Physicochemical Characterization of CaO Derived from Pearl Oyster Shells (Pinctada maxima) via Thermal Processing for Potential Biomedical Applications

Calcium oxide (CaO) produced through the thermal transformation of calcium carbonate (CaCO₃) from marine biogenic materials such as Pinctada maxima shells presents strong potential for biomedical material development. This study investigates the physicochemical properties of shell powder calcined at temperatures ranging from 700°C to 1100°C for 6 hours. Characterization was conducted using organoleptic tests, EDX, FTIR, SEM, and XRD. Organoleptic evaluation confirmed the powder to be odorless, white, and fine in texture. EDX analysis showed a marked increase in CaO content, peaking at 100% at 1100°C, indicating successful thermal decomposition of CaCO₃. FTIR results showed the disappearance of carbonate (CO32-) and C - H bands and the emergence of O - H and Ca - O bands, confirming the formation of CaO. XRD analysis revealed a phase transition from aragonite and calcite (orthorhombic) to CaO (cubic), along with a decrease in crystallinity from 56.95% to 48.32%. SEM analysis indicated irregular particle morphology with the largest average size (2638.77 nm) at 1100°C. These transformations in structure and composition demonstrate the material's biophysical relevance, particularly its potential in bone regeneration applications. This study provides fundamental insights into the conversion of marine shell waste into bioactive material for future biomedical use.