An approach to study the desulfurization mechanism and the competitive behavior from aromatics: A case study on CeY zeolite

Abstract

An approach to study the adsorption desulfurization mechanism and the competitive behavior from aromatics were explored. Cyclohexane, benzene, thiophene, and tetrahydrothiophene were selected to investigate the effect of the sulfur atom and conjugated π bond on thiophene adsorption. The adsorption results obtained in pure thiophene, thiophene–benzene, and thiophene–cyclohexane solutions were compared with each other to investigate how and why benzene affects thiophene adsorption. The sorbent with different active metal valence state was prepared by H2 reduction at different temperatures to study the effect of valence state of the metal loaded on thiophene and benzene adsorption. In order to verify this approach and make it more clearly, a case study on CeY sorbent was carried out. The results show that the approach explored is an effective way to study the adsorption desulfurization mechanism and the competitive behavior from aromatics. Over CeY sorbent, both thiophene and benzene are adsorbed via bonding between unsaturated conjugated π bonds and acid sites, whereas for thiophene, bonding between sulfur and Ce is also important. Moreover, benzene can compete strongly with thiophene for adsorption from a thiophene–benzene mixed solution because the unsaturated connection of benzene bonding to acid sites is stronger than that of thiophene. Replacing Ce(IV) by Ce(III) in CeY is favorable for improving the adsorption capacity of thiophene but not benzene.