Progress of various industries led to a drastic increase in industrial effluent discharge, causing dramatically environmental pollution. In this context the availability of clear water for various activities is becoming the most challenging task for researchers and engineers worldwide. The application of magnetic nanoparticles as adsorbent materials in solving environmental problems has recently received great attention due to their unique physical and chemical properties, which make them superior to traditional adsorbents. The present work describes the application of magnetic nanoparticles embedded within a matrix of activated carbon (MNC) as adsorbent for an acid dye, a metal-complex dye, and Cu(II) removal from wastewaters, in selected working conditions. MNC with mass ratio varying between 1/1 and 1/10 and ferrimagnetic behavior were prepared by combustion synthesis, using tartric acid as fuels. The effects of process variables: solution pH, adsorbent type, initial concentration of polutant, and adsorbent dose, was investigated in order to optimize the process. The removal efficiency of MNC increase from 77.63% to 98.23% for dyes, and between 77.54% and 84.49% for Cu ions showing a significant increase of the maximum adsorption capacity with the increase of the carbon content. The unique combination of enhanced adsorption capacity (due to the activated carbon), excellent separation capability (given by the presence of magnetite) and the short time span for reaching equilibrium (≈ 40 minutes) indicate that magnetite/carbon nanocomposites prepared by one step combustion synthesis are excellent adsorbent materials, with great potential for industrial scale wastewater treatment. Pseudo-second order kinetic model was fitted to the kinetic data, and adsorption isotherm analysis was used to determined the maximum adsorption capacity of MNC and to elucidate the adsorption mechanism.