DMF-Mediated Diffusion Regulation in Pyridine-Carboxylate Metal-Organic Frameworks Enables Efficient CHF₃ Capture.

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Industrial waste gas streams contain valuable but difficult-to-recover compounds like trifluoromethane (CHF3).
• Developing efficient, stable, and scalable adsorbents for high-purity CHF3 recovery remains a significant challenge.

Purpose of the Study:

• To present a novel metal-organic framework (MOF), PAIF-101, synthesized via a solvent-docking strategy.
• To evaluate PAIF-101's performance in capturing and separating trifluoromethane (CHF3) from industrial waste gas, specifically from nitrogen (N2).

Main Methods:

• Synthesis of PAIF-101 using a solvent-docking strategy with DMF coordination for precise pore tuning.
• Characterization of PAIF-101's adsorption properties, including uptake capacity, affinity at low pressures, and selectivity (IAST).
• Validation through breakthrough experiments, DFT calculations, and MD simulations to understand performance mechanisms and assess practical feasibility.

Main Results:

• PAIF-101 demonstrated the highest reported CHF3 uptake (3.54 mmol g-1) and exceptional IAST selectivity (140) for CHF3/N2 separation.
• Breakthrough experiments confirmed the production of high-purity (≥ 99.5%) CHF3 with good productivity (1.53 mmol g-1), even under humid conditions (60% RH).
• Scalable synthesis of PAIF-101 (approx. 5 g/batch) was achieved via a simple reflux method.

Conclusions:

• PAIF-101 exhibits outstanding trifluoromethane (CHF3) separation performance, high stability, and scalable synthesis.
• The solvent-docking strategy effectively tunes pore apertures and creates specific adsorption sites for enhanced gas recovery.
• PAIF-101 shows significant potential as a practical and efficient adsorbent for challenging industrial CHF3 separations.