Graphene sieve turns seawater into drinking water
New research demonstrates the real-world potential of providing clean drinking water for millions of people who struggle to access adequate clean water sources.
Until now, however, they couldn’t be used for sieving common salts used in desalination technologies, which require even smaller sieves.
Previous research at The University of Manchester found that if immersed in water, graphene-oxide membranes become slightly swollen and smaller salts flow through the membrane along with water, but larger ions or molecules are blocked.
The pore size in the membrane can be precisely controlled which can sieve common salts out of salty water and make it safe to drink.
When the common salts are dissolved in water, they always form a ‘shell’ of water molecules around the salts molecules.
"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."
Mr. Jijo Abraham and Dr. Vasu Siddeswara Kalangi were the joint-lead authors on the research paper: "The developed membranes are not only useful for desalination, but the atomic scale tunability of the pore size also opens new opportunity to fabricate membranes with on-demand filtration capable of filtering out ions according to their sizes."
This technology has the potential to revolutionise water filtration across the world, in particular in countries which cannot afford large scale desalination plants.
More information: Tunable sieving of ions using graphene oxide membranes, Nature Nanotechnology, nature.com/articles/doi:10.1038/nnano.2017.21