Non-dispersive absorption of CO2 in [emim][EtSO4] and [emim][Ac]: Temperature influence

• CO2 capture was studied using membrane contactor and two ionic liquids.
• Temperature influence was quantified in terms of efficiency and resistances.
• In the case of [emim][Ac] the chemical reaction dominates the process.
• The solubility controls the liquid phase when [emim][EtSO4] was used.

Post-combustion capture based on amines is conventionally used for carbon dioxide separation. Ionic liquids have emerged as new attractive alternative solvents because of their zero emission features compared to amines. The aim of the present work is to study the temperature influence on the efficiency in order to evaluate physical and chemical absorption using two ionic liquids, 1-Ethyl-3-methylimidazolium ethylsulfate [emim][EtSO4], and 1-Ethyl-3-methylimidazolium acetate [emim][Ac]. The temperature ranges from room temperature to 333 K. A polypropylene hollow fiber module is the membrane device where the CO2 absorption takes place. The CO2 removal efficiency was obtained from experimental data, showing a temperature dependence only in the case of using [emim][Ac] which doubles from 291 K to 318 K (16–34% for one contactor and 27–53% when two contactors were operated in series). The behavior of [emim][Ac] was correlated with the mass transfer enhanced by the chemical reaction. When [emim][EtSO4] is used, the efficiency is not influenced by the temperature and only the solubility controlled the mass transfer in the liquid phase.

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