Boosting Record Xe Uptake for Efficient Xe/Kr Separation under High Humidity in a Cage-Based MOF with Open Metal...

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Adsorptive separation of xenon (Xe) and krypton (Kr) is difficult due to their similar physical properties.
• Efficient separation is crucial for applications like nuclear fuel reprocessing.

Purpose of the Study:

• To develop a metal-organic framework (MOF) for efficient Xe/Kr separation.
• To investigate the Xe and Kr adsorption and separation performance of the MOF.

Main Methods:

• Synthesis of a cage-based MOF, Cu-BTA, with open metal sites.
• Characterization of pore structure and adsorption capacities.
• Gas breakthrough experiments for Xe/Kr mixture separation under various conditions.

Main Results:

• Cu-BTA exhibited record-high Xe gravimetric (7.61 mmol g⁻¹) and volumetric (7.54 mmol cm⁻³) uptake capacities.
• Excellent Xe/Kr separation performance was confirmed in breakthrough experiments.
• Efficient Xe capture was demonstrated even at ultralow concentrations (400 ppm).

Conclusions:

• The cage-based MOF, Cu-BTA, is a highly promising material for Xe/Kr separation.
• Its high Xe uptake and separation efficiency suggest potential for radioactive Xe removal from nuclear fuel reprocessing off-gas.