Enhanced Kinetic Performance of Amine-Infused Hydrogels for Separating CO₂ from CH₄/CO₂ Gas Mixture

The performance of amine-infused hydrogels (AIH) was investigated for capturing CO₂ from CH₄/CO₂ gas mixture. The amine-infused hydrogel was prepared via simply mixing monoethanolamine (MEA) solution with dried hydrogel particles; then, systematic experiments were carried out to analyze the performance of the AIH particles. The obtained results suggest that the AIH particles quickly capture CO₂ from the CH₄/CO₂ gas mixture with high selectivity, resulting in increased CO₂ uptake capacity compared to that of the MEA solution. The kinetic performance for CO₂ absorption was also investigated by varying the temperature, providing the mixing, and adding an additive. Higher temperatures showed a slightly faster CO₂ absorption rate in early stage. Mixing the AIH particles with the gas mixture increased the absorption rate, but the absorption capacity was dependent on the characteristics of AIH. We observed that the AIH particles tended to agglomerate with each other without mixing, which resulted in decreased CO₂ absorption capacity. Under mixing condition, AIH remained separated while the amount of captured CO₂ increased. The addition of decane and dodecyltrimethylammonium bromide (DTAB) helped to alleviate the coagulation between AIH particles and resulted in increased both CO₂ absorption rate and capacity.