Noncovalent guest-host interactions unlock the potential of MOFs for anesthetic xenon recovery: GCMC and DFT insights into real anesthetic conditions

Abstract

Innovative designs offering cost-effective and highly efficient methods for xenon (Xe) recovery are becoming important for developing sustainable applications. Recently, the use of metal–organic frameworks (MOFs) has shown promise as candidates for separating Xe from anesthetic gas mixtures, however, there are limited studies available. We conducted combined Grand Canonical Monte Carlo (GCMC) and Density Functional Theory (DFT) simulations to determine the Xe recovery capacities of 19 MOFs from the exhaled anesthetic gas mixture, Xe/CO${}_2$/O${}_2$/N${}_2$. COCMUE, GUHMIH, MAHCOQ, and PADKOK have demonstrated overall larger volumetric and gravimetric Xe uptake, demonstrating how ligand types can enhance selective Xe adsorption in MOFs. At low pressures, Xe atoms mainly adsorbed in close vicinity to the ligands, with tetrazole, phenyl, pyridyl, carboxamide, dicarboxylic acid, phenoxazine, and triazole ligands in the MOF structures acting as Xe trapping locations. Electronic structure analyses reveal that Xe-host interactions are primarily driven by charge-induced dipole and aerogen–$\pi$ interactions. Our combined GCMC and DFT study shows that a relatively high amount of anesthetic Xe can be captured from real anesthetic exhale gas mixtures using MOFs with the proper chemical and geometrical characteristics. These characteristics maximize noncovalent Xe-host interactions and ultimately enable the utilization of Xe as an anesthetic gas in clinical applications.