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Could This Be the Best Working System
to Turn Seawater into Drinking Water?
Researchers from University of Manchester have used graphene oxide.
There is a new attempt by researchers from
the UK to turn seawater into safe drinking
water. And it’s a technique that makes use of a
graphene-oxide membrane that sieves salt right
out of seawater.
Previously, graphene-based barriers are not
manufactured in large amounts because of
certain challenges, especially cost. Production
of a single layer of graphene, done through a
method called chemical vapor deposition, is
expensive so it’s not yet scalable.
RBut the researchers from University of
Manchester have turned from graphene alone
and solved that challenge by using a chemical
derivative called graphene oxide. It is relatively
easier to produce through an oxidation process
carried out in the laboratory.
Arriving to that solution took quite a while
before the major development. The researchers
carried out studies on graphene oxide
membranes, only to find out that when they are
immersed in water, they become a little swollen.
Hence, smaller salt molecules are let to flow
through the holes in the membrane along with
the water. Which is not how desalination works.
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Water Leaders • May 2017
To improve this setup, the researchers applied
epoxy resin walls on both sides of the graphene
oxide membrane, preventing it from swelling
when exposed to water. Plus, the pore size in
the membrane can now be adjusted, which
means that it already work effectively as a salt
sieve.
The technique is yet to be scaled up and is
limited at the lab for now. However, it brings
some kind of hope that this kind of desalination
of seawater will be the engineering solution the
humanity has been waiting for.
“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,” says Rahul Nair,
leader of the research team.
“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,” he
added.