Efficient SO2 capture by amine functionalized PEG

Abstract

Polyethylene glycols (PEGs) are a class of non-toxic, non-volatile, biocompatible, and widely available polymers. In this work, we synthesized N-ethyl-N-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)-2-aminoethanol (EE₃AE) that combines the properties of PEG and amines, and N-decyl-N-ethyl-2-aminoethanol (DEAE). Their performances to capture SO₂ were studied at different temperatures, pressures, and absorption times. The interaction between the absorbents and SO₂ were characterized by NMR and FTIR techniques. It was demonstrated that both EE₃AE and DEAE could absorb SO₂ efficiently, and there existed chemical and physical interactions between the absorbents and SO₂. In particular, the absorption capacity of EE₃AE could be as high as 1.09 g SO₂ per g EE₃AE at 1 atm. The absorption capacity of EE₃AE was much larger than that of DEAE because the ether group in the EE₃AE interacted with SO₂ more strongly than the alkyl group in the DEAE. The SO₂ absorbed by EE₃AE could be stripped out by bubbling N₂ or by applying a vacuum and the EE₃AE could be reused. Moreover, both absorbents exhibited a high SO₂–CO₂ selectivity.