Enhanced activation of peroxymonosulfate by a floating Cu0-MoS2/C3N4 photocatalyst under visible-light assistance for tetracyclines degradation and Escherichia coli inactivation

Transition metal-based photocatalysts have recently attracted much attention in photo-induced Peroxymonosulfate (PMS) activation systems. Herein, a novel floating catalyst Cu0-MoS2/C3N4-expanded graphite (Cu-MSCN-EG) was prepared by a chemical reduction method and applied as a PMS activator to remove tetracyclines (TCs) and inactivate Escherichia coli under visible light irradiation in aqueous solution. Over 99.0 % of TCs and Escherichia coli could be removed and inactivated within 1 h in Vis/PMS/Cu-MSCN-EG system. Compared to the MoS2/C3N4-EG system, the loading of zero-valent copper in the Vis/PMS/Cu-MSCN-EG system increased the reaction rate by 278 %. Raman spectroscopy and density functional theory (DFT) calculations indicated that ·OH and 1O2 were generated via two different adsorption patterns between PMS and copper (≡Cu+-OSO3-–OH and ≡Cu+–OH-OSO3-). With the light assistance, the photo-induced electrons reduced the copper leaching and enhanced the generation of ·SO4- and ·O2–, leading to a high recyclability and mineralization rate. Overall, this study provides a new insight into the fabrication of copper-based PMS activator with high efficiency and durability for contaminants degradation and pathogen inactivation.