Efficient and reversible separation of NH3by deep eutectic solvents with multiple active sites and low viscosities

The efficient separation and collection of ammonia (NH3) during NH3synthesis process is essential to improve the economic efficiency and protect the environment. In this work, ethanolammonium hydrochloride (EtOHACl) and phenol (PhOH) were used to prepare a novel class of deep eutectic solvents (DESs) with multiple active sites and low viscosities. The NH3separation performance of EtOHACl + PhOH DESs was analyzed completely. It is figured out that the NH3absorption rates in EtOHACl + PhOH DESs are very fast. The NH3absorption capacities are very high and reach up to 5.52 and 10.74 mol·kg−1at 11.2 and 100.4 kPa under 298.2 K, respectively. In addition, the EtOHACl + PhOH DESs present highly selective absorption of NH3over N2and H2and good regenerative properties after seven cycles of absorption/desorption. The intrinsic separation mechanism of NH3by EtOHACl + PhOH DESs was further revealed by spectroscopic analysis and quantum chemistry calculations.