Influence of calcination temperature in synthesizing eggshell-derived calcium phosphate

Abstract

Hydroxyapatite (HA) has been used in the biomedical field not only due to its structural resemblance to the natural bone but also for its being bioactive and thermodynamically stable in the body fluid. Generally, the synthesis of HA particles through various available methods has been directed in controlling the growth of HA particles size as this characteristic has an implicit effect on the mechanical properties, biocompatibility and biological activity of HA in the application. Raw materials for the synthesis of HA can be obtained from commercial chemicals and natural sources. Natural source, particularly eggshell has been favoured due to the presence of other elements inherent in the eggshell that induced better cell response. In this study, a direct solid-state method was used to synthesize HA powder utilizing a Ca source in carbonated form from calcined discarded eggshells. The milled mixture of calcined eggshell powder and phosphorus precursor was subjected to heat treatment at various temperatures in studying the influence of different calcination temperatures on the HA phase stability, particle size and morphology through X-Ray Diffractometer and Scanning Electron Microscope analysis. Overall, HA powder consisted of flower-like particles was successfully obtained from eggshell through the combination of dry powder mixing and heat treatment at 800 °C.