Abstract:

The degradation process of Astrazon Pink FG was investigated in aqueous solution by glow discharge electrolysis (GDE) technique. The active species such as HO·, H· and O· were detected by emission spectrum of GDE. The decolorization rate, removal rate of total organic carbon (TOC), solution pH, conductivity and intermediate products of the degradation solution at different discharge time were determined by ultraviolet spectrum, TOC analyzer, pH meter, conductivity meter and ion chromatography. The degradation mechanism of Astrazon Pink FG solutions was proposed according to various analysis results. The results showed that under the 600 V discharge voltage, highly active species such as HO·, O· and H· are produced. The decolorization rate and TOC removal rate of 200 ml 20 mg/L Astrazon Pink FG are up to 99.0% and 72.6% after treating 120 min. The solution pH is decreased and then increased. However, the conductivity of degradation solution is increased and then decreased. Ion chromatography test showed that the degradation process can produce a variety of small organic molecules, such as lactate, acetate, formate, malonate, malate, succinate and oxalate. Hydroxyl radical (HO·) plays a major role for the degradation of Astrazon Pink FG. It is found that under the HO·, the chemical bonds of Astrazon Pink FG is broken, and then hydroxylation of benzene ring is formed. After that, some of benzoquinone and lower molecular weight organic acids are produced. Finally, all of organic compounds are completely mineralized into Cl^-, NO₃^-, CO₂ and H₂O.

Key words: GDE, plasma, dye, waste water, degradation, HO·, degradation mechanism

摘要：

用辉光放电电解（GDE）技术对模拟染料废水阳离子桃红FG的降解过程进行了研究。通过发射光谱法测定了GDE产生的活性粒子，用紫外光谱和总有机碳（TOC）分析仪研究了不同放电时间下的脱色率和去除率，用电导率仪和酸度计测定了降解过程中溶液的电导率和pH的变化，同时用离子色谱对降解中间产物进行了分析。结合各种分析结果，探讨了GDE降解阳离子桃红FG的机理。结果表明，在最佳电压600 V时，溶液中产生HO·、O·、H·等高活性粒子；放电120 min时，200 ml 20 mg/L阳离子桃红FG的脱色率和TOC去除率分别可达99.0%和72.6%；降解液pH先减小后增大，电导率存在先增大后减小的趋势；离子色谱测试表明，降解过程中产生多种有机小分子酸。羟基自由基（HO·）对阳离子桃红FG的降解起关键作用，GDE降解阳离子桃红FG的机理为：HO·作用下助色基团键断裂，产生酚类等中间产物，然后继续被降解为醌和小分子有机酸，最终矿化为Cl^-、NO₃^-、CO₂和H₂O。

关键词: 辉光放电电解, 等离子体, 染料, 废水, 降解, 羟基自由基, 降解机理