A polyethylene glycol (PEG) – polyethersulfone (PES)/multi-walled carbon nanotubes (MWCNTs) polymer blend mixed matrix membrane for CO2/N2 separation

Abstract

Recently, carbon capture utilizing membrane technology has received much attention to limit the adverse effect caused by rising carbon dioxide (CO2) concentration in the atmosphere as they are less energy intensive and more environmentally friendly. Among the type of membranes, mixed matrix membranes (MMMs) has shown promising gas separation results. In this study, polymer blend MMMs were fabricated using polyethylene glycol (PEG), polyethersulfone (PES), multi-walled carbon nanotubes (MWCNTs) and solvent N,N-dimethylformamide (DMF) using wet phase-inversion technique. Results shown that functionalized MWCNTs (MWCNTs-F) were able to enhance gas separation performance of MMM. Furthermore, the effect of MWCNTs-F loading (0.005 wt% to 0.03 wt%) and polymer composition (PEG-PES weight ratio of 20:20, 30:10 and 32:8) were also studied. Results shown both parameters affect the gas separation performance of MMMs. The best performance in term of CO2/Nitrogen (N2) selectivity is found to be 1.235 ± 0.002 for MMM fabricated with 30 wt% PEG, 10 wt% PES and 0.02 wt% MWCNTs-F. In addition, MMM synthesized with PEG-PES weight ratio of 20:20 can withstand a pressure of 1.2 bar, indicating high mechanical strength. Hence, it is applicable in the post combustion carbon capture industry as typical flue gas has a pressure of 1.01 bar.