SURFACE COMPLEXATION OF CALCIUM MINERALS IN AQUEOUS SOLUTION .3. ION EXCHANGE AND ACID-BASE PROPERTIES OF HYDROUS FLUORITE SURFACES

摘要

The acid-base properties of hydrous fluorite surfaces and ion exchange reactions between surface lattice ions of F- and OH- ions in bulk solution have been investigated. The measurements were performed as potentiometric titrations with varied solid concentrations in 0.1 mol dm(-3) KCI medium at 25.0 degrees C using a glass electrode for -log?H+? and a fluoride ion selective electrode for -log?F-?. The experimental data could be explained by a model that assumes the surface equilibria ?GRAPHICS? log beta(-210-1)(S)(int)= -20.3 +/- 0.1 The equilibrium constants were evaluated using the computer program FITEQL assuming a constant capacitance model for the electric double layer. (C) 1995 Academic Press, Inc. [References: 14]