Graphene sheets could filter water more efficiently than existing methods
Researchers at MIT have developed a new approach for water desalination using graphene as a filtration material.
The method, which involves perforating graphene sheets with precisely sized holes, could be far more efficient and potentially less expensive than existing technology.
According to Jeffrey Grossman, associate professor of power engineering at MIT's department of materials science and engineering, the system offers improvements over traditional methods such as reverse osmosis because it can operate at much lower pressures, meaning energy costs can be reduced.
"The key to the new process is very precise control over the size of the holes in the graphene sheet," Grossman explained. "There's a sweet spot, but it's very small - between pores so large that salt could pass through and ones so small that water molecules would be blocked. The ideal size is just about 1nm, or one billionth of a meter. If the holes are just a bit smaller - 0.7nm - the water won't flow through at all."
Up until now, Grossman and graduate student David Cohen-Tanugi have been testing the method using computer simulations to determine its optimal characteristics. They are due to begin working on prototypes this summer.
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