be related to the metal ion's environments.
Tài liệu tham khảo
H. L. Smith & A. J. Cohen, Phys. Chem. Glasses 4, p. 173 (1963).
I. M. Thomas, S. A. Payne, & G. D. Wilke, J. Non-Cryst. Sol.151, p. 183 (1992).
N. Jacquet-Francillon, R. Bonniaud, & C. Sombret, Radiochim. Acta 25, p. 231 (1978).
R. Reisfeld and C. K. Jorgenson, editors, Chemistry, Spectroscopy, and Applications of Sol-Gel Glasses, Structure and Bonding, Vol. 77 (Springer, Berlin, 1992); and L. L. Hench and J. K. West, editors, Chemical Processing of Advanced Materials (Wiley, New York, 1992), p. 823.
D. Cohen, J. Inorg. Nucl. Chem.18, p. 211 (1961).
P. G. Hagan and J. M. Cleveland, J. Inorg. Nucl. Chem. 28, p. 2905 (1966).
R. E. Connick, M. Kasha, W. H. Mcvey, and G. E. Sheline, in The Transuranium Elements, edited by G. T. Seaborg, J. J. Katz, and W. M. Manning, McGraw-Hill Book Company, Inc., New York, 1949, p. 559–601.
D. A. Costanzo, R. E. Biggers, and J. T. Bell, J. Inorg. Nucl. Chem.35, p. 609 (1973).
J. C. Hindman, in The Transuranium Elements, edited by G. T. Seaborg, J. J. Katz, and W. M. Manning, McGraw-Hill Book Company, Inc., New York, 1949, p. 370–386.
R. K. Sjoblom and J. C Hindman, J. Amer. Chem. Soc. 73, p. 1744 (1951).
H. Escure, D. Gourisse, and J. Lucas, J. Inorg. Nucl. Chem. 33, p. 1871 (1971).
P. G. Eller, G. D. Jarvinen, J. D. Purson, R. A. Penneman, R. R. Ryan, F. W. Lytle, and R. B. Greegor, Radiochim. Acta 39, p.17(1985).