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采用程序升温脱附(TPD)、真空重量吸附、ESCA和正己烷的裂化反应研究了水热处理对ZSM-5沸石表面性质及催化性能的影响。不同Si/Al比的ZSM-5沸石均有两类不同酸强度的TPD峰。随着水热处理温度升高,较强酸峰Ⅱ比较弱酸峰Ⅰ下降快,同时单位晶胞的酸性中心数、表面积、表面硅铝比和环己烷的吸附量均下降,正己烷裂化活性上随之下降。水热处理前,不同Si/Al比的ZSM-5沸石晶胞中酸中心数相差甚大,730℃水热处理后,它们的酸中心数接近相同,其较强酸峰Ⅱ消失。
The effects of hydrothermal treatment on the surface properties and catalytic performance of ZSM-5 zeolites were investigated by temperature programmed desorption (TPD), vacuum weight adsorption, ESCA and n-hexane cracking reactions. There are two types of TPD peaks with different acid intensities for ZSM-5 zeolites with different Si / Al ratios. With the increase of hydrothermal treatment temperature, the peak I of stronger acid peak II decreased faster than the weak peak I of acid peak, meanwhile the number of acid centers, surface area, surface area ratio of silica to alumina and the adsorption capacity of cyclohexane decreased, and the cracking activity of n-hexane Drop down. Before hydrothermal treatment, the number of acid centers in ZSM-5 zeolites with different Si / Al ratios varied greatly. After the hydrothermal treatment at 730 ℃, their acid centers were close to the same, and the strong acid peak II disappeared.