The floating photocatalytic spheres loaded with weak light-driven TiO2-based catalysts for photodegrading tetracycline in seawater

To effectively treat organic pollutants in seawater, this study fabricated different floating photocatalytic spheres by loading TiO 2 -based photocatalysts to degrade tetracycline in simulated seawater. In photodegradation for tetracycline, the content of the active TiO 2 component in the powder photocatalyst played a major role in degrading the performance of the material. A polyurethane porous sponge with a large specific surface area was used as a carrier in loading the powder photocatalyst to avoid the interference of salt ions in seawater for photodegradation. The adsorption ability and performance in tetracycline photodegradation of the PU sponge-filled photocatalytic spheres were significantly higher than those of PMMA photocatalytic spheres under the same conditions. The Pt-deposited P25-A (Pt–P25-A) powder photocatalyst with the strongest visible light response exhibited the highest performance. The rate removal for tetracycline in the simulated seawater by the PU sponge-filled spheres loaded with Pt–P25-A exceeded 80% after 20 h. • A floating photocatalytic sphere for degrading tetracycline in seawater were prepared. • The contact between the floating spheres and pollutes determined their performance. • The TiO 2 content in loading active components determined the photocatalytic performance. • The PU sponge-filled spheres a stable performance in effectively degrading tetracycline.