Abstract
Alcohol amine solutions have a high absorption capacity and rate for CO(2) capture, however, there are some shortcomings such as high energy-consumption and low stability. To enhance CO(2) capture performance of aqueous MEA, a functional ionic liquid ([NH(2)e-mim][BF(4)]) was introduced based on the advantages for CO(2) capture. Absorbents were prepared with the molar concentration ratio of [NH(2)e-mim][BF(4)] to the 30 vol% aqueous MEA of 0 : 10, 1 : 9, 2 : 8, 3 : 7, 4 : 6 and 6 : 4. The density and the viscosity of the investigated absorbents were measured and the effects of the molar fraction of [NH(2)e-mim][BF(4)] (n (I)) and temperature on CO(2) absorption performance were investigated. CO(2) desorption performance of the solvent at different temperatures was discussed. The stability performance of the absorbent with n (I) of 2 : 8 (I/M(2:8)) was examined by five consecutive cyclic tests. The results showed that for pure CO(2), the I/M(2:8) displayed the highest absorption performance at 303 K under 1 bar: a comparable CO(2) absorption capacity of the 30 vol% aqueous MEA and a higher CO(2) absorption rate at the later absorption stage. Moreover, with the increase of temperature, CO(2) absorption capacity and rate decreased, while CO(2) desorption efficiency and rate increased. 393 K was chosen as the optimum desorption temperature with the desorption efficiency of 99.31%. The introducing of IL contributed to CO(2) desorption performance of the absorbents significantly. The properties (CO(2) absorption capacity, mass loss, density and viscosity) of the I/M(2:8) during the cycles suggested that the IL-MEA mixture had an excellent stability performance.