Effects of Surface Acidity on the Adsorption Desulfurization of Cu(I)Y Zeolites

Abstract

Cu(I)Y zeolites with different degrees of ion exchange were prepared by solid state ion exchange (SSIE) and liquid phase ion exchange (LPIE). The surface acidity of the Cu(I)Y zeolite was characterized by adsorbed pyridine infrared spectroscopy (Py-IR) and the adsorbents desulfurization capabilities were evaluated by a fixed-bed adsorption experiment. We observed that after modification using different ion exchange methods the Cu(I)Y zeolites retained the structure of the Y zeolite completely. The amount of exchanged Cu + and the surface acidity including the Bronsted (B) acid content and the Lewis (L) acid content greatly affected the adsorption desulfurization process. After SSIE and with an increased degree of ion exchange the B acid gradually transformed to the L acid as a result of an improvement in the adsorption capacity. The results revealed that decreasing B acid content might be the essiential reason for the evidently improved adsorption desulfurization activity for the Cu(I)Y zeolites prepared by different ion exchange methods.