A Microporous Titanate-Based Metal-Organic Framework for Efficient Separation of Acetylene from Carbon Dioxide

Separation of acetylene (C2H2) and carbon dioxide (CO2) is of prime importance in the petrochemical industry, but their similarities in molecular size and volatility make it particularly difficult. A desired adsorbent for highly efficient C2H2/CO2 separation should have high selectivity and C2H2 uptake simultaneously, and the introduction of functional groups into MOFs is an effective strategy to achieve this purpose. Herein, we report a titanium-based MOF material (MIL-125-NH2), featuring the suitable pore sizes and amino-functionalized pore surfaces to show the preferential adsorption of C2H2 over CO2 with both high C2H2 uptake and C2H2/CO2 selectivity. Theoretical simulation results indicate that the preferential C2H2 adsorption is mainly attributed to multiple hydrogen bonding interactions between C2H2 molecule and amino functional groups.