Molecular recognition and adsorption performance of benzothiophene imprinted polymer on silica gel surface

On the surface of silica gel chemically modified with γ-aminopropyltriethoxysilane and methacrylic acid, a molecularly imprinted polymer (MIP) for the selective benzothiophene recognition was prepared by using methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the crosslinker, and benzothiophene as the template molecule. The textural properties of MIP were characterized by FT-IR, elemental analysis and N₂ adsorption; its static adsorption performance for benzothiophene was tested with a model gasoline. The results showed that a porous thin layer of MIP was successfully grafted on the surface of silica gel carrier. The imprinted polymer exhibits good specific benzothiophene recognition; the adsorption of benzothiophene on it accords with Langergren quasi-one kinetic equation and Langmuir isotherm of monolayer adsorption. The adsorption capacity of MIP for benzothiophene reaches 57.4×10^-3, in comparison with 33.1×10^-3 of the non imprinted polymer; its adsorption capacity remains almost unchanged after regeneration for many times. This may provide a new approach for deep desulfurization of gasoline to remove sulfur-containing thiophenic compounds.