Chemical synthesis of bone-like carbonate hydroxyapatite from hen eggshells and its characterization

Carbonate hydroxyapatite (CHAp) was synthesized from domestic hen eggshells by using three alternative wet chemical methods at room temperature. In the first method, the powdered eggshells were reacted directly with H3PO4. In the other two methods, calcium acetate was obtained in a first step by dissolving the eggshells in acetic acid. Then, calcium acetate was reacted with Na3PO4 center dot 12H(2)O and (NH4)(2) HPO4 in the second and third methods, respectively. The synthesized CHAp was characterized by X-Ray Diffraction (XRD), Fourier Transformed Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Fine and poorly crystallized CHAp was obtained under all experimental conditions employed. Among all synthesized materials, the one produced by the first method showed the closest resemblance to bovine bone, which was related to similar carbonate contents in both materials. In general, acicular CHAp crystals with a size ranging from 10 to 100 nm were obtained, which had an aspect ratio of similar to 1/4. The morphology of the synthesized CHAp crystals was consistent with their estimated carbonate content.