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Interaction of Some Alkali Metal Citrates with Hydroxyapatite Ion-Exchange Adsorption and Role of Charge Balance

Published

Author(s)

D N. Misra

Abstract

Proper balancing of the concentration of citrate ions in soft drinks is important in order to regulate cariogenic potential of these ions. The uptake, or ion-exchange adsorption, of sodium or potassium citrates from their aqueous solutions onto synthetic hydroxyapatite at 22 degrees {Celsius} was investigated in the present study as a means to elucidate the role of citrate ions in the cariogenic process. For each salt, the amount of uptake, or removal of citrate ions from its aqueous solutions by the apatite, bears a simple ratio to the amount of calcium or phosphate ions released into the solutions by the substrate. The uptake isotherms may be represented by the Languir plots. The interaction is purely ion-exchange absorption; there is no indication of any foreign phase. Plausible equations for ion-exchange equilibria show that the surface is electrically charged upon the adsorption of salts, unlike that of the citric acid, and this may have a baring on the effective area occupied by the adsorbate species.
Citation
Colloids and Surfaces
Volume
141

Keywords

adsorption, alkali metal citrates, hydroxyapatite, Ion-exchange, surface charge

Citation

Misra, D. (1998), Interaction of Some Alkali Metal Citrates with Hydroxyapatite Ion-Exchange Adsorption and Role of Charge Balance, Colloids and Surfaces (Accessed April 24, 2024)
Created October 1, 1998, Updated June 2, 2021