Tailoring PES/PVAc Mixed Matrix Hollow Fiber Membranes with TiO2 Nanoparticles for Enhanced CO2/CH4 Separation Efficiency

To use renewable energy and mitigate the greenhouse gas effect on the environment, carbon dioxide (CO2) separation is crucial. Recent research has shown that using membranes for CO2 separation is a vital option, but challenges remain with permeability and selectivity. Blend hollow fiber membranes offer a solution to these challenges. In this study, a blend of hollow fiber membranes made of polyether sulfone (PES) and polyvinyl acetate (PVAc) was developed, along with the incorporation of fillers, to overcome the permselectivity challenge. This resulted in the creation of mixed matrix blend hollow fiber membranes by using the phase inversion method. The membranes that were developed were examined using FESEM, FTIR, XRD, TGA, and pure-gas permeation analysis. The polymer blend demonstrated miscibility and preserved strong morphological and structural stability during CO2 and CH4 separation tests, exhibiting little deformation and reliable performance across different feed pressures ranging from 2 to 8 bar. The addition of TiO2 improved the compatibility of the polymer blend and increased the mobility of CO2. At 8 bar, the optimized PES/PVAc–5 wt.% TiO2 hollow fiber membrane reached a CO2 permeance of 92.22 GPU, representing an enhancement of about 24.7% in CO2/CH4 selectivity compared to the standard membrane. This emphasizes its potential for effective biogas upgrading under high pressure.