Co-exchanged SSZ-13 zeolite membrane for boosting CO2/N2 separation

Abstract

Zeolite membranes such as SSZ-13 combining the pore structures of 3.8 Å × 3.8 Å and membrane advantages of low energy consumption are promising for gas separation of CO₂ from N₂. However, the fabrication of high-quality SSZ-13 zeolite membranes with excellent CO₂/N₂ separation performance remains a challenge. In this work, a facile strategy of ion exchange is utilized in the fabrication of highly continuous crystallized Co-SSZ-13 membrane with modified pore chemistry. The Co-SSZ-13 membrane exhibits the optimal CO₂ permeance of 6.6 × 10⁻⁸ mol s⁻¹ m⁻² Pa⁻¹ and CO₂/N₂ separation factor (SF) of 27.7 which is 154 % and 80 % higher than Na-SSZ-13 and Ca-SSZ-13 membranes, respectively. Moreover, such outstanding performance of the Co-SSZ-13 membrane is long-term stabilized for CO₂/N₂ separation. The introduction of Co(II) ions in the SSZ-13 structure can effectively reduce the pore size and provide the high electron density and d-orbitals which enhance both electrostatic and coordination interactions with CO₂. This study provides guidance for the fabrication of advanced membranes with high-efficiency CO₂ separation performance.