| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 675665 | Thermochimica Acta | 2006 | 6 Pages |
Abstract
The influence of the anionic substitution and the thermal treatment on the acid/base properties of hydroxyapatite was studied by temperature-programmed desorption of ammonia (TPD-NH3). Stoichiometric hydroxyapatite, A-type and B-type carboapatites have been synthesized. Substitution of OH− by the CO32− (Carbo-A) modifies the acid strength distribution, increases the overall acidity and acid site density (μmol/m2). Substitution of the PO43− (B-site) by the CO32− did not lead to noticeable changes on the adsorption sites. These results suggest that the Ca2+ ions are the most significant sites for ammonia adsorption.
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Authors
Neuman S. Resende, Marcio Nele, Vera M.M. Salim,