The current research aims at developing an amino acid-based green technology containing a secondary alkanolamine (DEA) and L-arginine amino acid (ARG) for CO2 capture process from a gas stream in a T-type micro-contactor. To strengthen the understanding of the mass transfer of biodegradable green ARG in the micro-reactor, the mass transfer performance of CO2 absorption has been experimentally assessed under liquid flow rate (QL: 3.0–9.0 ml/min), gas flow rate (QG: 120.0–300.0 ml/min) at a constant temperature of 45 °C, and atmospheric pressure. The aqueous composition of the blended solution was DEA-ARG (35–0 wt%), DEA-ARG (31–4 wt%), DEA-ARG (27–8 wt%), and DEA-ARG (23–12 wt%). It was found that an increase in the solvent flow rate from 3.0 to 9.0 ml/min enhanced the CO2 absorption efficiency (θ), volumetric gas-phase mass transfer coefficient (KGaV), and volumetric molar flux (NGaV) by 2.5, 12.8, and 2.6%, respectively. However, an increase in the gas flow rate from 120.0 to 300.0 ml/min reduces the efficiency by 6% but improves the KGaV and NGaV by 88% and 225%, respectively. Additionally, the KGaV values followed a declining trend as the contribution of the DEA in the blended solution increased. Employing response surface methodology (RSM), the optimized values for CO2 absorption efficiency and KGaV were attained 92.93% and 69.40 kmol/m3 h kPa for QL of 9.0 ml/min, QG of 263.4 ml/min, and DEA-ARG concentration, CDEA-ARG of (23–12 wt%). Comparing the gas–liquid mass transfer characteristics of the aqueous DEA-ARG mixture with the traditional aqueous amine solutions, it was illustrated that the presence of L-arginine amino acid with high composition of 12 wt%, as a substitute organic promoter in aqueous DEA 35 wt%, can boost the performance of CO2 absorption process.
