Revved-up carbon purifies radioactive water
After the Fukushima nuclear plant accident occurred, hundreds of millions of gallons of radioactive water was left over. That water is still being stored, as no one knows quite what to do with it. Scientists from Texas' Rice University and Russia's Kazan Federal University, however, may have an answer. They've developed a type of carbon that can reportedly filter radionuclides from water.
Known as oxidatively modified carbon (OMC), the material is made by treating existing carbon particles with oxidizing chemicals in order to increase their surface area and add oxygen molecules to their structure. Actually, two inexpensive types of carbon are used, due to their porous nature. One is called C-seal F, and it's already used in the oil industry as an ingredient in drilling fluids. The other, shungite, occurs naturally – mainly in Russia.
In lab tests, OMC has reportedly been highly effective at absorbing radioactive metal cations such as cesium and strontium from contaminated water. These are two of the main elements that were released into the environment when the Fukushima plant melted down. It can also trap elements that enter waterways during oil extraction, including uranium, thorium and radium.
According to the scientists, water could simply be run through OMC filters in a single pass, going straight into the ocean. The used filters would then have to been incinerated, leaving a relatively small amount of radioactive ash to be contained.
The research is being led by Rice chemist James Tour and Kazan research professor Ayrat Dimiev. It's described in a paper recently published in the journal Carbon.
Tour has previously collaborated with scientists at Lomonosov Moscow State University, on a project that used flakes of graphene oxide to separate radioactive contaminants from water. While the graphene oxide was better at removing strontium, OMC excels at filtering out cesium, plus it's less expensive, easier to synthesize, and easier to fit into existing filtration systems.
Source: Rice University