Nanoparticle technology developed rapidly due to the multifunctional utilization of nanoparticles in many disciplines such as medicine, drug delivery, environmental chemistry, food chemistry and analytical chemistry. In concept of this study, magnetic nanoparticles with a core-shell structure were synthesized and applied to the adsorption of copper and cadmium. The synthesis procedure consists of two steps. In the first step a core-shell structure was formed with Fe3O4 and humic acid. In the second step, the coating of synthesized core/shell structure with silver occurs. The characterization of synthesized nanoparticles was performed with the aid of Scanning Electron Microscope (SEM) images combined with an elemental distribution image (EDX mapping), Zeta Potential, and Dynamic Light Scattering (DLS) analyses. Adsorption isotherms of copper and cadmium on Fe3O4/HA/Ag multi-component structure were studied. The optimum adsorption conditions in aqueous solutions were fixed at pH 9 and at 300 K. As a result, the Fe3O4/HA/Ag multi-component structure showed excellent adsorption capacity for both copper and cadmium ions with removal percentages of 92% and 97% after the calculations were performed using the absorbance values measured by Flame Atomic Absorption Spectrometer (FAAS) respectively. Langmuir isotherm, which describes the monolayer adsorption was found to be the most adequate to fit the overall procedure.