Graphene’s tight atomic bonds make it impermeable for nearly all gasses and liquids. Curiously, water molecules are an exception. Because water can evaporate through graphene while most other gasses and liquids cannot, graphene could be an exceptional tool for filtration. Researchers at the University of Manchester tested graphene’s permeability with alcohol and were able to distill very strong samples of spirits, as only the water in the samples was able to pass through the graphene.
Graphene-based desalination membranes, https://www.nature.com/articles/s41545-018-0004-z
https://www.manchester.ac.uk/discover/news/supermaterial-goes-superpermeable/ ; Large area continuous multilayer graphene membrane for water desalination, https://www.sciencedirect.com/science/article/abs/pii/S1385894720336329