CuO/g-C3N4 2D/2D heterojunction photocatalysts as efficient peroxymonosulfate activators under visible light for oxytetracycline degradation: Characterization, efficiency and mechanism

In the current work, a CuO/g-C3N4 (Cu/CN) 2D/2D heterojunction photocatalyst was precisely designed to degrade oxytetracycline (OTC) by activating peroxymonosulfate (PMS) under visible light irradiation. The as-fabricated catalysts were explored in detail on the base of the characterization results. The optimum 5Cu/CN can degrade almost 100% of oxytetracycline (OTC) by activating PMS under visible light in 10 min, and also displays high degradation efficiency toward tetracycline (TC), ciprofloxacin (CIP), levofloxacin (LVX) and sulfadiazine (SDZ). Additionally, the effect of experimental conditions on OTC degradation was investigated, and the stability of the catalysts was evaluated. The electron spin resonance (ESR) and quenching results verified the generation of multiple reactive oxygen species (ROS), and the size of their roles in OTC degradation followed the sequence •OH & SO4•− > 1O2 > h+ > •O2−. The possible mechanism of higher OTC degradation efficiency in the 5CuO/CN/PMS/Vis system and the OTC degradation pathway were deeply explored. This work supplies a worthy reference for developing an efficient g-C3N4-based photocatalytic technology for rapid and efficient antibiotic elimination from the environment.