(80h) Research on the Construction of Advanced CO2 Capture Absorbent and the Regeneration Enhancement Strategy

Amine-based adsorbents have the advantages of high absorption rate and high CO₂ selectivity in terms of industrial CO₂ capture performance. However, their poor desorption performance has reduced the recyclability of absorbents and increased the process cost. To solve the above problems, this research aims to develop a novel type of ionic liquid deep eutectic absorbents based on product-oriented regulation strategy. By strengthening the deep eutectic interaction between ionic liquids and solvents, the CO₂ absorption-desorption reaction path will be regulated and new products with low activation barriers can be generated, so as to reduce the heat duty of desorption reaction and overcome the thermodynamic bottleneck. By regulating the interaction between anions and cations, the stability and self-aggregation degree of the carbamate product will be weakened, so as to increase the desorption rate, and overcome the bottleneck of desorption kinetics. Through theoretical calculations to guide experimental synthesis, a functionalized ILs [DBNH][1,3-DMU]-EG deep eutectic absorbent was constructed, which can maintain ultra-high CO₂ loading (1.87 mol/mol) at low concentrations (0.50 mol/L), and the desorption efficiency up to 84.00%. The quantum chemical calculation results showed that the anions and cations of [DBNH][1,3-DMU] were dominated by weak van der Waals forces, and its intermolecular interactions were low. In addition, the ILs had high steric hindrance and electron-inductive properties, which could reduce the binding energy of amino groups to CO₂, thus reducing the stability of the product and making it easier to desorb CO₂.