Aminated functionalized MXene nanosheets decorated synergic permselective membrane for efficient CO2/N2 separation
摘要
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 CO2/N2 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 CO2, improving reaction selectivity, and facilitates CO2 transport. Therefore, the PEO/f-MXene membrane exhibits excellent CO2 permeability and CO2/N2 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 CO2 permeability of 47.8 Barrer and a CO2/N2 selectivity of 280.9, which is 576.9% higher than that at 35 °C, exceeding the latest upper bound.
Graphical Abstract