咪唑类离子液体混合物吸收CO2性能研究

结合常规离子液体和功能型离子液体在吸收CO₂方面的优势,将两类咪唑类离子液体进行混合,对其吸收CO₂的效果和再生性能进行了实验研究。结果表明,两类咪唑类离子液体混合后流动性明显改善,与CO₂接触气液传质顺畅;常规离子液体[bmim][BF₄]和[bmim][Tf₂N]与胺功能型离子液体[NH₂e-mim][BF₄]混合物较单一的离子液体吸收CO₂的量大,[bmim][CH₃CO₂]与[NH₂e-mim][BF₄]混合后较单一的[bmim][CH₃CO₂]吸收量有明显的减低;随着常规咪唑类离子液体阳离子碳链增长,混合离子液体吸收CO₂的效果变强;与胺乙基功能型离子液体混合吸收CO₂时,阴离子为[Tf₂N]的常规咪唑类离子液体要比阴离子为[BF₄]的吸收效果好;离子液体混合物吸收CO₂后经再生循环利用10次,混合物质量基本不变,循环使用后吸收CO₂性能为初始吸收性能的75%~85%。

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 [bmim][BF₄] (or [bmim][Tf₂N]) and [NH₂e-mim][BF₄] than the single IL, and lower absorption capacity for the mixtures of [bmim][CH₃CO₂] and [NH₂e-mim][BF₄] than [bmim][CH₃CO₂]. 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.