Preparation of Cu-, Zn-, Co-Zeolites and Application for Adsorptive Desulfurization of Saudi Arabian Medium Crude

A series of Cu (II)-, Zn (II)-, Co (II)-loaded zeolites were successfully prepared by liquid phase ion-exchange method and characterized by X-ray diffraction (XRD), N2-adsorption specific surface area measurement (BET), X-ray fluorescence (XRF), and scanning electron microscopy (SEM) techniques. The adsorptive desulfurization performance of different adsorbents for treating Saudi Arabian medium crude oil was investigated, and the results showed that desulfurization efficiency declined in the following order: Zn(II)X > Cu(II)Y > Co(II)X > Cu(II)X > Co(II)Y> Zn(II)Y. The best desulfurization efficiency of 41.01% was achieved by using Zn(II)X as the adsorbent under the optimized conditions. The desulfurization performance of Zn(II)X in different distillates showed that a better performance was obtained in heavy petroleum fractions. Furthermore, the distribution of sulfur compounds in distillates after desulfurization was analyzed and the results showed that the adsorbent Zn(II)X could preferably adsorb aromatic sulfides such as thiophenes, benzothiophenes, and dibenzothiophenes. These results suggested that the π-complexation between zinc ions and sulfides would be crucial to the excellent desulfurization efficiency of Zn(II)X. In addition, the used adsorbent could be regenerated by heating at 700 °C in air, and around 84% of desulfurization capacity was recovered after the first cycle of regeneration.