New technique developed at MIT produces highly selective filter materials, could lead to more efficient desalination.
The MIT researchers used a four-step process to create filters from graphene (shown here): (a) a one-atom-thick sheet of graphene is placed on a supporting structure; (b) the graphene is bombarded with gallium ions; (c) wherever the gallium ions strike the graphene, they create defects in its structure; and (d) when etched with an oxidizing solution, each of those defects grows into a hole in the graphene sheet. The longer the material stays in the oxidizing bath, the larger the holes get. Reprinted with permission from O'Hern, S. C. et al. Nano Letters, Copyright 2014 American Chemical Society