Journal of Chemical and Engineering Data, Vol.64, No.12, 5439-5447, 2019
Stability Improvement of FAU Zeolites Ion-Exchanged with Copper-Ammonia Solution for the Removal of Thiophene and Benzothiophene from Model Fuel
Faujasite (FAU) zeolites with low Si/Al ratios (e.g., X-type zeolites) have much more exchangeable cation sites than those with high Si/AI ratios (Y-type zeolites) for Cu(I), which could improve the adsorption performance via pi-complexation. However, the structure of Cu-exchanged X-type zeolites was unstable during autoreduction at high temperatures as reported [Takahashi; et. al., Ind. Eng. Chem. Res., 2002, 41, 2487-2496]. Here, we proposed a scheme of Cu -exchanged X-type zeolites in copper-ammonia solution to improve the stability of the zeolite structure during autoreduction. Therefore, it makes us be able to study the adsorption properties of thiophenic compounds in Cu(I)-exchanged FAU zeolites from low to high Si/Al ratios. The modified zeolites were characterized by X-ray diffraction, high resolution transmission electron microscopy, inductively coupled plasma spectroscopy, X-ray fluorescence, and Brunauer-Emmett Teller analysis and tested by adsorption desulfurization experiments in model fuels. The results indicate that the modified zeolites with various Si/Al ratios show different adsorption properties for thiophene and benzothiophene. The adsorption capacity for thiophene decreased in the order Cu(I)Y-5.30 > Cu(I)X-1.23 > Cu(I)Y-2.30. For benzothiophene, the adsorption capacity decreased in the order Cu(I)Y-2.30 > Cu(I)Y-5.30 > Cu(I)X-1.23.