Catalytic conversion of residual raw material into biodiesel using a superior magnetic solid acid catalyst based on Zn-Fe ferrite: thermodynamic and kinetic studies.

This study investigates the potential and applicability of a novel solid magnetic catalyst constructed by incorporating molybdenum oxide (MoO3) into zinc ferrite (ZnFe2O4) to biodiesel production using Waste Frying Oil (WFO) as the residual raw material. The molybdenum amounts (5, 15, 25, 35 and 45%) present in the catalyst were studied and the catalyst demonstrated great characteristics and high acid properties, as well as superior magnetic and catalytic attributes. The one variable at time (OVAT) optimization method revealed that the application of the MoO3/ZnFe2O4 catalyst resulted in obtaining a biodiesel with 97.6% ± 0.727 conversion to fatty acid methyl esters (FAME) under the following optimized reaction conditions: temperature of 165 °C, methanol : WFO molar ratio of 40 : 1, catalyst amount of 6 wt% and reaction time of 3 h. In addition, the catalyst showed high reusability after six reaction cycles, with conversion to esters above 90%. Besides, the activation energy (E a) calculated in the kinetic study was 25.3 kJ mol-1. Moreover, the properties of the synthesized biodiesel met the standards set by the ASTM D6751 and EN 14214, which indicates the high MoO3/ZnFe2O4 potential for industrial application with low energy consumption as well as minimal negative environmental impact.

Tungsten oxide supported on copper ferrite: a novel magnetic acid heterogeneous catalyst for biodiesel production from low quality feedstock.

This study aims to synthesize a WO3/CuFe2O4 catalyst through a wet impregnation method and use it as a new magnetic acid catalyst in the transesterification process of waste cooking oil (WCO). The results of the characterization by XRD, FTIR, SEM, EDS, TG/DTG, VSM and Surface Acidity showed that the obtained bifunctional catalyst has been successfully synthesized. The study of the reaction parameters, such as reaction temperature (140-180 °C), reaction time (1-5 h), molar ratio MeOH : oil (25 : 1-45 : 1) and catalyst loading (2-10% m m-1) was performed in the conversion of WCO into biodiesel via transesterification. The reactional behavior showed the following optimal reaction conditions: reaction temperature of 180 °C, reaction time of 3 h, molar ratio MeOH : oil of 45 : 1 and catalyst loading of 6%. Based on the results, biodiesel with a maximum ester content of 95.2% was obtained using the WO3/CuFe2O4 magnetic catalyst under the optimal reaction conditions. The magnetic catalyst showed excellent catalytic and magnetic performance and it was applied in five reaction cycles with ester content above 80%. Biodiesel properties were found in accordance with ASTM limits. This research provided the development of a stable and reusable WO3/CuFe2O4 bifunctional catalyst for potential application in biodiesel production.