Whole-process ultrafast charge transfer for seconds-scale degradation in mineral processing wastewater:...

The rapid degradation of high-concentration pollutants in mineral processing wastewater always holds extraordinary significance and utmost importance for heterogeneous Fenton-like oxidation. However, its efficiency is often plagued by inherent limitations in interfacial charge transfer dynamics and inefficient electron flux to the oxidant. This dual challenge leads to a significant waste of the oxidant and ultimately compromised oxidative degradation kinetics. By constructing Ce-Fe dual active centers (DAC) in MIL-101 and integrating the piezo-photo synergistic effect, this study for the first time reported a piezo-phototronics effect enhanced Fenton-like oxidation process of metal-organic framework. The •OH yield reached 4845.6 μmol/h/g, with over 80% of sodium butyl xanthate-a typical pollute in mineral processing wastewater removed within only 10 seconds. In situ measurements and species investigations confirmed that the piezo-potential promoted the separation and transport of photogenerated charges, optimizing the valence cycle of the Ce-Fe DAC; Modeling and calculations revealed that the spatial separation of redox reaction zones reduced the activation energy barrier for H₂O₂, and enhanced the Fenton-like catalytic oxidation performance from both kinetic and thermodynamic aspects. Charge separation forms electron-rich zones that promote the activation of H₂O₂, while electron-poor zones directly undergo hole oxidation. Ultimately, the dual radical and nonradical pathways synergistically leads to the second-scale degradation of pollutants across multiple concentration orders. This study systematically elucidates the charge migration behavior under piezo-photo synergistic effects and its mechanism in promoting heterogeneous Fenton-like oxidation, providing significant reference value for developing high-efficiency catalytic technologies.