High-quality standard oil synthetic zeolite-13 (SSZ-13) membranes with thickness only ~ 1.0 μm 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 CO

2

permeances of 1.3×10

–6

and 1.5×10

–6

mol·m

-2

·s

-1

·Pa

-1

and CO

2

/CH

4

and CO

2

/N

2

selectivities of 125 and 27 for equimolar CO

2

/CH

4

and CO

2

/N

2

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 CO

2

permeance and CO

2

/CH

4

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 CO

2

capture from natural gas

biogas and flue gas.