Abstract: The direct oxidation and catalytic oxidation of simulated wastewater containing eriochrome black T with chlorine dioxide as an oxidant was studied. The COD, BOD removal efficiency, and decolor efficiency are 24.1%, 21.8%, and 70.0%, respectively, under the condition of wastewater COD 2928mg/L, an optimum pH value of 1.8, a dosage of chlorine dioxide 1200mg/L by reacting for 60min. The COD, BOD removal efficiency and decolor efficiency are 33.6%, 53.2%, and 75.2%, respectively, under the condition of wastewater COD 2928mg/L, the optimum pH value of 1.8, the dosage of chlorine dioxide 1200mg/L, and a dosage of TiO₂ 0.25g by reacting for 60min. The result indicates that the benzene ring and naphthalin ring in the eriochrome black T molecule is degraded to organic acid and benzoquinone, and further becomes inorganic substances by chlorine dioxide direct oxidation and catalytic oxidation, which is good for the further treatment of the refractory bio-degradation wastewater.

Key words: catalytic oxidation, refractory bio-degradation wastewater, eriochrome black T , chlorine dioxide