Graphene researchers engineer smallest possible slits for desalination  

The materials are made from graphene, hexagonal boron nitride (hBN) and molybdenum disulphide (MoS₂). According to the researchers, they were able to manufacture slits in these materials just several angstroms (0.1nm) in diameter. At this scale, it was possible to study how individual ions behaved while passing through the slits. The work, which is published in the journal Science, also sheds light on how similar scale biological filters function in nature.

The researchers made their slit devices from two 100nm thick crystal slabs of graphite measuring several microns across. They then placed rectangular-shaped pieces of 2D atomic crystals of bilayer graphene and monolayer MoS₂ at each edge of one of the slabs, placing another slab on top of the first. This produced a gap between the slabs that had a height equal to the spacers’ thickness.

“It’s like taking a book, placing two matchsticks on each of its edges and then putting another book on top,” explained Sir Andre Geim, one of the Manchester University physicists awarded a Nobel Prize in 2010 for their work on graphene.