Effect of Phosphate Precursor on the Production of Hydroxyapatite from Crocodile Eggshells

Abstract

The hydrothermal reaction at 250°C between crocodile eggshells and three phosphate precursors, (NH4)2HPO4, Ca3(PO4)2 and H3PO4 were studied. Only (NH4)2HPO4 and Ca3(PO4)2 precursors gave monophasic hydroxyapatite within 25 and 8 h, respectively. Pure hydroxyapatite could not be produced when using H3PO4. The characteristic vibration for PO43- are observed at 566-603, 1043-1093, 962-963 and 466-474 cm-1 and for OH- group at 3570-3572 and 633-634 cm-1. The morphology of the prepared hydroxyapatite is agglomerated plate-like crystals. The Ca/P ratio by ICP method is 1.62-1.64.