Pore Size Matching for SF₆/N₂ Separation in a Metal Azolate Framework.

Area of Science:

• Materials Science
• Environmental Chemistry
• Chemical Engineering

Background:

• Sulfur hexafluoride (SF₆) is a potent greenhouse gas with significant industrial applications.
• Efficient separation of SF₆ from N₂ is crucial for environmental protection and resource recovery.
• Existing separation methods often face challenges in efficiency, cost, or regeneration.

Purpose of the Study:

• To investigate the potential of an ultramicroporous metal azolate framework, Zn₃(atz)₆ (MAF-123-Zn), for SF₆/N₂ separation.
• To evaluate the adsorption properties and separation performance of MAF-123-Zn for SF₆/N₂ mixtures.
• To demonstrate the practical applicability of MAF-123-Zn in SF₆ recovery and regeneration.

Main Methods:

• Synthesis and characterization of the ultramicroporous metal azolate framework Zn₃(atz)₆ (MAF-123-Zn).
• Gas adsorption experiments to determine SF₆ and N₂ uptake and adsorption enthalpy.
• Dynamic breakthrough experiments using low-concentration SF₆/N₂ mixtures to assess separation efficiency and regeneration.

Main Results:

• MAF-123-Zn exhibits a high SF₆/N₂ uptake ratio of 20.2.
• The material shows a moderate adsorption enthalpy of 31.3 kJ mol^-1, indicating selective adsorption.
• Dynamic breakthrough experiments successfully achieved high-purity SF₆ (>99.9%) recovery from low-concentration mixtures.
• Facile regeneration of the adsorbent was confirmed using N₂ sweeping at room temperature.

Conclusions:

• The ultramicroporous metal azolate framework MAF-123-Zn is a promising candidate for efficient SF₆/N₂ separation.
• MAF-123-Zn offers high selectivity and capacity for SF₆, coupled with facile regeneration.
• This material holds potential for environmental applications in SF₆ recovery and greenhouse gas mitigation.