Selective and simultaneous removal of dibenzothiophene and 4-methyldibenzothiophene using double-template molecularly imprinted polymers on the surface of magnetic mesoporous silica

Abstract

A novel double-template molecularly imprinted polymer on the surface of magnetic mesoporous silica (Fe₃O₄@mSiO₂@DT-MIP) was prepared for the selective and simultaneous removal of dibenzothiophene (DBT) and 4-methyldibenzothiophene (4-MDBT) from gasoline fuel. The Fe₃O₄@mSiO₂@DT-MIP was characterized by transmission electron microscopy, N₂ adsorption–desorption isotherms, Fourier transform infrared spectroscopy and vibrating sample magnetometry. The adsorption behaviors of the Fe₃O₄@mSiO₂@DT-MIP including adsorption kinetics, isotherms and selectivity were investigated in detail by gas chromatography. The adsorption equilibrium was achieved within 60 min and the maximal adsorption amount towards DBT and 4-MDBT reached 104.2 and 113.6 mg g⁻¹, respectively. The adsorption of DBT and 4-MDBT on the Fe₃O₄@mSiO₂@DT-MIP followed the pseudo-second-order kinetic model and Langmuir isotherm. The Fe₃O₄@mSiO₂@DT-MIP could selectively recognize DBT and 4-MDBT in the presence of similar compounds. The Fe₃O₄@mSiO₂@DT-MIP could be used eight times without significant loss in the adsorption capacity. Finally, the Fe₃O₄@mSiO₂@DT-MIP was successfully applied to the desulfurization of trace DBT and 4-MDBT in real gasoline samples. It was concluded that the Fe₃O₄@mSiO₂@DT-MIP provides a new material for deep desulfurization of fuel oils.