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Deep eutectic solvents (DESs) have gained a great interest among researchers owing to their inherent advantages to become an adaptable alternative to ionic liquids (ILs) and common amine solutions for CO₂ capture. In the present study, we prepared five new three-component DESs by functionalization of choline chloride-ethanolamine (1,7, mol,mol) DES using different types of amines: diethanolamine (amine type 2), methyldiethanolamine (amine type 3), piperazine (amine type 2) as well as 1-(2-aminoethyl)piperazine (amine type 1 and 2). All of the prepared DESs are liquid at room temperature and their melting points were in the range of 265–276 K. The solubility of CO₂ in the studied DESs was measured at pressures up to 2 MPa and 298.15 K. The obtained experimental data were analyzed by the use of generic Redlich-Kwong equation of state (RK-EOS) model and Henry's law constant have been calculated from the obtained experimental data through the EOS correlation. All the studied DESs show chemical absorption of CO₂ which can be approved based on the excess enthalpy and Gibbs energy functions. FT-IR spectroscopy and ¹³C NMR verified the formation of carbamate in the CO₂ absorption process which revealed the chemisorption of CO₂ in the studied DESs. The ideal association model has been utilized to describe the excess thermodynamic functions and two different types of the chemical association have been detected AB₂ and AB, (A refer to DESs and B to CO₂). Based on the obtained solubility data, the amines that enhanced the absorption capacity of choline chloride-ethanolamine (1,7) follow the trend as follows: piperazine > aminoethylpiperazine > methyldiethanolamine > diethanolamine. Therefore, piperazine can be considered as an absorption enhancer. The viscosity of DESs before and after CO₂ absorption as well as the thermal behavior of the DESs were also investigated.