Solid-state synthesis of poultry waste derived hydroxyapatite: Effect of calcination temperature on crystallographic parameters and biomedical competency

The efficacy of hydroxyapatite (HAp) in a specific application depends on certain characteristics such as crystallographic parameters, phase, morphology, dimensional anisotropy, particle size, etc. The calcination temperature plays a crucial role in these properties, and selecting the optimum temperature for the intended application is very crucial. In this study, HAp was produced using eggshell of chicken, a type of poultry waste. The synthesis was carried out using the solid-state method. Subsequently, the material was subjected to calcination at three different temperatures: 750 degrees C, 850 degrees C, and 950 degrees C. The prepared S-HAp samples underwent characterization through XRD, FTIR, Raman, FESEM, EDX, DLS particle size (hydrodynamic diameter), and zeta potential. Crystallographic parameters, such as crystallite size (CS), degree of crystallinity (CI), lattice mea-surements, density of dislocations, micro-strain, and the proportions of beta-TCP in terms of percentage and volume, were also calculated. CS was calculated using five methods and CI was estimated using XRD, FTIR and Raman data. The biomedical competency of S-HAp samples in terms of cytotoxicity, hemolysis, antibacterial activity and bioactivity was investigated. Variance in crystallographic parameters with respect to calcination temperature was observed, although variance in biomedical competency was insignificant. The S-HAp samples synthesized using poultry waste were found to be highly biocompatible, bioactive, and antibacterial as well.