Potential for Using Simple 1,2,4-Triazole Salt Solutions as Highly Efficient CO2 Absorbents with Low Reaction Enthalpies

Abstract

Simple solutions of alkali metal salts of 1,2,4-triazole (TrizM) in polyethyelene glycol (PEG) and dimethylsulfoxide (DMSO) were prepared and assessed for CO2 capture. These aprotic heterocyclic anions (AHAs) containing solutions exhibit excellent CO2 capture performances. The TrizM salts absorb CO2 chemically in a 1:1 stoichiometry. What is more attractive is that the CO2 chemical absorption enthalpies are as low as −33 ∼ −21 kJ mol–1, close to that of physical absorption by traditional ionic liquids (ILs). This makes regeneration of the absorbents highly energy-saving. The TrizM-PEG solution has a steady CO2 capture performance due to the nonvolatility of PEG, and therefore, it is durable for CO2 capture. In comparison, the TrizM-DMSO solution has a higher absorption capacity (120 mg/g solution) because of the higher solubility of TrizM. Such simple and inexpensive solutions show new potential as promising candidates for highly efficient, energy-saving, and economical CO2 catchers.