Large–scale CO2 emissions have raised international concerns as they lead to global temperature rise. Consequently, mitigating CO2 emissions has emerged as a central focus of interdisciplinary research. Although onboard carbon capture technology proves effective in reducing a ship's CO2 emissions, challenges persist in the form of high desorption energy consumption and low CO2 loading of the absorbents. In this study, a novel polyamine–based mixed amine system based on marine engine exhaust CO2 capture technology has been developed to reduce desorption energy consumption and enhance CO2 loading. Additionally, the reaction mechanisms of CO2 with polyamine–based mixed amine were investigated using a combination of quantum chemical calculations and nuclear magnetic resonance (NMR) techniques. The results indicated that compared to monoethanolamine (MEA) with the same mass fraction, the CO2 loading of the new mixed absorbent tetraethylenepentamine (TEPA) + MEA increased by 7 % and the desorption heat duty reduced by 18.1 %. The analytical approach results showed that in the case of 7.5 wt% TEPA + 7.5 wt% MEA solution, proton transfer was predominantly governed by TEPA, whereas MEA primarily engaged in the reaction with CO2. During desorption at 368 K, the released CO2 primarily arose from HCO3− and CO32−. These findings hold academic and practical significance for the advancement of more efficient carbon capture technologies in maritime applications.
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