Computational Exploration of IRMOFs for Xenon Separation from Air

Abstract

Metal–organic frameworks (MOFs) found their well-deserved position in the field of gas adsorption and separation because of their unique properties. The separation of xenon from different gas mixtures containing this valuable and essential noble gas is also benefited from the exciting nature of MOFs. In this research, we chose a series of isoreticular MOFs as our study models to apply advanced molecular simulation techniques in the context of xenon separation from air. We investigated the separation performance of our model set through simulation of ternary gas adsorption isotherms and consequent calculation of separation performance descriptors, finding out that IRMOF-7 shows better recovering capabilities compared to the other studied MOFs. We benefited from visualization of xenon energy landscape within MOFs to obtain valuable information on possible reasoning behind our observations. We also examined temperature-based separation performance boosting strategy. Additionally, we noted that although promising candidates are present among the studied MOFs for xenon recovery from air, they are not suitable for xenon recovery from exhaled anesthetic gas mixture.

Dual-Force Zone Nonequilibrium Molecular Dynamics Simulations on Nanoporous Metal–Organic Framework Membranes for Separation of H2/CH4 Mixtures

“…It has been reported that the transport phenomenon of H 2 and CH 4 gas molecules through IRMOF-1 is described by Knudsen-type diffusion because the kinetic diameters of both gases (∼2.89 Å for H 2 and 3.8 Å for CH 4 ) are much smaller than that of the LCD (∼15.07 Å) of IRMOF-1. 21,46,47 In our study, the permeability values for H 2 and CH 4 for a mixture with an initial composition of the same number of molecules were 2.16 × 10 5 and 1.03 × 10 5 barrer, respectively. The CGD-NEMD simulations, performed in the present study, predicted the permeability of H 2 and CH 4 as 1.62 × 10 5 and 0.59 × 10 5 barrer, respectively, for the equimolar feed mixture.…”

“…Here, we discuss the general features of IRMOF-1 and its functionalization approach. The bare IRMOF-1 has PLD and LCD of 7.93 and 15.07 Å, respectively . Our rationale behind selecting IRMOF-1 was mainly driven from the standpoint of computational ease: (i) IRMOF-1 has a large pore size, which allowed our algorithm to add functional groups of different sizes without initial strong overlap between their atoms.…”

“…Here, as the kinetic diameter of H 2 is much smaller than the pore sizes in functionalized MOFs, as suggested by PSD analysis, the Knudsen-type diffusion mechanism can play an important role. 21,46,47 On the other hand, the CH 4 permeability follows the trend urea > acetamide > methyl. For several urea-and acetamidefunctionalized structures (except structures with 4 functional groups -U5 and A5), the permeability of CH 4 increases compared to the bare IRMOF-1.…”

“…The bare IRMOF-1 has PLD and LCD of 7.93 and 15.07 Å, respectively. 46 Our rationale behind selecting IRMOF-1 was mainly driven from the standpoint of computational ease: (i) IRMOF-1 has a large pore size, which allowed our algorithm to add functional groups of different sizes without initial strong overlap between their atoms. (ii) There are a number of experimental and computational studies performed on bare IRMOF-1 with the selected gas mixtures used in the present study, which allowed us to validate our results where possible.…”

Understanding the CO2/CH4/N2 Separation Performance of Nanoporous Amorphous N‐Doped Carbon Combined Hybrid Monte Carlo with Machine Learning

“…The adsorption calculations considers translation, rotation, insertion and identity‐change, including 3×10 5 Monte Carlo (MC) cycles, with the first half for equilibration and the remaining for data analysis. [ 39 ] The Peng–Robinson equation of state was applied to calculate fugacity from pressure. We simulated three mixture systems to further evaluate the adsorption selectivity, including CO 2 /N 2 (85:15), CO 2 /CH 4 (50:50) and CH 4 /N 2 (50:50).…”