Optimization and microfluidic fabrication of magnetic Na2CO3–MEA microcapsules for enhanced CO2 capture applications

This study develops a novel microencapsulated carbon sorbent (MECS) by integrating a composite Na 2 CO 3 -MEA (monoethanolamine) absorbent with droplet microfluidics technology. Building upon the activation mechanism of MEA, the CO 2 absorption performances of Na 2 CO 3 -MEA composites at different molar ratios are systematically investigated. A multi-objective optimization function identifies an optimal composition that achieves a 149 % increase in CO 2 capture rate compared to Na 2 CO 3 solution alone, while maintaining excellent cost-effectiveness. Subsequently, this high-performance absorbent is encapsulated within a photocurable organosilicone shell via a triple-coaxial capillary microfluidic device, forming stable core-shell microcapsules (MECS@Na 2 CO 3 –MEA). By leveraging hydrodynamic tuning, we achieved precise control over the microcapsule's geometry, systematically tuning shell thickness and particle size to fundamentally optimize the performance for CO 2 absorption. Under a pressure of 0.7 atm and an optimized temperature of 40 °C, the MECS@Na 2 CO 3 –MEA demonstrates a 36 % higher CO 2 absorption capacity compared to an equivalent mass of the unencapsulated absorbent. This significant enhancement persists even under low CO 2 concentration conditions, where 33 % and 57 % improvement are observed at 1 vol% and 5 vol% CO 2 , respectively. Furthermore, the microfluidic fabrication method also permits the incorporation of magnetic nanoparticles, endowing the MECS with dual functionality: magnetic responsiveness that enables remote steering and further improves CO 2 absorption performance. This work presents a promising, cost-effective approach for developing high-performance materials for carbon capture applications.