The finest sieve imaginable could turn sea water into drinking water. University of Manchester scientists have developed a graphene oxide membrane that can filter even nanoparticles like common salts out of water. Graphene-based filters developed in the past were too porous to do this. SOUNDBITE (English) PROFESSOR OF MATERIALS PHYSICS AT UNIVERSITY OF MANCHESTER, RAHUL RAVEENDRAN NAIR, SAYING: “The problem was that when you put the membrane in water the sieve became larger. Now we’ve solved that problem, so now we can take this salty water, put it back in our new filtration unit, where we can filter out even the smallest sodium chloride.” Water is pumped through the membrane made from layered graphene oxide flakes. It’s coated with epoxy resin to prevent swelling.
Water molecules pass through the membrane, but larger molecules like oil and salts are filtered out. Its developers say it’s ideal for desalination – currently an expensive and energy intensive process.
SOUNDBITE (English) PROFESSOR OF MATERIALS PHYSICS AT UNIVERSITY OF MANCHESTER, RAHUL RAVEENDRAN NAIR, SAYING: “What graphene brings is a more efficient process, so water filtration through the graphene membrane is much faster than the commercial polymer membrane which means you get more drinking water in short period of time, and the pressure required to make that drinking water is smaller than what the commercial membrane does,” The team behind the sieve hope that it could make desalination an option in developing countries. SOUNDBITE (English) PROFESSOR OF MATERIALS PHYSICS AT UNIVERSITY OF MANCHESTER, RAHUL RAVEENDRAN NAIR, SAYING: “It would be really nice if we could come up with a portable water filtration device – something similar but without this gas cylinder.
If you can have a hand pump or something like that then we can filter out dirty water from clean water. That is probably our long-term goal.” The United Nations predicts 1.8 billion people will face water scarcity by 2025. The Manchester team hope the sieve could play a part in giving them affordable clean water.