Degradation of Acid Orange 7 by Gliding Arc Discharge Plasma in Combination with Advanced Fenton Catalysis

A new plasma–catalysis process of gliding arc discharge (GAD) plasma with zero–valent iron (ZVI) was examined. Because GAD plasma creates an acidic environment, solid iron releases ferrous ions which act as a catalyst for the decomposition of the hydrogen peroxide. A comparative study of the catalytic effects between Fe²⁺ and Fe⁰ in GAD plasma was investigated. The decolorization reactions of Acid Orange 7 (AO7) followed pseudo–first–order kinetics. And the rate constants for the process of GAD with ZVI was increased by 30% and by 19%, respectively, compared with the process of GAD alone and the process of GAD with ferrous. The investigations of solution pH and hydrogen peroxide both demonstrated that the GAD plasma induced conditions are much suitable for advanced Fenton reactions. The corrosion of ZVI in GAD plasma can give continuous ferrous ions to sustain Fenton reaction. Also, ZVI was demonstrated to have favorable reusable feature.