Photocatalytic degradation of tetracycline with Fe₃O₄/g-C₃N₄/TiO₂ catalyst under visible light

Fe₃O₄/g-C₃N₄/TiO₂ catalyst has been fabricated using a simple ultrasonic method with high photocatalytic activity. The morphology, structure and optical properties of Fe₃O₄/g-C₃N₄/TiO₂ were systematically investigated by a variety of characterization techniques. The optimum degradation conditions were investigated by degrading tetracycline (TC) under visible light irradiation. The results showed that the degradation efficiency was the highest when the initial TC concentration was 5.0 mg/L, the pH value was 11 and the catalyst dosage was 1.0 g/L. After 100 min of visible light irradiation, the degradation efficiency of TC achieved at 73.61%, which was 1.64 and 1.19 times that of g-C₃N₄ and Fe₃O₄/g-C₃N₄, respectively. Moreover, Fe₃O₄/g-C₃N₄/TiO₂ had good stability and recyclability. The results of capture experiments showed that ‧O₂⁻ and ‧OH were the main active species during the photocatalytic process, and a possible photocatalytic reaction mechanism of Fe₃O₄/g-C₃N₄/TiO₂ catalyst was proposed. This study provides a new way to improve the photocatalytic performance of g-C₃N₄, which has great potential in degrading pollutants such as antibiotics in wastewater.