Impact of post-synthesis modification of nanoporous organic frameworks on small gas uptake and selective CO2 capture

Abstract

Porous organic polymers containing nitrogen-rich building units are among the most promising materials for selective CO 2 capture and separation applications that impact the environment and the quality of methane and hydrogen fuels. In this study, we report on post-synthesis modification of nanoporous organic frameworks (NPOFs) and its impact on gas storage (H 2 , CH 4 , CO 2 ) and selective CO 2 binding over N 2 and CH 4 under ambient conditions. The synthesis of NPOF-4 was accomplished via acid catalyzed cyclotrimerization reaction of 1,3,5,7-tetrakis(4-acetylphenyl)adamantane in ethanol/xylenes. NPOF-4 is microporous and has high surface area (SA BET ¼ 1249 m 2 g À1 ). Post-synthesis modification of NPOF-4 by nitration afforded NPOF-4-NO 2 and its subsequent reduction resulted in an aminefunctionalized framework NPOF-4-NH 2 that exhibits improved gas storage capacities and very high CO 2 /N 2 (139) and CO 2 /CH 4 (15) selectivities compared to NPOF-4.

Bottom-up Approach for the Synthesis of a Three-Dimensional Nanoporous Graphene Nanoribbon Framework and Its Gas Sorption Properties

“…We found exceptional CO 2 /CH 4 selectivities of 52.5 and 62.7 at 1 bar, 298 K for pre-GNF and GNF-1. GNF-1 showed the highest CO 2 /CH 4 selectivity compared to recently reported nitrogen containing nanoporous polymers such as, Li-POPs 29 , PAF-30 (24.3-30.2) 26 , ALP (4-8) 52 and NPOFs (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) 55 . The CO 2 /CH 4 selec- tivity of GNF-1 is also very high compared to the activated carbon (3.7) 56 , thus showing clearly the promise of our bottom-up approach for the preparation of carbon-based frameworks.…”

Porous imine-based networks with protonated imine linkages for carbon dioxide separation from mixtures with nitrogen and methane

“…These factors are comparable or only slightly lower than those of many other examples calculated with the IAST method such as BILP-10 (9, ratio of 0.5/95 at 298 K), 83 PAN-2 (10, ratio of 0.5/95 at 298 K), 80 NPOF-4-NO 2 (11, ratio of 0.5/0.5 at 298 K). 84 The analogousness of the selectivity values of PIN1 and PIN2 can be ascribed to the similar ultramicropore sizes, which is supported by the CO 2 uptakes, surface areas and heat of adsorption calculated from CO 2 isotherms.…”

Polymeric ionic liquids for CO2 capture and separation: potential, progress and challenges

“…71,[78][79][80][81][82][83][84][85][86][87][88] Various sorbents scanned for CO 2 sorption showed better separation and capture ability and the sorption values are typically expressed in mg g -1 for the evaluation of sorbents (see Table 2). MOFs owing to their large surface area and pore volume adsorbed significant amount of CO 2 at high pressure while at low pressure exhibited small CO 2 uptake.…”

“…78 The aforementioned materials have their own advantages and limitations as well. Therefore, porous organic materials such as triazine based microporous polycarbazoles (PCBZ), 83 nanoporous organic frameworks (NPOF-4), 84 porous polymer networks (PPN-80), 85 conjugated microporous polymers (CMP-1-COOH), 71 microporous polyimides (PI-1), 86 porous aromatic frameworks (PAF-1) 87 and hypercrosslinked polymers (HCP-1) 88 have been designed for better CO 2 sorption. Among the PILs as shown in Table 2, clPIL-2 taken up the highest carbon dioxide (20.24 mg g -1 ) at low pressure (1bar) that encourages for opportunities to tailor and design new PILs leading to increase in CO 2 sorption performance especially by immobilizing these PILs on various supports, 89 changing the polycation and increase of porosity.…”