Clays and Clay Minerals, Vol. 57, No. 3, 330–337, 2009.
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Authors
Hansen, Birte
Curtius, Hilde
Odoj, Reinhard
Issue Date
2009
Type
Article
Language
Keywords
Periodicals , Geology , Clay Pore-water , Layered Double Hydroxides , MgCl2-rich Salt Brine , Sorption
Alternative Title
Synthesis Of A Mg-cd-al Layered Double Hydroxide And Sorption Of Selenium
Abstract
Leaching experiments with metallic uranium-aluminum research-reactor fuel elements in repository-relevant MgCl2-rich salt brine (brine 2) were performed. A Mg-Al layered double hydroxide (LDH) with chloride as the interlayer anion was identified as a crystalline secondary-phase component. In the present study, the incorporation of Cd into the structure of the Mg-Al-Cl LDH was investigated. Synthesis by a coprecipitation method was performed and the Mg-Cd-Al-Cl LDH obtained was characterized. The sorption behavior of selenium on the LDH was investigated in water, clay pore-water (Mont-Terri-type), and brine 2. Using a LDH concentration of 10 g/L, the sorption kinetics were rapid and equilibrium was reached within 12 h. The sorption of selenium decreased with increasing amount of chlorideanions in thesolutions . Thechlorideanions acted as competing anions for thesorption of selenium. The effect of pH on selenium sorption was investigated and a large buffer capacity of the LDH was observed. For the range of selenium concentration used, linear sorption isotherms were obtained which obeyed the Freundlich and Dubinin-Radushkevich models. From these, the energies of selenium sorption werecalc ulated to bein therangeof ion-exchange processes.
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Citation
Clays and Clay Minerals, Vol. 57, No. 3, 330–337, 2009.
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