276937 Capture of SO2 by Lactate-Based Ionic Liquids

Wednesday, October 31, 2012: 1:58 PM
331 (Convention Center )
Shidong Tian1, Yucui Hou2, Chen Zhang1, Shuhang Ren1 and Weize Wu1, (1)Department of Chemical Engineering, State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, China, (2)Department of Chemistry, Taiyuan Normal University, Taiyuan, China

Sulfur dioxide (SO2), which is mainly emitted from the burning of fossil fuel, has caused serious environmental pollution. Up to date, flue gas desulfurization (FGD) is the most efficient way to control the emission of SO2. Recently, the capture of SO2 by ionic liquids (ILs) has drawn much attention all over the world for the unique properties of ILs. It is important to know how the cations and anions of the ILs influence the absorption and desorption behaviors of SO2 for the design of new ILs with high thermal stability and high absorption capacities. In this work, we synthesized five kinds of ILs based on quaternary ammonium, imidazolium, guanidine and alkanolamines cations and lactate acid anion. They are tetraethylammonium lactate ([N2222]L), 1-butyl-3-methylimidazolium lactate ([Bmim]L), 1-hexyl-3-methylimidazolium lactate ([Hmim]L), 1,1,3,3-tetramethylguanidinium lactate ([TMG]L) and monoethanolaminium lactate ([MEA]L). The effect of cations on the absorption and desorption of SO2 by these ILs was studied. It was found that the cations have significant influence on the absorption and desorption behaviors of SO2 . The effect of cations on the SO2 absorption capacities of the ILs follows the order: [N2222]+ > [Bmim]+  ~ [Hmim]+ > [TMG]+ > [MEA]+, and the effect of cations on the SO2 desorption efficiency follows the order: [MEA]+ > [TMG]+ > [Hmim]+ > [Bmim]+ ≈ [N2222]+. The absorption and desorption of SO2 by [Bmim]L were tested for five runs, and no obvious lose of SO2 absorption capacity was found. The result suggests that the ILs based on lactate acid anion are excellent absorbents for the removal of SO2from the flue gas.

The project is financially supported by the Natural Science Foundation of China (No. 21176020 and 20746001) and the Program for New Century Excellent Talents in University (NCET-08-0710)

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