| 초록 |
The deca-dodecasil 3 rhombohedral (DDR) zeolite which has a pore size of 0.36 × 0.44 nm2 is appropriate for CO2 (0.33 nm) separation from CH4 (0.38 nm). Herein, DDR@CHA hybrid zeolite membranes comprising mainly of DDR zeolite is reported. Choosing an appropriate calcination condition minimizes the defects in membranes and enhances the performance. Clearly, low-temperature calcination in O3 reduced defect formation, resulting in a high CO2/CH4 separation factor (ca. 523±96 at 50 °C) under dry condition. Interestingly, for high separation performances (CO2/CH4 SF of 422) under wet conditions required the formation of a few defects. The defect structures were quantitatively analyzed and the inhibition of water-molecule-adsorption on CO2 permeation rates was estimated. This demonstrated that fully opening the DDR zeolite micropores, while minimizing the formation of microdefects assisted in achieving the highest CO2 permselectivities for wet CO2/CH4 mixtures. |
