Аннотация:Modeling statics and kinetics of cesium sorption from tap water and 0.01 M NaCl solution was performed in order to describe mechanisms of cesium sorption by modified aluminosilicates. It was found that sorbents possess different sorption sites with more than 100 times different cesium distribution coefficients resulting in step appearance of sorption isotherms. The appearance of isotherms is reproducible. It was shown that different sorption sites work independently on each other; therewith cesium sorption by any sorption site may be successfully described by Langmuir isotherm. Cesium ions diffusion in the sorbent pores with, in a less degree, chemical reaction limits the process of cesium sorption by modified clinoptilolite. The method of scanning electronic microscopy confirmed change of the sorbent texture as a result of cesium sorption. Finally, chemical transformation of the ferrocyanide phase of the sorbent was shown.