THE PREPARATION AND APPLICATION OF MAGNETIC NANOPARTICLES WITH CORE-SHELL STRUCTURE

It is well-known that TiO₂ nanoparticles are highly efficient photocatalysts in decomposing organic substance in wastewater, especially when they are used in suspension state. However, if TiO₂ nanoparticles cannot be withdrawn and reused, it is difficult to apply them in purification of wastewater due to the economic consideration. In present work, TiO₂/SiO₂/Fe₃O₄ core-shell magnetic nanoparticles, constituted by Fe₃O₄ core, SiO₂ intermediary layer and the TiO₂ out-shell, have been prepared and applied in photocatalytic degradation of a modulated methylene blue containing water. The results indicate that the as-prepared TiO₂/SiO₂/Fe₃O₄ nanoparticles possess high photocatalytic activity and the methylene blue in wastewater can be degraded quickly. Through comparing with the photocatalytic performance of the famous commercial P25 TiO₂ nanoparticles in the same reaction condition, it has been found that as-prepared TiO₂/SiO₂/Fe₃O₄ nanoparticles exhibit similar photocatalytic activity to commercial P25 TiO₂ nanoparticles in the photocatalytic degradation of methylene blue containing water. But the TiO₂/SiO₂/Fe₃O₄ nanoparticles used in suspension state can be simply recovered from the liquid by using a magnet or a magnetic field. So the cost of wastewater purification by photocatalytic degradation with TiO₂/SiO₂/Fe₃O₄ nanoparticles can be significantly reduced through reuse of the photocatalyst. It implies that TiO₂/SiO₂/Fe₃O₄ nanoparticles possess the potential for industrial application.