Graphene Sieve Converts Seawater Into Drinking Water
Science & Tech / /
Water may cover most of the planet's surface, but because of the salt, it is not drinkable. However, researchers at the University of Manchester have developed a membrane of graphene oxide with equally and properly distributed pores, which can filter the seawater in order to remove the salt from it.
The development of such a product could help millions of people without access to drinking water. Sieve of graphene oxide could be very effective for that purpose and will now be tested and compared with the existing membrane desalination.
Earlier it was very difficult to produce scale membrane based on grapheme, in larger amounts. Scientists from the University of Manchester, who had their research published in the journal Nature Nanotechnology, say they have solved a lot of problems with the high cost of using chemical derivative called graphene oxide.
Since it was discovered and isolated, graphene has proved to have very specific and interesting properties. It is extremely powerful (one hundred times stronger than steel), a good conductor of electricity and quite elastic.
However, there is one problem. It is very difficult to produce large quantities of single-layer graphene using currently available methods, which are quite expensive.
"To make it permeable, you need to drill small holes in the membrane. But if the hole size is larger than one nanometre, the salts go through that hole. You have to make a membrane with a very uniform less-than-one-nanometre hole size to make it useful for desalination. It is a really challenging job," explained Dr Rahul Nair, leader of the team of researchers.
On the other hand, Dr. Nair, that graphene oxide could be produced easily by oxidation of graphene in the lab.
"As an ink or solution, we can compose it on a substrate or porous material. Then we can use it as a membrane,” Dr. Nair explained.
Until now, graphene oxide membranes could not be used to filter out common salts, mainly because they require even smaller sieves. But despite that they have already proven their worth in sieving out small nanoparticles, organic molecules and even large salts.