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论文类型：期刊论文

发表时间：2010-04-01

发表刊物：MICROPOROUS AND MESOPOROUS MATERIALS

收录刊物：SCIE、EI

卷号：129

期号：1-2

页面范围：22-29

ISSN号：1387-1811

关键字：Silicalite-1 membrane; Restricting growth; Diffusion; Hydrogen permeation

摘要：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 alpha-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 x 10(-6) mol m(-2) s(-1) Pa(-1)) and permselectivity (alpha(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. (C) 2009 Elsevier Inc. All rights reserved.