In Situ Growth of Continuous b-Oriented MFI Zeolite Membranes on Porous α-Alumina Substrates Precoated with a Mesoporous Silica Sublayer
In Situ Growth of Continuous b-Oriented MFI Zeolite Membranes on Porous α-Alumina Substrates Precoated with a Mesoporous Silica Sublayer
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DOI：
10.1021/cm048644j
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发表时间：
2005-02
影响因子：
8.6
通讯作者：
Fazhi Zhang;and Masayoshi Fuji;Minoru Takahashi
中科院分区：
文献类型：
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作者：
Fazhi Zhang;and Masayoshi Fuji;Minoru Takahashi
采用原位晶化法在介孔SiO_2/多孔α-Al_2O_3基体上制备了连续b取向的MFI膜。在298 ~ 473 K温度范围内，进行了丁烷异构体通过MFI膜的单一气体渗透。在此温度范围内，随着温度的升高，丁烷异构体在b-取向的MFI膜上的渗透率降低，这是由于弱的吸附效应。同时，发现b-取向膜在高温下可以保持较高的正丁烷/异丁烷的理想选择性。相反，在未涂覆的α-氧化铝基底上获得了具有随机取向的顶层的离散膜。进一步研究了两种载体上MFI膜的形成过程，重点是对沸石晶体取向生长的理解。所用基材的表面性质对不同膜厚的MFI膜的形成起着重要作用。
Continuous b-oriented MFI membranes were prepared on a mesoporous silica sublayer-coated porous α-alumina substrate by in situ crystallization. Single gas permeation of butane isomers through the MFI membrane was carried out as a function of temperature from 298 to 473 K. A decreased permeance of butane isomers on the b-oriented MFI membrane with increasing temperature is observed in this temperature range, which is attributed to a weak adsorption effect. Meanwhile, it was revealed that the b-oriented membrane can maintain a high ideal selectivity of n-butane/i-butane at elevated temperatures. On the contrary, a discrete membrane with a randomly oriented top layer was obtained on the uncoated α-alumina substrate. Further investigation on the evolution of the MFI membranes on the two kind substrates was performed with the focus on the understanding of the oriented growth of zeolite crystals. The surface properties of the substrates used played an important role in the formation of MFI membranes with differ...