Treatment of azo dye wastewater by high-voltage arc discharge nonthermal plasma
高压电弧放电处理偶氮染料废水

The nonthermal plasma technology using high-voltage arc discharge was investigated for the treatment of azo dye wastewater. Methyl orange solution was selected as the example to investigate the decolorization. The effects of power voltage, plasma-treatment time, different initial concentration of dye solutions, pH and addition of catalysts (Fe2+ and Fe3+) on the decolorization were studied. The experimental results indicated that abatement of 50 mg/L methyl orange wastewater increased with the discharging time and power voltage. The initial concentration had a significant impact on the removl of dye.Under the same conditions, higher decolorization was obtained when the initial concentration was lower. It was found that the extent of decolorization increased with the decrease of initial pH of dye solutions and the addition of Fe2+and Fe3+. About 99.72% of dye was removed after 3 min plasma-treatment with concentration of 20 mg/L initial Fe2+,at voltage of 8 kV. In the absence of catalyst,the removal of dye reached 89.64%.The best dosage of Fe2(SO4)3 was 5 mg/L (calculated by the concentration of Fe3+), while FeCl3 was 80 mg/L (calculated by the concentration of Fe3+).