Adsorption and Photocatalytic Activity of Nano-magnetic Materials Fe3O4@C@TiO2-AgBr-Ag for Rhodamine B

Background: TiO2 nanoparticles possess adsorption capacity and photocatalytic activity, and are thus fitted for removal of dyes from water. However, TiO2 nanoparticles are difficult to separate from the bulk solution due to high loss. Moreover, TiO2 can only use light with a wavelength of less than 387.5 nm, so the utilization efficiency of solar energy is very low. The present work prepared Fe3O4@C@TiO2-AgBr-Ag composites to overcome the shortcomings of TiO2. Objective: Adsorptive and photocatalytic performance of nano-magnetic materials Fe3O4@C@TiO2- AgBr-Ag. Methods: Fe3O4@C@TiO2 and Fe3O4@C@TiO2-AgBr-Ag magnetic nanocomposites were prepared by the sol-gel method. Their structure was characterized. Performances of Fe3O4@C@TiO2 and Fe3O4@C@TiO2-AgBr-Ag for removing Rh B were thoroughly investigated and compared. Langmuir– Hinshelwood kinetic model was applied to analyze the heterogeneous processes of adsorption and photodegradation. Results: Removal experiments were carried out with Rhodamine B as the subject. The effects of contacting time, pH, subject concentration, and doses of photocatalyst on the removal performance were studied. The removal of Rh B by Fe3O4@C@TiO2 and Fe3O4@C@TiO2-AgBr-Ag involved both adsorption and photodegradation, and the photocatalytic activity of Fe3O4@C@TiO2-AgBr-Ag was much higher than that of Fe3O4@C@TiO2. The optimum removal conditions were determined. Under the optimal conditions, the removal rate of Rhodamine B with Fe3O4@C@TiO2 was 77.8%, and the removal rate of Rhodamine B with Fe3O4@C@TiO2- AgBr-Ag was 87.3%. Conclusion: The coupling of the nanostructured metal Ag to the outer surface of TiO2 could effectively increase photocatalytic efficiency under visible light. The photocatalysts could be separated from bulk solutions by using a magnet and be easily recycled. The removal reaction kinetics fitted with the first-order model.