Advanced treatment of dyeing wastewater using catalytic ozonation process

The preparation method of NiO/γ-Al₂O₃ as catalyst was optimized through orthogonal test and the advanced treatment efficiency of dyeing wastewater through catalytic ozonation process was also discussed. Results showed that the optimal catalyst preparation conditions are: impregnating solution concentration of 3%, immersion time of 4 h, burning temperature of 450°C and burning time of 3 h. When kept ozone oxidation of 15 min, COD concentration decreased from 84.22 mg/L to 50.00 mg/L, the NH₃-N concentration decreased from 10.88 mg/L to 5.01 mg/L, and the chromaticity removal rate reached to 69%, which showed higher reaction efficiency than that of single ozone oxidation process.