Mutual-extraction-enhanced desorption achieves low-temperature gas separation

Gas separation technology faces the challenge of balancing high efficiency, selectivity, and low energy consumption. This work achieves efficient CO₂ capture through chemical absorption enhanced by a mutual extraction effect. A reversible biphasic system using hydrophobic N,N′-di- tert -butylethylenediamine (DTBEDA) and N,N-dimethylcyclohexylamine (DMCA) exploits unique absorption homogeneous-desorption phase separation characteristics, overcoming high-temperature desorption limitations of traditional absorbents. The absorbent exhibits CO₂ loading of 0.88 mol/mol with 98.84% desorption efficiency at 363 K, which is 30–40 K lower than conventional amine absorbents. The regeneration energy consumption is 1.45 GJ/t CO₂, 62.14% lower than MEA. A 630 MW coal-fired power plant equipped with the capture technology could save power by 50.38% and 33.78% compared with plants using MEA and current advanced absorbents. Molecular analysis via dipole moments, surface electrostatic potential, and intermolecular forces reveals the desorption mechanism. The technology enables industrial waste-heat-driven CO₂ capture with substantial cost reduction, offering new pathways for enhanced gas separation applications.