Study on thiol and thioether removal with modified Y zeolite

Samples of Cu (Ⅰ) Y, NiY and CeY were prepared by modifying a NaY type zeolite with a liquid ion-exchange method and characterized by means of XRD, ICP-MS, pyridine Py-FTIR, NH₃-TPD and low temperature N₂ adsorption-desorption.Use of micro coulombmeter WK-2D, sulfide luminescence detecting chromatography GC-SCD and fixed bed technology to evaluate the desulfurization performance of the samples for a 300 μg/g sulfur content model oil (dipropyl sulfide, cyclohexanol mercaptan and 1-heptyl mercaptan are prepared with nonane, etc.) and a hydrodesulfurization (HDS) gasoline. Results show that Cu (Ⅰ) Y has good adsorption desulfurization performance on those different oils. In the liquid ion-exchange process, the modified Y zeolite's surface acidity has greatly changed. The strong surface Bronsted (B) acidity of modified Y zeolite has negative effects on adsorption desulfurization through catalyzing mercaptan and thioether to form bigger molecules, which cover the surface of Y zeolite and block the adsorption activity sites, resulting in lower sulfur adsorption capacity of the catalyst. The weak surface Lewis (L) acidity has positive effects on adsorption desulfurization.