Size-inverse molecular sieving xenon/krypton separation through cation-tuned gating effect within Linde Type A...

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Xenon/krypton separation is difficult due to similar properties.
• Developing efficient noble gas separation technologies is crucial.

Purpose of the Study:

• To develop a highly selective method for xenon/krypton separation.
• To investigate a cation-tuned gating sieving mechanism in Linde Type A zeolites.

Main Methods:

• Cation exchange in Linde Type A zeolites using Ag+ and Ca2+.
• Isothermal adsorption measurements and breakthrough experiments.
• Synchrotron powder X-ray diffraction, X-ray absorption spectra, and ab initio DFT calculations.

Main Results:

• Achieved a high ideal adsorbed solution theory (IAST) selectivity for xenon/krypton over 1600.
• Developed Ag9Ca1.5A zeolite with a dynamic xenon/krypton selectivity of 30, the highest reported.
• Obtained a high dynamic xenon uptake of 1.65 mmol/g.

Conclusions:

• The cation-tuned gating mechanism in modified Linde Type A zeolites enables highly selective xenon/krypton separation.
• This approach overcomes kinetic limitations and achieves unprecedented separation performance.
• The study provides fundamental insights into the sieving separation mechanism at the molecular level.