Kinetic and optimization study of sustainable biodiesel production from waste cooking oil using novel heterogeneous solid base catalyst

The novel Na-SiO₂@TiO₂ heterogeneous base catalyst was designed and successfully applied to the trans-esterification reaction of waste cooking oil for sustainable biodiesel production. The designed catalyst was characterized by SEM, XPS, FT-IR and BET before treatment, illustrated its suitability for the catalytic trans-esterification reaction. Moreover, the influence of reaction temperature, time, catalyst concentration and WCO:MeOH molar ratio on the catalytic activity were also investigated, resultant 98% biodiesel yield was achieved. The reusability test demonstrated that the Na-SiO₂@TiO₂ catalyst has noticeable catalytic potency up to 5 successive runs. Besides, the kinetics study explains that the reaction is kinetically controlled by pseudo 1st order. The Ea was found to be 21.65 kJ/mol. Similarly, the important thermodynamic parameters such as ΔH^#, ΔS^# and ΔG^# were estimated to be 18.52 kJ.mol⁻¹, −219.17 J.mol⁻¹K⁻¹ and 92.59 kJ.mol⁻¹ respectively.