Fenton-like degradation of bisphenol A by Fe3O4 rhombic dodecahedrons

Developing highly active Fenton-like materials for the decontamination of water is a hot topic. Nanosized Fe3O4 particles are green catalysts for environmental remediation, but their application is limited by their low catalytic activity. Herein, Fe3O4 rhombic dodecahedral nanoparticles (Fe3O4-R) with exposed {110} facets were synthesized via the solvothermal method and used as a Fenton-like catalyst for the degradation of bisphenol A (BPA). Consequently, ∼100% of BPA was removed using Fe3O4-R/H2O2 at pH = 5.0, which was higher than that by commercial Fe3O4. Multiple experiments confirmed the presence of abundant Fe(II) active sites on the surface of Fe3O4-R, but they were unstable, resulting in the dissolution of Fe(II) from the solid surface via oxidation, and thus the homogeneous reaction was not negligible in the Fe3O4-R/H2O2 process. However, hydroxyl radicals (HO˙) were still the primary reactive species, playing a dominant role in the removal of BPA. Consequently, the degradation of BPA was easily disturbed by HCO3− and natural organic matter (NOM). Unfortunately, the inactivation of Fe3O4-R was observed in cycle experiments, which is ascribed to the stabilization of the surface of Fe3O4-R during the oxidation process, reducing the surface active sites of Fe(II). Therefore, this study provides new insight into the Fenton-like oxidation process for the degradation of pollutants by regulating the morphology of Fe3O4 nanoparticles.