Scaling up nanoporous graphene membranes

Practical desalination membranes with nanoporous graphene will need new morphologies Suitably engineered graphene-based materials could potentially be used to make water-separation membranes for applications such as desalination. Graphene-based materials with water-permeable pores can be made by creating either nanopores in graphene monolayers (see the figure, top) ( 1 , 2 ) or two-dimensional (2D) channels that form between nanosheets of graphene oxide (GO) (see the figure, middle) ( 3 ). Both approaches face challenges for scaling to practical membrane sizes on the meter scale. The former requires creating a high density of subnanometer pores ( 4 ) on a defect-free monolayer graphene sheet that has high out-of-plane mechanical strength ( 5 ), and materials meeting all these requirements have largely been limited to micrometer-scale lateral dimensions. On page 1057 of this issue, Yang et al. ( 6 ) report production of nanoporous graphene on the centimeter scale that can reject between 85 and 97% of the salt from saltwater.