Efficient SO2 capture by amine functionalized PEG.

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.