Customizing Pore System in a Microporous Metal-Organic Framework for Efficient C₂H₂ Separation from CO₂ and C₂H₄

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Selective adsorption is key for energy-efficient acetylene (C2H2) capture from CO2 and C2H4.
• Separating C2H2 is challenging due to similar molecular sizes and properties of C2H2, CO2, and C2H4.

Purpose of the Study:

• To develop a novel microporous metal-organic framework (MOF) for selective acetylene capture.
• To investigate the MOF's pore system and functional groups for enhanced C2H2 recognition.

Main Methods:

• Synthesis and activation of the NUM-14 metal-organic framework (NUM-14a).
• Gas adsorption capacity measurements under ambient conditions.
• Breakthrough experiments for gas mixture separation.
• Grand Canonical Monte Carlo (GCMC) simulations to study adsorption mechanisms.

Main Results:

• Activated NUM-14a demonstrated a high C2H2 loading capacity (4.44 mmol g-1).
• NUM-14a exhibited selective C2H2 adsorption over CO2 and C2H4, confirmed by breakthrough experiments.
• GCMC simulations revealed stronger C-H···O hydrogen bonding interactions between NUM-14a and C2H2.

Conclusions:

• The tailored pore size and nitro-functionalized surface of NUM-14a enable efficient C2H2 separation.
• NUM-14a shows promise for industrial applications in acetylene capture and purification.
• This study offers insights into designing MOFs for selective gas adsorption based on pore engineering and functionalization.