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Uranyl binding to humic acid under conditions relevant to cementitious geological disposal of radioactive wastes

Published online by Cambridge University Press:  05 July 2018

A. Stockdale  and
N. D. Bryan
A. Stockdale*
Affiliation:
Centre for Radiochemistry Research, School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
N. D. Bryan
Affiliation:
Centre for Radiochemistry Research, School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
*
*E-mail: tony@biogeochemistry.org.uk
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Abstract

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Few studies have sought to investigate the potential for dissolved organic matter (DOM) to bind (and thus potentially transport) radionuclides under the high pH regimes that are expected in cementitious disposal. We have used equilibrium dialysis to investigate uranyl binding to humic acid over a pH range of ∼10 to 13. The experimental results provide evidence that DOM can bind uranyl ions over this pH range, including in the presence of competing ions. There is a general decrease in binding with increasing pH, from ∼80% of total uranyl bound at pH 9.8 to ∼10% at pH 12.9. Modelling of the system with WHAM/Model VII can yield representative results up to pH ∼10.5.

Keywords

disposalhumic acidorganic matterradioactive wasteuranium speciationuranyl ion
Type
Research Article
Information
Mineralogical Magazine , Volume 76 , Issue 8 , December 2012 , pp. 3391 - 3399
Creative Commons
Creative Common License - CCCreative Common License - BY
© [2012] The Mineralogical Society of Great Britain and Ireland. This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY) licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2012

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