Abstract:
Refractory organic pollutants pose a serious threat to both water ecological security and human health due to their stable molecular structures and high biotoxicity to biological organisms. These pollutants resist natural degradation processes and require powerful chemical oxidation for effective destruction, often consuming large amounts of energy and oxidant. This has become a necessary approach for conventional wastewater treatment. Herein, we propose a novel strategy for low-energy water purification by utilizing the energy of endogenous substances through the interaction of a copper-cerium oxide dual-reaction-center catalyst (CCO) with trace activators. Characterization results and density functional theory (DFT) calculations confirm that the formation of Cu—O—Ce bonding bridges leads to a polarized electron distribution on the catalyst surface, creating electron-rich Ce centers and electron-poor Cu/O centers. This enhances pollutant removal efficiency in the CCO system. Under trace amounts of peroxymonosulfate (PMS) modulation, the CCO system can completely remove various refractory organic pollutants (such as acid orange 7 and ciprofloxacin) within 5 minutes, exhibiting excellent adaptability and stability across a wide pH range (3–11) and under complex anion coexistence conditions. Meanwhile, the CCO system also exhibits excellent adaptability and catalytic activity across a wide pH range (3–11) and in the presence of various anions (e.g., \mathrmHPO_4^2- , \mathrmSO_4^2- , \mathrmHCO_3^- , \mathrmNO_3^- and Cl
−). Notably, the CCO/PMS system achieved a pollutant removal rate of over 70% after 288 hours of continuous operation in a laboratory pilot plant. This demonstrates the exceptional stability of the CCO system, making it a promising candidate for practical application. Furthermore, the CCO system can rapidly remove organics from complex kitchen wastewater within 5 minutes, aided by trace amounts of PMS. In this reaction, PMS plays a non-traditional role, micro-regulating the distortion of water molecules′ hydrogen-bond network on the CCO surface. This induces the "one-electron" micro-reduction of naturally dissolved oxygen (DO) molecules at the electron-rich Ce center, driving continuous electron donation from pollutants at the electron-poor Cu/O centers. This avoids energy loss in the multi-electron reduction process of DO, enhances the utilization of intrinsic pollutant electrons and energy, and achieves high-efficiency, low-consumption water purification. This study provides new ideas for developing novel water treatment technologies based on the utilization of endogenous substances and energy of wastewater.