The absorption performance of liquid-liquid biphasic CO2 absorbent aqueous mixture of 1-butyl-3-methylimidazoliumtetrafluoroborate ([Bmim] [BF4]) and monoethanolamine (MEA) was measured
and the effects of[Bmim] [BF4] on the absorption properties and stratification were investigated. The stratification mechanism and substance distribution were analyzed with quantitative13C nuclear magnetic resonance (NMR) method. The results showed that the liquid-liquid stratification would occur when loaded with CO2
which was accompanied with the enrichment of the reaction products of CO2. The cause of the liquid-liquid stratification is the increase of the concentration of carbamates. The absorption rates of absorbents increase first and then decrease with the increase of the mass fraction of[Bmim] [BF4]. H2O is mainly distributed in the rich phase after stratification
and[Bmim] [BF4] is mainly distributed in the lean liquid phase. The mass fraction of H2O directly affects the mass transfer performance of the rich liquid phase.