Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-29T14:46:55.761Z Has data issue: false hasContentIssue false
  • English
  • Français

Comparison of a Non Electrostatic Surface Complexation Model and Surface Phase Theories for Prediction of Future Sorption Properties.

Published online by Cambridge University Press:  17 March 2011

Allan T. Emrén  and
Anna-Maria Jacobsson
Allan T. Emrén
Affiliation:
Materials and Surface Chemistry, Chalmers University of Technology, SE-41296 Goteborg, Sweden. E-mail, allan@chem.chalmers.se
Anna-Maria Jacobsson
Affiliation:
Materials and Surface Chemistry, Chalmers University of Technology, SE-41296 Goteborg, Sweden
Get access

Abstract

In performance assessments, sorption of radionuclides dissolved in groundwater is mostly handled by the use of fixed Kd values. It has been well known that this approach is unsatisfying. Only during the last few years, however, tools have become available that make it possible to predict the actual Kd value in an aqueous solution that differs from the one in which the sorption properties were measured.

One such approach is surface complexation (SC) that gives a detailed knowledge of the sorption properties. In SC, one tries to find what kinds of sorbed species are available on the surface and the thermodynamics for their formation from species in the bulk aqueous solution. Recently, a different approach, surface phase method (SP), has been developed. In SP, a thin layer including the surface is treated as a separate phase. In the bulk aqueous solution, the surface phase is treated as a virtual component, and from the chemical potential of this component, the sorption properties can be found.

In the paper, we compare advantages and disadvantages of the two kinds of models. We also investigate the differences in predicted sorption properties of a number of radionuclides (Co, Np, Th and U). Furthermore, we discuss under which circumstances, one approach or the other is preferable.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 824: Symposium CC – Scientific Basis for Nuclear Waste Management XXVIII , 2004 , CC7.2
Copyright
Copyright © Materials Research Society 2004

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

1 Davies, J. A. and Kent, D. B., “Surface Complexation Modeling in Aqueous Geochemistry”, Reviews in Mineralogy, ed. Hochella, M. F. and White, A.F., (Mineralogical Society of America, 1990) pp 177–260.Google Scholar
2 Hiemstra, T., W.H. van Riemduk, and Bolt, G.H., “Multiple Proton Adsorption Modeling at the Solid /Solution Interface of hydroxides: A New Approach”, J. Coll. Inerface Sci. 1, 133 (1989)Google Scholar
3 Bolt, G.H. and Riemduk, W.H. van, in Soil Chemistry, B. Physico-Chemical Models, Bolt, G.H. (ed), Ch 13 (1982)Google Scholar
4 Riemduk, W.H. van, Koopa, L.K., and Wit, J.C.M. de, Neth. J. Agric. Sci. 35 (1987)Google Scholar
5 Kosmulski, M., “Oxide/Electrolyte Interface: Electric Double Layer in Mixed Solvent Systems”, Colloids and Surfaces A: Physicochemical abd Engineering Aspects 95, 81–100 (1995)Google Scholar
6 Westall, J., “FITEQL, A Computer Program for Determination of Chemical Equilibrium Constants from Experimental Data”, Report 82-01 Dept. of Chemistry, Oregon State University, Corvallis Oregon (1982)Google Scholar
7 Lützenkirchen, J., “Comparison of 1-pK and 2-pK Versions of Surface Complexation Theory by Goodness of Fit in Describing Surface Charge Data of Hydroxides”, Environ. Sci. Technol. 32, 3149–3154 (1998)Google Scholar
8 Hiemstra, T., Venema, V., and Choo, Kwee, “Intrinsic Proton Affinity of Reactive Surface Groups of Metal Hydroxides: The Bond Valence Principle”, J. Coll. Interface Sci. 184, 680–692 (1996)Google Scholar
9 Kurbatov, M.H., Wood, G.B., and Kurbatov, J.D., “Isothermal Adsorption of Cobalt from Dilute Solutions”, J. Phys. Chem. 55, 1170–1180 (1950)Google Scholar
10 Labonne-Wall, N., Moulin, V., and Vilarem, J-P, “Retention Properties of Humic Substances onto Amorphous Silica: Consequences from the Sorption of Cations”, Radiochim. Acta 79 37–49 (1997)Google Scholar
11 Emrén, A.T., “An approach to sorption on minerals making use of surface phase thermodynamics”, Mat. Res. Soc. Symp. Proc., 807, 695–700 (2003)Google Scholar
12 Parkhurst, D. L., “User's Guide to PHREEQC - a Computer Program for Speciation, Reaction Path, Advective Transport, and Inverse Geochemical Calculations”, Water-Resources Investigations, USGS 143 pp (1995)Google Scholar
13 Jakobsson, A-M, “Measurement and Modelling using Surface Complexation of Cation (II to VI) Sorption onto Mineral Oxides.”, Thesis, Dept. Nuclear Chemistry, Chalmers University of Technology, Sweden (1999)Google Scholar