A cost-efficient approach to the treatment of radiocontaminated water stored at the disabled Fukushima nuclear power plant in Japan is based on the use of oxidatively modified carbon materials.

Researchers from the U.S. and Russia say OMC can also trap common radioactive elements found in water floods from oil extraction, such as uranium, thorium, and radium.C-seal F is seen magnified 20 times by a scanning electron microscope. Credit: Kazan Federal University

The material exploits the porous nature of two specific sources of carbon to absorb radioactive metal cations from water. One is an inexpensive, coke-derived powder known as C-seal F, used by the oil industry as an additive to drilling fluids. The other is a naturally occurring, carbon-heavy mineral called shungite, found mainly in Russia.

The carbon particles are treated with oxidizing chemicals to increase their surface areas and modified with the oxygen molecules needed to adsorb the toxic metals. The particles were between 10 and 80 microns wide.

While graphene oxide excelled at removing strontium, the two types of OMC proved superior to graphene at extracting cesium, which has been the hardest element to remove from water stored at Fukushima. The OMC was also much easier and less expensive to synthesize and to use in a standard filtration system.

In two-hour laboratory mixing tests, 800 mg of coke-derived OMC removed about 83% of cesium and 68% of strontium from 100 ml of water. Shungite-based OMC in the same concentrations adsorbed 70% of cesium and 47% of strontium.

Researchers at Rice University, TX, and Kazan Federal University in Russia note that the used carbon can be burned in a nuclear incinerator, and treated water can be safely discharged to the ocean.