Enhanced CO2 Separation Performance of Matrimid 5218 Membrane by Incorporation of Poly(Arylene Ether Sulfone) Containing Phenylphosphine Oxide Group

This study aims to synthesize and characterize poly(arylene ether sulfone) containing phenylphosphine oxide (PESPPO) group and incorporate it into Matrimid 5218 at different loadings to fabricate membranes for CO2 separation from CH4 and N2. Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), and Differential Scanning Calorimetry (DSC) are employed to study the interactions between PESPPO and Matrimid 5218. Structural, morphological, and thermal analyses of the fabricated membranes reveal excellent miscibility, even at higher PESPPO loadings. The single-gas permeability results for CO2, CH4, and N2 gases through the fabricated membranes demonstrate significant improvements in CO2 separation from CH4 and N2 compared to the neat Matrimid 5218 membrane. The maximum CO2 permeability is achieved at a 20 wt.% PESPPO loading. However, the highest CO2/N2 and CO2/CH4 selectivity is measured at 15 wt.% PESPPO loading. The optimized blend, comprising 15 wt.% PESPPO, exhibits a 2.36-times increase in CO2 permeability, along with a 2.10-times and 1.92-times enhancement in CO2/N2 and CO2/CH4 selectivity, respectively, compared to the neat Matrimid 5218. Moreover, feed pressure variations minimally influence CO2/N2 and CO2/CH4 selectivity, and prolonged testing time does not noticeably affect CO2 selectivity over N2 and CH4.