RMIT University researchers
have used breakthrough nanotechnology to create a pioneering sensor that can
precisely measure one of the world's most poisonous substances, mercury.
 | | RMIT’s research on mercury monitoring through nano-engineered gold surfaces recently featured on the cover of the prestigious journal, Physical Chemistry and Chemical Physics, a publication of the Royal Society of Chemistry. The research team behind the publication was led by Professor Suresh Bhargava and included Dr Prashant Sawant, Dr Vipul Bansal, Dr Samuel Ippolito and Dr Ylias Sabri. |
The mercury sensor developed by RMIT's Industrial Chemistry Group uses tiny
flecks of gold that are nano-engineered to make them irresistible to mercury
molecules.
In the effort to reduce mercury contamination in the environment and the associated
health risks, accurately measuring the toxin has become a priority for mercury-emitting
industries like coal-burning power generators and alumina refineries.
Professor Suresh Bhargava, Dean of the School of Applied Sciences, said traditional
mercury sensors used by industry could be unreliable.
"Industrial chimneys release a complex concoction of volatile organic
compounds, ammonia and water vapour that can interfere with the monitoring systems
of mercury sensors," Professor Bhargava said.
"We wanted a sensor that would be robust enough to cope with that kind
of industrial environment but also sensitive enough to give precise readings
of the amount of mercury vapour in these emissions."
The mercury sensor was developed with the use of patented electrochemical processes
that enabled the RMIT researchers to alter the surface of the gold, forming
hundreds of tiny nano-spikes, each one about 1,000 times smaller than the width
of a human hair.
These nano-engineered surfaces are then used with existing technologies such
as Quartz Crystal Microbalances - a finely tuned set of scales that measure
weight down to molecular levels - to determine the levels of mercury in the
atmosphere.
"We've known since ancient times that gold attracts mercury, and vice
versa, but a regular gold surface doesn't absorb much vapour and any measurements
it makes are inconsistent," Professor Bhargava said.
"Our nano-engineered gold surfaces are 180 per cent more sensitive than
non-modified surfaces.
"They're finely targeted, so they're unaffected by the usual gases found
in effluent gas streams.
"And the sensors we've created using those nano-engineered surfaces have
worked successfully at a range of extreme temperatures over many months, just
as they'll need to in an industrial location."
Funded through an Australian Research Council Linkage grant, the project was
supported by leading industry partners, who have now engaged RMIT to develop
a mercury sensing device for a pilot plant trial at one of their Australian
refineries.
The Industrial Chemistry Group's multi-disciplinary team is one of Australia's
leading research units working on solutions for the monitoring and clean-up
of gas and liquid mercury.
The group will extend its work on mercury removal technology through an international
collaboration with the Indian Institute of Chemical Technology at Hyderabad,
focusing on putting the nano-engineered gold surfaces to use in a system that
can absorb and remove mercury vapour from the air.
Posted May 27th, 2009
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