Highly Efficient and Reversible Absorption of SO2 by Aqueous Triethylenetetramine Tetralactate Solutions

The capture of SO 2 by ionic liquids (ILs) has drawn much attention. In this work, a series of triethylenetetramine (lactate) n ([TETA]L n ) was synthesized and triethylenetetramine tetralactate ([TETA]L 4 ) was selected to prepare aqueous IL solutions to absorb SO 2 . It has been found that the aqueous IL solutions can absorb large amounts of SO 2; the saturated mole ratio of SO 2 to IL in the aqueous IL solution decreases with increasing temperature, and increases with increasing water content of the aqueous IL solution; the density and viscosity of the aqueous IL solution decreases with increasing temperature and water content, and the density and viscosity of aqueous IL solution after SO 2 absorption is higher than that before SO 2 absorption. The absorption of SO 2 by the aqueous IL solution is reversible. Compared with other ILs, [TETA]L 4 has many advantages in application, including inexpensive synthetic materials, uncomplicated synthetic procedures, high SO 2 capacity, and excellent reversibility.