In this diploma thesis, the equilibrium adsorption of heavy metal ions (cobalt or copper) from the corresponding aqueous solution on the spent coffee ground was investigated. Adsorption was carried out in a batch reactor at different initial concentrations of heavy metal ions, at a constant temperature of 308 K, a stirring speed of 200 rpm min-1 for 96 h. The impact of heavy metal equilibrium concentrations (cobalt or copper) on the equilibrium amount of heavy metal adsorbed was investigated and it was found to increase with the equilibrium concentration of heavy metal in the solution until it achieves maximum adsorption capacity, after which it does not change significantly (in cobalt as heavy metal) or remains constant (in the case of copper ion adsorption). The maximum experimental adsorption capacity for experimental conditions used for the cobalt ion adsorption was qmax = 0.396 mmol g-1, while for copper was qmax = 0.164 mmol g-1. The adsorption efficiency of heavy metal ions on the spent coffee grounds decreases with the initial concentration of heavy metal ions in the solution, which can be attributed to the saturation of the available adsorption sites on the spent coffee grounds. The experimental data obtained were tested on Langmuir, Toth, Redlich-Peterson and Sips isotherms. By estimating the quality of adsorption models with experimental data, by comparing calculated maximum adsorption capacity values with experimentally obtained, and comparing statistical parameters for RMSE and χ2-test, it can be concluded that the best agreement with the experimental data showed Langmuir isotherm for the adsorption of cobalt ions while for the adsorption of copper ions the best agreement showed Toth and Sips isotherms.