Low concentration CO2 capture using physical adsorbents: Are metal–organic frameworks becoming the new benchmark materials?

Abstract

KeywordsCO 2 capture, traces CO 2 removal, air capture, physical adsorbents, MOFs AbstractThe capture and separation of traces and concentrated CO 2 from important commodities such as CH 4 , H 2 , O 2 and N 2, is becoming important in many areas related to energy security and environmental sustainability. While trace CO 2 concentration removal applications have been modestly studied for decades, the spike in interest in the capture of concentrated CO 2 was motivated by the need for new energy vectors to replace highly concentrated carbon fuels and the necessity to reduce emissions from fossil fuel-fired power plants. CO 2 capture from various gas streams, at different concentrations, using physical adsorbents, such as activated carbon, zeolites, and metal-organic frameworks (MOFs), is attractive. However, the adsorbents must be designed with consideration of many parameters including CO 2 affinity, kinetics, energetics, stability, capture mechanism, in addition to cost. Here, we perform a systematic analysis regarding the key technical parameters that are required for the best CO 2 capture performance using physical adsorbents. We also experimentally demonstrate a suitable 2 material model of Metal Organic Framework as advanced adsorbents with unprecedented properties for CO 2 capture in a wide range of CO 2 concentration. These recently developed class of MOF adsorbents represent a breakthrough finding in the removal of traces CO 2 using physical adsorption.This platform shows colossal tuning potential for more efficient separation agents.

A Fine-Tuned Fluorinated MOF Addresses the Needs for Trace CO2 Removal and Air Capture Using Physisorption

“…Inopportunely, the worldwide energy needs have doubled the fossil fuel consumption in the last two decades, [1][2][3][4][5][6][7][8][9][10][11] as a result of the eminent economic growth and the enhanced quality of living in emerging countries, and thus provoking the manifest and amplified global carbon dioxide emission. The foreseen deployment of a relatively cleaner alternative energy sources, e.g.…”

“…Explicitly, point-source carbon capture and storage (CCS) can be regarded as a plausible solution sanctioning the sustainable use of fossil fuels in power, steel and cement production plants, while direct air capture (DAC) can address and remediate the CO 2 emissions from mobile-sources such as automobiles and airplanes. [1][2][3][4][5][6][7][8][9][10][11] Markedly, the DAC offers a great prospective to remotely capture the emitted CO 2 at a different distant location and time. It is to note that the CO 2 capture from air using the chemical adsorption technology has been deployed, for over seven decades, to maintain a safe level of CO 2 in confined spaces such as space shuttles and submarines, where access to fresh air is limited.…”

“…12,13 Nevertheless, the CO 2 concentrations and the associated CO 2 quantities to the DAC (400 ppm CO 2 , worldwide average of 54 kg/person/day) and to the point-source CCS (7-15% CO 2 , worldwide average of 38 kg/person/day) entail a relatively larger scale footprint and/or an excessive energy penalty than the requisites for the CO 2 capture in confined spaces (1-5 % CO 2 and 1 kg/person/day). [1][2][3][4][5][6][7][8][9][10][11] Perceptibly, the cost associated to the CO 2 capture in confined spaces is not a disturbing concern, as the compulsory objective is the effective removal of CO 2 and the subsequent procurement of the indispensable clean air. Noticeably, the low CO 2 concentration in air (400 ppm) and the compulsory low CO 2 level in confined spaces (< 0.5 %) position chemical adsorbents, such as aqueous alkylamine solutions and lithium hydroxide (LiOH) (80-120 kJ/mol), as the conventional benchmark materials, with a high CO 2 -selectivity even in the presence of water vapor, for the carbon capture in diluted CO 2 concentrations 8 Nevertheless, largescale widespread of the chemically driven separation approach is hampered by the prohibitive high-energy requirement for the CO 2 desorption/regeneration process.…”

“…below 60 kJ/mol. 3,[14][15][16][17] Consequently, such a looked-for adsorbent will pave the way to an affordable, effective and energy-efficient recovery of CO 2 and renders the DAC competitive and self-sustainable. Considerately, the aerospace industry recognized the advantages of the physisorption-based separation and recently shifted their efforts to the utilization of recyclable physical adsorbents, such as the zeolite 5A (Ca 2+ ) and the SAPO-34 (Sr 2+ ), for the capture of CO 2 in confined spaces.…”

Carbonization of covalent triazine-based frameworks via ionic liquid induction

“…In light of the obtained uniform pores with triazine rings in the frameworks of KPOP-6b, a major metric in the selection of CO 2 adsorbents 41,42 , it was further selected to evaluate its CO 2 capture ability (Fig. S7).…”