Rational design and experimental evaluation of novel amino acid-based natural deep eutectic solvents for CO2 capture

• Published in: Separation and purification technology 2025-07, Vol.361, p.131554, Article 131554
• Main Authors: Cheng, Jie, Qiu, Yuxin, Chen, Jiahui, Gu, Yuqi, Wang, Jingwen, Chen, Guzhong, Qi, Zhiwen, Song, Zhen
• Format: Article
• Language: English
• Subjects: Absorption experiments; Amino acids; CO2 capture; Natural deep eutectic solvents; Solid-liquid equilibria
• ISSN: 1383-5866
• DOI: 10.1016/j.seppur.2025.131554

•Amino acids-based DES is developed as alternative CO2 absorbent.•Components are screened by predicting the eutectic potential and EHS-impacts.•SLE of 8 amino acids-based binary combinations are experimentally determined.•CO2 absorption capacity and physical properties of 7 DESs are measured. The inherent merits of natural deep eutectic solvents (NADESs) have endowed them as a class of promising solvents in many applications. In this study, amino acid-DESs are applied as absorbent for CO2 capture. A systematic method combining solid–liquid equilibria (SLE) prediction, EHS-impacts (environmental, health, and safety) evaluation of the second component, and experimental validation is employed to rationally identify promising CO2 absorbents. The melting point and fusion enthalpy of pure amino acid components is predicted by a recently proposed machine learning model, while COSMO-RS is used to predict the SLE of all possible combinations. Five key EHS-related properties of the second component are evaluated via the VEGA platform. From above, eight promising binary systems based on L-lysine and L-proline are screened from the initial pool of 2,500 combinations. The SLE, density, and viscosity are experimentally determined and the CO2 absorption experiments are finally performed, identifying L-proline: nonanoic acid (1:4) as the most promising eutectic absorbent.