Combined Effect of CNTs with ZIF-302 into Polysulfone to Fabricate MMMs for Enhanced CO₂ Separation from Flue Gases

Multiwalled CNTs and zeolitic imidazole frameworks (ZIF-302) were collegially incorporated into glassy polysulfone (PSF) to prepare mixed-matrix membranes (MMMs) to separate CO₂ from post- combustion flue gas stream. Varying loadings of both nanofillers were incorporated into PSF using solution-casting technique to optimize CO₂ separation performance of MMMs under dry and wet conditions. The flexible MMMs rendered homogeneous dispersion of fillers, improved polymer–filler adhesion, and thermally stable structure. Gas sorption analyses along with dry and wet gas permeation experiments demonstrated improved CO₂ permeability and CO₂/N₂ ideal selectivity of MMMs owing to collegial effect of nanofillers. The composite membrane containing 8 wt% CNTs and 12 wt% ZIF-302 nanofillers showed an optimum separation performance by providing a CO₂ permeability of 18 Barrers with CO₂/N₂ selectivity of 35. The permeation features of MMMs were slightly improved under humid conditions as compared to dry ones.