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

Abstract

Nitrous oxide (N₂ O), 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 N₂ O 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 -N₂ O separation in zeolite was studied comprehensively. In particular, the inverse adsorption of CO₂ -N₂ O was achieved by AgZK-5, which preferentially adsorbs N₂ O over CO₂ , making it capable of trapping N₂ O from an N₂ O/CO₂ mixture. AgZK-5 shows a recorded N₂ O/CO₂ selectivity of 2.2, and the breakthrough experiment indicates excellent performance for N₂ O/CO₂ separation. The density functional theory (DFT) calculation shows that Ag⁺ has stronger adsorption energy with N₂ O, and the kinetics of N₂ O is slightly faster than that of CO₂ on AgZK-5.