Biodiesel production on bench scale from different sources of waste oils by using NiZn magnetic heterogeneous nanocatalyst

Different types of waste oils (soybean, sunflower, corn, and cottonseed) were evaluated in simultaneous esterification and transesterification reactions for more sustainable production of biodiesel by heterogeneous magnetic catalysis. The Ni0.5Zn0.5Fe2O4 magnetic nanoparticles (MNPs) were synthesized by combustion reaction on a pilot-scale of 200 g/batch, showing obvious conditions for possible scalability for large scale production. The properties of the MNPs were investigated by X-ray diffraction, Rietveld refinement, UV-Vis, Brunauer, Emmett, and Teller/Barrett, Joyner, and Halenda method, granulometric distribution, pH, zeta potential, and NH3-TPD. The results confirmed the formation of the majority phase of the inverse NiZn spinel, with median particle of 39.6 nm, and surface area of 64 m(2)/g with acid character. The quality measures provide the adequacy of the biodiesel obtained and the gas chromatography showed conversions from 86.65% to 98.12%. Finally, the MNPs were successfully recovered and reused in three more cycles without activity loss, and with capacity for new recycles due to its high reactivity and stability.