Trivalent lanthanides sorption onto illite in the presence of carbonate

炭酸共存下におけるIII価ランタニド元素のイライトに対する収着

杉浦 佑樹  ; 石寺 孝充 ; 青柳 登   ; Mei, H.  ; 斉藤 拓巳*; 舘 幸男  

Sugiura, Yuki; Ishidera, Takamitsu; Aoyagi, Noboru; Mei, H.; Saito, Takumi*; Tachi, Yukio

The sorption behavior of trivalent lanthanides (Eu/Sm) onto illite in the presence of dissolved inorganic carbon (DIC) was investigated by batch sorption experiments. The results of the experiments were interpreted using a thermodynamic sorption model (TSM). The TSM predicted that Eu/Sm forms clay mineral-Eu/Sm-carbonate surface ternary complexes. Time-resolved laser fluorescence spectroscopy (TRLFS) measurements were performed to obtain information on the chemical forms of Eu sorbed on illite. Parallel factor (PARAFAC) analysis of the TRLFS data indicated the presence of multiple chemical species. The pH dependence of the relative intensity of the chemical species derived from PARAFAC analysis was consistent with that of the surface species predicted by the TSM. The dominant chemical species in the presence of DIC was inferred to be coordinating carbonate ions based on the fluorescence lifetime. These results confirm the existence of surface ternary complex and the validity of the TSM.