Adsorption of CO₂, CH₄, N₂O, and N₂ on MOF-5, MOF-177, and Zeolite 5A

Abstract

Adsorption equilibrium and kinetics of CO(2), CH(4), N(2)O, and N(2) on two newly discovered adsorbents, metal-organic frameworks MOF-5 and MOF-177 and one traditional adsorbent, zeolite 5A were determined to assess their efficacy for CO(2), CH(4), and N(2)O removal from air and separation of CO(2) from CH(4) in pressure swing adsorption processes. Adsorption equilibrium and kinetics data for CO(2), CH(4), N(2)O, and N(2) on all three adsorbents were measured volumetrically at 298K and gas pressures up to 800 Torr. Adsorption equilibrium capacities of CO(2) and CH(4) on all three adsorbents were determined gravimetrically at 298 K and elevated pressures (14 bar for CO(2) and 100 bar for CH(4)). The Henry's law and Langmuir adsorption equilibrium models were applied to correlate the adsorption isotherms, and a classical micropore diffusion model was used to analyze the adsorption kinetic data. The adsorption equilibrium selectivity was calculated from the ratio of Henry's constants, and the adsorbent selection parameter for pressure swing adsorption processes were determined by combining the equilibrium selectivity and working capacity ratio. Based on the selectivity and adsorbent selection parameter results, zeolite 5A is a better adsorbent for removing CO(2) and N(2)O from air and separation of CO(2) from CH(4), whereas MOF-177 is the adsorbent of choice for removing CH(4) from air. However, both MOF adsorbents have larger adsorption capacities for CO(2) and CH(4) than zeolite 5A at elevated pressures, suggesting MOF-5 and MOF-177 are better adsorbents for CO(2) and CH(4) storage. The CH(4) adsorption capacity of 22 wt.% on MOF-177 at 298K and 100 bar is probably the largest adsorption uptake of CH(4) on any dry adsorbents. The average diffusivity of CO(2), CH(4) and N(2)O in MOF-5 and MOF-177 is in the order of 10(-9) m(2)/s, as compared to 10(-11) m(2)/s for CO(2), CH(4) and N(2)O in zeolite 5A. The effects of gas pressure on diffusivity for different adsorabte-adsorbent systems were also investigated.

Activation and dissociation of CO2 on the (001), (011), and (111) surfaces of mackinawite (FeS): A dispersion-corrected DFT study

“…1,2 The first step in CO 2 reduction on heterogeneous catalyst surfaces is the activation of the C==O bond and charge transfer for the eventual formation of an anion radical species. 2 A significant number of studies exist in the literature regarding the adsorption, activation, and conversion of CO 2 using both heterogeneous, e.g., on metal/metal oxide surfaces [8][9][10][11] or metal-organic frameworks, [12][13][14][15] and homogeneous reactions, e.g., transition metal complexes. [16][17][18][19][20][21] More recently, transition metal sulfides have attracted significant attention for catalytic applications owing to their low cost, natural abundance, and prominent catalytic features.…”

Molecular Simulation Studies of Flue Gas Purification by Bio-MOF

“…Compared to traditional materials, they have advantages of low density, high specific area, and more tunable structures. 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].…”

Determination of heat capacities and thermodynamic properties of two structurally unrelated but isotypic calcium and manganese(II) 2,6-naphthalene dicarboxylate-based MOFs

“…Metal-organic frameworks (MOFs) are molecular architectures comprising metal ion nodes bridged by organic ligands, which have attracted much interest recently due to their potential interest for gas storage [1][2][3][4][5], gas separation [6][7][8][9][10], as catalytic active phases [11][12][13][14][15], and as luminescent materials [16][17][18]. Among the numerous synthetic routes leading to MOF materials, most of them involve the use of metal carboxylates as organic ligands that readily interact with various metal ions through their negatively charged ends.…”

“…The Mg compound, involving a permanent porosity with a large Langmuir surface area and specific pore volume, showed a significant hydrogen storage capacity. Among the Li-based lightweight MOF materials another compound synthesized in the presence of 1,3-BDC and dimethylformamide (DMF), Li 2 (1,3-BDC)(DMF) 0.5 , recently also proved highly sensitive to water and methanol [26].…”