Efficient visible light photo-Fenton-like degradation of organic pollutants using in situ surface-modified BiFeO3 as a catalyst

The visible light photo-Fenton-like catalytic performance of BiFeO₃ nanoparticles was investigated using Methyl Violet (MV), Rhodamine B (RhB) and phenol as probes. Under optimum conditions, the pseudo first-order rate constant (k) was determined to be 2.21 × 10⁻², 5.56 × 10⁻² and 2.01 × 10⁻² min⁻¹ for the degradation of MV (30 μmol/L), RhB (10 μmol/L) and phenol (3 mmol/L), respectively, in the BiFeO₃-H₂O₂-visible light (Vis) system. The introduction of visible light irradiation increased the k values of MV, RhB and phenol degradation 3.47, 1.95 and 2.07 times in comparison with those in dark. Generally, the k values in the BiFeO₃-H₂O₂-Vis system were accelerated by increasing BiFeO₃ load and H₂O₂ concentration, but decreased with increasing initial pollutant concentration. To further enhance the degradation of pollutants at high concentrations, BiFeO₃ was modified with the addition of surface modifiers. The addition of ethylenediamineteraacetic acid (EDTA, 0.4 mmol/L) increased the k value of MV degradation (60 μmol/L) from 1.01 × 10⁻² min⁻¹ in the BiFeO₃-H₂O₂-Vis system to 1.30 min^-1 in the EDTA-BiFeO₃-H₂O₂-Vis system by a factor of 128. This suggests that in situ surface modification can enable BiFeO₃ nano-particles to be a promising visible light photo-Fenton-like catalyst for the degradation of organic pollutants.