Review of research progress and stability studies of amine-based biphasic absorbents for CO2 capture

Amine Sorbents for Sustainable Direct Air Capture: Long-Term Stability and Extended Aging Study

“…Various materials can be employed for CO 2 adsorption, categorized based on the interaction between CO 2 and the sorbent: physisorbents and chemisorbents. , Physisorbents like metal–organic frameworks (MOFs), ,, activated carbons, − or zeolites , are noted for poor performance, exhibiting low CO 2 capacity at low concentrations and lacking selectivity. In contrast, chemisorbents prove highly effective at ultralow CO 2 concentrations, making them preferable for DAC at levels like 420 ppm in the air. ,, Among chemisorbents, amine-functionalized sorbents stand out due to their high CO 2 uptake, selectivity, adaptability to various conditions, and low energy requirements. , In these materials, CO 2 reacts with amines, forming chemical bonds that facilitate substantial uptake, even at low CO 2 concentrations through Reactions –, depending on moisture availability. ,, Solid amine-based sorbents are categorized by their preparation methods and the bonds formed between amines and the support material, as illustrated in Figure , . Class I involves physical amine impregnation into supports, offering easy preparation and higher amine loadings but suffering from stability issues due to amine leaching. ,, Class II sorbents feature chemical bonding through silane linkages, providing enhanced stability but lower CO 2 uptake and a more intricate synthesis process .…”

“…22,31 In these materials, CO 2 reacts with amines, forming chemical bonds that facilitate substantial uptake, even at low CO 2 concentrations through Reactions 1−4, depending on moisture availability. 7,32,33 Solid amine-based sorbents are categorized by their preparation methods and the bonds formed between amines and the support material, as illustrated in Figure 1 4,34 . Class I involves physical amine impregnation into supports, offering easy preparation and higher amine loadings but suffering from stability issues due to amine leaching.…”