A high-efficiency carboxylated choline amino acid ionic liquid for CO2 capture and its absorption-desorption performance

Efficient and low-energy absorbents are always desirable to control the greenhouse effect. In this study, a novel amino polycarboxylate ionic liquid absorbent is constructed by introducing carboxylate groups. The CO 2 absorption-desorption experiments in microchannel and macroscopic devices are performed to comprehensively investigate the performance of choline iminodiacetate ([Ch] 2 [IDA]). It is found that [Ch] 2 [IDA] could form soluble carbamic acid upon CO 2 absorption, thereby effectively preventing equipment blocking compared to choline glycine ([Ch][Gly]). The dual carboxyl groups in [IDA] 2− could generate a synergistic effect to weaken the negative inductive action of the amino group; consequently, [Ch] 2 [IDA] displays superior CO 2 absorption performance over [Ch][Gly]. Furthermore, [Ch] 2 [IDA] aqueous solution could release more CO 2 in the rapid desorption stage and effectively alleviate the sharp increase of energy consumption during the desorption termination period. Especially, it exhibits excellent cycling stability. Comparatively, [Ch] 2 [IDA] aqueous solution demonstrates great potential as a next-generation efficient and low-energy CO 2 absorbent.