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。
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.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
1996年第6期540-543,共4页
关键词
分子筛
热稳定性
水热稳定性
微孔
磷酸硅铝
SAPO 34 molecular sieve, Thermal stability, Hydrothermal stability
