FUEL 179 |
| A novel method is presented for the preparation of microporous silicon carbide membranes. The strategy comprises periodic coating of sacrificial interlayers and SiC pre-ceramic layers. In order to keep in place the interlayers; a solvent has been selected for the pre-ceramic polymer which does not dissolve the sacrificial interlayer during the dip-coating process or afterwards. Previously, we reported the advantages of first-layer conditioning of SiC tubular supports by slip-casting over solely the dip-coating technique in terms of enhancing both membrane performance and the success rate of preparing high quality membranes. The new preparation method involves first dip-coating the slip-casted supports in polystyrene (PS) solution, and then drying. The supports were subsequently dip-coated in allylhydridopolycarbosilane (AHPCS) solution, and then pyrolyzed at 750oC resulting in complete decomposition of the polystyrene, and the forming of a SiC membrane layer on the top. The procedure of coating, drying and pyrolyzing of PS and AHPCS layers was carried out for three additional times. Membranes prepared, so far, show single gas ideal separation factors of helium and hydrogen over argon in the range (176-420) and (100-200), respectively, with an increase of about two to three times in permeance compared to the our previously prepared membranes. We speculate that the sacrificial interlayers fill the pores and prevent their blockage by the pre-ceramic polymer. This new method shows good promise for application to a variety of other inorganic membrane systems. |
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Inorganic Membranes for Energy and Environmental Applications
1:00 PM-6:00 PM, Tuesday, August 21, 2007 Boston Park Plaza -- Chartes River Room, Oral
Division of Fuel Chemistry |