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A series of N-doped porous carbons with different textural properties and N contents was prepared from a mixture of algae and glucose and their capability for the separation of CO 2 /CH 4 , C 2 H 6 /CH 4 , and CO 2 /H 2 binary mixtures under different conditions (bulk pressure, mixture composition, and temperature) were subsequently assessed in great detail. It was observed that the gas (C 2 H 6 , CO 2 , CH 4 , and H 2 ) adsorption capacity at different pressure regions was primarily governed by different adsorbent parameters (N level, narrow micropore volume, and BET specific surface area). More interestingly, it was found that N-doping can selectively enhance the heats of adsorption of C 2 H 6 and CO 2 , while it had a negligible effect on those of CH 4 and H 2 . The adsorption equilibrium selectivities for separating C 2 H 6 /CH 4 , CO 2 /CH 4 , and CO 2 /H 2 gas mixture pairs on the porous carbons were predicted using the ideal adsorbed solution theory (IAST) based on pure-component adsorption isotherms. In particular, sample NAHA-1 exhibited by far the best performance (in terms of gas adsorption capacity and selectivity) reported for porous carbons for the separation of these three binary mixtures. More significantly, NAHA-1 carbon outperforms many of its counterparts ( e.g. MOFs and zeolites), emphasizing the important role of carbonaceous adsorbents in gas purification and separation.
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Cyclotetrabenzoin Acetate: A Macrocyclic Porous Molecular Crystal for CO 2 Separations by Pressure Swing Adsorption**
Abstract A porous molecular crystal (PMC) assembled by macrocyclic cyclotetrabenzoin acetate is an efficient adsorbent for CO2separations. The 7.1×7.1 Å square pore of PMC and its ester C=O groups play important roles in improving its affinity for CO2molecules. The benzene walls of macrocycle engage in an apparent [π⋅⋅⋅π] interaction with the molecule of CO2at low pressure. In addition, the polar carbonyl groups pointing inward the square channels reduce the size of aperture to a 5.0×5.0 Å square, which offers kinetic selectivity for CO2capture. The PMC features water tolerance and high structural stability under vacuum and various gas adsorption conditions, which are rare among intrinsically porous organic molecules. Most importantly, the moderate adsorbate‐adsorbent interaction allows the PMC to be readily regenerated, and therefore applied to pressure swing adsorption processes. The eluted N2and CH4are obtained with over 99.9 % and 99.8 % purity, respectively, and the separation performance is stable for 30 cycles. Coupled with its easy synthesis, cyclotetrabenzoin acetate is a promising adsorbent for CO2separations from flue and natural gases.
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- Award ID(s):
- 1904998
- PAR ID:
- 10226410
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 60
- Issue:
- 27
- ISSN:
- 1433-7851
- Format(s):
- Medium: X Size: p. 14931-14937
- Size(s):
- p. 14931-14937
- Sponsoring Org:
- National Science Foundation
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