Investigation of adsorption structure of radium on clay minerals by experiment and simulation

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K23432
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0202:Condensed matter physics, plasma science, nuclear engineering, earth resources engineering, energy engineering, and related fields
• Research Institution: Japan Atomic Energy Agency
• Principal Investigator: Yamaguchi Akiko 国立研究開発法人日本原子力研究開発機構, システム計算科学センター, 研究職 (80850990)
• Project Period (FY): 2019-08-30 – 2022-03-31
• Keywords: ラジウム / 粘土鉱物 / EXAFS / 第一原理計算

Outline of Final Research Achievements

Radium (Ra) is a radioactive element. Investigation of the environmental behavior of Ra is an important issue. However, experiments of Ra in molecular level have not been conducted because of the difficulty to treat Ra. In this study, extended X-ray absorption structure (EXAFS) spectra of Ra adsorbed on clay minerals were obtained. Ab initio simulation for Ra adsorbed on a clay mineral was also conducted. The results suggested that Ra is strongly adsorbed on a clay mineral, forming inner-sphere complexes.

Free Research Field

地球化学

Academic Significance and Societal Importance of the Research Achievements

本研究のEXAFS測定及びシミュレーションの結果により、Raイオンが粘土鉱物に対して脱水して吸着（内圏錯体を形成）し、強く固定されることが示された。この結果は、粘土鉱物が存在する環境（風化花崗岩層など）におけるRaの環境挙動の解明及び予測に重要である。それだけでなく、水中のRaイオンが粘土鉱物により除去できる可能性を示唆しており、Raの除去手法開発にも資する結果である。