Role of acetic acid on U(VI) sorption on silica

分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》

ZHAO Yu-Jia WEI Yue-Zhou Mercier-Bion Florence Lefevre Gregory

摘要： The influence of acetate on U(VI) sorption on silica from aqueous solutions was studied at pH 27 by complementary experimental methods of macroscopic measurement, spectroscopic investigation and thermodynamic calculation. Sorption percentage of U(VI) in the absence and in the presence of different acetate concentrations was determined by batch sorption procedures. Attenuated total reflection Fourier transform infra-red spectroscopy (ATR-FTIR) was used to elucidate the mechanisms of uranyl sorption on silica in the presence of acetate, by investigating, in-situ, the changes in the U(VI) sorption on silica surface in presence of ligand: the absorption bands of carboxylate (COO) in the range 13001700 cm-1 and those around 850950 cm-1 of uranyl species as(UO2) are followed. The decrease of U(VI) sorption with increasing acetate concentration was observed. Sorption of U(VI)-acetate (U-Ac) species on silica surface was demonstrated for the first time. ATR-FTIR investigations clearly evidenced the absorption bands characteristic of sorbed U-Ac complexes both from the acetate and uranyl spectral regions those the wavenumbers correspond to sorbed species. No sequence effect of acetate and uranyl on the sorption on silica in ternary systems U(VI)-acetate-silica was observed from the sorption data. From the ATR-FTIR investigations, we can induce that the sorption of U-Ac leads to chemical equilibria and makes possible the modeling of sorption isotherms by surface complexation models. The related thermodynamic constants were modeled using CCM surface complexation modeling.

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