Conclusions and Perspectives

In general, the emergence of various Two-Dimensional (2D) nanosheets demonstrates great potential in developing ultrathin membranes for gas or liquid separation. Particularly, various attempts on tuning the size and microenvironment of sub-nanometer channels in 2D-material membranes have demonstrated several orders of magnitude higher permeance than conventional membranes, largely advancing membrane technology toward energy-efficient separation. This concluding chapter addresses some critical issues on 2D-material membranes from the four aspects: materials preparation, membrane fabrication, scale-up application and transport mechanism. Up to now, only limited 2D materials have been applied for membrane separation and much more 2D nanosheets should be developed in the future. Effective strategies for fabricating large-area and non-defective 2D-material membrane are of great significance. 2D-material membranes are believed to become a next-generation separation membrane and be extended to other fields such as catalysis and energy conversion.