Improved SSZ-13 thin membranes fabricated by seeded-gel approach for efficient CO2 capture

High-quality standard oil synthetic zeolite-13 (SSZ-13) membranes with thickness only ti 1.0 lm were prepared on tubular supports by the new seeded-gel approach. Seeded-gel approach is simpler than the normal secondary-growth one since adding seeds in the gel is simpler than seeding on the support surface. The synthesis time was greatly reduced from 3.0 to 1.0 d after synthesis modification of gel aging and seed sizes. Low temperature ozone calcination was used for the removal of the organic structural directing agent. The best SSZ-13 membrane displayed CO2 permeances of 1.3 x 10-6 and 1.5 x 10-6 mol center dot m-2 center dot s-1 center dot Pa-1 and CO2/CH4 and CO2/N2 selectivities of 125 and 27 for equimolar CO2/CH4 and CO2/ N2 mixtures at 0.2 MPa pressure drop and 298 K, respectively. Separation performance of the membrane in the two binary mixtures is higher than that of most zeolite membranes. Three SSZ-13 membranes were reproducibly prepared on tubular supports by seeded-gel approach and the standard deviation ratios of CO2 permeance and CO2/CH4 selectivity are 12.5% and 7%, respectively. It suggests that this new synthesis approach is creditable. The effects of temperature and pressure on separation performance of the thin SSZ-13 membranes were studied in the two binary mixtures. The tubular SSZ-13 membranes displayed great potentials for CO2 capture from natural gas, biogas and flue gas.(c) 2022 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.