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The solubility of technetium(IV) at high pH

journal contribution
posted on 15.01.2008, 16:55 by Peter Warwick, S. Aldridge, Nick Evans, Sarah Vines
Technetium-99 is a β-emitting fission product of 238U. It is important when considering a safety case for nuclear waste disposal because of its high yield in radioactive waste and long half-life. The aqueous chemistry of Tc in a cementitious repository is likely to be dominated by Tc(VII), as TcO4 -, in aerobic areas and by Tc(IV), as TcO2 (am), in anaerobic. Some previous studies have shown an increase in Tc(IV) solubiltiy with increasing pH above pH 9.5 whilst others have not observed this increase. This study found that the solubility of Tc(IV) remains independent of pH until around 13.5, when a small increase can be seen which continues to increase linearly with pH. Modelling suggests that this increase occurs as the species TcO(OH)3 - is formed. The formation constant was estimated with data from this study and was found to be log K2 = -21.6 ± 0.3.

History

School

  • Science

Department

  • Chemistry

Citation

WARWICK, P. ... et al, 2007. The solubility of technetium(IV) at high pH. Radiochimica Acta, 95 (12), pp. 709-716

Publisher

© Oldenbourg

Publication date

2007

Notes

This article is Restricted Access. It was published in the journal Radiochimica Acta [© Oldenbourg] and can be found at: http://www.atypon-link.com/OLD/loi/ract

ISSN

0033-8230

Language

en

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