In this thesis, the equilibrium of copper ion sorption on zeolite NaX, with a mean particles diameter of less than 40 µm, and on dry baker’s yeast Saccharomyces cerevisiae with a mean particles diameter of less than 160 µm incorporated in alginate was investigated. The experiments were carried out using suspension of zeolite NaX, respectively dry baker's yeast Saccharomyces cerevisiae incorporated in alginate and copper(II) chloride dihydrate solution with different initial concentrations. The prepared suspensions were placed in a water bath shaker under isothermal conditions (T = 27 °C) and at a speed of 200 rpm. The suspensions were sampled, filtered, and filtrates were analysed at specific time intervals over a period of 72 hours using a UV/Vis spectrophotometer to verify the establishment of equilibrium in the system under investigation. The experimental data obtained were analysed using the Freundlich, Langmuir, Redlich-Peterson and Sips isotherms. The graphical fit of the experimental data with the adsorption isotherms and the calculated RMSE and chi-square test parameters showed that the Langmuir isotherm best describes the sorption process of copper ions on NaX zeolite and the sorption process of copper ions on Saccharomyces cerevisiae baker's yeast incorporated in alginate. The sorption efficiency decreases with the increase of the initial concentration of the copper(II) chloride dihydrate solution, the equilibrium state was reached in all suspensions after 24 hours. The amount of copper ions retained at equilibrium depends on the initial concentrations of the solutions. It can be observed that an increase in the initial concentration of the copper ion solution mainly leads to an increase in the amount of copper ions sorbed on zeolite NaX and to the baker's yeast Saccharomyces cerevisiae incorporated in alginate.