Gold-flecked nano-sensor detects poisonous mercury

May 28th, 2009 - 12:06 pm ICT by IANS  

Pratibha Patil Sydney, May 28 (IANS) Researchers led by an Indian Australian have pioneered a gold-flecked nano-sensor that can precisely measure one of the world’s most poisonous substances, mercury.
Developed by Royal Melbourne Institute of Technology (RMIT), the mercury sensor relies on gold flecks 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.

“Industrial chimneys release a complex concoction of volatile organic compounds, ammonia and water vapour that can interfere with the monitoring systems of mercury sensors,” said Suresh Bhargava, professor and dean of RMIT School of Applied Sciences.

“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,” added Bhargava, who was recently given an honorary degree of Rajasthan University by Indian President Pratibha Patil.

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, said an RMIT release.

“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,” Bhargava said. “Our nano-engineered gold surfaces are 180 percent 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.”

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