Recycling Eggshell Waste Into Calcium Oxide Nanoparticles: A Sustainable Approach for Nanomaterial Synthesis and Potential Applications

Eggshell (ES) wastes have been ranked as the $15^{\text {th}}$ food industry pollution due to the ever-increasing regular consumption of primary dietary products, eggs. Management and treatment of tons of discarded eggshells produced daily on a global scale are realized to be a predicament, and an immediate solution must be advocated to address the pollution. This sets a tone for the recyclability of this biowaste in a myriad of fields, like nanotechnology, biomedical, and environmental pollution control. Calcium carbonate in the shells makes it a safe precursor for producing calcium oxide as a nanomaterial by the top-down approach – calcination. This paper highlights a facile way to procure waste eggshell-derived metal oxide nanoparticles with reproducibility and recyclability. Calcium Oxide Nanoparticles (CaO NPs) obtained at two different calcination temperatures for optimization and this was characterized by SEM, FTIR, XRD, DLS, and Zeta Potential analyzer. CaONPs are less-studied metal oxide nanoparticles but hold promising applications in different fields. Hence, there is a scope for further investigation on the non-toxic, non-hazardous CaO NPs obtained facilely – an effort to minimize and regulate food wastes.