Study on regeneration characteristics of choline chloride-monoethanolamine deep eutectic solvent after capturing CO2 from biogas

Choline chloride-monoethanolamine deep eutectic solvent (ChCl-MEA DES) can deeply remove CO 2 from biogas. This study focused on regeneration of ChCl-MEA DES after CO 2 capture. The effects of regeneration temperature, time and water content on CO 2 absorption capacity, absorption rate and CO 2 /CH 4 absorption selectivity after regeneration were evaluated. The addition of HZSM-5 catalyst during regeneration further promoted regeneration efficiency. FTIR and NMR indicated that carbamates were formed after absorption, and water made it easier for the amino group to react with CO 2 to form carbamates. The highest regeneration percentage of absorbent was up to 99.89%, and the CO 2 absorption capacity even didn’t decrease significantly after 8 cycles. The ideal regeneration energy consumption in the experiment was also evaluated. This research provided a valuable reference for the application of this absorbent in CO 2 purification of biogas.