New material can safely clean up nuclear waste

By Liz T. Williams 9 November 2011
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Australian scientists have developed a new material that can safely and effectively clean up nuclear waste.

NUCLEAR DISASTERS LIKE THAT in Fukushima, Japan, could be cleaned up more safely and effectively thanks to a new material created by Australian scientists.

The nanomaterial is capable of filtering radioactive atoms from water and trapping them in a stable form for years to come.

Just one gram of the stuff – a powder containing a mix of titanate nanofibres and nanotubes – can be used to purify at least a tonne of contaminated water.

“This material has a high capacity and is very efficient,” says Professor Huai-Yong Zhu, a study author and chemist at the Queensland University of Technology in Brisbane. “We think it’s quite useful.”

Safe method to clean up nuclear waste

Unlike alternative filtering materials, the new technology, which the scientists refer to as T3, may offer a safe and relatively permanent way to capture and store radioactive atoms from polluted water.

“This material can capture the species and lock it in, never release it,” Huai-Yong says.

T3 material works to remove radioactive atoms, such as caesium, from water by undergoing a structural change that traps them in the fibres.

Once contaminated water is run through a column full of the material, the used nanofibres can be placed in a small lead container for safe storage.

Nuclear accident

Caesium-137 is one of the isotopes (variations of an atom) produced during the fission of uranium, and it’s one of the more dangerous radioactive waste materials released into the environment during nuclear accidents like that at Fukushima. Because it has a long half-life – over 30 years – significant amounts of it can remain in the environment for decades after an accident occurs.

Even now, 25 years after the Chernobyl disaster, the area within a 30km radius from the power plant is uninhabitable. This is primarily because of the large quantities of caesium-137 that have yet to decay within the region.

Iodine-131, another uranium fission product, is highly radioactive and may cause health problems if exposure if high, but is relatively short-lived.  It is also more challenging to capture, Huai-Yong says.

However, treating the T3 material with silver oxide can enable them to trap iodine instead of caesium.

Cleaning up nuclear disasters

While cleaning up nuclear accidents like that at the Fukushima Daiichi nuclear power plant is the first application that comes to mind for this new technology, the T3 material may also be useful in other settings.

Radioactive iodine, for example, is used to treat thyroid cancer in medical settings, and caesium-137 sources are frequently used for medical and industrial applications – and the T3 material may offer a safer and better way to clean up radioactive waste in hospitals.

“If we can produce a large quantity of these nanofibres, we can put them into a column and simply run the polluted water through the column,” says Huai-Yong. “I think the technology is not very difficult. The main secret is the material.”

Reducing nuclear risks

The relative simplicity – and safety – of the T3 material has attracted interest in the research community.

“What they’re doing is definitely of interest to the wider community,” says Dr Tracey Hanley, a chemist at the Australian Nuclear Science and Technology Organisation (ANSTO) in Sydney, who works on similar technologies. “They have materials that are simple and easy to produce, and the materials themselves don’t pose a hazardous risk, which is really important.”

But this research is not ready for commercialisation, Tracey says. Right now, the team can only produce 10-20 grams at a time – not enough to be of immediate practical use. While the team’s findings are certainly a promising start, many questions about the practicality and constraints of the new technology are yet to be answered.

“This is at the beginning of the innovation stage,” says Professor Lyndon Edwards, head of the Institute of Materials Engineering at ANSTO. “Only time will tell whether it will actually be an effective solution.”
Huai-Yong says he believes that scaling up the production will possible in the long term.

“I just hope someone really uses this technique to make a product,” Huai-Yong says.

This research was published last week in Angewandte Chemie International Edition.