Preparation of spherical apatite particles by the homogeneous precipitation method in the presence of magnesium ions and their ion-exchange properties

• Published in: Materials research bulletin 1999-10, Vol.34 (8), p.1215-1225
• Main Authors: Aizawa, Mamoru, Terado, Tomoko, Howell, F.S, Itatani, Kiyoshi
• Format: Article
• Language: English
• Subjects: A. inorganic compounds; B. chemical synthesis; C. electron microscopy; C. infrared spectroscopy; C. X-ray diffraction; Chemistry; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; General and physical chemistry; Growth from solutions; Ion-exchange; Materials science; Methods of crystal growth; physics of crystal growth; Other ion exchangers: preparations and properties; Physics; Surface physical chemistry
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/S0025-5408(99)00118-X

Spherical apatite particles were prepared by the homogeneous precipitation method in the presence of magnesium ions. The starting solutions were prepared by mixing 0.167 mol·L −1 of Ca(NO 3) 2, 0.100 mol·L −1 of (NH 4) 2HPO 4, 1.00 mol·L −1 of (NH 2) 2CO, 0.10 mol·L −1 of HNO 3, and a small amount of Mg(NO 3) 2. The carbonate-containing apatite powders were obtained by heating these solutions at 80∼95°C for 48∼192 h. Although fibrous particles with long-axis lengths of 30 to 60 μm were obtained from the magnesium-free solution, spherical agglomerates with diameters of ∼10 μm, which contained minute plate-like particles, were present in the apatite powders derived from the solutions with 5 mass% of magnesium ions. The ion-exchange test for the harmful ions (Pb 2+, Cd 2+, and Ni 2+) showed that the ion-exchange abilities of the apatite powders containing magnesium ions were much better than the ability of the magnesium-free apatite powder. The ion-exchanged amounts of the apatite powder containing magnesium ions were arranged in the following order: Pb 2+ >> Cd 2+ > Ni 2+.