Dynamic breakthrough performance of low concentration CO2 adsorption in fixed-bed column with porous amino acid ionic liquid composites

Low concentration carbon dioxide (CO 2 ) capture from air or confined spaces currently faces significant challenges, such as relatively poor dynamic adsorption breakthrough performance and cyclic stability. In our previous work, functionalized ionic liquid (IL) tetraethylammonium glycine ([N 2222 ][Gly]) and porous molecular sieve (SBA-15) were combined to synthesize porous amino acid IL composite 60 wt% [N 2222 ][Gly]@SBA-15 with microporous and ultra-microporous structures, which provide a new pathway for low concentration CO 2 capture. In order to further obtain the dynamic CO 2 adsorption breakthrough performance of this material under simulated actual working conditions, the effects of temperatures, relative humidity (RH) and CO 2 concentrations on CO 2 adsorption and desorption breakthrough performance of 60 wt% [N 2222 ][Gly]@SBA-15 in a fixed-bed column were systematically studied in this work. The results indicated that CO 2 adsorption capacity is up to 1.81 mmolCO 2 /g-adsorbent at 298.15 K, 1 bar and 0 % RH under 1 vol% CO 2 -containing gas mixture balanced with N 2 and reaches 2.44 mmolCO 2 /g-adsorbent at 15 % RH due to the mechanism change of CO 2 reaction with primary amine from 2: 1 under dry gas to 1: 1 stoichiometry in the presence of moisture. Moreover, the adsorbent maintains good cyclic adsorption-desorption performance. Further, CO 2 adsorption breakthrough behaviors were well fitted by Avrami kinetic model, and the CO 2 adsorption rate of 60 wt% [N 2222 ][Gly]@SBA-15 was controlled by intra-particle diffusion. This work implied that IL-modified adsorbents have great potentials for low concentration CO 2 capture applications.