Enhanced Binding Affinity, Remarkable Selectivity, and High Capacity of CO₂ by Dual Functionalization of a rht‐Type Metal–Organic Framework

Abstract

As a new family of adsorbent materials, porous metal-organic frameworks (MOFs) have attracted enormous attention over the past decade.[1] Having a large surface area, [2] tunable pore size and shape, [3] adjustable composition and functionalizable pore surface, [4] MOFs show unique advantages and promises for potential applications in adsorption-based storage and separation technologies for small gas molecules such as H 2 , CO 2 , and CH 4 . [1b,d, 5] CO 2 capture from flue gases is of particular importance in reducing greenhouse gas emissions and in preserving environmental health. A flue gas mixture is composed of nitrogen, carbon dioxide, water vapor, oxygen, and other minor components such as carbon monoxide, nitrogen oxides, and sulfur oxides.[1b, 6] Separation of low-concentration CO 2 (about 10-15 %) from nitrogen-rich streams remains a challenging task at the present time. Adsorption-based CO 2 capture and separation is considered an effective way and may have a real potential if adsorbents with both high CO 2 selectivity and capacity near room temperature (up to 50 8C) and in the lowpressure range can be developed. [7] Recent studies have revealed a number of MOFs that show a high performance in capturing and separating CO 2 from N 2 and other small gases under conditions mimicking power plant flue gas mixtures. [8]

Biomass Waste Carbon Materials as adsorbents for CO2 Capture under Post-Combustion Conditions

“…Under these conditions, CO2 capacities fall to the range of 0.7-1.2 mmol/g. It is worthy to highlight that these values are still higher or equal than those reported from some commercial carbon-based adsorbents, i.e., Norit R2030 CO2 (Plaza et al, 2015), BPL (Chue et al, 1995), Norit AC 1 Extra (Dreisbach et al, 1999), BrightblackTM (Hornbostel et al, 2013), or VR-5-M (Wahby et al, 2010), very similar to some carbon fiber composites obtained by petroleum pith (Thiruvenkatachari et al, 2013), or even to other attractive adsorbents such as some MOFs (Krishna and Van Baten, 2012;Li et al, 2012;Sabouni et al, 2013;Xu et al, 2013;Xian et al, 2015) and zeolites (Hefti et al, 2015), tested under similar operating conditions. In addition, it should be kept in mind that these materials would present the added value of having being prepared by valorization of highly available underutilized biomass residues and using much more inexpensive, straightforward, and easy to scale-up procedures.…”

Triazine containing N-rich microporous organic polymers for CO 2 capture and unprecedented CO 2 /N 2 selectivity

“…Here we have incorporated triazine moiety in the N-containing porous polymeric backbones, which is very desirable for post combustion CO2 capture application [36]. SB-TRZ-…”

High CO2/N2/O2/CO separation in a chemically robust porous coordination polymer with low binding energy

“…However, the CO 2 adsorption heat was too low (16)(17)(18)(19)(20) 2). Compared with our previous La-BTB framework, the space between adjacent ligands has enlarged from $3.8Å to $6.2Å, which should provide a suitable space for CO 2 diffusion with low binding energy.…”