Synthesis of Hydroxyapatite from Oyster Shell via Precipitation

In this work, oyster shell which predominantly composed of calcium carbonate, was used as a staring material for synthesizing hydroxyapatite powder. By calcinating the oyster shell powder at 1200 °C for 2 h, the pure calcium oxide characterized by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), was obtained. The XRD pattern also agreed with the standard JCPDS file No.001-1160. The obtained calcium oxide powder was reacted with nitric acid to form the calcium nitrate which was further reacted with di-ammonium hydrogen phosphate at various pH values from 8 to 10 at room temperature and calcined at 900 °C for 2 h. From XRD results, the HA powder was obtained at pH 10 as confirmed by the standard JCPDS file No. 076-0694. In addition, The crystallize size of HA was found to be 89.5 nm from XRD result.