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Comparison between specific surface complexation and Donnan ion-exchange models for describing the adsorption of cations on kraft fibres - literature evidence and EXAFS study of Cu(II) binding

Sundman, Ola; Persson, Per LU and Ohman, Lars-Olof (2010) In Nordic Pulp & Paper Research Journal 25. p.178-184
Abstract
A compilation of the applied experimental conditions when studying metal ion adsorption onto kraft fibres, and the resulting conclusion, revealed that the ionic strength conditions used during the experiments were an important dividing factor. At low ionic strengths, the conclusion has regularly been that the Donnan ion-exchange model could correctly predict the adsorption while, at higher ionic strengths, it has often been concluded that the formation of specific metal-ion fibre complexes must be assumed. To study this apparent influence from the presence of monovalent sodium ions, Cu K-edge EXAFS spectra of Cu(2+) ions adsorbed to kraft fibres were collected in media of "0" to 100 mM NaCl. Combined with previous data, these measurements... (More)
A compilation of the applied experimental conditions when studying metal ion adsorption onto kraft fibres, and the resulting conclusion, revealed that the ionic strength conditions used during the experiments were an important dividing factor. At low ionic strengths, the conclusion has regularly been that the Donnan ion-exchange model could correctly predict the adsorption while, at higher ionic strengths, it has often been concluded that the formation of specific metal-ion fibre complexes must be assumed. To study this apparent influence from the presence of monovalent sodium ions, Cu K-edge EXAFS spectra of Cu(2+) ions adsorbed to kraft fibres were collected in media of "0" to 100 mM NaCl. Combined with previous data, these measurements confirmed that at very low ionic strength, the importance of specific interactions between the chemically modified cellulose fibres and the Cu(II) ions significantly decreased. For a detailed description of the adsorption phenomenon, both types of interactions must be considered simultaneously. For most technical and engineering applications, however, the Donnan model can be used at low ionic strength conditions, i.e. I less than or similar to 10 mM. At higher ionic strengths, though, the inclusion of specific complexes in the model is necessary for correctly describing the adsorption of di- and trivalent cations with strong complex forming properties. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Nordic Pulp & Paper Research Journal
volume
25
pages
178 - 184
publisher
Arbor Publishing AB
external identifiers
  • Scopus:79551525455
ISSN
0283-2631
DOI
10.3183/NPPRJ-2010-25-02-p178-184
language
English
LU publication?
no
id
a73c3557-d97d-472e-af1e-f6d871fcf35d (old id 4332313)
date added to LUP
2014-03-04 09:46:16
date last changed
2016-10-13 04:34:39
@misc{a73c3557-d97d-472e-af1e-f6d871fcf35d,
  abstract     = {A compilation of the applied experimental conditions when studying metal ion adsorption onto kraft fibres, and the resulting conclusion, revealed that the ionic strength conditions used during the experiments were an important dividing factor. At low ionic strengths, the conclusion has regularly been that the Donnan ion-exchange model could correctly predict the adsorption while, at higher ionic strengths, it has often been concluded that the formation of specific metal-ion fibre complexes must be assumed. To study this apparent influence from the presence of monovalent sodium ions, Cu K-edge EXAFS spectra of Cu(2+) ions adsorbed to kraft fibres were collected in media of "0" to 100 mM NaCl. Combined with previous data, these measurements confirmed that at very low ionic strength, the importance of specific interactions between the chemically modified cellulose fibres and the Cu(II) ions significantly decreased. For a detailed description of the adsorption phenomenon, both types of interactions must be considered simultaneously. For most technical and engineering applications, however, the Donnan model can be used at low ionic strength conditions, i.e. I less than or similar to 10 mM. At higher ionic strengths, though, the inclusion of specific complexes in the model is necessary for correctly describing the adsorption of di- and trivalent cations with strong complex forming properties.},
  author       = {Sundman, Ola and Persson, Per and Ohman, Lars-Olof},
  issn         = {0283-2631},
  language     = {eng},
  pages        = {178--184},
  publisher    = {ARRAY(0x939ecc8)},
  series       = {Nordic Pulp & Paper Research Journal},
  title        = {Comparison between specific surface complexation and Donnan ion-exchange models for describing the adsorption of cations on kraft fibres - literature evidence and EXAFS study of Cu(II) binding},
  url          = {http://dx.doi.org/10.3183/NPPRJ-2010-25-02-p178-184},
  volume       = {25},
  year         = {2010},
}