Pore Space Partition within a Metal-Organic Framework for Highly Efficient C₂H₂/CO₂ Separation

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Developing advanced materials for selective gas separation is crucial for industrial processes.
• Metal-organic frameworks (MOFs) offer tunable porosity for gas adsorption applications.
• Separating acetylene (C2H2) from carbon dioxide (CO2) presents a significant challenge due to their similar properties.

Purpose of the Study:

• To design and synthesize a novel MOF (FJU-90) with dual functionalities for efficient C2H2/CO2 separation.
• To investigate the effect of pore space partition on gas adsorption and separation performance.
• To demonstrate the potential of the pore space partition strategy for creating advanced MOF materials.

Main Methods:

• Synthesis of a novel MOF (FJU-90) using a triangular ligand (Tripp) via the pore space partition (PSP) approach.
• Characterization of the MOF's pore structure, including pore aperture reduction.
• Gas adsorption measurements at ambient conditions (298 K, 1 bar) for C2H2 and CO2.
• Application of the Integrated Adsorption Science and Technology (IAST) model for performance prediction.
• Molecular modeling studies and experimental breakthrough experiments for validation.

Main Results:

• The pore space partition approach successfully reduced pore apertures in FJU-90 from 12.0 × 9.4 Å2 to 5.4 × 5.1 Å2.
• Activated FJU-90a demonstrated high C2H2 uptake (180 cm3 g-1) and lower CO2 uptake (103 cm3 g-1) at 298 K and 1 bar.
• FJU-90 exhibited excellent C2H2 gravimetric productivity for a 50%:50% C2H2/CO2 mixture, outperforming existing MOF materials.
• IAST calculations, molecular modeling, and breakthrough experiments confirmed the material's separation capabilities.

Conclusions:

• The pore space partition strategy is highly effective for designing MOFs with tailored pore sizes for challenging gas separations.
• FJU-90 is a promising dual-functional MOF material for efficient C2H2/CO2 separation under ambient conditions.
• This work highlights a powerful methodology for developing advanced porous materials for gas separation applications.