Highly active novel K2CO3 supported on MgFe2O4 magnetic nanocatalyst for low-temperature conversion of waste cooking oil to biodiesel: RSM optimization, kinetic, and thermodynamic studies

An innovative K2CO3/MgFe2O4 (KC/MGF) magnetic nanocatalyst for effective biodiesel generation from WCO is demonstrated here. To examine the physiochemical and morphological features of the catalyst, several charac-terization methods such as XRD, FT-IR, SEM-EDX, HR-TEM, AFM, XPS, BET, CO2-TPD, and VSM are used on the as-synthesized magnetic nanocatalyst. Optimization of K2CO3 loading on MgFe2O4 is achieved and 30KC/MGF was found as the optimum ratio. Response surface methodology (RSM) via central composite design (CCD) is constructed using optimization margins to clarify the optimal parametric conditions; catalyst loading (4-6 wt%), reaction time (90-120 min), and methanol to oil ratio (6:1-9:1) at a fixed low operating reaction temperature (50 & DEG;C). The obtained optimum reaction conditions are 4.4 wt% catalyst loading, 108 min reaction time, 6.6:1 methanol to oil ratio, at 50 & DEG;C achieving ca. 92.9% biodiesel conversion. 30KC/MGF is an energy-conserving magnetic nanocatalyst with excellent basicity that operates at low temperatures, for a markedly short period of time, and with a low methanol-to-oil molar ratio. Kinetics and thermodynamic parameters are estimated i.e., activation energy (Ea), change of enthalpy of activation (& UDelta;H#), and change of entropy of activation (& UDelta;S#) to be 31.5 kJ mol-1, 28.9 kJ mol-1, and-188.8 J mol-1 K-1, respectively. Gibbs free energy (& UDelta;G#) is appraised at 308, 313, and 318 K to be 87.1, 88, and 88.9 kJ mol-1, respectively. Due to K+ leaching, utilizing 30KC/MGF in sequential runs results in a significant activity plummet. The catalyst activity is recovered by re-impregnation with K2CO3 precursor solution, resulting in the same high FAME conversion as fresh 30KC/MGF. Finally, the physicochemical properties of biodiesel are investigated and determined to be compliant with international American and European standards.

Automated summary

An innovative magnetic nanocatalyst, KC/MGF, was developed for the effective production of biodiesel from WCO. The catalyst was characterized using various methods, and optimal reaction conditions were determined using response surface methodology. The kinetic and thermodynamic parameters of the catalyst were estimated, and the catalyst was found to be recoverable through re-impregnation. The physicochemical properties of the biodiesel produced were found to comply with international standards.