Modified Superparamagnetic Nanocomposite Microparticles for Highly Selective HgII or CuII Separation and Recovery from Aqueous Solutions

The synthesis of a reusable, magnetically switchable nanocomposite microparticle, which can be modified to selectively extract and recover Hg-II or Cu-II from water, is reported. Superparamagnetic iron oxide (magnetite) nanoparticles act as the magnetic component in this system, and these nanoparticles were synthesized in a continuous way, allowing their large-scale production. A new process was used to create a silica matrix, confining the magnetite nanoparticles using a cheap silica source [sodium silicate (water glass)]. This results in a well-defined, filigree micrometer-sized nanocomposite via a fast, simple, inexpensive, and upscalable process. Hence, because of the ideal size of the resulting microparticles and their comparably large magnetization, particle extraction from fluids by low-cost magnets is achieved.