Oxidative desulfurization of fuel oil catalyzed by magnetically recoverable nano-Fe3O4/SiO2 supported heteropoly compounds

The magnetically recoverable catalysts for fuel oil oxidative desulfurization Cs2.5H0.5PW12O40/nano-Fe3O4/SiO2 and H3PW12O40/nano-Fe3O4/SiO2 were successfully synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), vibrating sample magnetometer (VSM), transmission electron microscope (TEM) and elemental analysis (EA). Besides, the desulfurization conditions by using the prepared catalysts were selected according to the experiment. Under the selected conditions, the desulfurization rates by using H3PW12O40/nano-Fe3O4/SiO2 and Cs2.5H0.5PW12O40/nano-Fe3O4/SiO2 can reach 99.4% and 91.4% respectively in the simulated oil, indicating that the H3PW12O40/nano-Fe3O4/SiO2 exhibits higher catalytic activity. When H3PW12O40/nano-Fe3O4/SiO2 was used, the desulfurization rate for stabilized gasoline and catalytic diesel oil treated by the oxidative desulfurization combined with continuous extraction could reach 96.3% and 97.1%, respectively. Moreover, the catalyst can be easily recovered with the aid of an external magnetic field, maintaining the high catalytic activity after three times’ reuse. Compared with our previous work, these magnetic supported catalysts were easier to recover than H3PW12O40 and Cs2.5H0.5PW12O40. Also, the catalyst loss in the magnetic recycle process was sharply decreased compared with the traditional recycle process. Finally, the observed data of the oxidative reaction basically match the first order kinetic model.