Amine-Functionalized Covalent Organic Framework for Efficient SO2 Capture with High Reversibility

Abstract

Removing sulfur dioxide (SO2) from exhaust flue gases of fossil fuel power plants is an important issue given the toxicity of SO2 and subsequent environmental problems. To address this issue, we successfully developed a new series of imide-linked covalent organic frameworks (COFs) that have high mesoporosity with large surface areas to support gas flowing through channels; furthermore, we incorporated 4-[(dimethylamino)methyl]aniline (DMMA) as the modulator to the imide-linked COF. We observed that the functionalized COFs serving as SO2 adsorbents exhibit outstanding molar SO2 sorption capacity, i.e., PI-COF-m10 record 6.30 mmol SO2 g−1 (40 wt%). To our knowledge, it is firstly reported COF as SO2 sorbent to date. We also observed that the adsorbed SO2 is completely desorbed in a short time period with remarkable reversibility. These results suggest that channel-wall functional engineering could be a facile and powerful strategy for developing mesoporous COFs for high-performance reproducible gas storage and separation.

Reversible coordinative binding and separation of sulfur dioxide in a robust metal–organic framework with open copper sites

“…Porous metal-organic frameworks (MOFs) have been studied extensively for uptake and separation of a wide variety of gases, notably CO 2 , H 2 and hydrocarbons, 9-adsorbents ( Table 1, Fig 2), [15][16][17][18][19][20][21][22][23][24][25] but many exhibit limited stability and/or reversibility under near-ambient conditions. Current top-performing MOFs for SO 2 adsorption at 298 K and 1.0 bar include MFM-202a (10.2 mmol g -1 ) 18 and SIFSIX-1-Cu (11.0 mmol g -1 ) 16 .…”

Synthesis and Structure–Property Relationships of Polyimide Covalent Organic Frameworks for Carbon Dioxide Capture and (Aqueous) Sodium-Ion Batteries

“… 25 , 59 Although this concept has been extensively studied for boronate ester and imine-based COFs, such studies for more stable, high-performance COFs are scarce. 60 , 61 However, in order to utilize nanoporous adsorbents in industry applications, a thermally and chemically stable polymer backbone is often required. As such, polyimide-based COFs are expected to be promising candidates, 45 , 47 , 48 and systematically studying their gas sorption properties pushes the field forward.…”

Exploring the Acid Gas Sorption Properties of Oxidatively Degraded Supported Amine Sorbents

“…The latter two gases were chosen to evaluate the potential for using supported amines for impurity adsorption. [25,[43][44][45] In this section we normalize our results per gram of sorbent (g -1 ); this is due to the difficulties in contrasting systems of different classes, with different amine loadings, thus this format allows for a more reasonable comparison of the uptake of the sorbents. The MePEI-SBA series showed no notable CO2 uptake at 35 o C under dry conditions (as expected), however PEI-SBA and PEI90-SBA both showed significant uptake, with fresh PEI-SBA showing amine efficiencies of 0.21 and 0.12 for the 10 vol% and 400 ppm CO2 feeds, respectively (Table S1, Figure 4).…”

“…[44] Unlike CO2 sorption, recent literature suggests that secondary amines are more effective than tertiary or primary amines for SO2 sorption, but the reasons for this are currently not well-understood. [44] Similarly the binding mechanism of NO2 has been hypothesized, but never confirmed, with studies showing that it is able to indiscriminately bind to all types of amines, with similar affinities. [45] Aside from the differing adsorption behavior, another pivotal factor in the nature of the amine groups is their stability, specifically their reactivity with oxygen, at temperatures necessary for 6 acid-gas desorption.…”