Highly stable heterogeneous catalysts from electric furnace dust for biodiesel production: Optimization, performance and reaction kinetics

Highly stable heterogeneous catalysts were prepared by impregnating carbonates suspension solutions onto electric furnace dust (EFD) and being calcined at high-temperature for the production of biodiesel from soybean oil. Process of impregnating with CaCO3, BaCO3, SrCO3 and CdCO3 suspension solutions and being calcined at high-temperature did not promote improvement of catalytic activity of EFD powder, while the single impregnating with K2CO3 suspension solution can only improve its catalytic activity in the first use. Na2CO3@EFD catalyst synthesized by impregnating with only Na2CO3 suspension solution owned considerable catalytic activity from nano Na2CO3 (37.0 nm) and good recyclability from nano Fe3O4 (size of 30.0 nm & Ms of 26.77 Am2/kg) with biodiesel yield of 99.13 wt% at 65 °C in 2 h with 15/1 methanol/oil molar ratio and 7 wt% catalyst dosage in the first use (93.50 wt% in the eleventh use). The kinetic study with Na2CO3@EFD was carried out, and it was found that the activation energy was 32.81 kJ/mol and the frequency factor was 3760.85 /min, lower than reported solid base catalysts, which suggested synthesized Na2CO3@EFD catalyst owned remarkable potential for industrial application in biomass energy conversion.