Magnetic Fe3O4 Nanoparticles: Synthesis and Application in Water Treatment

Magnetic separation is based on the exertion of a magnetic field to selectively collect the magnetic responsive materials. With the development of nanotechnology, magnetic separations based on nanomaterials have found various applications largely benefited from the size effect and synthetic advancement in their preparation. In this review the synthetic methods for the preparation of magnetic iron oxide (Fe3O4) nanoparticles including co-precipitation, hydrothermal and solvothermal synthesis, microemulsion, and sonochemical hydrolysis are discussed. Problems related to the nanoparticle preparation such as broad size distribution, easy aggregation and difficulties in surface functionalization are summarized and directions for improvement are pointed out. Furthermore, a summary on the application of magnetic iron oxide nanoparticles in water treatment is given including heavy metal ions removal, residue pesticide determination and removal, absorption of toxic water soluble molecules, and oily water treatment, and their new application potential is addressed specifically as a novel draw agent for forward osmosis. Finally, the perspectives and problems related to the application of iron oxide nanoparticles in water treatment are given. This review is of interest to both nanomaterial research scientists and water treatment engineers