直接红染料的臭氧脱色与中间产物研究

Ozonation mechanism and intermediates of Direct Red B

以直接红B模拟染料废水为研究对象,考察了臭氧化过程中染料溶液的吸光度和TOC的变化,同时利用离子色谱仪和GC/MS对染料的降解过程进行了分析,最后用发光细菌法检测了染料溶液急性毒性的变化。结果表明,臭氧对染料的降解符合一级反应动力学,20 min时对染料的脱色率达到99.2%;反应40 min后TOC减少32.55%,染料分子有97.8%的S被氧化为SO42-,偶氮键被臭氧化为N2,分子中的仲胺基小部分转化成游离NH4+和NO3-;在臭氧化过程前期新生成的醛类和酰胺类物质使溶液急性毒性迅速上升,25 min后溶液毒性开始逐渐下降。

The degradation of Direct Red B was investigated using ozone in aqueous solution. Absorbance and TOC of dye solution were detected during the process. The ozonation mechanism of dye was analyzed using ion chromatography and GC/MS. Finally, the acute toxicity of dye solution was measured using the method of luminescent bacteria. The results show that the decolorization of dye followed the first-order kinetics. Decolorization efficiency exceeded 99.2% at 20 min during ozonation. After reaction, 32.55% of TOC was reduced, 97.8 percent of S atoms in dye molecular were oxidized into SO4^2-. The azo bond was transformed into N2. And a few part of sec-amine group were transformed into free NH4^＋ and NO3^-. During ozonation, the acute toxicity of dye solution increased at first because of the new formed aldehydes and amides compounds, and then decreased gradually after 25 min.