Can Metal–Organic Framework Materials Play a Useful Role in Large‐Scale Carbon Dioxide Separations?

Owing to environmental pollution and energy depletion, efficient separation of energy gases has attracted widespread attention. Low-cost and efficient adsorbents for gas separation are greatly needed. Here we report a family of quaternary pyridinium-type porous aromatic frameworks with tunable channels. After carefully choosing and adjusting the sterically hindered counter ions via a facile ion exchange approach, the pore diameters are tuned at an angstrom scale in the range of 3.4-7 Å. The designed pore sizes may bring benefits to capturing or sieving gas molecules with varied diameters to separate them efficiently by size-exclusive effects. By combining their specific separation properties, a five-component (hydrogen, nitrogen, oxygen, carbon dioxide and methane) gas mixture can be separated completely. The porous aromatic frameworks may hold promise for practical and commercial applications as polymeric sieves.

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“…As shown in Fig. 5 2 , respectively. The demonstrated PAF materials promise a potential application in gas separations with high efficiency.…”

Section: Article Nature Communications | Doi: 101038/ncomms5260mentioning

confidence: 74%

“…E fficient separations of light gases (H 2 , N 2 , O 2 , CO 2 and CH 4 ) are of great concern because most of them are very important raw ingredients in the chemical and petrochemical industry 1,2 . At present, air separation employing cryogenic distillation, as an energy-intensive method, needs to progress urgently 3 .…”

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confidence: 99%

Porous aromatic frameworks with anion-templated pore apertures serving as polymeric sieves

et al. 2014

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“…Owing to their many fascinating features, MOFs have shown promising performances over conventional adsorbents in separation of gas mixtures. 7,[22][23][24][25][26] Both experiments 27 and computational methods 28,29 have demonstrated that the introduction of polar functional groups in the frameworks significantly enhances the CO 2 adsorption capacity of MOFs. Moreover, MOFs with coordinatively unsaturated metal sites have been shown to adsorb increased amounts of CO 2 .…”

Section: Introductionmentioning

confidence: 99%

Enhanced selectivity of CO2 over CH4 in sulphonate-, carboxylate- and iodo-functionalized UiO-66 frameworks

et al. 2013

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aThree new functionalized UiO-66-X (X = -SO 3 H, 1; -CO 2 H, 2; -I; 3) frameworks incorporating BDC-X (BDC: 1,4-benzenedicarboxylate) linkers have been synthesized by a solvothermal method using conventional electric heating. The as-synthesized (AS) as well as the thermally activated compounds were characterized by X-ray powder diffraction (XRPD), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, thermogravimetric (TG), and elemental analysis. The occluded H 2 BDC-X molecules can be removed by exchange with polar solvent molecules followed by thermal treatment under vacuum leading to the empty-pore forms of the title compounds. Thermogravimetric analysis (TGA) and temperature-dependent XRPD (TDXRPD) experiments indicate that 1, 2 and 3 are stable up to 260, 340 and 360°C, respectively. The compounds maintain their structural integrity in water, acetic acid and 1 M HCl, as verified by XRPD analysis of the samples recovered after suspending them in the respective liquids. As confirmed by N 2 , CO 2 and CH 4 sorption analyses, all of the thermally activated compounds exhibit significant microporosity (S Langmuir : 769-842 m 2 g −1 ), which are comparable to that of the parent UiO-66 compound. Compared to the unfunctionalized UiO-66 compound, all the three functionalized solids possess higher ideal selectivity in adsorption of CO 2 over CH 4 at 33°C.

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“…In order to avoid energy-intensive CO 2 capture, we have to resort to physisorptive processes (enthalpy of adsorption, Qo40 kJ mol À 1 ) rather than chemisorptive ones (Q440 kJ mol À 1 ) (ref. 29). Physisorption, however, brings new challenges.…”

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confidence: 99%

Unprecedented high-temperature CO2 selectivity in N2-phobic nanoporous covalent organic polymers

et al. 2013

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Post-combustion CO 2 capture and air separation are integral parts of the energy industry, although the available technologies remain inefficient, resulting in costly energy penalties. Here we report azo-bridged, nitrogen-rich, aromatic, water stable, nanoporous covalent organic polymers, which can be synthesized by catalyst-free direct coupling of aromatic nitro and amine moieties under basic conditions. Unlike other porous materials, azo-covalent organic polymers exhibit an unprecedented increase in CO 2 /N 2 selectivity with increasing temperature, reaching the highest value (288 at 323 K) reported to date. Here we observe that azo groups reject N 2 , thus making the framework N 2 -phobic. Monte Carlo simulations suggest that the origin of the N 2 phobicity of the azo-group is the entropic loss of N 2 gas molecules upon binding, although the adsorption is enthalpically favourable. Any gas separations that require the efficient exclusion of N 2 gas would do well to employ azo units in the sorbent chemistry.

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Can Metal–Organic Framework Materials Play a Useful Role in Large‐Scale Carbon Dioxide Separations?

Cited by 576 publications

References 165 publications

Porous aromatic frameworks with anion-templated pore apertures serving as polymeric sieves

Porous aromatic frameworks with anion-templated pore apertures serving as polymeric sieves

Enhanced selectivity of CO2 over CH4 in sulphonate-, carboxylate- and iodo-functionalized UiO-66 frameworks

Unprecedented high-temperature CO2 selectivity in N2-phobic nanoporous covalent organic polymers

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