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Preparation of High Performance ZSM-5 Zeolite Membranes for CO2/H2 Separation
  • Seyed Mojtaba Mirfendereski,
  • Tayebeh Mazaheri
Seyed Mojtaba Mirfendereski
Arizona State University
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Tayebeh Mazaheri
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Abstract

High-quality ZSM-5 zeolite membranes were successfully synthesized on the outer surface of tubular α-alumina substrates by manipulating the microstructure of the zeolite layer using a new different-sized seeding (DSSM) in combination with variable-temperature/time (VTT) methodd. In this method the microcracks/defects in the primary seed layer are filled by smaller seeds and effectively eliminated using a proper temperature/time profile, resulting in a significant increase in selectivity without scarifying permeance. The effects of number and combination of seed layers, seed size, and synthesis conditions on the microstructure, N2/SF6 gas permeation, and H2/CO2 separation performance of membranes are evaluated in detail. The synthesized ZSM-5 membranes show the microstructure of thin, fully inter-grown, and densified zeolite layer that is responsible for high selectivity without any negative effect on the permeance. The best synthesized defect-free membranes exhibited a very low H2/CO2 selectivity of 0.1 with CO2 permeance of 3×10-5 mol m-2 s-1 Pa-1.