Characterization of nanosized hydroxyapatite from <i>Lates calcarifer</i> fish bones and optimization of thermal calcination process using response surface methodology

Abstract This study examines the influence of calcination temperature and time on the particle size of nano-hydroxyapatite (HAp) synthesized from Lates calcarifer seabass bones. The bone powders were pre-treated by alkaline treatment to remove proteins and lipids before undergoing calcination at temperatures ranging from 550 °C to 650 °C for 2.5–4.5 h. The resulting nano-HAp particles were characterized using x-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. To determine which factors most significantly impact nanoparticle size, response surface methodology was employed, focusing on calcination temperature and time. Results indicated that temperature primarily influences particle size reduction: as temperature increased within the 100 °C range studied, the average HAp size decreased from approximately 72.04–52.87 nm. Higher calcination temperatures yielded finer nanoparticles even when reaction time was held constant. In contrast, extending the calcination time at a constant temperature tended to increase HAp particle size, demonstrating a proportional relationship between calcination duration and particle growth. Calcination temperature plays a crucial role in obtaining sub-100 nm HAp, which is beneficial for biomedical applications, as precise nanoparticle size tuning can significantly influence bioactivity and material performance.