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Humate Complexation of Neptunium(V) and its Modeling

Published online by Cambridge University Press:  15 February 2011

Hirotake Moriyama
Affiliation:
Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590–04, Japan
Yasuhiro Nakata
Affiliation:
Department of Nuclear Engineering, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606–01, Japan.
Kunio Higashi
Affiliation:
Department of Nuclear Engineering, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606–01, Japan.
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Abstract

The complexation behavior of Np(V) with humate was investigated by spectrophotometry in the pH range from 5.7 to 10 in 0.01–0.5M NaClO4. The absorption peaks of NpO2+ and Np(V) humate were observed at 979.6nm and 989.9nm, respectively, and the apparent complexation constant of the Np(V) humate was found to be pH-dependent. A two-site complexation model was applied to the interpretation of the observed pH-dependence by considering the participation of the two functional groups of carboxylate and phenolate. The dissociation and complexation constants of both functional groups were determined.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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References

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