With the aim of replacing amine solvents, in the current study, the novel mixture solutions were proposed for CO2 absorption combining amino acid (L-Arginine) with primary, secondary, and tertiary alkanolamines. The mass transfer performance of CO2 capture in the aqueous solutions of MEA-ARG, DEA-ARG, and MDEA-ARG was intensified under operational conditions of 4–12 wt% arginine concentration, 120–300 mL/min feed solvent flow rate, 3–9 mL/min inlet gas flow rate. In this regard, a T-shape micro-reactor with a diameter of 800 μ and a length of 29.5 cm was utilized. All the experiments were performed under the atmospheric pressure and absorption temperature of 45 °C. Considering industrial restrictions, the total concentration of mixtures was kept constant at 25 wt% for MEA-ARG, 35 wt% for DEA-ARG, and 50 wt% for MDEA-ARG. The results of CO2 absorption efficiency (ef), overall volumetric mass transfer coefficient, OVGMTC, (KGaV), and volumetric mass transfer flux (NAaV) indicated that in all three cases, the aqueous MEA-ARG solution has the highest value of 96%, 90.95 kmol/m3.h.kPa, and 361.82 kmol/h.m3, respectively. Also, while the gas and liquid flow rates were kept constant in their middle points, adding arginine from 4 to 12 wt% enhanced the values of the ef from 92.55% to 93.76% for DEA-ARG and from 79.20% to 93.23% for MDEA-ARG solutions, respectively. However, the results were obtained differently for solution MEA-ARG.
