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Classic adsorption isotherms incorporated in modern surface complexation models: Implications for sorption of actinides

  • Dimitrii A. Kulik
Published/Copyright: September 25, 2009
Radiochimica Acta
From the journal Radiochimica Acta Volume 94 Issue 9-11

Computer-aided surface complexation models (SCMs) are widely used in describing mineral-water interface reactions such as sorption of actinides onto (hydr)oxides and clays. Most SCMs are built upon balances of surface binding sites. In fact, such models can reproduce only competitive Langmuir isotherms, plus optional electrostatic corrections. Hence, it may be difficult to extend such SCMs to some real-surface phenomena (site heterogeneity, lateral interactions, surface precipitation) described in isotherms other than Langmuir. In this contribution, a new approach to overcome this difficulty is presented which does not use surface site balances, is not restricted only to Langmuir isotherms, and can be implemented within the Gibbs energy minimization solvers of chemical (adsorption) equilibria. It is suggested to define the ideal behavior of a surface species using a linear isotherm only. Conversely, an adsorption isotherm equation of choice can be split into a linear term (involving the standard-state density and the equilibrium constant referenced to infinite dilution) and a non-linear surface activity coefficient term (SACT, involving the site density parameter). A simple method is proposed for deriving a SACT for the monodentate surface binding from the Langmuir isotherm. This method is then applied to obtain SACTs for mono-, bi-, tri- and tetra-dentate binding from the “quasi-chemical approximation” isotherm, as well as a SACT accounting for non-ideal lateral interactions between surface species from the Frumkin isotherm. The new approach is illustrated by modeling UVI adsorption on goethite at ambient conditions using a GEM SCM. It is shown that SACTs are useful at moderate- to high surface coverage, but only when the site density parameter is fixed from independent (crystallographic) data and not adjusted to fit the titration data. Ways to enhance SCMs with BET, Freundlich and other isotherms of interest for retention of actinides and fission products on mineral surfaces are also discussed.

Keywords: Adsorption isotherm; Langmuir; Frumkin; Surface complexation modeling; Surface activity coefficient term; Uranyl sorption
Received: 2005-8-12
Accepted: 2006-3-28
Published Online: 2009-9-25
Published in Print: 2006-11-1

© Oldenbourg Wissenschaftsverlag

Articles in the same Issue

  1. Preface Migration 2005
  2. Solubility measurement of zirconium(IV) hydrous oxide
  3. Solubility of ThO2·xH2O(am) and the formation of ternary Th(IV) hydroxide-carbonate complexes in NaHCO3-Na2CO3 solutions containing 0−4 M NaCl
  4. Ion interaction (SIT) coefficients for the Th4+ ion and trace activity coefficients in NaClO4, NaNO3 and NaCl solution determined by solvent extraction with TBP
  5. Leaching of neptunium from garnet- and murataite-based ceramics
  6. Coprecipitation of thorium and lanthanum with UO2+x(s) as host phase
  7. Rare Earth element (REE) incorporation in natural calcite: Upper limits for actinide uptake in a secondary phase
  8. Protonation of D-gluconate and its complexation with Np(V) in acidic to nearly neutral solutions
  9. Complexing properties of α-isosaccharinate: thorium
  10. Determination of the thermodynamic quantities of complexation between Eu(III) and carboxylic acids by microcalorimetry
  11. Potentiometric investigations on the interaction of humic acid with Cu(II) and Eu(III) ions
  12. Investigation of complexation of thorium by humic acid using chemically immobilized humic acid on silica gel
  13. Correlation between X-ray chemical shift and partial charge in Tc(IV) complexes: Determination of Tc partial charge in TcnOy(4n-2y)+
  14. Oxidation and dissolution rates of UO2(s) in carbonate-rich solutions under external alpha irradiation and initially reducing conditions
  15. On the stability of Pu(III) at different pH under non-inert conditions
  16. Reduction behavior of uranium in the presence of citric acid
  17. Leaching of zirconolite ceramics under H+ and He2+ irradiation
  18. Reduction of plutonium(VI) in brine under subsurface conditions
  19. Theoretical first step towards an understanding of the uranyl ion sorption on the rutile TiO2(110) face: A DFT periodic and cluster study
  20. Cm(III) sorption onto γ-Al2O3: New insight into sorption mechanisms by time-resolved laser fluorescence spectroscopy and extended X-ray absorption fine structure
  21. Modelling sorption data for the actinides Am(III), Np(V) and Pa(V) on montmorillonite
  22. 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
  23. The uptake of radium by calcium silicate hydrates and hardened cement paste
  24. Np(V)O2+ sorption on hydroxyapatite-effect of calcium and phosphate anions
  25. Uranium(VI) interaction with pyrite (FeS2): Chemical and spectroscopic studies
  26. Interaction of U(VI) with pyrite, galena and their mixtures: a theoretical and multitechnique approach
  27. Technetium sorption by stibnite from natural water
  28. Mechanisms of cesium sorption onto magnetite
  29. Sorption of cesium on granite under aerobic and anaerobic conditions
  30. Comparative study of cesium sorption on crushed and intact sedimentary rock
  31. The INE-Beamline for actinide research at ANKA
  32. Evaluation of the reversibility of iodide uptake by argillaceous rocks by the radial diffusion method
  33. Thermal diffusion of chlorine in uranium dioxide
  34. Effects of ionic strength on the coordination of Eu(III) and Cm(III) to a Gram-negative bacterium, Paracoccus denitrificans
  35. Interaction mechanisms of bacterial strains isolated from extreme habitats with uranium
  36. Biotransformation of plutonium complexed with citric acid
  37. Iodination of humic acid samples from different origins
  38. The fate of the epsilon phase (Mo-Ru-Pd-Tc-Rh) in the UO2 of the Oklo natural fission reactors
  39. Rhenium migration at the Maqarin natural analogue site (Jordan)
  40. Classic adsorption isotherms incorporated in modern surface complexation models: Implications for sorption of actinides
  41. Use of thermodynamic sorption models to derive radionuclide Kd values for performance assessment: selected results and recommendations of the NEA sorption project
  42. Modeling spent nuclear fuel alteration and radionuclide migration in disposal conditions
https://doi.org/10.1524/ract.2006.94.9-11.765
Keywords for this article
Adsorption isotherm; Langmuir; Frumkin; Surface complexation modeling; Surface activity coefficient term; Uranyl sorption

