Adsorption properties of ion-exchanged SSZ-13 zeolite for ethylene/ethane separation

Designing effective cyclic adsorption separation processes, e.g., ethylene/ethane PSA separation, is based on finding an appropriate adsorbent. In this matter, examination of equilibrium and kinetic properties of adsorbents, i.e., isotherms and diffusion coefficients of gasses, is critical. In this study, Na-SSZ-13 zeolite was first synthesized and then ion-exchanged with the Ag+ and Cu2+ cations. Afterward, ethane and ethylene equilibrium and kinetic adsorptions and IAST calculations on the mentioned zeolites were investigated. Results showed that all three adsorbents are ethylene-selective at equilibrium conditions. Ion-exchanging leads to higher adsorption selectivity in Cu2+, while Ag+ cation increases the adsorption capacity without altering the selectivity. Furthermore, ion-exchanging increases the diffusivities of both ethylene and ethane in the following order Ag-SSZ-13>Cu-SSZ-13>Na-SSZ-13. (C) 2021 Elsevier B.V. All rights reserved.