The sorption of cerium (III) ions on Na- and H-forms of clinoptilolite was studied in a wide range of time (30 min ¸ 48 hours) and concentrations (0.01¸0.1 N) of CeCl₃·7H₂O solutions. Ion-exchange equilibrium in the system (S:L) on Na and H-forms of clinoptilolite is achieved, respectively, in 24 and 48 hours. Kinetic (in statics) parameters of Ce(III) ion exchange on clinoptilolite monoforms are calculated. The intradiffusion mechanism of ion exchange has been established. The presented Ce(III) ion exchange isotherms for the Na-form of the zeolite are convex, and the H-forms, with an inflection, which corresponds to the values of the ion exchange constant calculated using the empirical Nikolsky equation (K>1, convex; K<1, concave). The influence of the pH environment on the achievement of the equilibrium sorption capacity of zeolites in monoforms relative to three-charged REE cations, in particular Ce(III), has been revealed

doi.org/10.32737/0005-2531-2024-70-75