Effect of pretreatment processes on physicochemical properties of hydroxyapatite synthesized from Puntius conchonius fish scales

The current study emphasizes on the novel idea of synthesizing hydroxyapatite (HAp) from Puntius conchonius fish scales’ bio-waste and study the effect of acid, alkali and acid–alkali pretreatments on its physicochemical properties. Material characterization is carried out to study the physicochemical properties of the synthesized HAp using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDX) and transmission electron microscopy (TEM) analysis. FTIR and XRD plots show peaks corresponding to natural bone apatite which confirms the formation of HAp. TG analysis shows a maximum weight loss of 2.28% indicating high thermal stability of HAp beyond 800 $$^\circ $$ C. SEM micrographs illustrate highly porous morphology with interconnected pores. EDX analysis of the HAp exhibits close proximity of the calcium/phosphorous (Ca/P) ratio to natural bone apatite. TEM micrographs show the formation of polycrystalline HAp particles with size ranging from $$38\pm 1.54$$ to $$219\pm 5.88~\hbox {nm}$$ . A comparative study on the physicochemical properties of HAp synthesized using three different pretreatment processes is performed. Results reveal that HAp synthesized from acid-treated fish scales show highest yield percentage, better thermal stability and highly porous morphology with a particle size of $$38 \pm 1.54~\hbox {nm}$$ . Thus, HAp synthesized from acid-treated fish scales can be a promising candidate for the development of porous bone scaffolds.