Functionalizing Porous Aromatic Frameworks with Polar Organic Groups for High-Capacity and Selective CO₂ Separation: A Molecular Simulation Study

Journal Article · Fri Feb 25 00:00:00 EST 2011 · Langmuir

DOI:https://doi.org/10.1021/la104827p· OSTI ID:1081743

Babarao, Ravichandar ^[1]; Dai, Sheng ^[2]; Jiang, De-en ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry

Porous aromatic frameworks (PAFs) were recently synthesized with the highest surface area to date; one such PAF (PAF-1) has diamond-like structure with biphenyl building blocks and exhibits exceptional thermal and hydrothermal stabilities. Here in this paper, we computationally design new PAFs by introducing polar organic groups to the biphenyl unit and then investigate their separating power toward CO₂ by using grand-canonical Monte Carlo (GCMC) simulations. Among these functional PAFs, we found that tetrahydrofuran-like ether-functionalized PAF-1 shows higher adsorption capacity for CO₂ at 1 bar and 298 K (10 mol per kilogram of adsorbent) and also much higher selectivities for CO₂/CH₄, CO₂/N₂, and CO₂/H₂ mixtures when compared with the amine functionality. The electrostatic interactions are found to play a dominant role in the high CO₂ selectivities of functional PAFs, as switching off atomic charges would decrease the selectivity by an order of magnitude. This work suggests that functionalizing porous frameworks with tetrahydrofuran-like ether groups is a promising way to increase CO₂ adsorption capacity and selectivity, especially at ambient pressures.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: AC05-00OR22725; AC02-05CH11231
• OSTI ID: 1081743
• Journal Information: Langmuir, Vol. 27, Issue 7; ISSN 0743-7463
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY