: In batch reactors, under the selected experimental conditions (experiment duration 96 h, rotation speed of 200 rpm, particle size < 500 μm and temperature of 308 K), the adsorption of cobalt ions as heavy metal ions on humus as an adsorbent from initial concentrations of cobalt(II) nitrate solutions (4.692 mmol dm-3, 8.365 mmol dm-3, 11.427 mmol dm-3, 24.896 mmol dm-3 and 36.325 mmol dm-3) was investigated. The obtained results point to a sudden increase in adsorbed cobalt ions on the humus due to an increase in the equilibrium concentration of cobalt ions in the solution. The maximum value of the equilibrium amount of adsorbed cobalt ions on humus is achieved at the highest selected initial concentration of the cobalt ion`s solution of 36.325 mmol dm-3 with the value of 0.367 mmol g-1, while the highest adsorption efficiency (8.699%) is reached at the lowest initial concentration of the solution of 4.692 mmol dm-3. Taking into account the assessment of the quality of the agreement of the sorption models with the experimentally obtained data, then the comparison of the calculated values for the maximum sorption capacity with the values of the sorption capacity obtained experimentally, as well as the values for the statistical parameters (RMSE and χ2-test), it is concluded that the Redlich-Peterson and Freundlich isotherms models best describes the obtained experimental data.