Chemical precipitation of nanocrystalline hydroxyapatite with calcium carbonate derived from green mussel shell wastes and several phosphorus sources

This work reports on a chemical precipitation experiment to produce nanocrystalline calcium hydroxyapatite (Ca-HA) using a calcium carbonate precursor derived from green mussel shells. Ammonium biphosphate and phosphoric acid were mixed with the precursor, achieving a pH of 13–14 by stirring magnetically at 30 °C for 48 hours. The nanocrystalline Ca-HA product (8–13 nm) was validated through X-ray diffraction and Fourier-transform infrared spectroscopy with an average calcium-to-phosphorus ratio molar of 1.8, influencing the thermal stability according to thermogravimetric and differential thermal analysis. Green mussel shell wastes are a recyclable calcium resource potentially used to synthesize nanocrystalline hydroxyapatite.