Publication Date:
2012-11-17
Description:
Zeolite Na A membranes were prepared hydrothermally by secondary crystallization process at different temperatures (55°C–75°C) on porous α-alumina-based support tubes (inner side) precoated with poly(ethyleneimine) (PEI) buffer layer and Na A seed particles. The Na A seed crystals synthesized at 65°C/2 h in the size range 100–200 nm having BET surface area of 71.57 m 2 g −1 were used for secondary crystallization of the membranes. The secondary crystallization at 65°C for (4 + 4) h (double-stage) showed highly dense Na A grains in the microstructure of the membrane with a thickness of 5 μm. It rendered the permeance values of 50.6 × 10 −8 , 2.47 × 10 −8 , and 0.55 × 10 −8 molm −2 s −1 Pa −1 for H 2 , N 2 , and CO 2 , respectively, with their permselectivity of 20.48 ( H 2 / N 2 ), 92 ( H 2 / CO 2 ), and 4.49 ( N 2 / CO 2 ). A tentative mechanism was illustrated for the interaction of PEI with the support substrate and Na A seed crystals.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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