Researchers develop graphene-based sieve that can remove salt from seawater

A UK-based team of researchers has developed a graphene-based sieve that can remove salt from seawater, which could help millions who do not have ready access to clean drinking water.

The promising graphene oxide sieve could be highly efficient at filtering salts, and would now be tested against  desalination membranes currently in use.

It had earlier been difficult to manufacture graphene-based barriers on an industrial scale.

The scientists from the University of Manchester led by Dr Rahul Nair had published their research in the journal Nature, in which they used a chemical derivative called grapheme oxide.

Graphene had been isolated and characterised by a University of Manchester-led team in 2004. It comprised a single layer of carbon atoms arranged in a hexagonal lattice and possessed properties such as extraordinary tensile strength and electrical conductivity. Graphene had therefore been considered as one of the most promising materials for future applications.

However, it had been difficult to produce large quantities of single-layer graphene using existing methods, such as chemical vapour deposition (CVD). Also production methods currently used had significant associated costs.

However, according to Dr Nair, graphene oxide could be produced by simple oxidation in the lab.

He told BBC News, "As an ink or solution, we can compose it on a substrate or porous material. Then we can use it as a membrane."

The discovery comes as the UN warned that around 1.2 billion people, or 14 per cent of the earth's population would find it difficult to access clean water by 2025.

With man-made climate change reducing citiy water supplies, countries had seen increased investment in "desalination" technologies.

According to Nair, it was a significant step forward that would "open new possibilities for improving the efficiency of desalination technology".