Recyclable purification-evaporation systems based on Fe3O4@TiO2 nanoparticles

It is clear that access to economically renewable energy sources is essential for the development of a globally sustainable society. Developing sustainable energy technologies, especially solar energy, becomes extremely important in securing future energy. As an important source of renewable energy, solar power holds a great potential to be converted into other energy forms such as thermal, electric and chemical energy. In recent years, nanoscale particles were usually applied in the utilization of solar power because of its excellent properties such as large specific surface area. Most solar-assisted systems were established without considering the utilization of all the functions. Moreover, the nanoparticles used in these systems should be reused otherwise secondary pollution could happens. These issues severely limit the large-scale application of the solar technology. In this study, we developed a solar-assisted recyclable purification-evaporation system basing on magnetic Fe3O4 nanoparticles decorating with TiO2 nanoparticles (Fe3O4@TiO2), which could be separated from water by controlling the magnetic field strength. The TiO2 nanoparticles in Fe3O4@TiO2 enhance the ability to absorb solar energy, thus making it stronger than that of Fe3O4 nanoparticles. The recovery rate and efficiency could be controlled by adjusting the magnetic field strength and the magnetism property of Fe3O4@TiO2 nanoparticles. In a word, this system study provides an approach to not only significantly reduce the material consumption in the design of solar evaporators, but also to realize broad solar energy applications for water purification and vapor generation.