Применение композитных сорбентов на основе ферроцианида никеля при определении содержания радионуклидов цезия в пробах природных вод

Abstract

The paper presents results of two inorganic sorbents for the cesium selective concentration in the scheme of 137Cs radio/chemical analysis in natural water samples. Nickel/ potassium ferrocyanide dispersed in a zirconium dioxide matrix obtained by the sol/gel method with subsequent drying at 100 ºC (Т-35 sorbent produced by AO “Termoksid”), and nickel/potassium ferrocyanide chemically deposited upon a matrix of hydrated titanium dioxide thermally treated at 400 ºC (NKF-GDT sorbent developed by UrFU). We have shown that in the dynamic conditions NKF-GDT sorbent possesses significantly higher sorption properties in comparison with T-35 in spite of close to similar sorption characteristics in the static conditions. For both sorbents we have shown that the degree of cesium sorption from acidulated sea water (pH = 2) is significantly higher that from neutral or low-alkaline water (pH = 28.2). This can be explained by formation of relatively stable pseudo/radio/colloid forms of cesium at pH = 28.2 that are to be destroyed with the solution acidulation. The authors have stated that NKF-GDT sorbent can be used for 137Cs selective concentration from various types of natural water samples. The radio/chemical analysis scheme has been tested with 7.2 l water sample from the Techa River (ChelyabinskOblast) with addition of 0.1 mg/l of stable cesium for determination of the output with ICP-MS instrument. Total chemical output of cesium in the process of concentration was 91.7 % and specific activity of 137Cs in the sample was 1.36±0.21 Bq/l.