Highly efficient nitric oxide absorption by low viscosity superbase/amide deep eutectic solvents through mutual promotion effect

A series of low-viscous deep eutectic solvents (DESs) with superbase as HBA and amide as HBD were designed and prepared for NO absorption. Impressively, both a comparably low viscosity of 8.07 mPa∙s and a high absorption capacity of 6.43 mol∙kg −1 (∼0.19 kg/kg) at 293.2 K were achieved, which was superior to that of other reported absorbents. Through a combination of absorption experiments, FT-IR characterization, and thermodynamic modelling, the results indicated that such a high solubility for NO was originated from the mutual promotion effect between the superbase and the amide. Considering that chemical absorption occurred accompanied with physical one, a reaction equilibrium thermodynamic model (RETM) equation was derived to correlate the experiment solubility data, so that the thermodynamic parameters were obtained to evaluate the absorption process. The absorption-desorption cycle experiment revealed that the regeneration efficiency of the superbase/amide DESs could be high up to 90 %. Given the low viscosity, high absorption capacity and excellent recycle efficiency, the superbase/amide DES was considered as a promising candidate for NO capture and utilization.