High-yield activated carbon based ZnO-Ce bifunctional catalyst for production of biodiesel from waste cooking oil.

• Waste cooking oil to biodiesel using avocado and mango seeds based catalyst. • Cost-effective bifunctional catalyst for the production of biodiesel from waste oil. • The catalyst's high surface area and effective metal dispersion were confirmed. • Low activation energy bifunctional catalyst. • 99.6% biodiesel yield, surpassing similar studies. Converting waste oil into biodiesel has significant economic and environmental benefits, including reducing waste disposal costs and reducing dependence on fossil fuels. However, bifunctional catalysts for esterification–transesterification reactions generally have low yields and high production costs, limiting their commercialization. This study addresses these issues by investigating the preparation and use of high-value energy products obtained from agricultural waste, especially avocado and fruit curd seed, for the production of biodiesel from waste oil. The bifunctional catalyst synthesized by the wet impregnation method showed remarkable efficiency in the esterification-transesterification reaction. The experimental setup has different reaction conditions such as temperature, catalyst loading, and microwave power for better biodiesel production. Characterization methods including SEM-EDS and FTIR confirmed the large surface area of the catalyst and efficient metal degradation. The improved purification increased the biodiesel yield to 99.6 %, exceeding results reported in similar studies. Kinetic studies revealed an activation energy of 45 kJ/mol, indicating good catalytic activity. Biodiesel complies with ASTM D6751 and EN 14214 standards and has properties such as a high heating value (HHV) of 40 MJ/kg and API absorption of 30. This demonstrates the potential of using waste products from agriculture to produce biodiesel to provide a sustainable pathway for waste management and renewable energy production. [ABSTRACT FROM AUTHOR]