不同晶化温度对ZSM-5分子筛结构和形貌的影响

Effect of Different Crystallization Temperature on the Crystalline Structure and Morphology of Zeolite ZSM-5

以四丙基溴化铵(TPABr)为结构导向剂,采用水热法制备了ZSM-5分子筛。利用XRD、FT-IR及SEM等表征手段研究了不同晶化温度对样品结构、形貌和粒径大小的影响规律。当晶化温度由95℃升高至175℃,结晶度由48.3%提高到95.1%,产物粒径分布更为均匀。晶化温度为195℃时,结晶度减至79.7%,部分粒径增大且不规则。由此可见,通过升高晶化温度可以提高ZSM-5分子筛的结晶度和粒径的均匀性,但是过高温度会使分子筛发生溶解-再结晶过程,部分转化成SiO_2。

ZSM -5 zeolites were prepared by hydrothermal synthesis method using TPABr as a structure directing agent. The effects of crystallization temperatures on structure, morphology and particle size of samples were investigated by using XRD, FT - IR and SEM. With increasing crystallization temperature from 95℃ to 175℃, the crystallinity rose from 48.3% to 95.1% and the particle size became more uniform. When it came to 195℃, the crystallinity was 79.7% and parts of particle size were irregularly increased. These results show that the increase of temperature can improve the crystallinity and uniformity of the particles; however, the extravagant temperature would cause dissolution - recrystallization reaction on zeolites and parts of them were transformed into quartz phase.