Abstract: The silica gel and allochroic silica gel were c characterized by X-ray diffraction （XRD），Fourier transform infrared spectrum （FT-IR），nitrogen adsorption and NH3-TPD. The results of XRD and FT-IR indicated that the two samples are amorphous structure. The average pore diameter of silica gel and allochroic silica gel are 18.46 nm and 1.80 nm，the surface areas are 437.86 and 623.39 m2/g，the pore volumes are 0.972 4 and 0.344 2 m3/g, respectively. The results of TPD showed that the acidity of allochroic silica gel is far stronger than that of silica gel. The adsorption removals of quinoline in model diesel over alumina，diatomite，silica gel and allochroic silica gel were investigated. The experiment results indicated that the adsorption denitrification performance of allochroic silica gel is much superior to that of other three adsorbents. The stronger acidity of allochroic silica gel is helpful to enhance its removal quinoline by adsorption. Moreover，the adsorption thermodynamics for removal of quinoline or pyridine over the allochroic silica gel from model diesel were further investigated. The adsorption isotherms of quinoline and pyridine belong to S type. Experiment data was fitted Langmuir and Freundlich equations with the R of two regression equations is much the same. But the adsorption of pyridine over allochroic silica gel belongs to Freundlich adsorption model; the R of Freundlich regression equation is far more than that of Langmuir.

Key words: allochroci silica gel, model diesel, quinoline, pyridine, adsorptive denitrogenation, absorption isotherm