Study On Degradation Of Organic Contaminants In Aqueous Solution By Jet-Swirling Cavitation

Owing to its large complex substances, big pH range, many polluted organics, high-toxic and hard-degradation, the printing and dyeing wastewater becomes one of the most unmanageable industry wastewater. With the development of the skills and application of new-style dyes and its assistants, and the more and more rigorous environment standard, the traditional wastewater treatment technology can not meet people’s demand. Because of its moderate reaction condition, low energy dissipation, effective degradation, can avoid secondary pollution, Hydrodynamic cavitation is getting more and more people’s attention.This thesis finds out that:the effect of aeration quantity on swirling cavitation is less; but the factors like aeration mode, diameter and distributed situation of the cavitation bubbles make much influence to swirling cavitation. The intensity of jet cavitation is low, but its special aeration mode has a synergistic effect with swirling cavitation. The paper applied the device of jet cavitation combined with swirling cavitation to wastewater treatment. We take Methylene Blue(MB) as the target contaminant, research the mechanism of degradation of MB in aqueous solution using swirling cavitation combined with jet aeration. We carried out the removal rate of MB on some factors, such as pressure, temperature, aeration quantity, salt, particles contended in the situation. After the comperhensive analysis, the summary follows:1. The influences of factors like pressure, temperature, aeration quantity on hydrodynamic cavitation of the two different devices were equal. But the influential intensity of the factors on different hydrodynamic cavitation devices is different. Pressure has the biggest effect on jet cavitation, and the biggest efffect on swirling cavitation is pressure too. The optimum condition for jet cavitation is:P=0.1MPa, T=40℃, G/L=0.05; The optimum condition for Swirling Cavitation is:P=0.3MPa, T=40℃, G/L=0.03.2. The removal rate of MB treated by jet cavitation device is 77.6%, but MB can not be degraded The removal rate of MB treated by swirling cavitation device is 94.6%, and MB can be degraded into small molecular substances. There is synergistic action between the Jet and swirling cavitation devices, but it can not be carried out completely by reason of equipment parameter. So we have to do something to optimize the device parameter.3.Salt contained in the wastewater has an inhibitory effect on hydrodynamic cavitation; but a certain particle size and content of granules is good to hydrodynamic cavitation. When both salt and particles contained in the wastewater, then salt will play dominant roles.