Graphene sieve that turns seawater into drinking water could be a game-changer

4 Apr 2017

Image: taffpixture/Shutterstock

By using a graphene sieve to turn seawater into drinking water, millions of lives could be saved all over the world.

Time and time again, the ‘wonder material’ graphene has shown itself to be a potential game-changer for many industries due to its superconductive properties, at only one atom in thickness.

A new discovery by a team from the University of Manchester (UM) – the very place that gave birth to graphene in its latest form – has found that its applications in the real world could have even greater effects.

Controlling the pores

In a research paper published in the journal Nature Nanotechnology, Jijo Abraham and Dr Vasu Siddeswara Kalangi, along with their team, have shown that a graphene-oxide membrane has exciting potential for gas separation and water filtration.

While graphene-oxide membranes have already proved to be promising in filtering out small nanoparticles and organic molecules, they couldn’t be used for sieving common salts used in desalination technologies, which require even smaller sieves.

With this latest breakthrough, however, salt water can be sieved through the graphene membrane to create clean, potable drinking water that could potentially benefit millions of people around the world.

Timely in face of climate change

The graphene membrane would originally swell allowing smaller salts to flow through, but the team found a way to prevent this by precisely controlling the pore size.

This allows the tiny capillaries of the graphene-oxide membranes to block the salt from flowing along with the water and, crucially, allows the desalinated water to flow quickly out the other end.

Prof Rahul Raveendran-Nair of UM 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.”

By creating smaller-scale graphene sieves, the hope is that more drinking water will be available, with predictions that 14pc of the world’s population will experience water scarcity by 2025 in the face of climate change.

Colm Gorey was a senior journalist with Silicon Republic