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利用XRD,~(27)Al MASNMR,IR和 NH_3-TPD等技术考察了水热处理温度、水热气氛及沸石硅铝比,在水热条件下对ZSM-5沸石骨架铝的迁移和表面酸性的影响,发现随着水热处理温度的升高,沸石表面酸性的变化和骨架铝的迁脱量有很好的对应关系,400℃时骨架铝迁脱量为600℃迁脱量的80％;表面强酸中心的递减速率较弱酸中心快。提高沸石硅铝比和在碱性水热气氛中处理可以减缓骨架铝的迁脱,保留了较多的酸性中心,在酸性气氛中则骨架铝的迁脱加速。
The hydrothermal treatment temperature, hydrothermal atmosphere and silica to alumina ratio of zeolite were investigated by XRD, ~ (27) Al MASNMR, IR and NH 3 -TPD techniques. The results showed that the migration and surface acidity of ZSM-5 zeolite framework aluminum under hydrothermal conditions It is found that the change of acidity on the zeolite surface correlates well with the migration of framework aluminum as the hydrothermal treatment temperature increases. The migration amount of framework aluminum is about 80% of the migration amount of 600 ℃ at 400 ℃. The rate of decrease of strong acid center is faster than that of weak acid. Increasing the Si / Al ratio of zeolites and the treatment in alkaline hydrothermal atmosphere can slow the migration of framework aluminum, retain more acidic sites and accelerate the migration of framework aluminum in acidic atmosphere.