Amino-functionalised ionic liquid hybrid metal-organic frameworks for carbon dioxide capture in the presence of water

Mitigating climate change caused by global warming and achieving cost-effective and practical carbon dioxide (CO₂) capture from flue gases and other diverse scenarios necessitates consideration of the impact of moisture on adsorbents. In this work, amino-functionalised imidazole ionic liquid (IL) was grafted onto the metal-organic framework (MOF) Mg/DOBDC for the first time, yielding a series of stable ionic liquid-hybrid materials for CO₂ capture. The influence of IL content on structural changes in hybrid materials was investigated, and the CO₂ dynamic adsorption capacity of the materials was determined via dynamic adsorption breakthrough curve testing. Subsequently, the water adsorption behaviour of the material and its structural stability before and after water absorption were measured under humid conditions. The enhancement of CO₂ capture performance under the presence of water was investigated through CO₂/water binary dynamic permeation experiments. Finally, the adsorption mechanism of ionic liquid hybrid MOF materials was discussed. Research findings demonstrated that the unsaturated metal centers within the MOF interact with the halide anions and -NH₂ moieties of the IL, thereby increasing the density of active adsorption sites and enhancing the effective adsorption of CO₂ by the material.