臭氧微气泡处理有机废水的效果与机制

Mechanism and efficiency of ozone microbubble treatment of organic wastewater

为解决臭氧氧化有机废水氧化效率差、臭氧利用率低这一问题,本文提出了臭氧微气泡处理有机废水的新技术。采用加压溶气法制备的臭氧微气泡处理苯酚配置的模拟废水,通过显微拍摄、动力学分析、紫外-可见吸收光谱、自由基屏蔽等手段对臭氧微气泡的形态大小、氧化效果、传质特性和氧化机制进行了研究,并对臭氧气泡直径和界面压力之间的关系进行了深入探讨。试验与数值计算表明,臭氧微气泡平均粒径为20.37μm,处理初始COD浓度为51.2mg/L的有机废水,COD去除速率分别是使用1μm曝气头和100μm曝气头曝气的1.59倍和3.61倍,臭氧利用率达到99.19%以上,氧化过程是自由基为主的间接氧化过程,污染物最终氧化产物为小分子烃和羧酸。微气泡影响下,臭氧分子传质速率和分解速率均有所提高,而臭氧微气泡表面较高的界面压力是其高效传质的原因之一。

In order to solve the problems of poor oxidation rate and low utilization of organic wastewater ozonation treatment,a new technology of ozone microbubble was proposed.The microbubbles were prepared by pressure dissolved gas method and the organic wastewater were composed of phenol.The morphology size,oxidation effect,mass transfer characteristics and oxidation mechanism of ozone microbubbles were studied by means of microphotography,kinetic analysis,UV-vis absorption spectrum and free radical shielding.The relationship between ozone bubble diameter and interfacial pressure was also discussed in detail.Experimental and numerical results indicated that the average particle size of ozone microbubble was 20.37μm,the COD removal efficiency could reach 89%within 40min,the reaction rate could reach up to 3.61 times of aerator aeration,and the ozone utilization efficiency achieved was more than 99.19%.Oxidation process was an indirect oxidation process dominated by free radicals,and the final oxidation products of pollutants were small molecular hydrocarbons and carboxylic acids.Under the influence of microbubbles,the mass transfer rate and decomposition rate of ozone were increased.At the same time,higher interfacial pressure on the surface of ozone microbubbles was one of the reasons for their high mass transfer efficiency.