3 Février 2013
January 31, 2013
31.01.2013_No30 / News in Brief
Research & Development
31 Jan (NucNet): Graphene oxide, a two-dimensional material that contains pure carbon, has “a remarkable ability” to quickly remove radioactive material from contaminated water and could be used in cleaning up contaminated sites such as the Fukushima-Daiichi nuclear plant, researchers at Rice University in Texas and Lomonosov Moscow State University have found.
Microscopic, atom-thick flakes of graphene oxide bind quickly to natural and human-made radionuclides and condense them into solids, Rice University said in a statement. The flakes are soluble in liquids and easily produced in bulk.
An abstract of the research published online said the results point towards “a simple methodology” to mollify the severity of nuclear waste contamination, leading to effective measures for environmental remediation.
The experimental results were reported in the Royal Society of Chemistry journal ‘Physical Chemistry Chemical Physics’.
The discovery, said Rice University chemist James Tour, “could be a boon in the cleanup of contaminated sites like the Fukushima nuclear reactors damaged by the 2011 earthquake and tsunami”. It could also cut the cost of hydraulic fracturing – known as fracking – for oil and gas recovery and help the mining of rare earth metals, he said.
Graphene oxide’s large surface area defines its capacity to adsorb toxins, said Stepan Kalmykov of Lomonosov Moscow State University. “So the high retention properties are not surprising to us,” he said. “What is astonishing is the very fast kinetics of sorption, which is key.”
The researchers focused on removing radioactive isotopes of the actinides and lanthanides – the 30 rare earth elements in the periodic table – from liquids, rather than solids or gases. “Though they don’t really like water all that much, they can and do hide out there,” said Steven Winston, a former vice-president of Lockheed Martin and Parsons Engineering and an expert in nuclear power and remediation who is working with the scientists. “From a human health and environment point of view, that’s where they’re least welcome.”
Mr Tour said that capturing radionuclides does not make them less radioactive, just easier to handle. “Where you have huge pools of radioactive material, like at Fukushima, you add graphene oxide and get back a solid material from what were just ions in a solution,” he said. “Then you can skim it off and burn it. Graphene oxide burns very rapidly and leaves a cake of radioactive material.”
The low cost and biodegradable qualities of graphene oxide should make it appropriate for use in permeable reactive barriers, a fairly new technology for in-situ groundwater remediation, he said.
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