Mixed matrix membranes with fast and selective transport pathways for efficient CO separation.

To improve CO separation performance, porous carbon nanosheets (PCNs) were used as a filler into a Pebax MH 1657 (Pebax) matrix, fabricating mixed matrix membranes (MMMs). The PCNs exhibited a preferential horizontal orientation within the Pebax matrix because of the extremely large 2D plane and nanoscale thickness of the matrix. Therefore, the micropores of the PCNs provided fast CO transport pathways, which led to increased CO permeability. The reduced pore size of the PCNs was a consequence of the overlapping of PCNs and the polymer chains penetrating into the pores of the PCNs. The reduction in the pore size of the PCNs improved the CO/gas selectivity. As a result, the CO permeability and CO/CH selectivity of the Pebax membrane with 10 wt% PCNs-loading (Pebax-PCNs-10) were 520 barrer and 51, respectively, for CO/CH mixed-gas. The CO permeability and CO/N selectivity of the Pebax-PCNs-10 membrane were 614 barrer and 61, respectively, for CO/N mixed-gas.