α-Fe₂O₃ catalytic ozonation coupled with ceramic membrane for phenol wastewater treatment

Catalytic ozonation is an effective method for the treatment of phenolic wastewater. In order to study the degradation efficiency of phenolic wastewater by α-Fe₂O₃ catalytic oxidation and effectively recover the catalyst, micron-sized α-Fe₂O₃ catalytic ozonation was applied to the simulated phenol wastewater, and the catalyst dispersed in the reaction system was intercepted and recovered by the ceramic membrane to realize the continuous operation of the process. The results showed that: Under the condition of intermittent operation, COD removal rate of wastewater reached more than 97% after catalytic oxidation reaction for 30 min. The main reason for the high COD removal rate was that α-Fe₂O₃ had strong catalytic activity for ozone and strong oxidizing product ·OH was produced during catalytic oxidation.Under the condition of constant pressure, R_r accounted for more than 50% of the total resistance, which was verified by membrane fouling model fitting and series resistance model. However, when the operating pressure exceeded 30 kPa, some reversible fouling gradually transformed into irreversible fouling, and R_ir increased significantly. The formation mechanism of membrane fouling was explored by kinetic fitting. The ceramic membrane fouling model during operation was intermediate blockage or filter cake blockage. Membrane fouling mainly occurred on the membrane surface. The membrane could effectively intercept α-Fe₂O₃ and recover the flux through backwashing. During the six-cycle operation of continuous influent, COD removal rate of simulated wastewater remained above 85%, the irreversible resistance of ceramic membrane was controlled below 13% of the total resistance, and the reaction system maintained stable operation.