Engineers at Vanderbilt University have created a technique that fixes variations in pore size in graphene membranes that could enhance how water is cleaned and filtered. The defect-sealing technology ensures the pores stay small enough to trap salt ions while still allowing water to pass through.
Creating thin membranes like this while maintaining uniformity in pore size is a difficult engineering challenge, requiring the drilling of accurately placed holes in a sheet of carbon atoms just a single atom thick. The margin of error is slim to none.
“How do you poke trillions of holes between the size of 0.3 and 0.6 nanometers over a square centimeter of material that is just one-atom thick? That is 3 angstroms tolerance using processes that are scalable and roll-to-roll manufacturing compatible,” said Piran Kidambi, assistant professor of chemical and biomolecular engineering.
The team’s method involved forming holes in the graphene sheet using a combination of low-temperature chemical vapor deposition, ultraviolet light, and ozone gas.
The findings have the potential to filter a variety of particles from water, including salts, proteins, and other nanoparticles. Membranes like those made by the Vanderbilt team could also be useful in purifying substances used in pharmaceuticals