With the world’s freshwater reserve dwindling rapidly, scientists are increasingly looking for energy- as well as cost-efficient ways to desalinate seawater. Now a team of 13 researchers from UK’s University of Manchester has uncovered a new and innovative technique to remove salts from ocean water using the versatile one-atom-thick allotrope of carbon known as graphene.
Hailed as the world’s strongest material, graphene has previously shown promise as a filtration agent. In the past, for instance, graphene oxide-based membranes have been used to separate large salt particles from water. For the current research, the team has designed more efficacious graphene films that can easily filter out a wide variety of small salts.
As explained by the scientists, one needs to use fine sieves to sift common salt molecules out of seawater. Although it sounds quite simple, there are no existing technologies that can actually do that. One of the reasons is that graphene-oxide membranes tend to swell up when placed in ocean water, thus losing the ability to capture the tiny salts.
According to Rahul Nair, a professor at the University of Manchester, the new research focuses on an ingenious way to control and limit the pore sizes of the graphene atoms, making the task of filtrating out small salt particles much easier. Speaking about the breakthrough, recently published in the Nature Nanotechnology journal, Nair said:
Realisation of scalable membranes with uniform pore size down to atomic scale is a significant step forward and will open new possibilities for improving the efficiency of desalination technology… This is the first clear-cut experiment in this regime. We also demonstrate that there are realistic possibilities to scale up the described approach and mass produce graphene-based membranes with required sieve sizes.
The new technology, the scientists believe, could pave the way for cheaper and more efficient desalination techniques, which could in turn help combat the burgeoning freshwater crisis.
Source: University of Manchester