INVESTIGADORES
NARDA Griselda Edith
artículos
Título:
ADSORPTION OF CITRIC ACID FROM DILUTE AQUEOUS SOLUTIONS BY HYDROXYAPATITE
Autor/es:
E.D.VEGA; G. E. NARDA; F.H.FERRETTI
Revista:
JOURNAL OF COLLOID AND INTERFACE SCIENCE
Editorial:
ACADEMIC PRESS INC ELSEVIER SCIENCE
Referencias:
Lugar: Amsterdam; Año: 2003 vol. 268 p. 37 - 42
ISSN:
0021-9797
Resumen:
The role of citric acid in the demineralization of dental enamel, which is mainly constituted by hydroxyapatite, is important for periodontal
regeneration and in the conditioning of enamel or dentin for bonding restorative resins. The adsorption of citric acid from aqueous solutions
onto synthetic hydroxyapatite at 278, 288, 298, and 308 K and pH 4.8 has been studied by means of UV spectroscopy. The adsorption reaction,
which takes place by an interaction between phosphate groups and citrate anions at the solidsolution interface, yields an adsorbateadsorbent
complex of high stability. The adsorption isotherms fit the Langmuirian shape. The proposed adsorption model, where citrate species interact
in a bidentate manner (one citrate ion links two phosphate sites), is coherent with the experimental data. The activation standard heat and
activation standard entropy were calculated. All the thermodynamic and kinetic parameters were in concordance with the adsorption reaction
proposed in this work.