A U.K.-based team of researchers has created something that could help millions of people around the world with no ready access to clean drinking water. The researchers have created a graphene-based sieve capable of eliminating salt from seawater, making it suitable for drinking.
Graphene used to filter salt out of seawater
Graphene oxide membranes are useful for filtering out large salt and organic molecules and small nanoparticles. However, they could not be used to remove common salts until now. Common salts require even smaller sieves.
Previous work has shown that a graphene oxide membrane grows bigger when immersed in water, enabling smaller salts to flow through the pores with water molecules. Now, a research team at the University of Manchester has demonstrated that placing epoxy resin-made walls on either side of the graphene oxide membrane stopped the expansion, reports the BBC. An epoxy resin is a substance that is used in glues and coatings.
According to the BBC, the graphene-based sieve will now be tested against existing desalination membranes. The extraordinary properties of graphene oxide, like electrical conductivity and its great strength, make it one of the most promising materials for future applications, notes the BBC.
Graphene, the thinnest material in the world, is a form of carbon, and it is comprised of a single layer of carbon atoms arranged in a hexagonal lattice. It is 200 times stronger than steel, notes Sky News. Originally, this material was isolated by researchers Kostya Novoselov and Andre Geim in 2004 at the University of Manchester. Later, the two researchers won the Nobel Prize for Physics for their work.
This could help solve the water crisis
The research was published in the journal Nature Nanotechnology. In the study, the research team, led by Dr. Rahul Nair, showed how they met some of the challenges by using a chemical derivative called graphene oxide.
However, producing large quantities of graphene by using existing methods is not only tough but also very costly. Currently, methods like chemical vapor deposition (CVD) are used to produce single-layer graphene-oxide, notes the BBC. But according to Dr. Nair, it can be produced in a lab by simple oxidation.
Dr. Nair told the BBC, “As an ink or solution, we can compose it on a substrate or porous material. Then we can use it as a membrane.”
Graphene oxide has a potential advantage over single-layered graphene in terms of cost and scalability, Nair said. This is an important step forward, and it will open new possibilities to improve the efficiency of desalination technology, he said. The discovery has the potential to revolutionize water filtration around the world and solve many water-related issues, especially in places that cannot afford large-scale desalination plants.
According to WaterAid, an international development charity, about one in ten people in the world don’t have access to clean water, and nearly 315,000 children under the age of five die every year from diseases that are caused by unclean water. The United Nations expects about 14% of the world’s population to encounter water scarcity by 2025.