Molecular Simulation Studies of Separation of CO₂/N₂, CO₂/CH₄, and CH₄/N₂ by ZIFs

Abstract

In this work, molecular simulations were performed to evaluate the separation performance of two typical zeolitic imidazolate frameworks (ZIFs), ZIF-68 and ZIF-69, for CO 2 /N 2 , CO 2 /CH 4 , and CH 4 /N 2 mixtures. To do this, we first identified a suitable force field for describing CO 2 , N 2 , and CH 4 adsorption in ZIFs. On the basis of the validated force field, adsorption selectivities of the three mixtures in these ZIFs were simulated then. The results show that ZIF-69 is more beneficial for separating CO 2 from CO 2 -related mixtures than ZIF-68, mainly due to the presence of chlorine atoms in cbIM linkers in the former for the pressures we have considered. The overall separation performances of these two ZIFs for separating the chosen mixtures are comparable to typical MOFs and zeolites. In addition, this work demonstrates that the electrostatic interactions produced by the frameworks are very important for achieving high adsorption separation selectivities in ZIFs, and ideal adsorbed solution theory (IAST) may be applicable to ZIFs. Furthermore, the effect of water on the separation performance of the two ZIFs was also investigated.

Molecular Simulation Studies of Flue Gas Purification by Bio-MOF

“…The data of other MOFs are taken from our previous works [28] and other literatures [5,29,30]. Figure 3 shows that bio-MOF-11 displays better separation performance than other eight common MOFs, which indicates that bio-MOF-11 can easily separate CO2/N2 gas mixtures.…”

“…Metal-organic frameworks (MOFs) have emerged as a kind of novel porous materials are thought to be promising materials for gas storage and separation [2][3][4][5][6]. They are formed by coordinating transition or lanthanide metal cations with organic linkers.…”

“…Besides, they are synthesized under milder conditions, thus, MOFs have drawn much attention in recent years [7][8][9][10][11] and many researches [12][13][14][15][16][17][18][19][20][21][22] have been carried out to study the performance of MOFs. For example, we have studied the adsorption separation of CO2/N2, CO2/CH4, and CH4/N2 by ZIFs [5]. Zhao et al [13] studied the permeation and gas mixture separation properties of MOF-5 membranes.…”

High H2 Sorption Energetics in Zeolitic Imidazolate Frameworks

“…28 The better CO 2 sorption properties of ZIF-69 relative to those of ZIF-68 likely arise from the presence of the electronegative chlorine atoms in the former, which can interact favorably with the CO 2 molecules.…”

Molecular Simulations for Adsorption-Based CO2 Separation Using Metal Organic Frameworks

“…Several molecular simulation studies examined a single MOF or a few MOFs at a time [50][51][52][53][54][55][56][57][58][59]. Most of these studies focused on adsorption-based separation of CO 2 using the two most widely studied MOFs, MOF-5 and CuBTC [60][61][62][63][64].…”