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ties of plasma treated carbon nanotubes. ¡°Firstly, ultralong nanotubes have
a very large surface area that is ideal for filtration. Secondly, nanotubes are
easy to modify, which allows us to tailor their surface properties through
localised nanoscale plasma treatment,¡± he says.
Now that the researchers have proven the effectiveness of the method, they
plan to extend their research to investigate the filtration properties of other
nanomaterials. They will begin by looking at graphene, which has similar
properties to carbon nanotubes, but could be made considerably denser
and stronger.
The study ¡®Carbon nanotube membranes with ultrahigh specific capacity
for water desalination and purification¡¯ is a collaborative work between
Singapore University of Technology and Design, CSIRO, Massachusetts
Institute of Technology (MIT), the University of Sydney, and Hong Kong
Polytechnic University. (source: Yang HY, Han ZJ, Yu SF, Pey KL, Ostrikov
K, Karnik R. 2013. Carbon nanotube membranes with ultrahigh specific
adsorption capacity for water desalination and purification [www.nature.
com/ncomms/2013/130813/ncomms3220/full/ncomms3220.html].)
Next Generation Water Desalination/Purification
Rechargeable, Inexpensive, More Effective, Portable Devices
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¡°Study paves way for next generation of
portable water purification devices, which
could provide relief to the 780 million
people around the world who face every
day without access to a clean water supply¡±
Access to safe drinking water is a step closer
to being a reality for those in developing
countries, thanks to new research published
in Nature Communications and released by
CSIRO, the Commonwealth Scientific and
Industrial Research Organisation, Australia¡¯s
national science agency, on August 14.
An international team of researchers, led
by Associate Professor Hui Ying Yang from
Singapore University of Technology and De-
sign, showed that water purification mem-
branes enhanced by plasma-treated carbon
nanotubes are ideal for removing contami-
nants and brine from water.
The team included Dr Zhaojun Han and
Professor Kostya (Ken) Ostrikov from
2013 September #4-8
CSIRO¡¯s world-leading Plasma Nanoscience Laboratories.
The study paves the way for the next generation of portable water purification
devices, which could provide relief to the 780 million people around the world
who face every day without access to a clean water supply.
According to Dr Han, these membranes could be integrated into portable water
purification devices the size of a tea pot that would be rechargeable, inexpensive
and more effective than many existing filtration methods. Contaminated water
would go in one end, and clean drinkable water would come out the other.
¡°Small portable purification devices are increasingly recognised as the best way
to meet the needs of clean water and sanitation in developing countries and in
remote locations, minimising the risk of many serious diseases,¡± Dr Han says.
¡°The large industrialised purification plants we see in other parts of the world
are just not practical ¨C they consume a large amount of energy and have high
labour costs, making them very expensive to run.¡±
Dr Han acknowledges that some smaller portable devices do already exist.
However, because they rely on reverse osmosis and thermal processes, they are
able to remove salt ions but are unable to filter out organic contaminants from
the briny water found in some river and lake
systems.
¡°For people in remote locations, briny water
can sometimes be the only available water
source,¡± he says. ¡°That¡¯s why it¡¯s important
to not only be able to remove salts from
water, but to also be able to put it through a
process of purification.¡±
¡°Our study showed that carbon nanotube
membranes were able to filter out ions of
vastly different sizes, meaning they were
able to remove salt, along with other impuri-
ties,¡± he says.
According to Professor Ostrikov, the other
downside of existing portable devices is that
they require a continuous power supply to
operate their thermal processes. ¡°On the
other hand, the new membranes could be
operated as a rechargeable device.¡±
Professor Ostrikov attributes the success of
the new membranes to the unique proper-
The next generation of water purification devices will use plasma-
treated carbon nanotube filters to purify the world water supply.