Incorporating ethylene glycol into hydrophilic poly(ether‐b‐amide) membranes for enhanced gas dehumidification performance

Abstract In the present study, ethylene glycol (EG) was incorporated into hydrophilic poly(ether‐b‐amide) matrix membranes to enhance the membrane performance for gas dehumidification (e.g., H 2 O/N 2 , H 2 O/CH 4 , and H 2 O/CO 2 separations). Exploiting EG as a hygroscopic agent, enhanced water vapour permeability was achieved. This study was also expanded to evaluate potential CO 2 capture (i.e., CO 2 /N 2 and CO 2 /CH 4 separations) using the membranes. As high as 20 wt.% of EG could be incorporated into the membrane to enhance water vapour permeability without compromising the membrane stability. The membranes were characterized using contact angle measurements, Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and thermogravimetric analysis (TGA). The water vapour permeability of the membrane was shown to increase exponentially with an increase in temperature and water vapour concentration in the feed. However, the membrane selectivity was compromised at higher temperatures for the gas pairs of interest, and the adverse impact of temperature on the membrane selectivity was lessened by the presence of EG in the membrane. The membrane stability for gas dehydration was demonstrated, and the membrane performance was shown to be largely constant over a testing period of 28 days when subjected to continuous separation of water vapour from humidified nitrogen.