Encapsulated Ionic Liquids with MOF-Driven CO₂ Channels: Overcoming Kinetic Limits for Rapid Carbon Capture

The urgent challenge of anthropogenic climate change has intensified demand for innovative carbon capture solutions. However, conventional CO₂ capture technologies such as adsorption, absorption, and membrane separation are limited by high energy costs and scalability limitations, which restrict their viability as future-oriented solutions. This study introduces a novel microcapsule capture system (MECS) that synergizes liquid-phase selectivity and solid-phase mass transfer efficiency, overcoming kinetic bottlenecks from the low specific surface area and high viscosity of ionic liquids. The ionic liquid [Bmim][Ac] was encapsulated within a sodium alginate gel matrix. This strategy significantly enhances the interfacial contact area with CO₂, which accelerates capture kinetics. The spatial confinement within microcapsules mitigates viscosity-induced kinetic bottlenecks that improves adsorption capacity. Further, adding a zirconium-based metal-organic framework (UiO-66-NH₂) into the shell creates engineered CO₂ transport channels and reduces diffusion resistance and increases the capture rate ∼5 times. Under simulated flue gas, UiO-66-NH₂-embedded microcapsules achieved a CO₂ adsorption capacity of 1.62 mmol/g and surpassed that of pure [Bmim][Ac] (0.99 mmol/g). They demonstrated CO₂/N₂ selectivity of 28 and exceptional mechanical resilience, withstanding loads up to 20000 times their mass. Thus, under typical industrial conditions, the microcapsules show superior stability, capture capacity, and efficiency, which makes them well-suited for large-scale carbon capture.