High-Efficiency Absorption of SO<sub>2</sub> by a New Type of Deep Eutectic Solvents
Kai Sheng, Yong Kang, Jie Li, Hongyang Xu, Dan Li
Abstract
In this work, a new type of deep eutectic solvents (DESs), EmimCl–EPyBr, was prepared for SO2 absorption. The liquid DESs were composed of 1-ethyl-3-methylimidazolium chloride (EmimCl) and N-ethylpyridinium bromide (EPyBr), which are common ionic liquids (ILs) with a solid state at room temperature. The results showed that EmimCl–EPyBr all had excellent performance at different temperatures and SO2 partial pressure. Especially, the SO2 absorption capacity of EmimCl–EPyBr (3:1) can reach 0.698 g SO2/g DES at 20 °C and 0.1 atm, which was higher than all DESs and ILs in the present literature. EmimCl–EPyBr also had the same reversibility as most reported DESs and ILs. The saturated EmimCl–EPyBr can be desorbed by heating and blowing N2. Moreover, the mechanisms of EmimCl–EPyBr's formation and SO2 absorption were studied. EmimCl and EPyBr in the new DESs were combined with two hydrogen bonds. This new way to develop DESs would broaden the application scope of ILs. The SO2 absorption of EmimCl–EPyBr was physical absorption process according to the spectra of FTIR and 1H NMR.