Abstract: Selective adsorptive desulfurization of model gasolines containing different amounts of aromatics and olefin compounds, such as benzene and 1-octene, on Ce(IV)Y zeolite was studied using a fixed-bed adsorption column, Fourier transform-infrared spectroscopy (FT-IR), and ultraviolet diffuse reflection spectroscopy (UV-DRS) techniques. It was found that both benzene and 1-octene had strong inhibiting effects on the desulfurization which could be detected by the decreases in the desulfurization capacities of the Ce(IV)Yin the presence of benzene and 1-octene in the model gasoline. The FT-IR and UV-DRS spectra of the Ce(IV)Y zeolites adsorbing the model gasolines revealed that benzene was desorbed easily because of the formation of π-complexes, while 1-octene was desorbed difficultly due to the strong interactions between the double-bond of 1-octene and the Ce4+ to form the π-complexes through the σ-π electron donations. Therefore, it could be concluded that the effect of benzene on the adsorptive removal of sulfur compounds could be ascribed to the competitive adsorption on the Ce(IV)Ybetween the aromatics and the organosulfur compounds in the fuels. While for the effect of 1-octene, the Ce(IV)Y zeolites adsorbed preferentially the 1-octene molecules onto adsorption sites, resulting in descending adsorptive selectivity for removing thiophene from the model fuel containing even minor amount of olefin.

Key words: Zeolite, Selective adsorption, Desulfurization mechanism, FT-IR, UV-DRS