Soils electroremediation

The electroremediation method was developed and used for ¹³⁷Cs release from contaminated soils long time ago. Suspension of soil with suitable electrolyte was electrolyzed at a constant current in special electrolytic cell and the released radiocaesium was separated in the column with caesium specific absorber. The column activity was measured and the decontamination yield during the process was determined. The contaminated soil was obtained from area of the first nuclear power station in the former Czechoslovakia, where it was contaminated in the 70’s and 80’s. In the experiments, the role of voltage, current, electrolyte composition, and temperature in the decontamination process were studied. It is shown that the method allows separating more than 99% of radiocaesium within 14 h with energy consumption 120–160 Wh g⁻¹.     

Transformation of synthetic γ-FeOOH (lepidocrocite) in aqueous solutions of ferrous sulphate

The course of the transformation of synthetic γ-FeOOH (lepidocrocite) samples, prepared by different methods was investigated and the effect of a preliminary heat treatment of the initial material on the product phase composition and morphology studied. Both the goethite-tohematite ratio and the particle size of the products depend on the preparation method and on the preliminary heat treatment of the initial lepidocrocite. The results are discussed in terms of the dissolution of the less stable lepidocrocite followed by the crystallization of the more stable phases α-FeOOH and α-Fe₂O₃ from the solution. The final product phase composition and the particle size are affected considerably by a presence of goethite and/or hematite germs in the initial γ-FeOOH.