ELECTRODE RIDDING RADIOACTIVITY IN WATER

Researchers in China highlight the efficacy of carbon electrodes in removing uranyl from wastewater around nuclear plants, and oceans.

- KUNAL TALGERI

LECTRODE materials have the potential to replace powder-based materials in the removal of radioactive uranyl from wastewater and seawater, according to a review published by researchers from the College of Environmental Science and Engineering in Beijing, and North China Electric Power University.

The sustainable materials research is significant for the nuclear power industry: uranium is the primary fuel for nuclear reactors, and must be managed properly, in a safe and sustainable manner. Annual production of natural uranium worldwide has been between 55,000 and 65,000 tonnes of uranium metal, similar to the fuel demand, according to the International Energy Agency (IEA).

In the natural environment, uranium oxides exist in two states: the hexavalent uranyl ions (highly soluble and mobile), and the tetravalent form (insoluble and immobile). An environment-friendly and sustainable strategy to recover uranyl from water systems involves reducing the mobile uranyl ions to the insoluble tetravalent form. Uranyl is the soluble uranium compound found in radioactive wastewater in the vicinity of nuclear power plants. It is also present in seawater: as oceans are rich in oxygen and slightly alkaline, uranium naturally exists as the uranyl ion. While uranyl is a radioactive pollutant for water systems around nuclear plants, it can double up as a fuel source that can be reprocessed and used. Globally, nuclear power plants have widely adopted electrochemical methods like electrosorption to extract uranyl from radioactive wastewater. Electrosorption uses electricity to selectively remove various ions, including lithium, copper, arsenic, uranium, phosphate, nitrate, and sulfate from mixed salt solutions.