Effects of concentration and viscosity on the absorption of CO2 in [N1111][Gly] promoted MDEA (methyldiethanolamine) aqueous solution

• Absorption capacity, absorption rate of CO2 and viscosity were measured.
• Temperature slightly influences the absorption rate of CO2.
• Competitive effects of concentration and viscosity on absorption rate were illustrated.
• Effects of temperature, concentration and CO2 loading on viscosity were demonstrated.

The absorption of CO2 in tetramethylammonium glycinate ([N1111][Gly]) promotedMDEA (methyldiethanolamine) aqueous solution was investigated. The temperature ranged from 303.2 K to 323.2 K. The mass fractions of MDEA and [N1111][Gly] respectively ranged from 0.3 to 0.45 and 0.05 to 0.15. The influences of temperature and concentration on the absorption capacity of CO2 were determined. The viscosities of CO2-unloaded and CO2-loaded MDEA-[N1111][Gly] aqueous solutions were measured and correlated. The experiments showed that the absorption rate of CO2 obviously increased when the MDEA aqueous solution was promoted by [N1111][Gly]. The effects of temperature, concentration and solution viscosity on the absorption rate were illustrated.