Korea Atomic Energy Research Institute Develops Technology to Remove 99.4% of Cesium and Strontium

Core Components of Fukushima Nuclear Wastewater... Patents Acquired in Korea and Japan, Pending in the USA

[Asia Economy Reporter Kim Bong-su] Domestic researchers have developed an adsorbent that can selectively remove large amounts of radioactive contamination nuclides cesium and strontium formed during uranium fission. This has attracted attention as these components are abundantly included in the contaminated water from the Fukushima nuclear power plant that the Japanese government plans to discharge.

The Korea Atomic Energy Research Institute announced on the 27th that Dr. Yang Hee-man's research team from the Decommissioning Technology Research Department, together with Professor Choi Min-ki's research team from the Department of Biological and Chemical Engineering at the Korea Advanced Institute of Science and Technology (KAIST), succeeded in developing a 'sulfur-zeolite composite' with such performance. Zeolite is a material widely used for adsorbing radioactive nuclides but has the disadvantage of low adsorption affinity for cesium and strontium.

The research team compensated for this drawback by using sulfur. They sublimated sulfur, which has high chemical affinity with cesium and strontium, into the pores of commercially available zeolite to encapsulate it, synthesizing the sulfur-zeolite composite for the first time in the world. It can be manufactured by a relatively simple and low-cost method, raising expectations for commercialization.

Until now, various adsorbents have been developed worldwide to selectively remove cesium and strontium, but most had limitations such as complex manufacturing processes and high costs.

The research team also confirmed that regardless of the type of zeolite, the more sulfur encapsulated, the greater the adsorption selectivity for cesium. When the mass percentage of sulfur in chabazite, a type of zeolite commonly used for cesium adsorption, was 5% and 10%, the cesium adsorption selectivity increased by 3.2 times and 7.1 times, respectively, compared to conventional chabazite.

On the other hand, the adsorption selectivity for strontium showed a maximum at a specific sulfur content depending on the type of zeolite. When the mass percentage of sulfur in zeolite A (NaA Zeolite), commonly used for strontium adsorption, was 3%, it increased up to 1.5 times compared to conventional zeolite A, but at 10%, it only increased by 1.33 times.

Experiments purifying contaminated groundwater using the sulfur-zeolite composite removed more than 99.4% of radioactive cesium and strontium, respectively. In particular, even under conditions where radioactive cesium and strontium coexist, both nuclides were removed by more than 97.5%. This is immediately applicable for treating large amounts of radioactive contaminated water generated during nuclear facility decommissioning in the future.

The research team plans to conduct additional studies on whether the existing process for stabilizing used zeolite can be directly applied to the sulfur-zeolite composite and will also promote technology transfer.

Dr. Yang Hee-man of the Korea Atomic Energy Research Institute said, “The manufacturing cost is low and the process is simple, making it suitable for mass production. It can directly replace the general zeolite currently used in contaminated water treatment processes, making commercialization very advantageous,” and added, “We will optimize the synthesis method to enhance adsorption performance for cesium and strontium and continue various applied research such as sulfur-zeolite-based separation membranes and micro underwater robots.”

This technology completed patent registration in Korea and Japan last April and is currently under patent examination in the United States. It has been consecutively published in international academic journals ‘Chemistry of Materials’, ‘Applied Surface Science’, and ‘Chemosphere’.

This content was produced with the assistance of AI translation services.