Microwave-assisted biodiesel production from WCO using snail shell-derived CaO@Coal fly ash: Optimization via RSM, cost analysis, kinetics, thermodynamics, and bibliometrics

The global energy crisis and growing environmental alarms have hastened the search for renewable energy sources. This study explores a novel approach to biodiesel synthesis using microwave-assisted transesterification with a composite catalyst derived from snail shell-derived calcium oxide (CaO) supported on coal fly ash. The synthesized catalyst exhibits FAME conversion of 98.03 % under optimal conditions. Diverse analytical techniques were utilized to characterize the catalyst using TGA, XRF, BET, CO₂-TPD, XRD, XPS, SEM, ICP-OES, and TEM analysis. Kinetic and thermodynamic parameters resulted in an activation energy of 36.6 kJ mol⁻¹, an activation enthalpy of 33.62 kJ mol⁻¹, and an entropy of −0.173 kJ mol⁻¹ K⁻¹, respectively. The cost analysis effectively demonstrated the economic viability of this method. A comprehensive bibliometric analysis also provided insights into the research trends and developments in biodiesel production from waste materials regarding feedstock and catalysts. The findings indicate that microwave-assisted biodiesel production with eco-friendly catalysts offers a promising alternative for sustainable energy, meeting economic and environmental objectives as the Sustainable Development Goals (SDGs).