Core-shell magnetic nanoparticles, a class of magnetic nanoparticles with core-shell structure. Its core-shell structure makes it easy to be functionalized to meet the requirements of different occasions. In terms of size, nanoparticles have a high specific surface area. They are easy to be recycled and reused by permanent magnets because of their magnetic properties. They are currently widely used in biological research, health care and catalysis. In the study of environmental remediation, the nanophase material meets the requirements of adsorbents and will be one of the ideal materials for future waste water treatment. There are various methods for preparing core-shell magnetic nanoparticles, and a suitable preparation method is more conducive to the purpose of efficiently removing contaminants. The preparation order of the core and the shell needs different experimental conditions. Besides, the preparation method of the core is different from the shell. And the combination of different preparation methods also has different effects on the size of the core and the shell. The ability of core-shell magnetic nanoparticles to adsorb pollutants, the potential risks inherent in the environment and the environmental impact of additional facilities are compelling. At present, the preparation methods of core-shell magnetic nanoparticles have been mainly from core to shell. The preparation of magnetic core has been mainly by chemical coprecipitation method and solvothermal method. The shell layer has been probably prepared by Stöber method and sol-gel method. The combination of coprecipitation method and Stöber method has gradually become one of the classical methods for preparing Fe3O4@SiO2. Core-shell magnetic nanoparticles can efficiently remove a variety of pollutants, including organic pollutants and heavy metal ions. The adsorption process mostly has conformed to the Langmuir adsorption isotherm model and the pseudo second-order kinetic model. A small number of core-shell magnetic nanoparticles have been less harmful to the ecological environment, and excessive core-shell magnetic nanoparticles may have adverse effects on biological cells. Static magnetic field can not only recover core-shell magnetic nanoparticles, but also reduce sludge volume index and so on. This paper attempts to summerize the preparation of core-shell magnetic nanoparticles and gives a brief description and comparation about the various methods. It not only generalizes the removal effects of these adsorbents on the pollutants and the adsorption processes, but also the environmental risks caused by absorbents. In addition, the effects of additional facilities such as static magnetic fields on activated sludge were explained. At the end of the paper, the development direction of core-shell magnetic nanoparticles was prospected. © 2019, Materials Review Magazine. All right reserved.
