Adsorption and Transport of CH₄, CO₂, H₂ Mixtures in a Bio-MOF Material from Molecular Simulations

Abstract

Accurate description of gas adsorption and diffusion in nanoporous materials is crucial in envisioning new materials for adsorption-based and membrane-based gas separations. This study provides the first information about the equilibrium and transport properties of different gas mixtures in a bio-metal organic framework (bio-MOF). Adsorption isotherms and self-diffusivity coefficients of CH 4 , CO 2 , H 2 , and their binary mixtures in bio-MOF-11 were computed using grand canonical Monte Carlo and equilibrium molecular dynamics simulations. Results showed that bio-MOF-11 exhibits significantly higher adsorption selectivity for CO 2 over CH 4 and H 2 than the widely studied MOFs. Bio-MOF-11 outperforms several isoreticular MOFs, traditional zeolites, and zeolite imidazolate frameworks in membrane-based separations of CH 4 /H 2 , CO 2 /CH 4 , and CO 2 / H 2 mixtures due to its high gas permeability and permeation selectivity. The methods used in this work will assess the potential of bio-MOFs in gas separations and accelerate development of new bio-MOFs for targeted applications by providing molecular insights into adsorption and transport of gas mixtures.

Molecular Simulation Studies of Flue Gas Purification by Bio-MOF

“…It is clearly noted that bio-MOF-11 exhibits higher membrane selectivity than most of the materials studied because of the high adsorption selectivity. A similar phenomenon also occurs in bio-MOF-11 membrane separation of CH4/H2, CO2/CH4, and CO2/H2 gas mixtures [27]. …”

“…The topology of the material is tetragonal and the space group is I41/A. Bio-MOF-11 consists of cobalt-adeninate-acetate paddle wheel clusters and adenine, which has multiple Lewis basic sites including an amino group and pyrimidine nitrogens [27]. The detailed structural properties of bio-MOF-11 are summarized in Table 1.…”

“…An et al [26] found that bio-MOF-11 has extraordinary ability of CO2 capture than many other MOFs. Erhan et al [27] predicted permeation selectivities and gas permeabilities of bio-MOF membranes for three kinds of different gas mixtures, compared these bio-MOFs with several other nanoporous membranes, and found that bio-MOF-11 was a good candidate for membrane separation.…”

Recent Advances in Molecular Dynamics Simulations of Gas Diffusion in Metal Organic Frameworks

“…Self diffusivities of H 2 , CH 4 and CO 2 in bioMOF-11 were computed from canonical ensemble MD simulations at 298 K. (Atci et al, 2011) BioMOFs are another subclass of MOFs that have been recently discovered. They incorporate simple biomolecules and biocompatible metal cations in their structures as linkers and metals.…”

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].…”