Preparation of Pd/SAPO-34/PSS composite membranes for hydrogen separation: Effect of crystallization time on the zeolite growth on PSS support

In this study, palladium composite membranes were fabricated on porous stainless steel (PSS) supports using silicoaluminophosphate (SAPO) zeolite (SAPO-34) as a diffusion barrier and substrate modifier. The vacuum-assisted seeding and secondary growth method was used to coat the SAPO-34 zeolite layer on the PSS substrates. The morphologies and microstructures of the membranes were analyzed by AFM, XRD, BET, ICP-AES, FESEM and EDX techniques. The effect of crystallization time (24, 48 and 72 h) on the morphology and quality of SAPO-34 modified supports was studied. A continuous palladium layer with a thickness of about 9 p.m was deposited on the SAPO-34 modified PSS support (72 h crystallization time) by electroless plating (ELP) route. The hydrogen permeation tests were carried out in the feed pressures range of 2-4 bar and various temperatures (623, 673 and 723 K). The values of the hydrogen permeance and ideal selectivity of H-2/N-2 for the PSM3 membrane were achieved 7.1 x 10(-7) mol m(-2)s(-1) Pa-1 and 866, respectively a feed pressure of 2 bar and 723 K. In addition, the PSM3 membrane showed perfect stability during 260 h hydrogen permeation experiment at a feed pressure of 2 bar and 623 K. (C) 2019 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.