δ-FeOOH coupled BiOBr0.5I0.5 for efficient photocatalysis-Fenton synergistic degradation of organic pollutants

The development of effective catalysts is crucial for refractory antibiotics pollutants removal. A visible light-driven δ-FeOOH/BiOBrxI1−x photocatalyst for the tetracycline (TC) degradation was fabricated and a photocatalysis-Fenton synergy system was formed in the presence of H2O2. δ-FeOOH/BiOBrxI1−x indicated better photo-Fenton catalytic activity and good cycle stability under visible light irradiation. Especially, δ-FeOOH/BiOBr0.5I0.5 exhibited the highest photo-Fenton catalytic activity and the removal efficiency of TC was 93% within 1 h, which was 1.63 times of the degradation efficiency of photocatalysis alone. This could be attributed to the synergistic effects of δ-FeOOH and BiOBr0.5I0.5, which promoted the separation of the photoinduced charge carriers and thus improved the photo-Fenton performance. Meanwhile, the presence of H2O2 enabled the conversion between Fe2+ and Fe3+. In addition, the •O2−and •OH active radicals were confirmed to greatly accelerate the degradation of TC and the possible mechanism was revealed. This study might provide a promising candidate for the development of effective catalyst in the treatment of antibiotic wastewaters.