Preparation of high specific surface area hydroxyapatite for environmental applications
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We report the preparation of hydroxyapatite in powdered form by aqueous reaction of calcium nitrate or hydroxide with phosphate ion at room temperature. With a slow maturation step of 48 h avoiding heat, the resulting products show large specific surface areas above 150 m2/g. The specific surface areas also depend on stirring speed with a maximum observed with gentle mixing. Ageing causes a decrease in specific surface area which tends to stabilize near 100 m2/g following a 1 year period. The hydroxyapatite may be spray dried and conserve interesting physical properties for environmental applications.
KeywordsHydroxyapatite Calcium Phosphate Calcium Hydroxide Calcium Nitrate Tricalcium Phosphate
We gratefully acknowledge help from Solvay HSE (Belgium) in the form of a research stipend. Our gratitude goes to ADEME (French Environment Agency) for funding this research under the grant No 02-74-111.
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