The polylysine-based ionic liquid non-aqueous phase change system for CO2 capture performance and mechanism

Aiming at the issues of high corrosion and high energy consumption in the traditional aqueous absorption system, this study adopts organic alcohols as the absorption medium instead of water. Organic alcohol solvents enhance the absorption efficiency and the corrosion resistance of the system by forming hydrogen-bond networks with ionic liquids. Meanwhile, by introducing of alcohol ether solvents as phase separation promoters has successfully established an efficient, low corrosive, and low energy consuming liquid-liquid phase change absorption system. The system’s CO 2 absorption loading can reach 4.71 mol CO 2 /mol PILs, the absorption loading in simulated flue gas reaches 3.98 mol CO 2 /mol PILs, the volume fraction of the CO 2 -rich phase is 35.0 %, and its corrosivity is only 17.3 % that of MEA solution. The cyclic performance indicates that after five cycles, the CO 2 absorption loading of the system can still reach a good state. Analysis by ¹³C‐NMR spectra reveal that the absorption mechanism adheres to the zwitterionic mechanism. The phase separation phenomenon is closely related to changes in polarity, density, and viscosity. This system opens a new direction for the development of low corrosion and high energy efficiency phase change absorption technologies.