[1B01-03] Waste treatment and solidification

9:30 AM - 9:45 AM JST(12:30 AM - 12:45 AM UTC)

[1B01] Adsorption of metal ions by Fe-modified natural clinoptilolite for radionuclide decontamination and immobilization by calcination

*Kanta Masataki Masataki¹, Hiromichi Aono¹, Yoshiteru Itagaki¹ (1. Ehime Univ.)

Keywords:

Clinoptilolite,Radionuclide,Adsorption,Immobilization by calcination,Fe modification

Natural clinoptilolite (CPL) was used to adsorb simulated radionuclide metal ions (Cs, Sr, Mn, Zn, Co, and Fe), and immobilization performance upon calcination at 600–1100°C was investigated. Adsorption efficiencies exceeded 90% for Cs, Sr, Mn, Zn, and Fe. Fe-modified CPL showed lower 14-day cumulative leaching rates in both pure water and artificial seawater than natural CPL, confirming enhanced immobilization by Fe modification. XRD analysis of high-concentration samples detected no complex oxide diffraction peaks, precluding phase identification. However, EDS analysis revealed a clear correlation between Fe and adsorbed ions in samples calcined at 1100°C, absent in uncalcined samples. These results suggest that Fe promotes localized formation of sparingly soluble complex oxides, contributing to improved immobilization performance after calcination.