During the 2nd half of Year I, we continued the development of the microporous ceramic layer as a transition layer for the deposition of the carbon molecular sieve membrane on the stainless steel substrate offered by Pall Corp. Based upon the positive result from the feasibility study conducted in the 1st half of Year I, our activities in this period focused on eliminating the high pore size peak and the minimization of defect. A microporous ceramic layer with 40A pore size and <1% initial flow have been successfully prepared. Further, this modified membrane has demonstrated excellent thermal stability, <1% initial flow after the 5 thermal cycles. In addition we began the CMS layer deposition on the AccuSep with the ceramic transition layer. The CMS membranes fired at the low temperature range demonstrate an excellent hydrogen permeance, up to >5 m(sup 3)/m(sup 2)/hr/bar, with the selectivity of (approx)20 for H(sub 2)/N(sub 2). The extremely high permeance is indicative of the extremely thin CMS membrane layer, which becomes possible as a result of the uniform and defect free transition layer. This could be an ideal membrane for hydrogen recovery applications where the hydrogen permeance is the primary concern. Presently we are actively pursuing the intermediate temperature firing to enhance the selectivity to above this range without sacrificing too much permeance.
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