Magnetic cobalt ferrites (CoFe2O4) were synthesized by sol-gel method. These nanoparticles were ultra-sonicated with surface modified multi-walled carbon nanotubes (SM-MWCNTs) to form CoFe2O4/SM-MWCNTs nanocomposites. The as-prepared materials were used as an adsorbent for the removal of hexavalent chromium (Cr(VI)) arising from the presence of dichromate ions (Cr2O7 2) in the electroplating effluent. The synthesized nanocomposites were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-Ray diffraction (XRD), Fourier transmission infrared spectroscopy (FT-IR), raman spectroscopy, thermo-gravimetric analysis (TGA), and zeta analyzer. The effect of the environmental chemistry of the solution on the adsorption has been discussed. The adsorption isotherm of Cr(VI) adsorption onto the as-synthesized CoFe2O4/SM-MWCNTs best fitted the Langmuir Adsorption Isotherm model. The high adsorption capacity of 100mg/g was achieved at 40°C under optimized conditions. Besides, the magnetic properties of synthesized CoFe2O4/SM-MWCNTs nanocomposites allow them to separate from the aqueous solution by magnetization easily. Even after seven consecutive adsorption-desorption cycles, the CoFe2O4/SM-MWCNTs nanocomposites presented an efficiency loss of less than 20% for the removal of Cr(VI) ions. This study clearly shows that cobalt nanocomposites are promising candidates in environmental applications.