Preparation, Characterization Of Magnetic Solid Base And Its Application In Biodiesel Production

Biodiesel as a green renewable energy, it has many advantages, such as better lubricity, biodegradation, at the same time, non-containing sulfur and aromatic-free. At present, biodiesel is produced through esterification or transesterification by homogeneous acid or homogeneous alkali. This technique has high reaction rate and conversion rate, but more waste liquid, difficulty in separation, complex process and so on. Using solid alkali as the catalyst, it could be avoided the problem caused by homogeneous catalyst in reaction, and it has many advantages, such as mild reaction conditions, reusability of catalyst, automated continuous production, no corrosion of equipment and no pollution to environment.In this thesis, two kinds of magnetic solid base catalyst of double function (K/BC-Fe3O4and K/ZrO2-Fe3O4) is designed to solve the problem of difficult recovery of the solid base catalyst. The optimization of preparation conditions and characterization of magnetic solid base catalyst have been studied, then the two catalysts were applied to the production of biodiesel by transesterification reactions. The main research contents are as follows:(1)The optimum preparation conditions of magnetic solid-base K/BC-Fe3O4which is prepared by in-situ method is as follows:KNO3amount:30%; calcination temperature:500C; calcination time:3h.The characterization results of SEM (Scanning Electron Microscope), low temperature N2adsorption-desorption, XRD (X-Ray Diffraction) and VSM (Vibrating Sample Magnetometer) indicate that the magnetic catalyst possesses the characteristics of mesoporous materials. The basic sites were produced after calcination of precursor. And the characteristic diffraction peak of γ-Fe2O3and α-Fe2O3phase appears in the spectrogram. The saturation magnetization of magnetic catalyst calcined at500C is highest and approaches35.4emu/g. The optimum conditions for transesterification are shown as follows:catalyst amount:2.5wt.%of oil, molar ratio of methanol/oil8:1, reaction time:60min, reaction temperature:60C and the biodiesel yield reaches98.0%.(2)The optimum preparation conditions of magnetic solid-base K/ZrO2-Fe3O4 which is prepared by gel-sol method is as follows:KOH amount:30%; calcination temperature:600C; calcination time:4h. The characterization results of TEM (Transmission Electron Microscope), low temperature N2adsorption-desorption, XRD (X-Ray Diffraction) and VSM (Vibrating Sample Magnetometer) indicate that the nano-magnetic catalyst possesses the characteristics of mesoporous materials. The Zr(OH)4is converted to ZrO4with the production of basic site after calcination. The saturation magnetization of magnetic catalyst calcined at600C is highest and approaches15.4emu/g. The optimum conditions for transesterification are shown as follows: catalyst amount:5.0wt.%of oil; molar ratio of methanol/oil:10:1; reaction time:3.0h; reaction temperature:65C, and the yield of biodiesel reaches93.6%.(3) The duck oil is employed as a new feedstock for the production of biodiesel by transesterifi cation. The fatty acid composition and content examination of raw duck oil is conducted by GC-MS analysis. The composition and content of fatty acid methyl ester (FAME) is also evaluated during transesterifi cation catalyzed by NaOH.