The Preparation Of Nickel-iron Composite Magnetic Nanomaterials And Their Application In Wastewater Treatment

As a new kind of adsorbent materials, magnetic nanomaterials have entered into our sight because of the superior magnetic separation characteristics, easy separation and recover ability of the external magnetic field, desorption process simple and easy to be recycled which compared to conventional adsorbents. And modified with functional groups of magnetic nanoparticles have great potential applications in the field of wastewater treatment.In this paper, a series of nickel-iron alloy particles and pure nickle nanoparticles were synthesized by hydrothermal reduction method under nitrogen atmosphere. Ferrous sulfate and nickel chloride was chosen as raw materials, hydrazine hydrate as reducing agent, and sodium citrate as cooperation agent. Results showed that the composition of nickel-iron alloy composition, morphology, structure and magnetic of the products can be controlled by different conditions, including the molar ratio of the nickel and iron, the reaction time, the reaction temperature, pH and etc.. And the products were characterized by XRD, VSM, SEM and TG-DTA.Magnetic nanocomposite particles were prepared through coated silicon dioxide shell on the surface of magnetic alloy core using sodium silicate carbonic acid decomposing method. And products morphology and structure were characterized by XRD, VSM, SEM and TG-DTA. It can be found that the particle size of the composite particles were uniform and monodispersed. Moreover the oxidation resistance of the composite particles is obviously better than the alloy particles.Aa-synthesized magnetic alloy particles and the composite magnetic particles were applied in the field of wastewater treatment in this paper. The influence of initial concentration, adsorbent dosage, different particles and etc. on removal efficiency of nickel ions and adsorbents’ desorption and reuse was discussed. It is found that the removal efficiency of magnetic nanoparticles on nickel ions increased with the increasing of initial concentration, adsorbent dosage and the thickness of the silicon dioxide. The study also showed that adsorbent particles can be desorbed and recycled in weak acid conditions and have relative stability on adsorption nickel ions.The adsorption kinetics and thermodynamics on magnetic adsorbent adsorption organics (rhodamine B) and heavy metal ions (nickel ions) using the stir adsorption method was discussed. Adsorption kinetics was found to be well predicted by the pseudo-second-order kinetic model and the adsorption process of Ni2+ and rhodamine B on the magnetic nanoparticles can be described by Freundlich isotherm due to obey the hypothesis of the theory, the adsorption process is largely controlled by chemical adsorption. The study showed that the methods of stir adsorption has better absorption capability on nickel ions, when the initial concentration is 160mg·L-1, its equilibrium adsorption quantity is 44.9640mg·g-1.