Nowadays, Fe₃O₄-based magnetic nanomaterials have shown broad prospects in multidisciplinary areas, especially in the efficient elimination of radionuclides and heavy metal ions from large volumes of aqueous solutions as they have special physicochemical properties, such as large specific surface area, large amounts of oxygen-containing functional groups and active sites, and easy magnetic separation from wastewater. However, the magnetic nanomaterials have some weak points like easy coagulation, and poor dispersibility and chemical stability in the meantime. To overcome these shortcomings, the surface functionalization of Fe₃O₄ nanomaterials with different oxygen-containing functional groups is an efficient method. In this review, the types and properties of Fe₃O₄-based magnetic nanocomposites synthesized by variety surface modification methods are reviewed, and the merits and demerits of these synthetic methods are discussed as well. The types of the Fe₃O₄-based magnetic nanocomposites for the removal of radionuclides or heavy metal ions are classified. And then, their removal ability, advantages and disadvantages in the removal of radionuclides or heavy metal ions on each kind of functionalized magnetic nanomaterials are compared and summarized, and the interaction mechanism of the radionuclides or heavy metal ions with the Fe₃O₄-based magnetic nanocomposites are discussed in detail. The possible application of functionalized magnetic nanocomposites in the efficient removal of radionuclides and heavy metal ions are prospected.
Contents
1 Introduction
2 Synthesis of Fe₃O₄-based nanomaterials
2.1 Solvothermal method
2.2 Coprecipitation method
2.3 Plasma-induced grafting technique
2.4 Other methods
3 Classification of Fe₃O₄-based nanomaterials
3.1 Organics modified magnetic nanomaterials
3.2 Inorganics modified magnetic nanomaterials
4 The applications and mechanisms of Fe₃O₄-based nanomaterials
4.1 Removal of radionuclides
4.2 Removal of heavy metal ions
5 Conclusion