Three-Component Mwcnts-Based Hybrid Membranes With Enhanced CO2 Capture Properties

Three-component hybrid membranes containing Pebax, PEO-based polymers and multi-walled carbon nanotubes (MWCNTs) were prepared and characterized. Pebax solutions were slowly added to PEO-based polymer solutions containing MWCNTs then evaporated to get the hybrid membranes. Scanning electron microscope (SEM) images presented the improved dispersion of MWCNTs in polymer matrix with the pre-dispersing of PEO-based polymers. The embedded MWCNTs disrupted the polymer chain packing and decreased crystallinity, which was confirmed by X-ray diffraction. Influences of PEO-based polymers and MWCNTs contents on CO₂, N₂ and CH₄ permeation were investigated. These results revealed that incorporating of high molecular weight PEO-based polymers favored for CO₂/CH₄ separation, while low molecular ones favored for CO₂/N₂ separation. For all these hybrid membranes, the enhanced CO₂ permeability was attributed to the more amorphous polymer structure. The incorporation of MWCNTs decreased CO₂/CH₄ selectivity while increased CO₂/N₂ selectivity for the size and solubility parameter differences of these two gas pairs. In particular, a selectivity of 108 and CO₂ permeability up to 743 Barrer at 10 bar and room temperature were documented, which showed promise for CO₂ capture from flue gas.