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 ~ 0.9 µm. 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 ~ 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 radicals are responsible for the BR 46 degradation.