CO2 absorption behavior in dual-amine blends of primary and tertiary amine: machine learning, NMR analysis, and performance evaluation

• Machine learning models predict CO 2 solubility in MEA-based blended solvents. • PSO-BPNN model achieves highest accuracy with MAPE below 2.2 %. • 13 C NMR reveals carbamate and bicarbonate dynamics in blended amine solutions. • MEA + DEEA blend demonstrates superior absorption and desorption performance. • Energy demand for 2 M MEA + 3 M DEEA is lowest among tested solutions . Accurately predicting CO 2 equilibrium solubility is essential for optimizing amine-based sorbents in carbon capture processes. However, traditional experimental approaches require extensive testing, making data collection time-consuming and often incomplete. In this study, we address this challenge by developing six machine learning models to predict CO 2 solubility in three dual-amine blends (MEA + MDEA, MEA + DEEA, and MEA + DMEA), significantly reducing the reliance on labor-intensive experiments. The PSO-BPNN model achieved the highest accuracy, with errors below 2.2 %, demonstrating the potential of machine learning to provide reliable solubility data without exhaustive experimental measurements. Additionally, we experimentally evaluated the CO 2 absorption and desorption performance of MEA-based blends, complemented by 13 C NMR spectroscopy to elucidate reaction mechanisms. Among the tested systems, the 2 M MEA + 3 M DEEA blend exhibited the highest CO 2 loading, fastest desorption rate, and lowest heat duty compared to 5 M MEA, underscoring its potential as a superior sorbent for energy-efficient CO 2 capture.