Abstract: This paper studied the direct oxidation and catalytic oxidation of simulated wastewater containing naphthol green B with chlorine dioxide as oxidant. The COD, BOD removal efficiency, and decolor efficiency are 45.3%, 11.2%, and 92.5%, respectively, at the condition of wastewater's COD 1533 mg/L, the optimum pH value 1.2, the dosage of chlorine dioxide 1500 mg/L by reacting for 60 min. The COD, BOD removal efficiency, and decolor efficiency are 52.5%, 48.1%, and 96.4%, respectively, at the condition of wastewater's COD 1533 mg/L, the optimum pH value 1.2, the dosage of chlorine dioxide 1500 mg/L, the dosage of TiO2 0.25 g by reacting for 60 min. The result indicates that the naphthalin ring in Naphthol green B molecule is degraded as organic acid and benzoquinone, and further becomes inorganic substances by chlorine dioxide direct oxidation and catalytic oxidation so that the ability to biology treatment of the difficulty degradation wastewater is improved, which is good for the further treatment.

Key words: catalytic oxidation, difficulty degradation wastewater, naphthol green B , chlorine dioxide