Sorption Composites Based on K-Ni and K-Zn Mixed-Metal Ferrocyanides for Extracting Cesium from Seawater

An original method was proposed for manufacturing sorption composite materials based on K-Ni and K-Zn mixed-metal ferrocyanides (FCs) formulated with siloxane–acrylate emulsion and polyethylene. The originality of the method consists in the hydrophobization of the material via the incorporation of polyethylene fibers into the FC structure. The surface morphology and structure of the manufactured sorbents were studied by scanning electron microscopy, X-ray powder diffraction, and low-temperature nitrogen adsorption. The specifics of the batch extraction of micro- and macroconcentrations of Cs + and 137 Cs radionuclides from seawater were studied. The experimental sorption values were fitted by the Langmuir and Freundlich equations, and the limiting sorption G max and adsorption equilibrium constants K l were calculated. The sorbents comprising polyethylene (PE) have the best sorption characteristics, providing up to 99% cleaning of seawater from cesium ions. The cesium distribution ratio in seawater averages 3.7 × 10 4 mL/g at S : L = 1000 mL/g, which indicates the promise of these sorbents for use in cleaning seawater from radioactive cesium.