Catalytic oxidation and spectroscopic analysis of simulated wastewater containing acid chrome blue K by using chlorine dioxide as oxidant

An activated carbon-MnO₂ catalyst was prepared by the dipping-calcination method using activated carbon as catalyst support. The catalyst was used for the catalytic oxidation of simulated acid chrome blue K wastewater. The COD removal efficiency and decolor efficiency by catalytic oxidation are 72.0% and 87.8%, respectively, at the condition of wastewater's COD is 2,418 mg/L, the optimum pH value is 1.2, the dosage of chlorine dioxide is 1,200 mg/L, the dosage of activated carbon-MnO₂ catalyst is 4 g by reacting 50 min. The COD removal efficiency by catalytic oxidation is great than that of chemical oxidation. The COD removal efficiency only decreased a little after the catalyst used 8 times. The FTIR spectra indicate that the active ingredient of manganese dioxide is linked with activated carbon by chemical bond, not merely mechanical blending. The intermediates during the degradation process were obtained by using online infrared spectrum analysis. The degradation reaction mechanism of acid chrome blue K by chlorine dioxide oxidation was proposed based upon the experiment evidence.