Synthesis of the hexaferrite semiconductor SrFe12O19 and its application in the photodegradation of Basic Red 46

The present work aims at the characterization of SrFe12O19 prepared by nitrate route and its photo-electrochemical properties as well as its application for the photodegradation of Basic Red 46 (BR 46), a hazardous and persistent dye. The semiconductor is identified by X-ray diffraction to confirm the single phase. The scanning electron microscopic indicates regular grains with spherical shapes and an average dimension of similar to 0.9 mu m. The optical properties were measured by the diffuse reflectance and a direct gap of 2.56 eV was determined. The photo-electrochemistry enables us to determine the conduction type. SrFe12O19 is an n-type semiconductor with a flat band potential of - 0.42 V-SCE. The second part of this work is devoted to the BR 46 photodegradation on the hetero-system SrFe12O19/ZnO under visible irradiation. The effect of pH, BR 46 initial concentration, catalyst dose and mass ratio of the hetero-system SrFe12O19/ZnO were studied. The best degradation yield occurs at neutral pH similar to 7 within 90 min with a percentage of 99% for BR 46 concentration of 10 mg/L and a ratio SrFe12O19/ZnO (75/25) and a catalyst dose of 0.75 g/L. The photoelectrochemical properties show that (OH)-O-center dot radicals are responsible for the BR 46 degradation.