Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-15T19:19:57.508Z Has data issue: false hasContentIssue false
  • English
  • Français

Sorption of Tc(IV) to some geological materials with reference to radioactive waste disposal

Published online by Cambridge University Press:  05 July 2018

R. J. Hallam ,
N. D. M. Evans  and
S. L. Jain
R. J. Hallam
Affiliation:
Department of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK
N. D. M. Evans*
Affiliation:
Department of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK
S. L. Jain
Affiliation:
Department of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK
*
*E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

One of the most important isotopes to be considered for disposal in the proposed UK Geological Disposal Facility (GDF) for higher-activity radioactive wastes will be 99Tc, due to its long half-life, high fission yield and ability to migrate through the geosphere as the pertechnetate ion. Much of the Tc is likely to be in the lower Tc(IV) oxidation state due to the low Eh in the near field. Batch Tc(IV) sorption experiments have been performed from pH 3–13, using 95mTc as a spike, in the presence of quartz, hematite, goethite, plagioclase feldspar, sand and shale. Solutions containing Tc(IV) were prepared at trace concentrations to avoid precipitation of TcO2. Values for the partition coefficient (Rd) were found to range from ∽4 up to ∽2 × 104 cm3 g–1. Rd was heavily dependent on pH in all cases, with the highest values being found in the circumneutral area. These data will inform the performance assessment for the near-field behaviour of technetium in the UK's planned higher-activity wastes GDF. Surface complexation modelling has been performed, fitting the data using both monodentate and bidentate binding models.

Keywords

technetiumradioactive wastesorption
Type
Research Article
Information
Mineralogical Magazine , Volume 75 , Issue 4 , August 2011 , pp. 2439 - 2448
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Aldridge, S., Warwick, P., Evans, N. and Vines, S. (2007) Degradation of tetraphenylphosphonium bromide at high pH and its effect on radionuclide solubility. Chemosphere, 66, 672—676.CrossRefGoogle ScholarPubMed
Baker, S., Baston, G.M.N., Manning, M.C., McCrohon, R. and Williams, S. (2000) The Aqueous Solubility Behaviour of Selenium, Technetium and Tin. AEA Technology Report, AEAT/R/ENV/0233. AEA Technology, Harwell, Oxfordshire, UK.Google Scholar
Copplestone, D., Jackson, D., Hartnoll, R.G., Johnson, M.S., McDonald, P. and Wood, N. (2004) Seasonal variations in activity concentrations of 99Tc and 137Cs in the edible meat fraction of crabs and lobsters from the central Irish Sea. Journal of Environmental Radioactivity, 73, 29–48.CrossRefGoogle ScholarPubMed
Cui, D. and Eriksen, T.E. (1996) Reduction of pertechnetate by ferrous iron in solution: influence of sorbed and precipitated Fe(IF). Environmental . Science & Technology, 30, 2259–2262.CrossRefGoogle Scholar
Grambow, B., Fattahi, M., Montavon, G., Moisan, C. and Giffaut, E. (2006) Sorption of Cs, Ni, Pb, Eu(III), Am(III), Cm, Ac(III), Tc(IV), Th, Zr, and U(IV) on MX 80 bentonite: an experimental approach to assess model uncertainty. Radiochimica Ada, 94, 627—636.Google Scholar
Ilett, D.J., Pilkington, N.J. and Tweed, C.J. (1998) Complexation of radionuclides. Proceedings of the Royal Society of Chemistry/Nirex Symposium: The chemistry of deep disposal of radioactive waste. Nirex Science Report, S/98/008. Nirex, Harwell, Oxfordshire, UK.Google Scholar
Kemp, S.J., Turner, G. and Wagner, D. (2009) Initial testing and a laboratory manual for the Micromeritics Gemini VI physisorption system. British Geological Survey Internal Report, IR/08/ 086. British Geological Survey, Keyworth, Nottingham, UK.Google Scholar
Reed, J. (2004) Technetium to go. Nuclear Engineering International, 49, 14—17.Google Scholar
Van der Lee, J. (2000) JCHESS 2.0. Ecole des Mines de Paris, Centre d'Informatique Geologique, Paris. [http://chess.geosciences.ensmp.fr/].Google Scholar
Warwick, P., Aldridge, S., Evans, N. and Vines, S. (2007) The solubility of Technetium(IV) at high pH. Radiochimica Ada, 95, 709–716.Google Scholar