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United States Department of Agriculture

Agricultural Research Service

Title: Inconsistency in the Triple Layer Model Description of Ionic Strength Dependent Boron

item Goldberg, Sabine

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 28, 2004
Publication Date: October 31, 2004
Citation: Goldberg, S.R. 2004. Inconsistency in the triple layer model description of ionic strength dependent boron. Soil Science Society of America. Paper No. 3972.

Technical Abstract: This study was conducted to evaluate the ability of the triple layer model, a chemical surface complexation model. to describe the effect of changes in solution ionic strength and solution pH on B adsorption by goethite, gibbsite, kaolinite, and montmorillonite, and two soils. Ionic strength dependence of adsorption suggest an inner-sphere adsorption mechanism for goethite, kaolinite, montmorillonite, and the two soils and an outer-sphere adsorption mechanism for gibbsite. The triple model, containing an inner-sphere adsorption mechanism, was able to describe B adsorption on goethite, kaolinite, montmorillonite, and the two soils. The model was able to describe B adsorption on gibbsite using an outer-sphere adsorption mechanism. A problematic inconsistency exists between the type of B surface complex defined and the ionic strength dependence of the model result. That is, postulating an inner- sphere adsorption mechanism in the model resulted in an ionic strength dependence appropriate for the formation of outer-sphere surface complexes and vice versa. Additional tests of the ability of the triple layer model to describe ionic strength dependent adsorption of additional ions are needed to establish whether the inconsistencies are limited to the B system or are of concern in other triple layer model applications.

Last Modified: 12/18/2014
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