Trace Carbon Dioxide Capture by Metal–Organic Frameworks

Abstract

Climate deterioration is closely related to the CO 2 concentration in atmosphere, which is considered one of the major environmental challenges we are facing today. It is urgent to take immediate actions to prevent further climate change. In comparison with post-combustion CO 2 capture technologies from flue gas, trace CO 2 capture directly from air is still a challenge but very important for both CO 2 control in atmosphere and air condition control in confined space. This review highlights recent research advances in the use of metal-organic frameworks (MOFs) for trace CO 2 capture, with the emphasis on employing amine functionalized MOFs and ultra-microporous MOFs. Herein, the reported strategies to enhance CO 2 adsorption capacity and selectivity by MOFs are categorized into three main directions, including the developments of MOFs with open metal sites, ultra-microporous MOFs, and amine functionalized MOFs. The mechanisms combined with trace CO 2 capture performance by these MOFs are discussed in detail, offering some promising adsorption solutions for future practical applications of MOF materials. In addition, the performance for CO 2 capture under humid conditions and the regenerability of these MOF adsorbents are revealed. In order to address major issues of capacity, selectivity and stability especially under humid conditions, precise construction and engineering of MOFs to achieve the optimized porous materials are needed.

Large-Scale Screening and Machine Learning to Predict the Computation-Ready, Experimental Metal-Organic Frameworks for CO2 Capture from Air

“…The traditional technique for separating carbon dioxide is solvent washing, such as the use of an alcohol amine solution [7][8][9][10]. Although this conventional method can reduce the concentration of carbon dioxide in the air, it is extremely expensive, the solvent is difficult to regenerate, the operation is complicated, and it consumes a great deal of energy [11]. In fact, the energy consumption of solvent washing is 3 to 4 times that of CO 2 captured from exhaust gas [12].…”

“…Conventional adsorbents, however, including activated carbon, zeolite, silica gel, and metal oxides have poor scavenging effects on carbon dioxide in the air due to inferior separation selectivity and regeneration difficulty. For example, silica gel, which has amorphous properties, does not have a continuous uniform porous structure and exhibits unfavorable diffusion properties [11]. Therefore, the development of a new type of adsorbent is imperative.…”

“…Compared with common adsorbents, MOFs exhibit many advantages such as various structures and properties, large specific surface area, high porosity, and structural control. Therefore, they are widely used in gas adsorption [11] and separation [14][15][16][17][18][19], as well as general materials in processes including storage [20], optics [21], catalysis [22][23][24][25], and drug delivery [26,27]. To date, thousands of MOFs have been synthesized, some of which have been utilized in the attempt to capture CO 2 from the air.…”

“…Peng et al [28] designed and synthesized 2 incorporated MOFs to study their stability and ability to capture CO 2 from the air. Liu et al [11] used an amine-functionalized MOF and an ultra-microporous MOF to capture CO 2 directly from the air, and further investigated the performance of CO 2 capture and the reproducibility of MOFs under humid conditions. Osama et al [29] synthesized an isomorphic MOF SIFSIX-3-Cu with uniform adsorption sites for capturing CO 2 from the air.…”

Direct CO2 Capture from Air via Crystallization with a Trichelating Iminoguanidine Ligand

“…To achieve high capture efficiency for DAC, the materials should exhibit strong affinity, high selectivity, and fast kinetics for CO 2 . Porous materials such as carbon materials, 11 , 12 zeolites, 13 , 14 and metal–organic frameworks 15 have been largely reported for CO 2 sorption, but they were not so efficient due to the weak physical interaction between such sorbents and CO 2 , which resulted in a lower capacity and poorer selectivity over N 2 and H 2 O molecules under a low CO 2 partial pressure. 16 , 17 Therefore, the chemisorption materials are more promising for DAC.…”