Sorption of 60Co with Composite Sorbent Termoksid-35 in the Presence of Humic Acids

According to the data of static method of sorption of trace amounts of Co(II) ions by the Termoksid-35 (T-35) sorbent in a chloride-acetate solution, the cobalt distribution coefficient K d was calculated as a function of pH, concentration of humic acids (HA), and temperature. The distribution of the complexes Co 2+ , CoAc + , CoCl + , Co(OH) + , Co(OH) 0 2 , Co(OH) 3 – between the solution and the sorbent was modeled within the framework of the surface complexation concept. The found stability constants of the Co(OH) + and Co(OH) 2 0 complexes coincide with the thermodynamic values. In the presence of HA (10.0 mg/L), the best agreement between the model function of K d –pH and the experimental data corresponds to the sorption of a complex with the composition Co(OH)A 0 , where A – is the anion of humic acids. It was concluded that T-35 can be used as a sorbent for removal of Co(II) radionuclides from industrial process at pH > 7 and natural water in the presence of humic acids.