Highly permselective Pebax/MWCNTs mixed matrix membranes for CO 2 /N 2 separation

Development of high-performance CO 2 separation membrane materials is the most vital challenge in membrane separation technology for carbon emission reduction and carbon neutrality. Mixed matrix membranes (MMMs) were prepared using polyether-block-polyamide (Pebax-1074) as the membrane matrix and multi-walled carbon nanotubes (MWCNTs) as the filler. The morphology, microstructure, surface functional groups, and thermal properties of the MMMs were characterized by scanning electron microscope, X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis, respectively. The effects of MWCNTs content, permeation temperature, and permeation pressure on the microstructure and gas separation properties of the prepared MMMs were investigated. The results show that the microstructure and the gas separation performance of the membrane can be significantly regulated through varying the content of MWCNTs. The optimal separation performance is attained to 291.4 Barrer of CO 2 permeability and 160.2 of CO 2 /N 2 selectivity for the MMMs containing 12% MWCNTs under the condition of 30 °C and 0.2 MPa. The exceptional separation performance is far beyond the commercially attractive Robeson upper-bound.