Trends in Solid Adsorbent Materials Development for CO₂ Capture

Abstract

A recent report from the United Nations has warned about the excessive CO2 emissions and the necessity of making efforts to keep the increase in global temperature below 2 °C. Current CO2 capture technologies are inadequate for reaching that goal, and effective mitigation strategies must be pursued. In this work, we summarize trends in materials development for CO2 adsorption with focus on recent studies. We put adsorbent materials into four main groups: (I) carbon-based materials, (II) silica/alumina/zeolites, (III) porous crystalline solids, and (IV) metal oxides. Trends in computational investigations along with experimental findings are covered to find promising candidates in light of practical challenges imposed by process economics.

Assessment of poly(L‐lactide) as an environmentally benign CO2 capture and storage adsorbent

“…It is evident such as the fPLA shows the highest adsorption capacity of 16 wt% (3.64 mmol/g) at 15 bar. These values are comparable with several adsorption materials, [35] but they are lower than majority ACs which present a range of adsorption capacity between 2 and 5 mmol/g at 1 bar. [30,31] In any case, it should be noted that the value found is associated with a material that has a SSA of 7.2 m 2 /g and a pore volume of 0.03 cm 3 /g against the 3,000 m 2 /g and 0.5-2 cm 3 /g of the ACs, respectively.…”

“…[29] Among carbon-based materials, ACs derived from biomass have become increasingly attractive due to their stability, variable porosity and eco-friendly nature. In the last year, ACs were prepared starting from natural, organic, sea, and agricultural wastes, such as seaweed, [30] popcorn, [31] wood, [32] pine cone, [33] and others, [34,35] showing high specific surface areas (SSAs), micro-porosity, and good CO 2 storage capacity. However, ACs preparation process requires chemical activating agents to enhance their porosity, a washing step to get rid of the unreacted residual chemicals and a thermal treatment to high temperatures.…”

Solvent‐ and Catalyst‐Free Carbon Dioxide Capture and Reduction to Formate with Borohydride Ionic Liquid

“…This value is in good agreement with the NMR data ([HB(OCHO) 3 ] − and [H 2 B(OCHO) 2 ] − as products). Unlike conventional CO 2 absorbers such as solid amines, [EMPY][BH 4 ] can fix 5–6 times more moles of CO 2 per mole of IL . Furthermore, the CO 2 is also reduced to formate under ambient conditions and without a catalyst.…”

“…This effect seems to increase as the concentration of CO 2 decreases, which means that a sufficient concentration of reagent (CO 2 ) is required for the formation of triformatoborohydride. Nevertheless, [EMPY][BH 4 ] demonstrates considerable potential for the simultaneous capture and reduction of CO 2 from CO 2 ‐rich streams, such as flue gas, which contains approximately 14 % CO 2 , with more than 0.8 g g −1 IL . To determine the capture performance, we quantified the amount of CO 2 retained in a bed of the IL by using MS (Figure S4).…”

Metal-Free Modified Boron Nitride for Enhanced CO2 Capture

“…One of the challenges in this area relates to the manufacturing of new adsorbents that enables enhancing good diffusion kinetics and providing improved performance [10]. In this regards, porous materials with high porosity, chemical and thermal stability are promising solid adsorbents for capturing CO 2 [11,12]. Among various kinds of porous materials, such as zeolites [13,14], porous polymers [15], metal-organic framework [16,17] and activated carbons [18], porous BN has become one of the new classes of CO 2 adsorbents.…”