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Article Dans Une Revue Physical Review Materials Année : 2023

Metal-organic-framework transparency to water interactions for enhanced CO2 adsorption

Résumé

Today, the capture of post-combustion CO2 has become a global priority, particularly in order to curb rising temperatures in the coming decades. CO2 physisorption in porous materials such as metal-organic frameworks is likely one of the most effective approaches to addressing this problem, thanks to its low energy requirement and improved regeneration process. In this study, I investigated CO2 capture in humid conditions using the Al-MIL-53-TDC metal-organic framework through molecular simulations. I observed that water filling occurs gradually through pore capillary condensation. Remarkably, the presence of water (at a hydration rate of 4.4 wt%) resulted in a significant increase of 283% in the adsorbed amount of CO2 (1.8 mmol/g at 0.2 bar) due to a unique transparency property. The thin molecular walls between the uniaxial channels enable van der Waals and electrostatic interactions between water and adsorbed gas, which allow media on opposite sides of the walls to influence each other. The increase in isosteric heat of adsorption (46 kJ/mol) is attributed to the contribution of water/water energy resulting from the truncation of the hydration shell of water. This truncation increases the number of hydrogen bonds, which can be linked to a kosmotropic effect. Additionally, the selectivity of hydrated Al-MIL-53-TDC for CO2/N2 increased by 185% at 0.2 bar (composition 20:80), compared to the unhydrated MOF material with QsT < 50 kJ/mol.
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Dates et versions

hal-04387053 , version 1 (11-01-2024)

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Aziz Ghoufi. Metal-organic-framework transparency to water interactions for enhanced CO2 adsorption. Physical Review Materials, 2023, Physical Review Materials, 7 (12), pp.126001. ⟨10.1103/physrevmaterials.7.126001⟩. ⟨hal-04387053⟩
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