Um Woo-yong, a professor in the Department of Advanced Nuclear Engineering and the Department of Environmental Engineering at Pohang University of Science and Technology POSTECH, and his research team have developed a graphene-based technology that can separate dangerous tritium from radioactive wastewater in a liquid state.
Tritium is a radioactive hydrogen produced in nuclear power plants and mostly exists in the form of water molecules. When it enters the human body, it can emit radiation internally, making thorough management necessary; however, until now, tritium could only be separated in a gaseous state, and the removal of liquid-phase tritium remained a significant challenge.
The research team focused on graphene, a material made of carbon atoms arranged in a two-dimensional plane. The atom-thin layer of graphene allows only protons to pass through while blocking other radioactive isotopes, including tritium, demonstrating a unique separation capability. In this study, the researchers completed the separation membrane by adding a type of plastic, polytetrafluoroethylene (PTFE), to a polymer electrolyte membrane called Nafion and transferring graphene onto it.
Results from tests on the separation membrane showed that when an electric field was applied, light hydrogen ions passed through the membrane quickly, while heavy deuterium and tritium could not pass through and were concentrated. This demonstrated that relatively heavier hydrogen isotopes experience a greater energy barrier during movement, inhibiting their passage. Diffusion experiments due to concentration differences also indicated that tritium moves 3.1 times slower than protons through the membrane.
The greatest advantage of this technology is its ability to separate tritium at a high level even in the liquid state at room temperature, such as in nuclear power plant wastewater. In particular, while existing commercialized technologies required high processing expenses, the developed membrane allows for the filtration of tritium in water at room temperature. Its application is expected to enable effective and safe treatment of radioactive wastewater from nuclear power plants, such as the contaminated water from Fukushima.
Professor Um Woo-yong noted, "This technology will greatly assist in solving the radioactive wastewater issues in the nuclear and fusion industries and in the utilization of tritium," highlighting the significance of the research.
This research was published online in the international journal of materials, 'ACS Applied Materials & Interfaces,' by the American Chemical Society (ACS) on July 2nd.
References
Applied Materials & Interfaces (2025), DOI: https://doi.org/10.1021/acsami.5c08414