Hydroxyapatite nanocrystals synthesized from calcium rich bio-wastes

Hydroxyapatite nanocrystals were synthesized by wet chemical precipitation using bio-waste shells of mollusk (clam and mussel) and egg as feedstock materials. The powdered shells were calcined, dissolved in water, and the resulting product was reacted with phosphoric acid. X-ray diffraction analysis identified pure phase of hydroxyapatite for the three different raw materials. Transmission electron microscopy observations of hydroxyapatite indicated that rod-like crystals were produced in nanometric scale, which showed pH-dependent surface charges using zeta potential analysis. Overall, this study proved that calcium-rich bio-wastes are valuable materials to be used as feedstock for production of high purity and economically feasible hydroxyapatite nanocrystals for biomedical and technological applications. (C) 2018 Elsevier B.V. All rights reserved.