Inverse Adsorption Separation of N₂O/CO₂ in AgZK-5 Zeolite

Nitrous oxide (N2O), as the third largest greenhouse gas in the world, also has great applications in daily life and industrial production, like anesthetic, foaming agent, combustion supporting agent, N or O atomic donor. The capture of N2O in adipic acid tail gas is of great significance but remains challenging due to the similarity with CO2 in molecular size and physical properties. Herein, the influence of cation types on CO2-N2O separation in zeolite was studied comprehensively. In particular, the inverse adsorption of CO2-N2O was achieved by AgZK-5, which preferentially adsorbs N2O over CO2, making it capable of trapping N2O from an N2O/CO2 mixture. AgZK-5 shows a recorded N2O/CO2 selectivity of 2.2, and the breakthrough experiment indicates excellent performance for N2O/CO2 separation. The density functional theory (DFT) calculation shows that Ag+ has stronger adsorption energy with N2O, and the kinetics of N2O is slightly faster than that of CO2 on AgZK-5.