Visible-Light-Driven Peroxymonosulfate Activation for Accelerating Tetracycline Removal Using Co-TiO₂ Nanospheres

Heterogeneous catalysts have been widely used for peroxymonosulfate (PMS) activation to remove persistent contaminants in water. This study successfully prepared cobalt-doped TiO₂ using a simple two-step approach for activating PMS to remove tetracycline (TC). The batch experiments showed complete TC degradation within 25 min caused by Co-TiO₂ (0.1 g/L) activation of PMS (1 mM) under visible light. The system also demonstrated excellent catalytic efficiency in various water environments, such as artificial seawater, tap water, and wastewater. According to the radical capture tests and electron spin resonance analysis, the contribution of active species involved in the degradation of TC with the Vis/Co-TiO₂/PMS system were in the following order: ¹O₂> SO₄^•−> O₂^•−> •OH. The possible TC degradation pathway was proposed using intermediate identification and Fukui function calculation. This study provides a promising method toward organic pollutants degradation and provides a novel perspective on the rational design of competent and stable catalysts.