Synthesis of amino-functionalized Fe3O4@SiO2 Core–Shell magnetic nanoparticles for rapid removal and recovery of Ni(II) ions

Coastal soils and the Persian Gulf waters in the Pars Special Economic Energy Zone contain heavy metals including lead, cadmium and nickel ions. The removal of heavy metals from waste water is essential for improving the quality of the marine environment. Magnetic nanoparticles are one of the adsorbents used for heavy metals removal. The coating of magnetic nanoparticles with silica and effective amine substrates, in addition to increasing the adsorption rate, allows the use of adsorbents several times.Amino–functionalized silica coated Fe3O4 (Fe3O4@SiO2–NH2) nanoparticles were synthesized and characterized by FTIR, FESEM-TDS, TEM an X–ray diffraction and magnetic measurements.The nanoparticles applied to adsorb Ni(II) from aqueous solutions. Effects of contact time, pH, nanoparticle and heavy metal concentration were investigated. The adsorption isotherm agreed with the Langmuir model, having a maximum adsorption capacity was 91percent in 10 min, at pH = 7.35 and T = 298 K. The Ni(II)–loaded Fe3O4@SiO2–NH2 could be readily separated by an external magnetic field.Stability in the acidic environment during the wash cycle and the possibility of reuse of the adsorbent, as well as increasing the rate of heavy metal adsorption, will help to design a system that allows continuous removal of heavy metals.