High performance of magnetic BiFeO3 nanoparticle-mediated photocatalytic ozonation for wastewater decontamination

• Magnetic BiFeO3 is used as active catalyst in photocatalytic ozonation system.
• O3/Vis/BiFeO3 shows high performance in removing oxalic acid and norfloxacin.
• BiFeO3 nanoparticle exhibits excellent stability in O3/Vis/BiFeO3 process.

In this paper, bismuth ferrite (BiFeO3) magnetic nanoparticles were used as visible light photocatalyst in the photocatalytic ozonation coupling system. It was successfully synthesized by thermal decomposition of a glyoxylate complex. The as-prepared photocatalyst was characterized by XRD, FT-IR, SEM, TEM, UV–Vis DRS and vibrating sample magnetometer. The magnetic hysteresis loop demonstrated that BiFeO3 possessed certain magnetization. Oxalic acid (OA) and norfloxacin (NFX) were selected as target pollutants for photocatalytic ozonation reactions to evaluate the catalytic ability of BiFeO3. The pseudo-first-order kinetic rate constants of degrading OA and NFX removal in O3/Vis/BiFeO3 at given time are 5.48 and 1.65 times as great as the sum of that when using Vis/BiFeO3 and O3, respectively. This enhancement was due to a synergy between photocatalysis and ozonation triggered by BiFeO3. In O3/Vis/BiFeO3 process, the photo-generated electrons produced on BiFeO3 could be trapped by ozone and reaction with them. Subsequently, the improved yield of hydroxyl radicals enhanced the degradation efficiency of organics. In addition, the stability and reusability of BiFeO3 in photocatalytic ozonation process were examined in this work.