Exploration of Calcium Oxide Nano-catalyst from Snail Shells for Production Optimization of Biodiesel from Waste Cooking Oil

Abstract

The increasing demand for sustainable energy has driven the exploration of waste cooking oil (WCO) as a low-cost feedstock for biodiesel production. Hence, the objective of this paper was the exploration of calcium oxide nanocatalyst from snail shells for production optimization of biodiesel from waste cooking oil using appropriate standard methods via calcination at 900 °C and catalytic performance of pretreated WCO. Data obtained show that Catalyst characterization using XRF, FTIR, and SEM confirmed high CaO purity (93.67 wt%), porous morphology, and suitable surface chemistry for catalysis. Process optimization was performed using Response Surface Methodology coupled with Central Composite Design (RSM-CCD), involving 20 experimental runs. The quadratic model showed excellent fit (R² = 0.9927) with a maximum biodiesel yield of 91.49% at optimum conditions of 9:1 methanol-to-oil ratio, 1.5 wt% catalyst loading, and 50 °C reaction temperature. The produced biodiesel exhibited favorable physicochemical properties, including kinematic viscosity of 4.32 mm²/s, flash point of 168 °C, cetane number of 54.8, and ester content of 96.8%, largely complying with ASTM D6751 and EN 14214 standards. This study demonstrates the potential of waste-derived CaO nanocatalyst as an efficient, eco-friendly, and cost-effective heterogeneous catalyst for sustainable biodiesel production from WCO