Abstract:

Aminopropyl functional ionic liquids exhibit a good selectivity for carbon dioxide(CO₂)absorption.In order to reveal the effects of water concentration on the CO₂ solubility in 1-aminopropyl-3-methylimidazolium bromide([APMim]Br)aqueous solutions,the experiments based on an isochoric technique by using a high-pressure quartz glass cell were performed to test the solutions of 55.90%,65.78%,76.80% and 85.76% water mass fractions.The equilibrium data for CO₂ solubility in these aqueous solutions were obtained in range of 278.15-348.15 K and 0.1-4.5 MPa.A mathematical model that can correctly reflect the experimental data changes was obtained by mechanism analysis of absorption.The results indicated that the chemical absorption mechanism is predominant at lower pressure while the CO₂ solubility can be doubled comparing to the chemical one when the water concentration increased and the physical absorption ability prevailed.In 65%-85% water mass fraction,the solutions have an excellent CO₂ absorption and release ability in considerable large temperature and pressure ranges and may have a promised future for engineering application.

Key words: ionic liquid, aqueous solution, water concentration, carbon dioxide, absorption property

摘要：

氨丙基功能型离子液体对CO₂具有良好的选择吸收特性,以[APMim]Br离子液体水溶液体系为例,在有效吸收(水含量大于55%)区间,水含量对CO₂的化学吸收和物理吸收都具有显著影响。依据[APMim]Br水溶液在278.15~348.15 K,0.1~4.5 MPa,水质量分数为55.90%、64.50%、76.80%和85.80%范围的CO₂吸收特性数据,对溶液体系的化学吸收和物理吸收模型进行分析研究,获得两种吸收机理的数学表达,并对实验数据进行回归分析,得到能够正确反映化学吸收和物理吸收的计算模型。结果表明,低压下化学吸收占主导作用,随水含量增大,溶液体系对CO₂吸收能力成倍增加,而且产生的物理吸收效应远大于离子液体本身的化学吸收能力。水的质量分数在0.65~0.85区间,[APMim]Br水溶液在相当大的温度和压力范围内具有优良的CO₂吸放气特性,显示出良好的工程应用前景。

关键词: 离子液体, 水溶液, 水含量, 二氧化碳, 吸收性能