Novel DEEA-based biphasic solvent with low regeneration temperature and good cyclic absorption/desorption stability for CO2 capture

Tertiary amine-based biphasic solvents exhibit desorption properties, which is beneficial for reducing energy consumption. A DEEA/AMP/2-Me/H 2 O biphasic solvent was proposed. DEEA, a tertiary amine, was used as the main absorbent, 2-Me served as a phase splitter, and AMP functioned as an activator. The introduction of AMP (4 %) raised the CO 2 loading from 3.83 to 4.10 mol/L, constituting 95.7 % of captured CO 2 . Moreover, the absorbent demonstrated robust cyclic stability and exceptional desorption ability at low temperatures, attributable to its deprotonation regeneration mechanism. Notably, it achieved a remarkably high desorption capacity of 3.61 mol/L at 363.15 K, accompanied by a desorption efficiency of up to 88.0 %. These values surpassed those of 30 wt% MEA, which exhibited a desorption capacity of 1.73 mol/L and an efficiency of 58.8 % at 393.15 K, by 209 % and 150 %. Given that 363.15 K was beneath the boiling point of H 2 O, the Q latent was exceptionally minimal (0.034 GJ/t CO 2 ), leading to a remarkably decreased regeneration heat (1.51 GJ/t CO 2 ). A combination of NMR analysis, DFT and MD simulations was utilized to elucidate the phase separation mechanism. The primary factor contributing to phase separation was identified as the formation of a robust hydrogen bonding network among the absorption products.