| 초록 |
Si-DDR zeolites, which have a pore size of 0.36 × 0.44 nm2, are highly desirable for separating CO2 (0.33 nm) from N2 (0.364 nm) on the basis of the size difference. Despite their potential as CO2 separators, the synthetic protocols that allow for the uniform-sized DDR zeolite particles have not been thoroughly studied. We found that a seeded growth of irregular Si-DDR particles obtained by non-seeded growth, resulted in mono-dispersed with diamond-like Si-DDR particles and the size of the Si-DDR particles decreased when seed amount increased. Adsorption isotherms of CO2, N2, and H2O in Si-DDR particles and the corresponding heats of adsorption (~25-27, ~15-22, and ~32-40 kJ·mol-1, respectively) were comparable with the literature data. The estimated CO2/N2 ideal sorption and permeation selectivities (~15.3-18.0 and ~7.7-9.0 at 303 K, respectively), showing the potential to be adsorbents and membranes for CO2/N2 separations. Also, Al atoms could be incorporated into the DDR framework via seeded growth. The adsorption of H2O was affected by defects, and more strongly, on the amount of Al species. |
