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SAPO-34分子筛的热稳定性及水热稳定性
THERMAL AND HYDROTHERMAL STABILITY OF SAPO 34 MOLECULAR SIEVE
【摘要】 利用高温X射线衍射技术,结合差热分析,对SAPO-34分子筛烧除模板剂及随后吸附-脱附水的过程进行了研究.发现模板剂烧除的强放热效应不会导致分子筛骨架结构的破坏,活化后的分子筛中吸附-脱附水,其X射线衍射强度可逆地减弱与恢复.高温(800℃)长时间焙烧及水蒸气处理考察结果表明,SAPO-34分子筛具有优异的热稳定性和良好的水热稳定性.800℃条件下连续焙烧300h,SAPO-34的结晶度仍大于80%,但同温度下长时间水热处理将导致SAPO-34向无定形转变,并伴有硅原子向晶体表面迁移
【Abstract】 Thermal and hydrothermal stability of SAPO 34 molecular sieve have been studied by using high temperature XRD and DTA techniques. It has been found that the thermal effect during the removal of template does not destroy the framework of SAPO 34 molecular sieve. However, water adsorption on the template free SAPO 34 causes the intensity decrease of its XRD peaks. After the desorption of water, the intensity of the XRD peaks restores. Calcination at high temperature (800℃) for a long time (300 h) shows that SAPO 34 possesses good thermal stability (its crystallinity is still greater than 80%). Steam treatment at the same temperature for a shorter time ( ca 100 h) will result in the destroy of framework and migration of Si atoms from bulk to surface.
【Key words】 SAPO 34 molecular sieve; Thermal stability; Hydrothermal stability;
- 【文献出处】 催化学报 ,CHINESE JOURNAL OF CATAL YSIS , 编辑部邮箱 ,1996年06期
- 【分类号】O647.33
- 【被引频次】61
- 【下载频次】735