Molecular Simulation Studies of Flue Gas Purification by Bio-MOF

Abstract

Abstract:As a new branch of MOFs which are composed of biocompatible metal ions and organic ligands, bio-metal-organic frameworks (bio-MOFs) have attracted much attention recently. Bio-MOFs feature multiple Lewis basic sites which have strong interaction with CO2 molecules, thus they have great potential in the separation and purification of gas mixtures containing CO2. In this work, molecular simulation studies were carried out to investigate the adsorption and diffusion behaviors of CO2/N2 gas mixtures in bio-MOF-11. Results show that bio-MOF-11 displays excellent adsorption selectivity towards CO2 in CO2/N2 gas mixtures which was dominated by electrostatic interaction between material and CO2. In addition, we found both CO2 and N2 molecules were preferably adsorbed around the pyrimidine ring and exocyclic amino and transferred to the secondary favorable adsorption sites (methyl groups) with increasing pressure. Bio-MOF-11 membranes show superior permeation selectivity, but low permeability for CO2/N2 gas systems. The reason is that the small pores restrict the movement of gas molecules, leading to the observed low permeability. The information obtained in this work can be applied to other theoretical and experimental studies of bio-MOFs adsorbents and membranes in the future.

Computational Screening of Metal–Organic Frameworks for Membrane-Based CO2/N2/H2O Separations: Best Materials for Flue Gas Separation

“…We calculated CO 2 /N 2 selectivity of ZIF-8 as 5.2, which is in good agreement with the previously computed value of 5.7 at infinite dilution . Li et al computed CO 2 /N 2 selectivity of the bio-MOF-11 membrane as 22 for the CO 2 /N 2 : 15/85 mixture at 1 bar and 298 K. This value is close to the selectivity computed in this work, 18. Watanabe and Sholl considered 179 MOFs with very narrow pores, 2.2 < PLD < 3.6 Å, to study the molecular sieve effects of MOF membranes and predicted CO 2 /N 2 selectivities in the range of 2–2.6 × 10 4 at infinite dilution.…”

“…Because of the computational expense and long time requirement of modeling CO 2 and N 2 molecules, molecular simulations of the entire MOF database have not been performed for CO 2 /N 2 separation. Molecular simulations generally examined a single type of MOF membrane such as IRMOF-1, 27 CuBTC, 28 MgMOF-74, 29 ZnMOF-74, 29 MOF-177, 29 ZIF-8, 30 and BioMOF-11 31 for CO 2 /N 2 separation. Sumer and Keskin 32 computed CO 2 selectivity and permeability of five different MOFs for CO 2 /N 2 : 15/85 mixtures, and Yilmaz and Keskin 33 predicted CO 2 /N 2 separation performances of 15 different MOFs using molecular simulations.…”

Recent advances in simulating gas permeation through MOF membranes

“…Therefore, mixture simulations which consider industrially relevant gas compositions are needed to unlock the real gas separation performances of MOF membranes. For example, Li et al 118 predicted performance of Bio-MOF-11 membrane using GCMC + EMD approach for CO 2 /N 2 :15/85 and CO 2 /N 2 :50/50 mixture separations and showed that membrane selectivity of Bio-MOF-11 increases from ∼50 to ∼80 without a significant change in its CO 2 permeability (from 3.4 × 10 4 Barrer to 1.2 × 10 4 Barrer) when the mixture conditions are used in molecular simulations.…”

Solvent- and Temperature-Driven Photoluminescence Modulation in Porous Hofmann-Type SrII–ReVMetal–Organic Frameworks

“…29−33 CPs built of d-or f-block metal ions are a great source of optical thermometers 8,34−36 and solvatochromism related to the porous structure. 37,38 Moreover, porous MOFs and CPs were found to be promising adsorbents for gas and energy storage, 39−42 as well as molecular separation 39−44 and purification, 45,46 because of the attractive predictability and tunability of the pore size, shape, and functionalities. 47,48 We focused on a specific class of CPs, called Hofmann-type frameworks, typically composed of inorganic cyanido-bridged {M-[M′(CN) 4 ]} or {M-[M″(CN) 2 ] 2 } layers (M = divalent 3d metal ions; M′ = Ni II , Pd II , Pt II ; M″ = Ag I , Au I ) bonded by pyrazine or bipyridyl organic spacers.…”