New Desalination Filter Developed

A sensational new material that could offer clean water for millions of people around the world has been created in the lab in the north of England.

Researchers at Manchester University have used a graphene filter to create a membrane that could be revolutionary in desalination - the process by which salt-water is turned into fresh water. It could also be used for drinking water from rivers, Mail Online reported on April 4.  

The discovery could lead to the development of new small and low-cost filtration devices for use in areas with no access to clean running water, opening up large swathes of currently unlivable land.

The newly developed filter sieves out common salts from water.

It works by creating a membrane of graphene-oxide - a lattice of carbon and water atoms, with each layer just one atom thick - which allows water to pass through, but stops any larger molecules.

Those membranes previously developed at the National Graphene Institute at Manchester University already demonstrated the potential of filtering out small nano-particles, organic molecules, and even large salts using graphene-oxide.

But researchers found that the membranes became slightly swollen when immersed in water, allowing smaller salts to flow through.

Now the research team has overcome the problem, by controlling the pore size in the membrane so precisely that the salts can no longer pass through.

When common salts are dissolved in water, a ‘shell’ of water molecules forms around the salt molecules.

 Ideal for Huge Plants  

This allows the tiny capillaries of the graphene-oxide membranes to block the salt from flowing along with the water.

Water molecules are able to pass through the membrane barrier and flow very quickly.

This makes them ideal for desalination plants where vast volumes of water may flow through on a daily basis.

Professor Rahul Nair, at The University of Manchester said: ‘Realization 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 findings were published today in the journal Nature Nanotechnology.

The research team did not say if and when the new service will become commercially available.