Study On The Sonochemical Degradation Of Dye Wastewater And Its Strenghened Approaches

In recent years, with development of textile industry, the amount of discharged wastewater in dyeing and printing industry is very high and could not be treated effectively with traditional methods for its deep color, poor biochemical degradation and complicated components.Ultrasound has been successfully used to degrade the organic pollutants in wastewater and many water treatment experts pay more attention to study the ultrasonic irradiation technology. Ultrasound is an effective way in oxidizing organic contaminants in wastewater either as the independent operation unit or in combination with other treatment methods. It has the characteristics of the advanced oxidation processes, incineration and supercritical oxidation. The ultrasonic technology can be operated under mild reaction condition. The degradation rate is rapid and it can treat various kinds of wastewater alone or with other water treatment technologies.The mechanism of sono-degradation of organic contaminants and the way of degradation were firstly dissertated in the paper. Some basic factors which influence the efficiency of degradation, such as ultrasonic frequency, power, temperature, pH value and dissolved gas were analyzed; it summarized that the achievement of ultrasound in the field of water disposal. Based on sonochemical theory, the experimental research of sonication of reactive red X-3B dyestuff and disperse blue 2BLN dyestuff in aqueous solution, chosen as modle of dyes, were studied. And the researches on the technologies of ultrasonic irradiation alone, ultrasound/hydrogen peroxide and ultrasound/Fe-hydrogen peroxide were used to effectively degrade dyestuff wastewater.①Ultrasonic degradation reactive red X-3B and disperse blue 2BLN dyestuff in aqueous solution were studied. The research focused on the effects of initial concentration, pH value, temperature on the degradation rate. The results indicated the decolorization of reactive red X-3B and disperse blue 2BLN dyestuff follows first-order reaction kinetics and the main mechanism of sonolysis was oxidation by·OH radical. The way of degradation of reactive red X-3B is deduced elementarily according to reseraches before.②The effects of ultrasound/H₂O₂,ultrasound/Fe-H₂O₂ process on degradation of reactive red X-3B and disperse blue 2BLN dyestuff were also carried out. The results showed that with ultrasound/H₂O₂, the decolorization was a little higher to initial concentration of 50mg/L dyestuff aqueous solution, than ultrasound solely and H₂O₂ solely, but the synergism does not exist; the decolorization with ultrasound/Fe-H₂O₂ process was higher than ultrasound solely and Fe-H₂O₂ solely, and the synergism exists here. Under this experiment condition, the optimal technical parameters about using ultrasound/H₂O₂, ultrasound/Fe-H₂O₂ process decomposition of the two dyestuffes were achieved.③Hydrogen peroxide is an important substance releasing in water by ultrasonic irradiation. The production of hydrogen peroxide releasing in water irradiated by ultrasound was measured by UV-Vis process. Experiments were carried out to determine the effect of ultrasonic power, temperature and pH value.