TEMPERATURE-PROGRAMMED DESORPTION DIFFUSION OF AMMONIA IN MOLECULAR-SIEVES .5. ZSM-5 ZEOLITE

被引：23

作者：

FORNI, L ^{[1
]}

VATTI, FP ^{[1
]}

ORTOLEVA, E ^{[1
]}

机构：

[1] UNIV MILAN,CTR CNR,I-20133 MILAN,ITALY

来源：

MICROPOROUS MATERIALS | 1995年 / 3卷 / 4-5期

关键词：

ZSM-5; ZEOLITES; TEMPERATURE-PROGRAMMED DESORPTION; AMMONIA; HZSM-5; NAZSM-5;

D O I：

10.1016/0927-6513(94)00051-V

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

Some ZSM-5 zeolite samples with an SiO2/Al2O3 ratio of 10.3 have been analysed by temperature-programmed desorption (TPD) of ammonia to investigate how the rate-determining step of the desorption-diffusion process depends on some experimental parameters and on the physicochemical characteristics of the zeolite. By comparison with previous results on a ZSM-5 sample with SiO2/Al2O3 = 33.6, a shift of the probable rate-determining step from intracrystalline diffusion of the desorbed gaseous base to desorption of the latter without appreciable readsorption has been noticed. On the other hand, both the change of the temperature ramp from 10 to 2 K/min and the substitution of Na+ for H+ by ion exchange shift the rate-determining step to desorption with free readsorption of the desorbed base.

引用

页码：367 / 375

页数：9

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