Performance enhancement and mechanistic insights of CO2 capture by PZ-activated sterically hindered amines

Amine-based chemical absorption remains a promisingly powerful technology for carbon dioxide (CO 2 ) capture. However, enhancing the performance of absorbents remains a significant challenge. In this study, three sterically hindered amines (SHAs), including 2-( tert -butylamino)ethanol, 2-amino-2-methyl-1-propanol, 2-amino-2-methylpropane-1,3-diol were selected as the primary absorbents with piperazine (PZ) employed as an activator. Absorption and desorption experiments were conducted for various PZ-SHAs systems with a total amine concentration of 30 wt% under conditions of 313 K and 13 kPa CO 2 partial pressure. The CO 2 absorption capacity, initial absorption rate, desorption rate, and desorption energy consumption were systematically evaluated, indicating that the addition of PZ as an activator could effectively improve the trapping capacity of the spatially hindered amine, and keep a high recycling capacity and low regeneration energy. Finally, the CO 2 reaction mechanism under the new system was clarified by 13 C nuclear magnetic resonance (NMR) technique.