Abstract
Efficient recognition and selective capture of NH(3) is not only beneficial for increasing the productivity of the synthetic NH(3) industry but also for reducing air pollution. For this purpose, a group of deep eutectic solvents (DESs) consisting of glycolic acid (GA) and phenol (PhOH) with low viscosities and multiple active sites was rationally designed in this work. Experimental results show that the GA + PhOH DESs display extremely fast NH(3) absorption rates (within 51 s for equilibrium) and high NH(3) solubility. At 313.2 K, the NH(3) absorption capacities of GA + PhOH (1:1) reach 6.75 mol/kg (at 10.7 kPa) and 14.72 mol/kg (at 201.0 kPa). The NH(3) solubility of GA + PhOH DESs at low pressures were minimally changed after more than 100 days of air exposure. In addition, the NH(3) solubility of GA + PhOH DESs remain highly stable in 10 consecutive absorption-desorption cycles. More importantly, NH(3) can be selectively captured by GA + PhOH DESs from NH(3)/CO(2)/N(2) and NH(3)/N(2)/H(2) mixtures. (1)H-NMR, Fourier transform infrared and theoretical calculations were performed to reveal the intrinsic mechanism for the efficient recognition of NH(3) by GA + PhOH DESs.