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.

Photocatalytic degradation of tetracycline with Fe3O4g-C3N4TiO2 catalyst under visible light
    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Preparation of Fe3O4g-C3N4TiO2
        2.3 Characterization
        2.4 Photocatalytic activity
    3 Results and discussion
        3.1 Photocatalyst characterization
        3.2 Photocatalytic activity
    4 Conclusions
    Acknowledgements 
    References

• Rui Liu(Center of Pharmaceutical Engineering and Technology, Harbin University of Commerce, Harbin 150076, China) Corresponding author
• Xin Zhang(Center of Pharmaceutical Engineering and Technology, Harbin University of Commerce, Harbin 150076, China)
• Xue Han(Center of Pharmaceutical Engineering and Technology, Harbin University of Commerce, Harbin 150076, China)
• Yuan Sun(Center of Pharmaceutical Engineering and Technology, Harbin University of Commerce, Harbin 150076, China)
• Shuang Jin(College of Pharmacy, Heilongjiang University of Chinese Medicine, Harbin 150040, China)
• Ri‑jia Liu(Center of Pharmaceutical Engineering and Technology, Harbin University of Commerce, Harbin 150076, China)