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Synthesis and property of silicalite-1 membranes by restricting growth method with dilute solution

โœ Scribed by Wei Xiao; Jianhua Yang; Dong Shen; Jinming Lu; Jinqu Wang


Publisher
Elsevier Science
Year
2010
Tongue
English
Weight
990 KB
Volume
129
Category
Article
ISSN
1387-1811

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โœฆ Synopsis


A specific synthesis mode, based on precursor diffusion through the support channels, the restricting growth method (RGM) with ultra-dilute precursor has been designed to prepare silicalite-1 zeolite membranes on seeded macroporous a-Al 2 O 3 tubular supports. Several parameters were systematically investigated to evaluate their influence on performance of the membranes, including the H 2 O/SiO 2 ratio, template type and crystallization temperature. X-ray diffraction (XRD), scanning electron microscopy (SEM) and single-gas permeation tests were used to characterize the as-prepared membranes. Results showed the membrane prepared under optimum parameters (H 2 O/SiO 2 ratio of 800, TPAOH as template and crystallization at 443 K) was continuous, dense and with a controllable section thickness almost the same as that of the seed layer. It displayed preferable hydrogen permeance (1.2 ร‚ 10 ร€6 mol m ร€2 s ร€1 Pa ร€1 ) and permselectivity (a H2/SF6 = 134) at 298 K under 0.1 MPa pressure drop. Moreover, due to the utilization of ultra-dilute precursor, this technique has the advantage of reduced chemical consumption. On the contrary, the uncompacted membranes with poor permeation behavior were obtained by the conventional secondary growth method under the same synthesis parameters.


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