高频超声降解偶氮染料活性红MX-5B废水的研究

Research in High Frequency Ultrasonic for Degradation of Azo Dye Wastewater Containing MX-5B

采用高频超声降解偶氮染料活性红MX-5B模拟废水,考察了溶液初始pH值、超声参数、曝气、Fe2+浓度以及多频效应对活性红MX-5B超声降解过程的影响,并初步探讨了活性红MX-5B的超声降解规律.结果表明,酸性条件下,高频超声能有效降解MX-5B,当pH=3.5,f=418.3kHz,P=69W时,反应180 min后,MX-5B模拟废水脱色完全.微量Fe2+与超声空化产生的H2 O2形成类Fenton体系,可强化MX-5B的脱色反应.曝气有利于MX-5B脱色,但影响不大.多频超声对MX-5B的脱色效果优于单频超声处理效果.超声降解MX-5B以自由基氧化机制为主,并遵循表观一级反应动力学.染料分子中的NN形成的共轭发色体系已完全破坏,芳香结构也大部分遭到了羟基自由基的破坏.

The degradation of azo dye wastewater,containing MX-5B,was investigated by using high frequency ultrasonic irradiation.The effect of different factors like the initial pH of solution,sonolysis parameters,air-blowing,Fe2 ＋ concentration were studied,the synergistic action of complex frequency and the mechanism of degradation was explored primarily.The results show that MX-5B in aqueous solution can be degraded efficiently by ultrasonic irradiation,when the pH 3.5,ultrasonic frequency 418.3kHz,ultrasonic power 69 W,color removal rate up to 100% in 180 min.Adding of Fe2 ＋ and blowing air had some effects.The results also indicated that radical-oxidation controlled the ultrasonic decompose of MX-5B and MX-5B ultrasonic removal was observed to behave as pseudo-first-order kinetics under different experimental conditions tested in the present work.Comparison of UV-Vis absorption spectrums before and after treatment showed that all of the conjugate structure and part of aromatic structure were destroyed after being ultrasonic irradiation.