The adsorption capacities of modified chitosan towards Cd(II), Mn(II) and Ni(II) ions removal were examined. It verify the development of new groups, the modified chitosan characterized by X-ray, thermogravimetric analysis, field-emission (SEM), and IR. Variables including the impacts of pH, the dose of adsorbent, time, concentration and the temperature were used to examine the adsorption and kinetics studies of the process. The pseudo-second-order made well sense in the kinetic results. Removal effectiveness was found to rise with increasing time, temperature, and pH from 3 to 8 but decrease with increasing initial ions concentration and dose. Of these, the highest percentages of Cd(II), Mn(II) and Ni (II) removal were 67.15, 70.44, and 74.02%, respectively. An analysis of the isothermal properties was highly consistent with Langmuir's isotherm. D-R, Freundlich, and Langmuir models, the maximum uptake yields and isotherm parameter values were determined. Physical adsorption method was demonstrated by the relatively low average values of the energy of adsorption (1.48–2.26 kJ/mol). It was established that the thermodynamic parameters were endothermic (positive ∆H°) and spontaneous (negative ∆G°).