Synthesis and investigation of composite sorbents based on mixed K-Co and K-Cu ferrocyanides for cesium extraction from aqueous media

A new method of creating composite sorption materials based on mixed K-Co and K-Cu ferrocyanides using polyethylene is proposed. The uniqueness of this method lies in the hydrophobisation of the material by integrating polyethylene fibres into the ferrocyanide structure. The surface morphology and structure of the obtained sorbents were investigated by scanning electron microscopy, X-ray phase analysis and low-temperature nitrogen adsorption. The peculiarities of extraction of micro- and macro concentrations of Cs+ cations and 137Cs radionuclide from sea water under static conditions were studied. The approximation of experimental sorption data using the Langmuir and Freundlich equations has been carried out, and the values of limiting sorption Gmax and adsorption equilibrium constant Kl have been calculated. It is demonstrated that the sorbents synthesised with the addition of polyethylene have the best sorption characteristics, achieving up to 99% purification of seawater from caesium ions. The average distribution coefficient of caesium in seawater is 3.8×10^4 ml/g at a solid-to-liquid phase ratio of 1000 ml/g, which indicates the prospects of their application for purification of seawater from radiocaesium.