Preparation of Cu(I)-Ce(IV)-Y adsorbent and its adsorptive desulfurization performance

Cu(I)Y, Ce(IV)-Y and Cu(I)-Ce(IV)-Y adsorbents were successfully prepared by liquid-phase ion-exchange of Y zeolites with combined Cu and Ce ions. The adsorbents were characterized by means of X-ray diffraction (XRD) and N₂-adsorption specific surface area measurements (BET). The effect of preparation conditions on the adsorptive desulfurization properties over Cu(I)-Ce(IV)-Y were studied by a static desulfurization method. The breakthrough sulfur capacities of the adsorbents were studied in a fixed-bed reactor system. Meanwhile, adsorptive desulfurization selectivities of the adsorbents were studied through model fuels, which made up of 1-octane solution of benzothiophene and thiophene, then respectively mixed with a certain amount of toluene, cyclohexene or pyridine. The results indicate that the optimum preparation conditions of Cu(I)-Ce(IV)-Y is ion-exchange time of 48 h, Cu/Ce molar ratio of 1, and calcination temperature of 550 ℃. Cu(I)-Ce(IV)-Y adsorbent exhibited the best desulfurization performance with model fuels, which contain a certain amount of toluene and cyclohexene. The effect of toluene, cyclohexene and pyridine at the same concentration, on the metal ion-exchanged Y zeolites for sulfur removal is in the order: pyridine > cyclohexene > toluene. The introduction of Cu⁺ can improve the desulfurization activity of adsorbent, while the introduction of Ce⁴⁺ can improve the selectivity of adsorbent. The synergistic effect of Cu⁺ and Ce⁴⁺ contribute to Cu(I)-Ce(IV)-Y not only has the high sulfur adsorption capacity but also has the ability of resistance to aromatics and olefins.