On the mechanism of specific phosphate adsorption by hydroxylated mineral surfaces: A review
作者:
Sabine Goldberg,
Garrison Sposito,
期刊:
Communications in Soil Science and Plant Analysis
(Taylor Available online 1985)
卷期:
Volume 16,
issue 8
页码: 801-821
ISSN:0010-3624
年代: 1985
DOI:10.1080/00103628509367646
出版商: Taylor & Francis Group
关键词: Anion adsorption;ligand exchange;surface chemistry;O‐phosphate
数据来源: Taylor
摘要:
The mechanism of specific phosphate adsorption by hydroxy‐lated mineral surfaces comprises two aspects: the phosphate‐hydroxyl surface reaction and the configuration of the adsorbed phosphate ion. Evidence pointing to ligand exchange as the mechanism of the phosphate‐surface hydroxyl reaction include kinetics of adsorption and desorption; hydroxyl ion release; infrared spectroscopy, and stereochemical calculations. Data pertaining to the coordination of adsorbed phosphate on hydroxy‐lated mineral surfaces have not been conclusive overall. Isotopic exchange experiments and studies of desorption kinetics do not provide definitive information on surface coordination. Measurements of hydroxyl ion release and crystallographic calculations provide support for the existence of both monodentate and bidentate surface complexes of phosphate ions. Infrared spectroscopic investigations suggest a binuclear complex on dried, phosphated goethite. However, these studies cannot be extrapolated automatically to soil minerals, since the addition of water favors formation of a monodentate surface complex. Further research is needed to establish the configuration of adsorbed phosphate ions.
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