Boosted biodiesel production from waste cooking oil using novel SrO/MgFe2O4 magnetic nanocatalyst at low temperature: Optimization process

Abstract

This study addresses the development of a heterogeneous magnetic nanocatalyst composed of SrO/MgFe2O4 (Sr/MGF) for efficient methanolysis of waste cooking oil (WCO). The thus-prepared magnetic nanocatalyst is characterized by TGA, XRD, FT-IR, FE- SEM, mapping EDX, BET, CO2-TPD, NH3-TPD, and VSM. A systematic parametric study is screened to evaluate the optimum reaction conditions. The experimentally obtained optimum conditions are: 2 wt% catalyst loading with SrO:MGF molar ratio of 7:1 operating at 45 °C for 180 min, and 12:1 methanol to oil molar ratio affording 96.8 % biodiesel conversion. Sr/MGF is an energy conserver heterogeneous catalyst operating at low thermal energy input with markedly high biodiesel conversion. This is attributed to the superb basicity of the prepared catalyst. Kinetic and thermodynamic parameters are calculated, i.e., activation energy (Ea), change of enthalpy of activation (ΔH#), and change of entropy of activation (ΔS#) as 48.4 kJ mol−1, 45.7 kJ mol−1, and –132.5 J mol−1 K−1, respectively. Change of Gibbs free energy (ΔG#) is estimated at 318 K, 323 K, and 328 K as 87.9 kJ mol−1, 88.5 kJ mol−1, and 89.2 kJ mol−1, respectively. Furthermore, the physicochemical properties of the produced biodiesel fit perfectly within the limits of ASTM D-6751 and EN-14214 international standards. A reusability study of the catalyst reveals a significant conversion of 92.6 % at the 3rd cycle.