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.