Water Enables Efficient CO₂ Capture from Natural Gas Flue Emissions in an Oxidation-Resistant Diamine-Appended Metal–Organic Framework

Abstract

Supported by increasingly available reserves, natural gas is achieving greater adoption as a cleaner-burning alternative to coal in the power sector. As a result, carbon capture and sequestration from natural gas-fired power plants is an attractive strategy to mitigate global anthropogenic CO 2 emissions. However, the separation of CO 2 from other components in the flue streams of gas-fired power plants is particularly challenging due to the low CO 2 partial pressure (∼40 mbar), which necessitates that candidate separation materials bind CO 2 strongly at low partial pressures (≤4 mbar) to capture ≥90% of the emitted CO 2. High partial pressures of O 2 (120 mbar) and water (80 mbar) in these flue streams have also presented significant barriers to the deployment of new technologies for CO 2 capture from gas-fired power plants. Here, we demonstrate that functionalization of the metal−organic framework Mg 2 (dobpdc) (dobpdc 4− = 4,4′-dioxidobiphenyl-3,3′dicarboxylate) with the cyclic diamine 2-(aminomethyl)piperidine (2-ampd) produces an adsorbent that is capable of ≥90% CO 2 capture from a humid natural gas flue emission stream, as confirmed by breakthrough measurements. This material captures CO 2 by a cooperative mechanism that enables access to a large CO 2 cycling capacity with a small temperature swing (2.4 mmol CO 2 /g with ΔT ≥ 100°C). Significantly, multicomponent adsorption experiments, infrared spectroscopy, magic angle spinning solid-state NMR spectroscopy, and van der Waals-corrected density functional theory studies suggest that water enhances CO 2 capture in 2-ampd−Mg 2 (dobpdc) through hydrogen-bonding interactions with the carbamate groups of the ammonium carbamate chains formed upon CO 2 adsorption, thereby increasing the thermodynamic driving force for CO 2 binding. In light of the exceptional thermal and oxidative stability of 2-ampd−Mg 2 (dobpdc), its high CO 2 adsorption capacity, and its high CO 2 capture rate from a simulated natural gas flue emission stream, this material is one of the most promising adsorbents to date for this important separation. ■ INTRODUCTION 40 The combustion of fossil fuels in the energy sector is currently 41 responsible for the release of 32 Gt/year of CO 2 into the 42 atmosphere, or approximately 65% of annual anthropogenic 43 greenhouse gas emissions. 1,2 To limit the contribution of these 44 emissions to global climate change, mitigation strategies are 45 needed during the transition to cleaner fuel sources. 2 One of 46 the most widely studied emission mitigation strategies is 47 postcombustion carbon capture and sequestration (CCS), in 48 which CO 2 is selectively removed from the flue gas streams of 49 fossil fuel-or biomass-fired power plants and sequestered 50 underground. 1−4 To date, the large majority of efforts toward 51 implementing CCS have focused on coal-fired power plants, 52 which are currently responsible for approximately 45% of 53 energy-related CO 2 emissions. 4,5 However, global consump-54 tion of natural gas has been increasing steadily, and i...

Self-adjusting binding pockets enhance H2 and CH4 adsorption in a uranium-based metal–organic framework

“…Metal-organic frameworks are a class of chemically-robust, porous, and oen rigid materials, composed of metal ions or clusters connected by bridging organic linkers. [1][2][3][4] The physical and chemical properties of these materials are highly tunable based on choice of metal and linker, and thus metal-organic frameworks have been proposed for a wealth of applications, [5][6][7][8][9] including catalysis, [10][11][12][13][14][15] sensing, [16][17][18] carbon capture, [19][20][21][22][23] gas separations, [24][25][26] and gas storage. [27][28][29][30][31] Metal-organic frameworks have attracted particular interest as candidate gas storage materials for H 2 and CH 4 that could enable more efficient use of these energy carriers as cleaner fuel alternatives.…”

Strategies to Enhance Carbon Dioxide Capture in Metal‐Organic Frameworks

“…Diamine functionalized Mg 2 (dobpdc) materials appear therefore the best option to date for the realization of a MOFbased carbon dioxide capture process. [85,89,93] These materials in fact own a good CO 2 uptake capacity together with a significant stability under water vapor and a general structural robustness. In contrast to the MOFs described previously, CO 2 is adsorbed into diamine functionalized Mg 2 (dobpdc) chemically, which Figure 6.…”

“…Seeing the outstanding oxidative and thermal stability of 2-(aminomethyl)piperidine-Mg 2 (dobpdc), its outstanding CO 2 uptake capacity, and its remarkable CO 2 capture rate from a simulated natural gas flue emission stream, this MOF is certainly one of the best candidate to date for this highly significant technology. [93] Other MOFs with sufficiently large pores can accommodate amines. As an example, the CO 2 capture performance of MIL-101(Cr) was increased by alkylamine functionalization.…”

“…For this material, it was observed that hydrogen‐bonding interactions between water and the carbamate chains enhance the CO 2 capture. Seeing the outstanding oxidative and thermal stability of 2‐(aminomethyl)piperidine–Mg 2 (dobpdc), its outstanding CO 2 uptake capacity, and its remarkable CO 2 capture rate from a simulated natural gas flue emission stream, this MOF is certainly one of the best candidate to date for this highly significant technology …”

Cooperative Carbon Dioxide Adsorption in Alcoholamine‐ and Alkoxyalkylamine‐Functionalized Metal–Organic Frameworks

“…[6] This mechanism is characterized by step-shaped CO 2 adsorption profiles,which contribute to high material working capacities and low regeneration energies.A dditionally,t he pressure and temperature at which the adsorption step occurs can be tuned simply by changing the diamine,m aking these materials promising candidates for ar ange of carbon capture applications. [6][7][8][9][10][11][12][13] Ammonium carbamate chain formation remains the only cooperative CO 2 chemisorption mechanism known to date,a nd the development of new cooperative adsorption mechanisms would greatly expand the scope of these energyefficient carbon capture materials.…”