Iron-nitrogen co-doped carbon nanotubes decorated with Cu2O possess enhanced electronic properties for effective peroxymonosulfate activation

Highlights: • FNC was used to enhance the electronic characteristics of Cu₂O nanoparticles. • Cu₂O/FNC showed much higher reactivity for activating PMS to degrade FLC. • The application potential of the Cu₂O/FNC catalysts was evaluated in detail. • FLC degradation pathway and PMS activation mechanism are proposed. Exploiting the full potential of copper-based nanoparticles in the activation of peroxymonopersulfate (PMS) is a great challenge due to their insufficient dispersity and electronic properties. We report here a novel iron‑nitrogen co-doped carbon nanotube (FNC) modified with a Cu₂O nanocomposite (Cu₂O/FNC) that exhibits ultrahigh catalytic performance in the activation of PMS to degrade fluconazole (~95%). Catalytic performance evaluation illustrated that Cu₂O/FNC also has wide pH applicability (3.0–11.0), long-term stability and excellent adaptability. In addition, luminescent bacteria toxicity tests confirm that Cu₂O/FNC/PMS significantly reduced the acute biotoxicity of various recalcitrant pollutants (reduced by 45–83%). By identifying the reactive oxygen species (ROS) and catalytic performance for various pollutants, we propose that pollutants that interact weekly with activators are mostly destroyed by sulfate radicals and hydroxyl radicals, whilst both radical and non-radical routes were involved in the degradation of pollutants that were easily adsorbed. By modifying Cu₂O with FNC, several crucial properties such as the specific surface area, surface defects, active sites and the charge transfer rate were significantly improved, leading to excellent catalytic performance for pollutant removal. Finally, a reasonable reaction mechanism is advanced for the fluconazole degradation pathway. This study not only develops a novel PMS oxidation system for fluconazole degradation, but also provides a new strategy to improve the reactivity and applicability of PMS activators by combining radical and non-radical activation pathways.