Abstract
The degradation of methyl orange, an important pollutant from the dyeing industry, has been enhanced by combining hydrodynamic cavitation with chlorine dioxide oxidative treatment, using an orifice-plate type hydrodynamic cavitation reactor device. The effects of inlet pressure, solution temperature, solution pH, chlorine dioxide concentration, and reaction time on the methyl orange degradation rate were analyzed. An optimal degradation rate of 90.5% was achieved at an inlet pressure of 0.4 MPa, temperature of 35 °C, chlorine dioxide concentration of 8 mg/L, and reaction time of 90 min, which is 4.9 and 2 times higher than that obtained with hydrodynamic cavitation or chlorine dioxide treatment alone (degradation rates of 18.5% and 45.8%, respectively),and enhancement factor f is 3.625.This combined technique is insensitive to the solution pH, and the good degradation effect could achieved when pH varies from 3 to 9. The combined technique effectively degrade the methyl orange according to the changes of UV-Vis spectrum.
