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Structure and bonding of orthophosphate ions at the iron oxide aqueous interface

Persson, Per LU ; Nilsson, N. and Sjoberg, S. (1996) In Journal of Colloid and Interface Science 177. p.263-275
Abstract
The surface speciation of orthophosphate ions on goethite has been studied as a function of pH, time, total phosphate concentration, and ionic medium by means of diffuse reflectance FTIR spectroscopy. The samples were prepared in accordance with a distribution diagram of surface species as calculated from thermodynamic data. In agreement with the thermodynamic model three dominating surface complexes could be distinguished with IR spectroscopy, and the relative distribution of the species was shown to be primarily a function of pH. The IR characteristics of the individual surface complexes were indicative of molecular symmetries of the PO4 unit of C-3v, C-2v, and C-3v, respectively. This was concluded to be incompatible with the bidentate,... (More)
The surface speciation of orthophosphate ions on goethite has been studied as a function of pH, time, total phosphate concentration, and ionic medium by means of diffuse reflectance FTIR spectroscopy. The samples were prepared in accordance with a distribution diagram of surface species as calculated from thermodynamic data. In agreement with the thermodynamic model three dominating surface complexes could be distinguished with IR spectroscopy, and the relative distribution of the species was shown to be primarily a function of pH. The IR characteristics of the individual surface complexes were indicative of molecular symmetries of the PO4 unit of C-3v, C-2v, and C-3v, respectively. This was concluded to be incompatible with the bidentate, bridging structural model previously suggested. Instead, the IR data are in good agreement with a monodentate coordination of phosphate to the surfaces, where the three surface complexes only differ in the degree of protonation. A comparison between the adsorption behavior of phosphate on goethite and hematite was also made. Here the importance of the aqueous stability of the adsorbent on the adsorption mechanism was shown. (C) 1996 Academic Press, Inc. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Colloid and Interface Science
volume
177
pages
263 - 275
publisher
Elsevier
external identifiers
  • scopus:0029977851
ISSN
1095-7103
DOI
10.1006/jcis.1996.0030
language
English
LU publication?
no
id
8098af2b-323e-4f36-b01c-f1c98d6eaec1 (old id 4332673)
date added to LUP
2014-03-04 09:44:11
date last changed
2017-08-20 03:28:05
@article{8098af2b-323e-4f36-b01c-f1c98d6eaec1,
  abstract     = {The surface speciation of orthophosphate ions on goethite has been studied as a function of pH, time, total phosphate concentration, and ionic medium by means of diffuse reflectance FTIR spectroscopy. The samples were prepared in accordance with a distribution diagram of surface species as calculated from thermodynamic data. In agreement with the thermodynamic model three dominating surface complexes could be distinguished with IR spectroscopy, and the relative distribution of the species was shown to be primarily a function of pH. The IR characteristics of the individual surface complexes were indicative of molecular symmetries of the PO4 unit of C-3v, C-2v, and C-3v, respectively. This was concluded to be incompatible with the bidentate, bridging structural model previously suggested. Instead, the IR data are in good agreement with a monodentate coordination of phosphate to the surfaces, where the three surface complexes only differ in the degree of protonation. A comparison between the adsorption behavior of phosphate on goethite and hematite was also made. Here the importance of the aqueous stability of the adsorbent on the adsorption mechanism was shown. (C) 1996 Academic Press, Inc.},
  author       = {Persson, Per and Nilsson, N. and Sjoberg, S.},
  issn         = {1095-7103},
  language     = {eng},
  pages        = {263--275},
  publisher    = {Elsevier},
  series       = {Journal of Colloid and Interface Science},
  title        = {Structure and bonding of orthophosphate ions at the iron oxide aqueous interface},
  url          = {http://dx.doi.org/10.1006/jcis.1996.0030},
  volume       = {177},
  year         = {1996},
}