Cao et al. (2024): Highly efficient direct air capture using solid–liquid phase separation in aqueous diamine solution as sorbent

Furong Cao, Soichi Kikkawa, Hidetaka Yamada, Seiji Yamazo IN: Bulletin of the Chemical Society of Japan, 97, 9, https://doi.org/10.1093/bulcsj/uoae096

In this work, a series of aqueous diamine solutions was examined for 400 ppm CO₂ absorption at ambient temperature. The absorbents exhibited CO₂ absorption with molar ratio of 1 mol_CO2/mol_amine, and aqueous isophorone diamine (IPDA) in particular showed >99% CO₂ removal even under a 500 mL min⁻¹ flow of 400 ppm CO₂–N₂ with the contact rate of 13,761.5 h⁻¹ between CO₂ and IPDA aqueous solution and the CO₂ absorption rate of 4.46 mmol/L min. A precipitate of carbamic acid of IPDA was formed by reaction with CO₂, and the CO₂ removal efficiency was enhanced by increasing the solution viscosity by the formation of this precipitate.

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