Catalytic performance of NiFe2O4 and Ni0.3Zn0.7Fe2O4 magnetic nanoparticles during biodiesel production

In this study, catalytic performance of nanoferrites NiFe₂O₄ and Ni_0.3Zn_0.7Fe₂O₄ is reported. Nickel–ferrite and mixed nickel–zinc ferrite were successfully synthesized by combustion reaction using a conical reactor with production of 10 g per batch. Crystallinity and purity or quantitative analysis of the catalyst were checked by using X-ray diffraction and energy dispersive X-ray analysis. Surface chemistry was examined via Fourier transform infrared (FTIR) analysis; N₂ physisorption at 77 K was conducted to obtain textural properties of the catalyst; a thermogravimetric analysis, a scanning electron microscope and a transmission electron microscopy were used to check the thermal stability and morphology of the catalyst, respectively. The catalysts were used to convert soybean oil into biodiesel in a batch mode and the reaction mixture was analyzed using a pre-calibrated gas chromatograph (GC). The presence of a single-phase spinel structure in the synthesized nanoparticles was confirmed by the XRD results. The Ni_0.3Zn_0.7Fe₂O₄ had a lower surface area value of 71.5 m²g⁻¹ and higher saturation magnetization value of 31.50 emu/g than sample NiFe₂O₄ which had 87.6 m²g⁻¹ and 17.85 emu/g, respectively. Biodiesel yield of 94% was obtained with Ni_0.3Zn_0.7Fe₂O₄ and 49% was obtained with NiFe₂O₄. Better performance of Ni_0.3Zn_0.7Fe₂O₄ when compared to that of NiFe₂O₄ could be attributed to higher acidity of the former. Findings from this study suggest that the development of nickel-zinc ferrite nanoparticles as magnetic heterogeneous catalysts could provide an environmentally friendly platform for biodiesel production.