Enhanced CO2 Capture Properties of Mwcnts-Embedded Hybrid Membranes By Using PEO-Based Additive

Hybrid membranes consisting of multi-walled carbon nanotubes (MWCNTs) embedded in Pebax with PEO-based polymers as additives were fabricated by solution casting method. Scanning electron microscope (SEM) images showed the addition of PEO-based polymers with different molecular weights improved the dispersion of MWCNTs in polymer matrix. The incorporation of MWCNTs disrupted the polymer chain packing thus diminishing the crystallinity, which was confirmed by X-ray diffraction. The content of PEO-based additives and MWCNTs in hybrid membranes were investigated for CO₂/N₂ and CO₂/CH₄ separation. The results revealed that 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 incorporation of MWCNTs increased the gas permeability and decreased selectivity for CO₂/CH₄, while increased permeability and selectivity was found for CO₂/N₂ separation. In particular, the Pebax-PEGDME(40)/MWCNTs(5) membrane with 40wt.% PEGDME and 5wt.% MWCNTs showed high CO₂ permeability and selectivity (575 Barrer and 89, respectively) for CO₂/N₂ separation at 2bar and room temperature, which showed great promise for CO₂ capture from flue gas.