The demand for global water resources increases with the increase of the human population leading to higher costs and stricter regulations. The higher the demand for water resources the higher the pressure on natural resources and the higher the damage made to the environment, causing a big threat to the sustainability of the economic development. The wastewater generated by industries represents a threat to human health so its treatment is necessary prior discharging into the environment. In this diploma thesis, the adsorption of copper, cobalt, and nickel ions on the zeolite 13X was studied depending on different initial concentrations of heavy metal ions from the ternary solutions. The experiments were conducted in batch reactors at a constant temperature of 27°C, with a stirring speed of 200 rpm for 72 h. The adsorbed amount of copper and cobalt ions increases with the increase in the initial concentration of selected ions in the ternary solutions, while in case of nickel ions it varies with the increase in the initial concentration. The highest amount of heavy metals adsorbed from the solutions was one corresponding to the copper ions with the value of qe = 1.496 mmol/g obtained at the initial concentration of c0 = 35.006 mmol/L. The adsorption efficiency of the zeolite 13X for all heavy metal ions (copper, cobalt, and nickel ions) from the ternary solutions decreases with the increase in the initial concentrations. The experiments conducted showed that the best adsorption efficiency was achieved for the removal of copper ions and equals ≈ 95% for the lowest initial concentration of copper ions in ternary solution. The results obtained were tested using Langmuir and Freundlich isotherm models. The best-fitting with the experimental results for the adsorption of copper, cobalt, and nickel ions on the zeolite 13X is obtained by applying the Langmuir model, while the Freundlich isotherm model showed significantly lower fitting with the experimentally obtained results.