Characterization and absorption of carbon dioxide into aqueous solution of amino acid ionic liquid [N1111][Gly] and 2-amino-2-methyl-1-propanol

Amino acid ionic liquid tetramethylammonium glycinate ([N1111][Gly]) was mixed with 2-amino-2-methyl-1-propanol (AMP) aqueous solution to form a new solvent for CO2 capture. The density, viscosity and pH of 0–0.40 mol L−1 [N1111][Gly] + 0.95 mol L−1 AMP aqueous solution were investigated at a temperature range of 298–323 K. Solubility and diffusivity of CO2 in [N1111][Gly] + AMP solutions at the same temperatures and concentrations was estimated. The reaction kinetics of CO2 absorption into [N1111][Gly] + AMP aqueous solution was investigated using a double stirred-cell absorber with a planar gas–liquid interface. The results indicated that [N1111][Gly] promoted the absorption of CO2 in 0.95 mol L−1 AMP aqueous solutions. The kinetics region of absorption CO2 into aqueous [N1111][Gly] + AMP solution was the fast pseudo-first order reaction regime. Moreover, the enhancement factor E   was linear with CB01/2 and ΔE linear with the concentration of [N1111][Gly] in the mixed aqueous solution, and the activation energy of [N1111][Gly] + AMP aqueous solution absorbing CO2 was 40.7 kJ mol−1.

► [N1111][Gly] accelerated the absorption of CO2 in AMP aqueous solutions.
► [N1111][Gly] + AMP aqueous solution was characterized for CO2 absorption purpose.
► [N1111][Gly] + AMP solution absorbing CO2 was the fast pseudo-first order reaction.
► E was linear with square root of [N1111][Gly] + AMP initial concentration.