Salty

The part about drilling holes was for context, explaining why the alternative (single-layer graphene) was currently impractical. In the case of graphene oxide, which this article is about, the challenge was the swelling, the solution to which seems to be the key discovery in this article.

Graphyne. Cyclohexane rings connected by poly-yne chains of equal length.

Allows for a somewhat tunable pore size, with no "drilling" necessary. Graph-di-yne and graph-tri-yne are nearest the appropriate pore size for water. A series of graphyne filters with larger pore sizes would likely be needed to clear out particulates and larger ions, so that the final purification step proceeds at a reasonable flow rate.

https://arxiv.org/abs/1312.3179

Similar problem as graphene, in that it has not only never been outside of the lab, but also never been outside of the computer model.

right but that's the point - graphene is pretty much the only material so far we've been able to drill holes that size in to