Aminated functionalized MXene nanosheets decorated synergic permselective membrane for efficient CO2/N2 separation

In this study, a top-down etching method is used to obtain MXene nanosheets with an accordion-like structure, and the surface of the MXene nanosheets is functionalized with 3-aminopropyltriethoxysilane to obtain functionalized MXene nanosheets (f-MXene), which is combined into polyethylene oxide (PEO) copolymer matrix for fabricating mixed matrix membranes (MMMs). The f-MXene nanosheets enhance the CO 2 /N 2 separation performance of membranes in multiple ways. Firstly, the accordion-like structure of f-MXene increases the channel for rapid gas transport. Secondly, the two-dimensional sheet-shaped material has a high aspect ratio, which effectively weakens the interaction between polymer chains and inhibit crystallization. This increases free volume for molecular transport and helps improve gas permeability. Thirdly, the amino group can react reversibly with CO 2 , improving reaction selectivity, and facilitates CO 2 transport. Therefore, the PEO/f-MXene membrane exhibits excellent CO 2 permeability and CO 2 /N 2 selectivity. To explore more efficient separation technology, the membrane separation performance at low-temperature is investigated. At − 20 °C, the PEO/f-MXene-3% membrane has a CO 2 permeability of 47.8 Barrer and a CO 2 /N 2 selectivity of 280.9, which is 576.9% higher than that at 35 °C, exceeding the latest upper bound. Graphical