A scalable Zn-Mn-enabled catalytic ozonation process for robust drinking water purification

In this study, a highly active oxygen-vacancy-rich Zn-Mn oxide catalyst (ZnMnO₃) and its kilogram-scalable form (ZnMn@CMs) were synthesized via a simple co-precipitation method for catalytic ozonation of drinking water, targeting enhanced removal of assimilable organic carbon precursors (AOC‑P) and trace emerging contaminants (ECs). Catalytic performance was evaluated using atrazine (ATZ) degradation as a model reaction, together with AOC-P and trace ECs removal under low O₃ dosages in real drinking water. The catalytic mechanism was elucidated through material characterization, oxygen vacancies (OVs) and reactive oxygen species (ROS) identification, Zn-Mn synergistic effects, and Fourier transform ion cyclotron resonance mass spectrometry analysis of ROS-dissolved organic matter interactions. Results demonstrated that OVs integrate Zn-Mn dual active sites and promote interfacial electron transfer, enhancing the exposure of hydrated hydroxyl groups at Zn sites and the adsorption of O₃ at Mn sites. Meanwhile, OVs could also be served as electron donors to activate O₂ for H₂O₂ generation, strengthening ROS transformation. Therefore, ZnMnO₃ with abundant OVs exhibited superior ozonation performance, achieving 96.71% ATZ degradation and a 7.80-fold rate enhancement over sole ozonation, along with excellent anion tolerance and cycling stability. In real drinking water treatment, the synergistic action of multiple ROS enables the O₃/ZnMn@CMs process to achieve outstanding removal efficiency for AOC-P (>90%), fluorescent components (>60%) and trace pharmaceuticals and personal care products (>66%), while maintaining excellent long-term catalytic stability (≥20 days) and low metal leaching. The scalable, oxygen-vacancy-rich Zn-Mn oxide catalyst developed herein provides an effective strategy for safeguarding high‑quality drinking water.