Significantly promoted SO2 uptake by the mixture of N-methylated ethylene imine polymer and 1-ethyl-3-methylimidazolium tetrazolate

Abstract

A novel class of hybrid solvents (mEIP:Tetz) comprising of N-methylated ethylene imine polymer (mEIP) and 1-ethyl-3-methylimidazolium tetrazolate ([Emim][Tetz]) were developed for the highly efficient and reversible capture of SO2. The synergistic interactions rather than simple mixing between mEIP and [Emim][Tetz] were confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and density functional theory (DFT) calculations. Besides, it was experimentally demonstrated that mEIP:Tetz mixtures exhibited improved kinetics for SO2 absorption, and the production of viscous solids were completely eliminated, compared with using mEIP alone. More significantly, an exceedingly high solubility of 0.308 g SO2·g−1 absorbent in 2mEIP:8Tetz was received for trapping SO2 from simulated flue gas containing 2000 ppm SO2, which was much higher than most of the results reported in previous literatures under the same conditions. Finally, the absorption and desorption mechanisms were proposed according to the results of FTIR and 1H NMR analysis.