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Preparation And Properties Of The Carbon-based Zeolite Composite Membranes

Posted on:2006-03-20Degree:MasterType:Thesis
Country:ChinaCandidate:B X ZouFull Text:PDF
GTID:2121360152485355Subject:Chemical processes
Abstract/Summary:PDF Full Text Request
Zeolite membrane with well-defined crystalline structures offers great impressive applications in separations and catalysis. Most of the early efforts were focused on the study on zeolite films supported on ceramics. But ceramics have a little etching of aluminum by strong alkaline synthesis solutions and also more expensive. Porous carbon materials are promising candidates as zeolite supports because it not only reduces the cost of zeolite composite membranes, but also develops a novel method for tailoring and improving carbon pore structure of porous carbon materials. In this paper, Silcaliate-1 and template-free ZSM-5 zeolite membranes have been successfully synthesized on the carbon tubes by seeded secondary synthesis, and their properties were characterized by XRD, SEM, single gas permeance and pervaperation test.1. Nano-sized silicalite-1 zeolite crystals have been synthesized using TPAOH ethanol solution as a template in a clear synthesis solution. The factors influencing particle size have been investigated.2. Silicalite-1 membranes on porous carbon tubes were prepared using a simple pre-seeding process. The important factors on the synthesis of zeolite silicalite-1 membranes have been systematically examined. The calcination conditions for template removal were optimized. At suitable temperature and N2 gas flow, by using one calcination after one synthesis method, the template can be remolved without any membrane destroyed. At room temperature, the H2 permeance is 20.6×10-8 mol m-2 s-1 Pa-1 and the ideal selectivitis of H2/N2 and H2/C3H8 are 4.29 and 26.41 respectively, which showed a good gas permselectivity.3. Template-free ZSM-5 membranes with high Si/Al ratio supported on carbon tubes have been synthesized for the first time. The peameance of H2 of the membrane is 19x10 mol m-2 s-1 Pa-1 and the ideal selectivities of H2/N2, H2/O2and H2/C3H8 are 3.11, 3.39 and 5.90, respectively.4. The liquid separation potential of the Silicalite-1 and ZSM-5 zeolite membranes supported on the carbon tube was investigated by pervaporation of an aqueous ethanol solution. Ethanol was effectively removed from water through the synthesized Silicalite-1 composite membrane, and water was preferentially permeated through the ZSM-5 membrane with a low separation factor due to its lower selective sorption of ethanol and presence of nonzeolic pores.
Keywords/Search Tags:Nano-sized silicalite-1, zeolite membrane, porous carbon, pervaporation
PDF Full Text Request
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