Intelligent absorbent removes radioactive material from water
By Darren Quick
November 1, 2011
Nuclear power plants are located close to sources of water, which is used as a coolant to handle the waste heat discharged by the plants. This means that water contaminated with radioactive material is often one of the problems to arise after a nuclear disaster. Researchers at Australia's Queensland University of Technology (QUT) have now developed what they say is a world-first intelligent absorbent that is capable of removing radioactive material from large amounts of contaminated water, resulting in clean water and concentrated waste that can be stored more efficiently.
The new absorbent, which was developed by a QUT research team led by Professor Huai-Yong Zhu working in collaboration with the Australian Nuclear Science and Technology Organisation (ANSTO) and Pennsylvania State University, uses titanate nanofiber and nanotube technology. Unlike current clean-up methods, such as a layered clays and zeolites, the new material is able to efficiently lock in deadly radioactive material from contaminated water and the used absorbents can then be safely disposed of without the risk of leakage - even if the material were to become wet.
When the contaminated water is run through the fine nanotubes and fibers, the radioactive Cesium (Cs+) ions are trapped through a structural change. Additionally, by adding silver oxide nanocrystals to the outer surface, the nanostructures are able to capture and immobilize radioactive iodine (I-) ions used in treatments for thyroid cancer, in probes and markers for medical diagnosis, and also found in leaks of nuclear accidents.
"One gram of the nanofibres can effectively purify at least one ton of polluted water," Professor Zhu said. "This saves large amounts of dangerous water needing to be stored somewhere and also prevents the risk of contaminated products leaking into the soil."
"Australia is one of the largest producers of titania that are the raw materials used for fabricating the absorbents of titanate nanofibres and nanotubes. Now with the knowledge to produce the adsorbents, we have the technology to do the cleaning up for the world," added Professor Zhu.
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