[2H01-06] Migration/Sorption 1

[2H02] Structural analysis and site selectivity of Cesium adsorption on Calcium Silicate Hydrates

*Keita Higuchi¹, Takahiro Ohkubo¹, Kumi Negishi², Masahito Shibata², Yukio Tachi³ (1. Chiba Univ., 2. Taiheiyo Consultant, 3. JAEA)

Keywords:Calcium Silicate Hydrates, Cs adsorption, Nuclear Magnetic Resonance

Structural analyses of adsorbed Cs on calcium silicate hydrate (C-S-H) were performed by ¹³³Cs solid-state NMR and Cs adsorption experiments. ¹³³Cs solid-state NMR spectra of C-S-H with adsorbed Cs gave one (A) or two peaks (A and B) depending on Ca/Si and Cs content. The peaks A and B were assigned to Cs adsorbed sites on interlayer silanol groups (site A) and exchangeable Ca sites bridging silicate chain (site B). Since the peak A was only observed for the sample with small amount of Cs, adsorption of Cs on C-S-H occurs preferentially at site A. After the saturation of adsorption on site A, adsorption on site B occurs in the sample with higher Cs content.