Enhancement of CO2 Desorption from Reinforced 2‑(2-Aminoethylamine) Ethanol Aqueous Solution by Multi-walled Carbon Nanotubes

CO2 desorption in 2-(2-aminoethylamine) ethanol (AEE) aqueous solution promoted by different types of multi-walled carbon nanotubes (pristine MWCNT, MWCNT-OH, and MWCNT-COOH) was investigated in a continuous absorption–desorption apparatus. The CO2 absorption (313 K) and desorption (393 K) processes with each solid at concentrations of 0.01–0.07 wt % in 2 mol/L AEE aqueous solution were investigated by comparing CO2 desorption rate, desorption volume, and cyclic absorption capacity at ambient pressure. It was found that each kind of MWCNT can significantly increase the CO2 desorption rate comparing to the blank test. The average desorption rates in 30 min of pristine MWCNT, MWCNT-OH, and MWCNT-COOH were enhanced by 26.7% (0.05 wt %), 32.4% (0.05 wt %), and 29.5% (0.07 wt %), respectively. The amount of CO2 desorbed increased with the increasing addition amount of MWCNTs, and stable absorption loading is improved up to 18%. The MWCNTs were characterized by XRD, NH3-TPD, FT-IR, N2-BET, and SEM before and after several absorption–desorption cycles. The characterization results verified their stability and activity for AEE aqueous solution. Adding MWCNT-OH into the AEE solution exhibits application feasibility in the industrial CO2 capture process to increase the desorption rate.