Photocatalytic Degradation of Reactive Dyes Using the Novel Hexagonal Magnetic Titanium Dioxide Composites

Abstract

The novel magnetic photocatalysts, TiO₂/Fe₃O₄ and TiO₂/SiO₂/Fe₃O₄ composites were prepared for degradation of reactive dyes. The photoactive TiO₂ was deposited onto the magneticFe₃O₄or SiO₂/Fe₃O₄ cores by using a sol-gel coating technique. The morphologies and structures of the photocatalysts were characterized by transmission electron microscopy and X-ray diffraction. The photocatalytic activities of TiO₂/Fe₃O₄ under UV light irradation were investigated by studying the effects of the initial pH values of the solutions and irradiation times on the degradation rates of various of reactive dyes. Compared with TiO₂, the TiO₂/Fe₃O₄ and TiO₂/SiO₂/Fe₃O₄ composites expressed excellent photocatalytic activities for various reactive dyes. The recycling experimental results showed that TiO₂/SiO₂/Fe₃O₄ was a highly effective decolouring agent and could effectively be seperated from wastewater under the external magnetic field. After being recycled many times, the novel photocatalyst could hold on the degradation rate of 85 % on reactive brilliant blue.