A Novel TiO2-Cuttlebone Photocatalyst for Highly Efficient Catalytic Degradation of Tetracycline Hydrochloride

The harmful effects of antibiotics on aquatic environments have become a growing concern of modern society. Developing high-performance photocatalysts capable of degrading antibiotics under solar light is, therefore, crucial. In this study, TiO2-cuttlebone composites are prepared via the sol–gel method, to produce carbonate radicals (•CO3−) under solar light irradiation. The •CO3− radicals exhibit high selectivity for the degradation of tetracycline hydrochloride (TC). Compared to TiO2 alone, the TiO2-cuttlebone composite demonstrates excellent solar-driven photocatalytic activity for TC degradation in both freshwater and seawater. The reaction pathways of TC degradation in seawater are elucidated using HPLC-MS/MS analysis. Moreover, a TiO2-cuttlebone self-suspending photocatalyst device is fabricated using 3D printing technology and low-temperature deposition methods, with aluminum–plastic (AP) as a substrate. This innovative device is easily recyclable from photocatalytic solutions while maintaining high stability, making it highly desirable for practical applications.