Developments and structures of mesopores in alkaline-treated ZSM-5 zeolites
Developments and structures of mesopores in alkaline-treated ZSM-5 zeolites
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DOI：
10.1007/s10450-006-0561-1
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发表时间：
2006-09
期刊：
影响因子：
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通讯作者：
Y. Tao;H. Kanoh;K. Kaneko
中科院分区：
文献类型：
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作者：
Y. Tao;H. Kanoh;K. Kaneko
在325 K下，在0.05 M氢氧化钠水溶液中对SiO2/Al 2 O3摩尔比为24的ZSM-5沸石进行不同时间的处理。通过77 K氮气吸附、场发射扫描电子显微镜、X射线衍射和傅里叶变换红外光谱对样品进行了表征。实验结果表明，碱处理时间对ZSM-5分子筛中孔的发育和结构有影响。碱处理初期，中孔主要由MFI沸石的边界部分向本体发展，而长时间的碱处理则破坏了中孔，碱处理1.5h时，中孔率最高。另一方面，根据X射线衍射和傅里叶变换红外光谱的检测，碱处理沸石中的堆积和短程有序几乎没有变化。
ZSM-5 zeolites with SiO2/Al2O3molar ratio of 24 were treated in 0.05 M aqueous sodium hydroxide solution at 325 K in different periods. The samples were characterized by means of nitrogen adsorption at 77 K, field emission scanning electron microscopy, X-ray diffractometry, and Fourier transform infrared spectroscopy. Analysis of the experimental results showed that the alkaline treatment periods have influence on the developments and structures of mesopores in the alkaline-treated ZSM-5 zeolites. Alkaline treatment initially develops mesopores mainly from the boundary portion of MFI zeolites to the bulk, while prolonged treatment destroys the mesopores, and an optimum mesoporosity is obtained by the treatment for 1.5 h. On the other hand, crystallinities and short-range order in alkaline treated zeolites have remained virtually unchanged according to the examination from X-ray diffractometry and Fourier transform infrared spectroscopy.