Abstract
Background: Oxidative desulfurization of fuel oils has attracted much attention in recent years. Ti-containing microporous zeolites exhibited good reactivity in oxidative desulfurization of thiophene with small molecular size. However, they were almost not active in oxidative desulfurization of sulfur compounds with relatively large molecular size mainly due to the inaccessibility of active sites located in micropores. To remedy this shortage, it has been of great interest to synthesize Ti-containing hierarchical zeolites by the introduction of additional mesopores or/and macropores. The aim of this work is to improve the catalytic performance of Ti-containing zeolite Y in oxidative desulfurization of sulfur compounds with relatively large molecular size by synthesizing Ti-containing hierarchical zeolite Y.
Methods: The hierarchical zeolite Y was firstly synthesized by post-treatment method. Then, Ticontaining hierarchical zeolite Y with different Ti contents was prepared by wet impregnation technique.
Results: The catalytic performance of catalysts was evaluated by oxidative desulfurization of dibenzothiophene. Ti-containing hierarchical zeolite Y with 30% Ti content exhibited superior catalytic activity.
Conclusion: Ti-containing hierarchical zeolite Y with more active sites and relatively large mesopore volume exhibited superior catalytic performance. The removal efficiency of DBT over this catalyst with 30% Ti content reached 97% after a reaction time of 120 min at 323 K. Accordingly, the sulfur content in model fuel was reduced from 1000 ppm to 30 ppm. Such catalyst has potential applications for ODS of fuel oils due to richly accessible active sites and low preparation cost.
Keywords: Zeolite Y, hierarchical, titanium, oxidative desulfurization, dibenzothiophene, heterogeneous catalysis.
Graphical Abstract
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