Deproteinization Controlled Phase Selection in Calcium Phosphate Biomaterials Derived from <i>Tenualosa ilisha</i> Fish Scale Waste: A Sustainable Valorization Approach

The sustainable management of fishery waste is a growing environmental concern, with fish scales offering promising sources for high-value biomaterials. In this study, calcium phosphate biomaterials (CPBs) were selectively synthesized by varying the chemical treatment of Tenualosa ilisha fish scales. Single-step acid (1 N HCl) or base (1 N NaOH) deproteinization followed by calcination at 1000 °C yielded the magnesium-containing β-tricalcium phosphate (β-TCP, whitlockite) phase, confirmed through X-ray diffraction (XRD) analysis. In contrast, a sequential acid–base treatment led to the formation of highly crystalline monoclinic hydroxyapatite (HAp). Detailed crystallographic analysis revealed superior crystallinity, larger crystallite size, and lower lattice strain for the HAp phase compared to those of the whitlockite phase. Crystallite sizes of 52, 48, and 118 nm were…