A facile one-pot process has been proposed to prepare the novel ethylenediaminetetraacetic acid (EDTA)-modified magnetite nanoparticles (EDTA-MNPs). The bared Fe3O4 magnetite nanoparticles and EDTA-MNPs were characterized using FTIR spectroscopy, TEM, VSM, and X-ray diffraction. The application of the modified magnetite nanoparticles for metal ion uptake was studied using Ni(2+) as a model. The adsorption was fast and the equilibrium was established within 5 min, and the adsorption kinetics of Ni(2+) onto EDTA-MNPs followed the pseudo second-order chemisorption mechanism. Maximum adsorption capacity for Ni(2+) reached as high as 41.3 mg/g at pH 6. The successive adsorption-desorption studies indicated that the EDTA-MNPs kept the adsorption and desorption efficiencies constant over ten cycles. Importantly, EDTA-MNPs were able to remove nearly 100 % of Ni(2+) from real water.