###### Abstract  
For the first time, new sorbents based on polyacrylamide (PAN) fiber and transition metal ferrocyanides were obtained. The main difference between the obtained sorbents and the existing ones is the stage of preliminary preparation of the initial support by converting it into the forms PAN-Fe(OH)\({}_{3}\) or PAN-MnO\({}_{2}\), due to which additional ion exchange groups (carboxyl, carbonyl, etc.) are formed, which increases the amount of ferrocyanide fixed to the support. The best components and conditions for the synthesis of new sorbents were determined (concentration (0.1-0.2 mol/L), as well as pH (1 for sorbents based on PAN-Fe(OH)\({}_{3}\), and 1-5--PAN-MnO\({}_{2}\)) of potassium ferrocyanide solution, concentration of transition metal salts (0.02 mol/L), temperature conditions). The influence of the studied solution composition (pH, concentration of Na\({}^{+}\), K\({}^{+}\), NH\({}_{4}\)\({}^{+}\) ions) on the cesium distribution coefficients during its recovery by the obtained sorbents was assessed. The possibility of cesium recovery from solutions with pH 1-9 containing macro quantities of cations was demonstrated. The sorbents derived were characterized by modern structural methods such as infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy with EDS analysis. A study of the trace amount sorption of \({}^{137}\)Cs was carried out in comparison with commercially available highly efficient sorbents (FNS-10 and Termoksid-35), and it was shown that the resulting sorbents are not inferior to industrial ferrocyanide sorbents and can be used for \({}^{137}\)Cs selective sorption from technological solutions and natural waters. c 2024 14  
of which is liquid radioactive waste of low and medium levels of activity. They pose a great environmental hazard due to their significant volume and high total activity, as well as the possibility of uncontrolled spread in emergencies and, as a consequence, environmental pollution [1]. In addition, despite the efforts made to localize radioactive substances as a result of nuclear defense programs implementation, the functioning of nuclear fuel cycle enterprises, as well as the occurrence of emergencies, radionuclides enter the environment, significantly changing the natural radioactivity of soils, natural waters, and bottom sediments, which causes serious environmental threats requiring urgent measures [2]. Radionuclide \({}^{137}\)Cs, whose half-life is 30.1 years [3], is characterized by high migration ability in the external environment, as well as ease of integration into food chains. It is intensively sorbed by soil and bottom sediments and is found in water mainly in the ion form. Entering the human body, cesium is distributed relatively evenly, which leads to an almost uniform irradiation of organs and tissues. Constant systematic monitoring of \({}^{137}\)Cs activity in natural waters makes it possible to identify new and relevant sources of radioactive contamination [4]. In addition, to determine the accumulation coefficients of a given radionuclide in aquatic organisms, it is necessary to have information about its content in water. In this regard, the urgent task is to develop new methods for \({}^{137}\)Cs selective recovery from low- and intermediate-level waste, as well as methods for \({}^{137}\)Cs radioanalytical monitoring in environmental objects. To solve the problem of isolating and concentrating cesium from technological and natural waters of various compositions with low radionuclide content, high salt content, and the presence of significant amounts of isomorphic potassium and sodium, sorption methods can be used.