Cationic ligand exchange is one of the most predominant mechanisms for the removal of ammonia from wastewater through complex formation. The complexation technique occurs between the metal ions loaded on the surface of Amberlite IR-120 (R-H) and ammonia which is present in medium. Cu(II)-loaded Amberlite IR-120 (R-Cu2+) was prepared and described using FT-IR, TGA, XRD, SEM, EDX techniques. The prepared R-Cu2+ was applied for elimination of ammonia from aqueous solution. Different cations such as Co2+, Ni2+ were loaded onto Amberlite IR-120 to study the impact of counter cation on the removal efficiency of ammonia. The ammonia removal percentage followed the order; R-Cu2+ > R-Ni2+ > R-Co2+. The removal of ammonia using R-Cu2+ obeyed Freundlich isotherm model. Thermodynamic parameters characteristics of the adsorption of ammonia onto R-Cu2+ were determined. The time-adsorption data were followed the pseudo-second-order and intraparticle diffusion models. Moreover, the resulting product (R-Cu(II)-amine composite) from the adsorption process exhibited high catalytic activity and could be applicable as low cost catalyst for enhancement the elimination of dyes from wastewater.