CO2 capture by a highly-efficient aqueous blend of monoethanolamine and a hydrophilic amino acid ionic liquid [C2OHmim][Gly]

• A hydrophilic ionic liquid [C2OHmim][Gly] was utilized to enhance MEA process for CO2 capture.
• The optimum proportion of the blend was chosen as 0.7 mol L−1 MEA and 0.3 mol L−1 [C2OHmim][Gly].
• The new absorbent had a reduced degradation and evaporation rate, an enhanced absorption capacity.
• The antioxidation and thermal stability was greatly improved in MEA/[C2OHmim][Gly] solution.

A hydrophilic amino acid ionic liquid [C2OHmim][Gly] synthesized by our laboratory was utilized to enhance the process of MEA for CO2 capture from low-pressure flue gas. The optimum proportion of the mixed solution was chosen as 0.7 mol L−1 MEA and 0.3 mol L−1 [C2OHmim][Gly]. The absorption capacity of the new absorbent was 0.534 mol CO2/mol absorbent under 3% O2, and was higher than that of MEA (0.430 mol CO2/mol amine). The capacity of MEA/[C2OHmim][Gly] solution was maintained at 0.50 mol CO2/mol absorbent even with 8% of O2. Only 12.6% of decrease in the absorption capacity was noticed compared with that in the absence of O2. Furthermore, it was well recycled with a regeneration efficiency of 90.2% by thermal regeneration after fourth-cycle experiments in 3% O2. The new absorbent is proved to have a reduced degradation and evaporation rate, an enhanced absorption capacity and a high stability and regeneration efficiency for the CO2 capture.