Synthesis and gas transport properties of sulfonated poly(ether ether sulfone) membranes containing pendant sulfonic acid groups

Abstract

A series of gas separation membranes based on sulfonated poly(ether ether sulfone)s (SPEESs) can be synthesized by the polycondensation and sulfonation reactions. The structural characteristics of copolymers were confirmed by 1H-NMR spectroscopy, Fourier-transform infrared spectroscopy, gel permeation chromatography, and ultraviolet–visible absorption spectroscopy. The permeability and selectivity behavior of these membranes were investigated using three single-gases (CO2, O2, and N2) at different temperatures of 25–55°C and pressures of 1.0–3.0 atm. The effect of sulfonation degree (SD), operating temperature, and pressure on gas permeability was explored and discussed. The results showed that SPEESs containing pendant sulfonic acid groups exhibited different separation performance. In particular, the SPEES-4 membrane with an SD of 67% exhibited the highest permeability (CO2 = 513.8 Barrer and O2 = 78.19 Barrer) at 55°C and 1 atm, whereas CO2/N2 and O2/N2 selectivity was 31.09 and 4.73, respectively.