Preparation of ternary deep eutectic solvents for efficient CO2 absorption and regeneration

Twelve ternary DESs were prepared for efficient and regenerable CO 2 capture. • AA-PZ-EG (1:1:8) reached 0.18876 mol mol −1 at 303.15 K and 810 kPa. • CO 2 solubility was accurately correlated with a maximum AAD of 0.299%. • FTIR verified physical dissolution coupled with amine-assisted chemical capture. • DES2 retained >80% regeneration efficiency after three capture-release cycles. To address the greenhouse effect and climate change caused by excessive CO 2 emissions, the development of efficient, green, and regenerable CO 2 absorbents has become a major research focus in the fields of energy and environmental science. In this study, twelve ternary deep eutectic solvents (DESs) were synthesized from acetamide, piperazine, 1,4-diazabicyclo[2.2.2]octane (DABCO), ethylene glycol, and diethylene glycol via a one-step heating and stirring method. The density, viscosity, potential ecotoxicity of the constituent components, CO 2 absorption performance, and short-term cyclic performance were systematically investigated. With increasing temperature, the prepared DESs exhibited an approximately linear decrease in density, while their viscosity displayed a temperature-dependent reduction consistent with Arrhenius behavior. Ecological Structure-Activity Relationships (ECOSAR) screening suggested relatively low predicted aquatic toxicity for most of the individual components, whereas the ecotoxicity of the complete DES mixtures remains to be assessed experimentally. Among the twelve ternary DESs, DES2, which exhibits combined physical dissolution and reversible chemical interactions at the PZ sites, showed the best CO 2 absorption performances, with a CO 2 uptake of 0.1294 g CO 2 /g DES at 303.15 K and 810 kPa. The CO 2 solubility data were correlated using the Jou and Mather equation within the investigated temperature and pressure ranges, and the model showed good agreement with the experimental data. Moreover, DES2 (AA:PZ:EG = 1:1:8) retained over 80% of its initial CO 2 absorption capacity after three consecutive absorption–desorption cycles, indicating favorable short-term cyclic performance. Download: Download high-res image (162KB) Download: Download full-size image