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Sulfate adsorption on goethite

Journal Article:

Abstract

Recent spectroscopic work has suggested that only one surface species of sulfate is dominant on hematite. Sulfate is therefore a very suitable anion to test and develop adsorption models for variable charge minerals. The authors have studied sulfate adsorption on goethite covering a large range of sulfate concentrations, surface coverages, pH values, and electrolyte concentrations. Four different techniques were used to cover the entire range of conditions. For characterization at low sulfate concentrations, below the detection limit of sulfate with ICP-AES, the authors used proton-sulfate titrations at constant pH. Adsorption isotherms were studied for the intermediate sulfate concentration range. Acid-base titrations in sodium sulfate and electromobility were used for high sulfate concentrations. All the data can be modeled with one adsorbed species if it is assumed that the charge of adsorbed sulfate is spatially distributed in the interface. The charge distribution of sulfate follows directly from modeling the proton-sulfate adsorption stoichoimemtry sine this stoichiometry is independent of the intrinsic affinity constant of sulfate. The charge distribution can be related to the structure of the surface complex by use of the Pauling bond valence concept and is in accordance with the microscopic structure found by spectroscopy. The intrinsic affinity constant follows  More>>
Publication Date:
Oct 15, 1999
Product Type:
Journal Article
Reference Number:
EDB-00:007039
Resource Relation:
Journal Name: Journal of Colloid and Interface Science; Journal Volume: 218; Journal Issue: 2; Other Information: PBD: 15 Oct 1999
Subject:
54 ENVIRONMENTAL SCIENCES; GOETHITE; SORPTIVE PROPERTIES; SULFATES; ADSORPTION ISOTHERMS; ENVIRONMENTAL TRANSPORT
OSTI ID:
20013620
Research Organizations:
Wageningen Univ. (NL)
Country of Origin:
United States
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0021-9797; JCISA5; TRN: IM200010%%488
Submitting Site:
DELTA
Size:
page(s) 511-521
Announcement Date:

Journal Article:

Citation Formats

Rietra, R P.J.J., Hiemstra, T, and Riemsdijk, W.H. van. Sulfate adsorption on goethite. United States: N. p., 1999. Web. doi:10.1006/jcis.1999.6408.
Rietra, R P.J.J., Hiemstra, T, & Riemsdijk, W.H. van. Sulfate adsorption on goethite. United States. doi:10.1006/jcis.1999.6408.
Rietra, R P.J.J., Hiemstra, T, and Riemsdijk, W.H. van. 1999. "Sulfate adsorption on goethite." United States. doi:10.1006/jcis.1999.6408. https://www.osti.gov/servlets/purl/10.1006/jcis.1999.6408.
@misc{etde_20013620,
title = {Sulfate adsorption on goethite}
author = {Rietra, R P.J.J., Hiemstra, T, and Riemsdijk, W.H. van}
abstractNote = {Recent spectroscopic work has suggested that only one surface species of sulfate is dominant on hematite. Sulfate is therefore a very suitable anion to test and develop adsorption models for variable charge minerals. The authors have studied sulfate adsorption on goethite covering a large range of sulfate concentrations, surface coverages, pH values, and electrolyte concentrations. Four different techniques were used to cover the entire range of conditions. For characterization at low sulfate concentrations, below the detection limit of sulfate with ICP-AES, the authors used proton-sulfate titrations at constant pH. Adsorption isotherms were studied for the intermediate sulfate concentration range. Acid-base titrations in sodium sulfate and electromobility were used for high sulfate concentrations. All the data can be modeled with one adsorbed species if it is assumed that the charge of adsorbed sulfate is spatially distributed in the interface. The charge distribution of sulfate follows directly from modeling the proton-sulfate adsorption stoichoimemtry sine this stoichiometry is independent of the intrinsic affinity constant of sulfate. The charge distribution can be related to the structure of the surface complex by use of the Pauling bond valence concept and is in accordance with the microscopic structure found by spectroscopy. The intrinsic affinity constant follows from the other measurements. Modeling of the proton-ion stoichoimetry with the commonly used 2-pK models, where adsorbed ions are treated as point charges, is possible only if at least two surface species for sulfate are used.}
doi = {10.1006/jcis.1999.6408}
journal = {Journal of Colloid and Interface Science}
issue = {2}
volume = {218}
journal type = {AC}
place = {United States}
year = {1999}
month = {Oct}
}