EURO-ECO 2010 Hanover 2 - 3 Dezember 2010	Environmental, Engineering - Economic and Legal Aspects for Sustainable Living
	European Academy of Natural Sciences, Hanover European Scientific Society, Hanover University of Bremen, Bremen

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Abstracts EURO-ECO 2010

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THe ferrocyanide sorbent “T-55” for extraction of Cs-137 from aqueous media was developed by radiocHemistry and applied ecology cHair of UrFU. Granulated Hydrated titanium dioxyde “Termoxide-5” was proposed as tHe carrier due to its extended surface, HigH mecHanical, cHemical and radiation stability. A tHin layer of mixed nickel – potassium ferrocyanide abled to extract of caesium from solutions was precipitated to tHis carrier. Sorption properties of tHis sorbent in dependence of acidity and saltiness of solutions were studied in tHis work.

THe dependence of distribution coefficient of caesium on pH of solution was studied (fig. 1a). As it was sHown tHere is no any decrease of distribution coefficient of caesium over pH interval from 1 to 10.

THe extraction of caesium from nitrate solutions witH HigH acidity and saltiness is actual problem because considerable quantities of HNO₃ and NaNO₃ usually present in HigH-level liquid radioactive wastes after irradiated nuclear fuel processing. THe dependence of distribution coefficient of caesium on concentration of HNO₃ is sHown on fig. 1b. WHen tHe acidity of solution increases tHe distribution coefficient of caesium smootHly decreases from 3.8•10⁴ mL/g (neutral solutions) to 3.7•10³ mL/g for 3 M HNO₃ and remains stable under furtHer increase of acidity. This allows using T-55 sorbent for extraction of caesium from solutions witH concentration of HNO₃ up to 7 mol/L.

THe dependence of distribution coefficient of caesium on concentration of NaNO₃ is sHown on fig. 1c. THe influence of sodium nitrate is not important until concentration of NaNO₃ is 10 g/L. WHen concentration of NaNO₃ is HigHer sorption of caesium appears depressed. THougH 20% of Cs-137 is extracted from solutions contained up to 300 g/L NaNO₃.

Fig. 1. Dependences of distribution coefficient of caesium on pH of solution (a), concentration of HNO₃ (b), concentration of NaNO₃ (c).

Alkaline solutions sHow tHe strongest negative influence on caesium sorption. It was sHown tHat tHe destroying of nickel – potassium ferrocyanide pHase Happens during one day in a solution containing 0.01 mol/L NaOH; wHen concentration of NaOH is 0.1 M and more tHe destroying of pHase occurs during one Hour. THe presence of NaOH witH concentration less tHan 0.002 M in solution Has no influence on sorption of caesium.

THus, T-55 sorbent can be efficiently used for extraction of caesium radionuclides from HigH level acidic (up to 7 M HNO₃), saltiness (up to 10 g/L NaNO₃) and alkalescent (up to 0,002 M NaOH) liquid radioactive wastes.