Studies on CO₂ absorption performance by imidazole-based ionic liquid mixtures

Conventional and functional imidazole-based ionic liquids (abbr. ILs) were mixed based on their advantage and disadvantage on CO₂ reduction. Additionally, CO₂ absorption effect and regeneration performance of imidazole-based IL mixtures were discussed. It was showed that imidazole-based IL mixtures had good fluidity and smooth of transferring CO₂. It had better absorption capacity of CO₂ for the mixtures of bmimBF₄ (or bmimTf₂N) and NH₂e-mimBF₄ than the single IL, and lower absorption capacity for the mixtures of bmimCH₃CO₂ and NH₂e-mimBF₄ than bmimCH₃CO₂. While the cation of conventional imidazolium ILs became longer and the mixtures could absorb CO₂ more obviously, more strong effect was shown on CO₂ absorption with the anion Tf₂N than the anion BF₄ for the conventional imidazolium IL. CO₂ absorption capacity of the imidazole-based IL mixtures had maintained 75%~85% of the initial capacity during 10 times of the absorption/regeneration cycles, while the quality of the regeneration was unchanged.