nitro wastewater;  decolorization;  ultrasound;  Fenton reagent

In order to reduce the color of nitro wastewater, the feasibility of three methods to reduce the color of nitro wastewater was studied by three methods: corn cob adsorption, ultrasonic - H2O2 and ultrasonic - Fenton reagent - flocculant. The experimental results show that the treatment effect of corn cob adsorption method and ultrasonic-H3O2 method is not satisfactory. The color of wastewater before and after treatment almost unchanged, while the decolorization of ultrasonic-Fenton reagent-flocculant method showed obvious changes in the color of wastewater before and after treatment. The correlation between ultrasonic time, ultrasonic power, H2O16 addition, FeSO45 addition and pH value of wastewater liquid on wastewater color was experimentally studied by applying orthogonal design L2(2). Considering the economic factors, the experimental conditions were optimized: the addition amount of H4O2 was 2 mL/L, the addition amount of FeSO3 was 4 mg/L, the pH of the wastewater liquid was = 100, the chromaticity (dilution factor method) was 4, and the decolorization rate was more than 5%.