Articles in the same Issue

  1. Preface Migration 2005
  2. Solubility measurement of zirconium(IV) hydrous oxide
  3. Solubility of ThO2·xH2O(am) and the formation of ternary Th(IV) hydroxide-carbonate complexes in NaHCO3-Na2CO3 solutions containing 0−4 M NaCl
  4. Ion interaction (SIT) coefficients for the Th4+ ion and trace activity coefficients in NaClO4, NaNO3 and NaCl solution determined by solvent extraction with TBP
  5. Leaching of neptunium from garnet- and murataite-based ceramics
  6. Coprecipitation of thorium and lanthanum with UO2+x(s) as host phase
  7. Rare Earth element (REE) incorporation in natural calcite: Upper limits for actinide uptake in a secondary phase
  8. Protonation of D-gluconate and its complexation with Np(V) in acidic to nearly neutral solutions
  9. Complexing properties of α-isosaccharinate: thorium
  10. Determination of the thermodynamic quantities of complexation between Eu(III) and carboxylic acids by microcalorimetry
  11. Potentiometric investigations on the interaction of humic acid with Cu(II) and Eu(III) ions
  12. Investigation of complexation of thorium by humic acid using chemically immobilized humic acid on silica gel
  13. Correlation between X-ray chemical shift and partial charge in Tc(IV) complexes: Determination of Tc partial charge in TcnOy(4n-2y)+
  14. Oxidation and dissolution rates of UO2(s) in carbonate-rich solutions under external alpha irradiation and initially reducing conditions
  15. On the stability of Pu(III) at different pH under non-inert conditions
  16. Reduction behavior of uranium in the presence of citric acid
  17. Leaching of zirconolite ceramics under H+ and He2+ irradiation
  18. Reduction of plutonium(VI) in brine under subsurface conditions
  19. Theoretical first step towards an understanding of the uranyl ion sorption on the rutile TiO2(110) face: A DFT periodic and cluster study
  20. Cm(III) sorption onto γ-Al2O3: New insight into sorption mechanisms by time-resolved laser fluorescence spectroscopy and extended X-ray absorption fine structure
  21. Modelling sorption data for the actinides Am(III), Np(V) and Pa(V) on montmorillonite
  22. 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
  23. The uptake of radium by calcium silicate hydrates and hardened cement paste
  24. Np(V)O2+ sorption on hydroxyapatite-effect of calcium and phosphate anions
  25. Uranium(VI) interaction with pyrite (FeS2): Chemical and spectroscopic studies
  26. Interaction of U(VI) with pyrite, galena and their mixtures: a theoretical and multitechnique approach
  27. Technetium sorption by stibnite from natural water
  28. Mechanisms of cesium sorption onto magnetite
  29. Sorption of cesium on granite under aerobic and anaerobic conditions
  30. Comparative study of cesium sorption on crushed and intact sedimentary rock
  31. The INE-Beamline for actinide research at ANKA
  32. Evaluation of the reversibility of iodide uptake by argillaceous rocks by the radial diffusion method
  33. Thermal diffusion of chlorine in uranium dioxide
  34. Effects of ionic strength on the coordination of Eu(III) and Cm(III) to a Gram-negative bacterium, Paracoccus denitrificans
  35. Interaction mechanisms of bacterial strains isolated from extreme habitats with uranium
  36. Biotransformation of plutonium complexed with citric acid
  37. Iodination of humic acid samples from different origins
  38. The fate of the epsilon phase (Mo-Ru-Pd-Tc-Rh) in the UO2 of the Oklo natural fission reactors
  39. Rhenium migration at the Maqarin natural analogue site (Jordan)
  40. Classic adsorption isotherms incorporated in modern surface complexation models: Implications for sorption of actinides
  41. Use of thermodynamic sorption models to derive radionuclide Kd values for performance assessment: selected results and recommendations of the NEA sorption project
  42. Modeling spent nuclear fuel alteration and radionuclide migration in disposal conditions
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