Surpassingly efficient, selective, and reversible absorption of SO2 through pyridine based deep eutectic solvents.

Convenient synthesis of deep eutectic solvent for effective, selective, and reversible capture of SO 2. [Display omitted] • Pyridine based DESs could be received through a facile procedure with a low cost. • The obtained DESs show remarkable absorption capacity & rapid absorption rates. • DESs' desirable selectivity & cycling performance indicates its potential usage. • The absorption process was revealed in detail via FT-IR, NMR & DFT calculations. In this study, deep eutectic solvents (DESs) consisting of 1-ethyl-3-methylimidazolium chloride (EmimCl) and pyridine derivatives were prepared through a facile procedure. The studied DESs exhibit superb absorption behavior for SO 2 at 298.15 K and 1.0 bar, of which per g EmimCl: 2-NH 2 Py (7: 1) could capture 1.247 g SO 2 , exceeding the vast majority of the previously reported DESs and ionic liquids (ILs). The factors that could affect the absorption capacity were explored orderly, like the category and molar ratio of pyridine derivatives, the absorption temperature, and SO 2 partial pressure. Based on the above investigation, EmimCl: 2-NH 2 Py (7: 1) exhibits rapid equilibration time (<45 s), outstanding SO 2 /CO 2 selectivity (312/1), and ultra-high recycling performance (40 times), which is far superior to the other reported DESs and ILs. In addition, the possible absorption process was studied from both experimental and theoretical aspects. The obtained data indicate that Lewis acid-base interaction and SO 2 ···Cl- covalent interaction both exist between SO 2 and DES, leading to an ideal absorption capacity and selectivity for SO 2. This study might provide a novel insight to remove SO 2 and other gaseous pollutants. [ABSTRACT FROM AUTHOR]