A new seeding method, dry rolling applied to synthesize SAPO-34 zeolite membrane for nitrogen/methane separation

Abstract

A new seeding method for the secondary growth of zeolite membrane, dry rolling, was applied to synthesize SAPO-34 zeolite membrane. In dry rolling, seeds are introduced on the outer surface of tubular support by mechanically rolling support in a cylindrical container with dry seed particles. During the process, plate-like SAPO-34 seeds fractured into smaller particulates which were uniformly distributed on the support and partially infiltrated into the pores of the support. The low speed and long seeding provided a more homogeneous seed layer due to uniform distribution of fractured tiny seeds and no mechanical damage of support. The homogeneous seed coating reliably developed SAPO-34 separation layer with better performance during the secondary growth process compared with conventional manual rubbing. The membrane synthesized at an optimum condition showed N2/CH4 permselectivity of 4.38 and N2 and CH4 permeance of 399 and 91 GPU, respectively. The performance was comparable or better than generally reported single gas performance, but the performance reliability was much better. Therefore, it could be concluded that dry rolling can be one of the reliable seeding processes for the preparation of zeolite membranes.