(377r) A Novel Glycine-Modified Cu-BTC with High Capacity and Enhanced Stability for Efficient Separation of C2H6and C2H4

Ethylene is the most important feedstock in the petrochemical industry. The high purity of ethylene is primarily obtained by the removal of ethane in mixture of ethane and ethylene, which is currently performed by cryogenic distillation, an energy-intensive process. Hence, developing efficient separation of ethane and ethyleneat room temperature is great challenging. Herein, we developed a novel Gly@Cu-BTC with high capacity and selectivity for separation of C₂H₄/C₂H₆. We proposed a bifunctional SBU-tuning strategy of grafting glycine (Gly) to the secondary building units (SBUs) of Cu-BTC through the nano-seed assistant ultrafast room temperature synthesis, and thus synthesized a series of Gly@Cu-BTCs. Results showed that Gly0.4@Cu-BTC exhibited superior C₂H₆and C₂H₄adsorption capacities of 6.79 and 7.98 mmol/g at 298 K and 1 bar, higher than the most of adsorbents reported previously, and its adsorptive selectivity for the equimolar C₂H₄/C₂H₆mixtures was up to 3.7. Fixed-bed experiments confirmed that the C₂H₄/C₂H₆mixture can be completely separated at ambient conditions. More importantly, stability experiments confirmed that after the exposure to moisture air (RH of 55%) for 20 days, Gly0.4@Cu-BTC still remained its crystal structure, exhibiting its excellent stability against water vapor. Molecular simulation revealed the origination of the improved stability under moist and adsorption property of Gly0.4@Cu-BTC. Gly0.4@Cu-BTCis a type of promising adsorbent for the effective separation of C₂H₆/C₂H₄.