Study On Methyl Orange Degradation By Hydrodynamic Cavitation With Chlorine Dioxide

Methyl orange is a sort of representative azo dyes, which is difficult to be degraded by traditional methods, and it will do harm to the ecological environment. Methyl orange in water can be degraded effectively by hydrodynamic cavitation with chlorine dioxide,which is a method that has a guidance meaning for azo dyes wastewater treatment.A porous equipment of hydrodynamic cavitation was developed, for degrading simulated methyl orange wastewater, the influence parameters of hydrodynamic cavitation only, chlorine dioxide only and technology of hydrodynamic cavitation,combining with chlorine dioxide were studied, the results of these treatment methods were analyzed and compared. What’s more, the intermediate products of the technology of hydrodynamic cavitation degradation combined with chlorine dioxide on methyl orange were analyzed, on the basis of the above results, the law of chemical reaction dynamics was explored. The main contents were as follows:(1)When solution temperature was 40℃, inlet pressure was 0.4MPa, and cavitation generator was porous plate 7(β = 0.0684, staggered holes), the degradation rate of methyl orange was the best, reaching 13.5%; a better range of temperature to degrade methyl orange by chlorine dioxide was 30℃~35℃, and the degradation rate of methyl orange increased with the increase of running-time and chlorine dioxide concentration(2mg/L~10mg/L); when solution temperature was 35℃, inlet pressure was 0.4MPa,chlorine dioxide concentration was 8mg/L, and cavitation generator was porous plate 7(β = 0.0684, staggered holes), the degradation rate of methyl orange was up to 82.8%,which was the best result.(2)Combination of hydrodynamic cavitation with chlorine dioxide could increase degradation rate of methyl orange significantly, and its efficiency was 6 times more than that of using hydrodynamic cavitation alone(degradation rate of methyl orang 13.5%),and 2 times more than that of only using chlorine dioxide(degradation rate of methyl orange 38.6%).(3)The changes of UV-Vis spectra of hydrodynamic cavitation degradation combined with chlorine dioxide on methyl orange, suggesting that methyl orange in water can be degraded effectively by hydrodynamic cavitation with chlorine dioxide.(4)The degradation of methyl orange by hydrodynamic cavitation with chlorine dioxide accorded with first-order kinetics, its apparent rate constant was 0.45×10-3 s-1and half life was 26 min.