Dual synergistic modification of Pebax 2533 membranes with sorbitol and silver nanoparticles for enhanced CO2 separation efficiency

CO2 separation from N2 and CH4 is increasingly important due to environmental and industrial concerns. Membrane-based separation using polymeric materials offers advantages such as energy efficiency, easy processing, and cost-effectiveness. In this study, mixed matrix membranes (MMMs) based on CO2-philic Pebax 2533 were fabricated and modified in two steps to enhance CO2 separation performance. In the first step, Sorbitol was incorporated at various loadings (5–20 wt%), with 15 wt% found to be optimal, achieving CO2 permeability of 394.5 Barrer and selectivities of 13.11 (CO2/CH4) and 48.70 (CO2/N2) at 30 °C and 2 bar. Sorbitol enhanced membrane crystallinity and thermal stability, as confirmed by FTIR, DSC, and TGA. In the second step, Ag nanoparticles (AgNPs) were introduced (up to 5 wt%) into the Pebax/Sorbitol matrix to exploit facilitated CO2 transport mechnisem. FESEM showed changes in morphology and increased chain rigidity. The optimized membrane (P/S-15/Ag-5) exhibited a 19.5% increase in CO2 permeability compared to P/S-15, while maintaining the selectivities. The combined effect of Sorbitol and AgNPs led to improved thermal and separation properties, making the developed MMMs promising candidates for efficient CO2 separation applications.