Radiation safety is an integral part of environmental safety and includes a set of measures to protect people and the environment from the harmful effects of ionizing radiation. Ferrocyanides of transition metals are among the most highly effective and selective collectors for concentrating radionuclides. Under certain conditions of synthesis, ferrocyanide compounds can be formed having a layered structure, for example, the ferrocyanide 2Co2[Fe(CN)6] K4 [Fe(CN)6] 3H2O, however, taking into account the structure of the starting material it was decided to use Fe3+ polyhydroxy complexes as a modifying agent. The effect of the amount of modifiers on the sorption properties of cobalt ferrocyanide was studied in the course of the work.