Graphene-oxide Membranes Could Make Seawater Into Freshwater
A new method could turn seawater into drinking water for millions around the world without access to clean water.
Researchers at the University of Manchester in England say they’ve successfully used graphene-oxide membranes to filter common salts from seawater, turning it into drinking water more affordably than current desalination techniques.
Graphene-oxide membranes have already been shown to be effective at filtering small nanoparticles, organic molecules and large salts, but they had not yet been effective in filtering out common salts.
“This is the first clear-cut experiment in this regime,” said professor Rahul Nair, at the University of Manchester. “We also demonstrate that there are realistic possibilities to scale up the described approach and mass produce graphene-based membranes with required sieve sizes.
“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,” he said.
The United Nations says that by 2025, 14 percent of the world’s population will suffer water scarcity.
Previous attempts to use the membranes saw smaller salts passing through, researchers said, but the Manchester group discovered that the size of the pores on the membrane could be “precisely controlled” allowing it to block smaller salts.
Specifically, the researchers said the graphene-oxide membranes have tiny capillaries that stop the flow of salts, while allowing fresh water to pass through.
“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,” said co-lead author Jijo Abraham.
The study was published Monday in the journal Nature Nanotechnology.
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