Highly efficient CO2 capture by a non-aqueous amine-based absorbent of 3 aminopropanol/polyethylene glycol 200: Experimental and computational simulation

Abstract

In the present work, a novel non-aqueous 3-aminopropanol/polyethylene glycol 200 (3AP/PEG200) absorbent for efficient carbon dioxide (CO₂) capture was designed using environment-benign and non-toxic polyethylene glycol 200 (PEG200) as an alternative to water. The mechanism, physical, thermodynamic, and kinetic properties of absorption process was investigated through a combination of experimental and multi-scale computational simulation approaches including molecular dynamics (MD) simulation and quantum chemical (QC) calculations. It was found that the addition of PEG200 not only enhanced the thermal stability of the absorbent, but also did not significantly increase the viscosity. In addition, kinetic studies revealed that the absorption process conforms to a pseudo-first-order equation, with the activation energy (E_a) value of 20.40 kJ/mol, significantly lower than that of the benchmark 30 % monoethanolamine (MEA) aqueous solution used in industrial CO₂ capture. Furthermore, the enthalpy change (ΔH) and entropy change (ΔS) values were found to be more negative than those of other liquid absorption systems, indicating that the 3AP/PEG200 absorbent is favorable for CO₂ absorption even at low partial pressures. Most importantly, the absorption system exhibited good regeneration capability, as demonstrated by five absorption–desorption cycle experiments. In conclusion, the non-aqueous 3AP/PEG200 absorbent exhibits low viscosity, high thermal stability, enhanced absorption capacity, and excellent cyclic performance, positioning it as a promising candidate for CO₂ absorption in industrial applications.