A greener approach towards sustainable production of biodiesel from waste frying oil using biowaste-derived Unio pictorum shell-Musa acuminata peel ash nanocomposite catalyst

Abstract

Sustainable biodiesel production from waste-derived feedstock utilizing an efficient, eco-friendly catalyst offers the dual benefits of waste mitigation and renewable energy generation. In this work, an environmentally benign heterogeneous nanocomposite catalyst was synthesized from biowastes, including Unio pictorum shells and Musa acuminata peels, for the production of biodiesel from waste frying oil (WFO). Physicochemical characterizations revealed that the synthesized catalyst was predominantly composed of CaO and K₂CO₃ as active constituents responsible for the methanolysis of triglycerides. Numerous transesterification process parameters were optimized using response surface methodology (RSM) within the Box–Behnken design (BBD) model to maximize biodiesel conversion while minimizing resource utilization. An excellent biodiesel conversion of 98.2% and a biodiesel yield of 97.5% were achieved under optimal reaction conditions. Additionally, the proposed catalyst demonstrated exceptional reusability over 7 catalytic cycles with minimal activity loss, indicating high conversion efficiency and structural stability throughout the reaction. Transesterification kinetics conformed to the pseudo-first-order model, while thermodynamic studies indicated that the reaction is non-spontaneous and endothermic. Achieving a high turnover frequency and lower values of green metrics suggests that the subsequent transesterification process is clean, efficient, and environmentally friendly. Furthermore, several of its fuel characteristics, including the calorific value, cetane number, kinematic viscosity, cloud point, and pour point, complied with the ASTM D-6751 standards, rendering it suitable for diesel engines. This research showcases a clean and sustainable approach to producing biodiesel using biowaste-derived catalysts, aligning with green chemistry principles and promoting the circular economy.