Graphene oxide acts as sponge for radioactive material

Scientists have recently discovered adding graphene oxide to water contaminated by radioactive material will make environmental clean up easier. They discovered the compound quickly causes radionuclides to clump into particles that can more efficiently be removed from the water.

In a post-Fukushima world, that comes as welcome news.

Houston's Rice University and Lomonosov Moscow State University conducted the joint experiments with atom-thick flakes of the graphene oxide. They found the water-soluble flakes quickly attracted both natural and man-made radionuclides, creating solid clumps that make for easier disposal.

The large surface area of the graphene oxide is what makes it able to absorb large amounts of toxins, creating the clumps. The real surprise to scientists was the speed of the reaction.

In a Rice University press release, Stepan Kalmykov from Lomonosov Moscow State University noted:

"…the high retention properties are not surprising to us," he said. "What is astonishing is the very fast kinetics of sorption, which is key."

Researchers put the compound through its paces regarding speed. They used water containing highly toxic uranium and plutonioum along with other substances such as calcium and sodium. The latter two compounds have been found to slow down absorption in normal circumstances, but the graphene oxide was not affected by the PH of the water and still clumped the radioactive toxins in minutes.

The team also tested whether graphene oxide would work on natural radioactive isotopes that may come to the surface as a result of fracking and mining of rare earth metals. Often the groundwater that comes to the top during the process is too radioactive to put back in the ground and must be treated.

The current process uses bentonite clays and activated carbon, and while it gets the job done, the experiments with graphene oxide proved the larger solid clumps formed quicker and were more easily harvested and disposed of.

Rice University chemist James Tour said in the press statement:

"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. "Then you can skim it off and burn it. Graphene oxide burns very rapidly and leaves a cake of radioactive material you can then reuse."

Fukushima taught us that radioactive disasters can occur on a large scale, and water can easily be contaminated. Non-disaster scenarios like fracking and mining also play their part.

The discovery of a quicker, easily reproduced compound such as graphene oxide means these kinds of contaminations can be more efficiently dealt with, hopefully mitigating human health dangers by enabling quicker clean up.

The results of the joint Rice University and Lomonosov Moscow State University study were reported in the Royal Society of Chemistry journal Physical Chemistry Chemical Physics.

Rice University
Gizmag

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