Magnetically Separable and Durable MnFe2O4 for Efficient Catalytic Ozonation of Organic Pollutants

Magnetically separable MnFe 2 O 4 was prepared successfully by a sol–gel combustion method. The synthesized MnFe 2 O 4 was characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area, zeta potential, and magnetic hysteresis loops. The catalytic activity of MnFe 2 O 4 was evaluated by the ozonation of 4-chlorophenol (4-CP) at different solution pH value, ozone gas concentration, MnFe 2 O 4 dosage, and initial 4-CP concentration. The ozone consumption was monitored and the ·OH exposure was calculated in different processes. It was found that MnFe 2 O 4 was highly effective in catalyzing ozone decomposition and favored to generate more hydroxyl radicals. Moreover, the synergistically catalytic effect between Mn and Fe in MnFe 2 O 4 was confirmed. Finally, lifetime of MnFe 2 O 4 was measured in a novel integrated membrane-heterogeneous catalytic ozonation reactor designed for the first time. All the experimental results show that MnFe 2 O 4 is a highly recoverable, efficient, and durable catalyst in the ozonation.