Supported ionic liquid membranes (SILMs) as a contactor for selective absorption of CO₂/O₂ by aqueous monoethanolamine (MEA)

Application of membrane contactors in a combination of monoethanolamine as a solvent system for post-combustion CO₂ capture has been extensively studied in the last decades. Due to the better performance to capture CO₂ at low concentration, the potentialities of novel technology of supported ionic liquids membranes (SILMs) for absorption process in gas-liquid membrane contactor system are currently being explored to improve and compliment previous technology. In this study, a modified hydrophobic gas-liquid membrane contactor system was prepared using Liqui-Cel® parallel flow module as a membrane support and 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide [emim] [NTf₂] ionic liquid as a supporting phase. Under moderate operating conditions, parallel flow mode and use of monoethanolamine (MEA) as an absorbent, the effects of absorbent temperature and gas velocity on the CO₂ absorption efficiency and CO₂/O₂ selectivity were determined using this modified module. Further investigation to compare the performances of blank and modified membrane module was implemented at different temperatures (303–348 K) and gas velocities (4.63 × 10⁻⁶ to 3.70 × 10⁻⁵ m s⁻¹). Results revealed that efficiency of the CO₂ absorption process of the modified module is almost doubled with an average selectivity factor of CO₂/O₂ around 5 times compared to blank contactor system. Thus, this modified membrane contactor system had shown a great potential for further used in the real industrial CO₂ capture and beneficial to bottleneck the issue of MEA oxidation that usually occurred in previous gas-liquid membrane contactor system.