Síntese de biodiesel utilizando catalisador bifuncional baseado em ferrita com óxido metálico suportado

Abstract

In this study, a solid magnetic acid catalyst MoO3/SrFe2O4, composed of molybdenum oxide (MoO3) supported on strontium ferrite (SrFe2O4), was synthesized and applied in the transesterification of waste cooking oil (WCO). The catalyst was characterized by acid-base titration method in order to determine Surface acidity, Thermogravimetric analysis (TG/DTG), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy dispersion X-ray spectroscopy (EDS) and Vibrating sample magnetometry (VSM) techniques. A central composite design of centered face 24 (FCCD) and a mathematical model was developed in order to describe the behavior of the ester content as a function of the independent variables temperature, alcohol:oil molar ratio, catalyst dosage and time reaction. The mathematical model (R2=0.9900) was validated and showed a relative error below 5% between the experimental and predicted values. Using linear regression methods and response surface methodology (RSM) the conditions of biodiesel synthesis reaction were optimized and 95.4% conversion into esters was obtained from the use of the reaction temperature of 164 °C, alcohol:oil molar ratio of 40:1, catalyst dosage of 10% and reaction time of 4 h . The catalyst showed high reusability, since it was possible to use it in 8 reaction cycles which it is an indication of its good prospectus for development and application as bifunctional catalyst.