Utilizing Macroscopic Polarization for Effective Fe3+/Fe2+ Cycling and H2O2 Activation in Fenton-like Aniline Aerofloat Degradation

The great ecological hazards of mineral processing wastewater containing aniline aerofloat dictate the need to implement thorough mineralization degradation, such as Fenton-like catalysis. To address the low efficiency of H2O2 conversion and the short reactive duration in Fenton-like aniline aerofloat degradation, in this study, we demonstrated a novel piezo-enhanced mechanism that utilizes piezo-induced macroscopic polarization to significantly enhance H2O2 conversion and Fe3+/Fe2+ cycling in the Fe3O4–Bi4Ti3O12 heterojunction. The reaction activity was increased 2-fold, resulting in the removal of almost 85% of aniline aerofloat within 40 min at a pH of 4–10. The combination of piezoelectric force microscopy, in situ electrochemical measurement, transmission electron microscopy, and X-ray photoelectron spectroscopy demonstrated that Fe3O4–Bi4Ti3O12 exhibited a strong piezo-response and improved charge migration when exposed to a piezo-potential. The piezo-induced large-scale charge transfer facilitated the adsorption of H2O2 and released the kinetic constraints for Fe3+/Fe2+ cycling by inducing charge enrichment, as confirmed by radical monitoring, photoluminescence spectroscopy, and theory calculations. Consequently, the optimization of the aforementioned key processes enhances the yield rate (1.363 μmol min–1), selectivity of HO• conversion (18.88%) by H2O2, and the reaction's persistence. This work presents an innovative concept to enhance the performance and endurance of Fenton-like reactions. It also provided an understanding of the advanced oxidation process treatment of mineral processing wastewater.