Sparse and uncertain SCM parameter sets – what are the consequences?


Sparse and uncertain SCM parameter sets – what are the consequences?

Richter, A.; Brendler, V.

The effect of parameter consistency and uncertainty (protolysis constants, equilibrium constants) in surface complexation modeling (SCM) is illustrated. As example the blind prediction of Cu(II) sorption onto goethite was selected, applying the Diffuse Double Layer Model (DDLM) as the electrostatic model requiring the smallest set of parameters.
All randomly generated normal distributed pK parameter sets did predict the experimentally determined conventional distribution coefficients KD within one order of magnitude or better. Thus, the formally large spreading of the pK values as extracted from literature is actually not critical. Concerning the uncertainty of the formation constant of the surface species the effect of using parameters linked to electrostatic models other than DDLM was investigated. In case of sparse SCM data matrices such inconsistencies may be tolerated.
We conclude, that the application of DDLM can indeed be used for estimating distribution coefficients for contaminants in well-defined mineral systems.

Keywords: sorption; surface complexation modeling; RES3T database; distribution coefficient; uncertainty; consistency

  • Abstract in refereed journal
    American Chemical society: Abstracts of scientific papers 231(2006), 99-GEOC
    ISSN: 0065-7727
  • Invited lecture (Conferences)
    ACS National Meeting, 26.-30.03.2006, Atlanta, United States
  • Contribution to external collection
    Barnett M.O., Kent D.B.: Adsorption of Metals by Geomedia II: Variables, Mechanisms, and Model Applications (Serioes: Developments in Earth & Environmental Sciences, Vol. 7), Amsterdam: Elsevier, 2008, 978-0-444-53212-1, 267-291

Permalink: https://www.hzdr.de/publications/Publ-7828
Publ.-Id: 7828