Abstract:

The direct oxidation and catalytic oxidation of simulated wastewater containing naphthol green B with chlorine dioxide as an oxidant were studied. When the wastewater's COD was 1533mg/L, the optimum pH value was 1.2, the dosage of chlorine dioxide was 1500mg/L after reacting for 60min and the COD removal efficiency and the decolor efficiency were 45.3% and 92.5%, respectively. The COD removal efficiency and decolor efficiency were respectively 70.9% and 96.8%, when the wastewater's COD was 1481mg/L, the optimum pH value was 1.2, the dosage of chlorine dioxide was 1000mg/L, and the dosage of MnO2-SiO2 catalyst was 5g after reacting for 30min. The BOD5/CODcr of original wastewater improved from 0.22 to 0.71. The ability to biologically treat the difficult degradation wastewater improved. The catalyst did not lose activity when used nine times. The IR spectra indicated that the active ingredient of the manganese dioxide was linked with silicone by a chemical bond, not merely mechanical blending.

Key words: chlorine dioxide; catalytic oxidation; manganese dioxide; difficult degradation wastewater; naphthol green B