Liquid amine–solid carbamic acid phase-separation system for direct capture of CO2 from air



The phase separation between a liquid amine and the solid carbamic acid exhibited >99% CO2 removal efficiency under a large-scale gas stream of 400 ppm CO2. Isophorone diamine [IPDA; 3-(aminomethyl)-3,5,5-trimethylcyclohexylamine] reacted with CO2 in the CO2/IPDA molar ratio of ≥ 1 even in H2O as a solvent. The captured CO2 was completely desorbed at 333 K because the disolved carbamate ion releases CO2 at low temperature. The reusability of IPDA under CO2 adsorption-and-desorption cycles without degradation, the >95% efficinecy kept for 100 hours under direct air capture condition, and high CO2 capture rate (214 mmol/h for 1 mol amine) suggest that the phase separation system using IPDA is robust and durable for practical use.


Supplementary material

Supporting Information
Supplementary Information for this paper
Supporting Information Video S1
Supporting Information Video for this paper