Optimizing Pore Space for Flexible-Robust Metal-Organic Framework to Boost Trace Acetylene Removal

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) are crucial for gas separation.
• Efficient removal of trace acetylene from ethylene is vital in industrial processes.
• Existing MOFs face limitations in selectivity and capacity for acetylene/ethylene separation.

Purpose of the Study:

• To develop a flexible-robust MOF for adsorptive removal of trace acetylene from ethylene.
• To enhance pore structure and binding sites for selective acetylene adsorption.
• To investigate the performance of a copper-analogue MOF compared to its zinc prototype.

Main Methods:

• Isoreticular principle for MOF design.
• Substitution of zinc(II) with copper(II) to modify pore dimensions.
• Gas isotherms and single-crystal structure analysis for adsorption validation.
• IAST selectivity calculations and breakthrough experiments.

Main Results:

• Copper-analogue MOF exhibits expanded pore cavities (3.6 × 4.3 × 4.2 ų).
• Achieved significant acetylene uptake (4.57 mmol g⁻¹) and high selectivity (over two orders of magnitude) for C₂H₂/C₂H₄.
• Demonstrated superior performance compared to benchmark MOFs for acetylene/ethylene separation.
• High ethylene productivity (14.9 mmol g⁻¹).

Conclusions:

• The flexible-robust copper-based MOF is highly efficient for adsorptive removal of acetylene from ethylene.
• The optimized pore size and binding sites are key to selective acetylene adsorption.
• This MOF presents a promising solution for industrial gas purification applications.