Masoud Mofarahi

The development of efficient and environmentally friendly solvents is critical for advancing post-combustion carbon capture. This study presents a comprehensive evaluation of potassium sarcosine (KSar) + H2O and KSar + N-methyldiethanolamine (MDEA) + H2O for CO2 absorption. CO2 equilibrium solubility was experimentally determined at temperatures ranging from 303.15 to 333.15 K and CO2 partial pressures of 2–27 kPa. The performance of semi-empirical, thermodynamic (Deshmukh-Mather, D-M), and artificial neural network (ANN) models in predicting the solubility data was systematically assessed. The ANN model demonstrated superior predictive accuracy, yielding absolute average deviations (AAD) of 0.34% and 1.00% for the KSar–H2O and KSar–MDEA–H2O systems, respectively; these values are significantly lower than those generated by alternative models. The D–M thermodynamic model was employed to derive absorption enthalpies and equilibrium speciation profiles. The analysis reveals that KSar-based solvents exhibit a favorable combination of high CO₂ loading capacity at low partial pressures and a reduced heat of absorption compared to conventional alkanolamines (e.g., MEA, MDEA). Furthermore, a comparative environmental assessment positions amino acid salts such as KSar as markedly superior to alkanolamines, exhibiting negligible ecotoxicity (EC₅₀ > 10,000 mg/L) and high biodegradability (>65%). These findings underscore the significant potential of KSar-based solvents, especially in blended systems with MDEA, as high-performance, sustainable alternatives for industrial CO₂ capture.