Experimental and theoretical investigation on sorption of copper ions (A) in very broad range of concentration of CuSO4, by chitosan hydrogel (ch) has been studied. Equilibria were described by Langmuir, Freundlich, Langmuir-Freundlich, Redlich-Peterson, Toth and Dubinin-Raduszkiewicz equations. To describe sorption kinetics a new model was proposed, which combine chemical reaction on sorbent surface and intraparticle diffusion. The process of sorption is described by two parameters: diffusion coefficient D-AB=0.623.10(-9) m(2)s(-1) and surface process rate constant k(v) = 16.9.10(-4) s(-1). Calculation base on the model properly correlates with experimental data. (C) 2016 Elsevier B.V. All rights reserved.