Decolorization of acid orange 7 with DC diaphragm glow discharge

This paper investigated the decolorization of acid orange 7 (AO) in aqueous solution induced by DC diaphragm glow discharge (DGD). The glow discharge occurred around the hole on quartz tube which divided the electrolyte cell into two compartments. The decolorization efficiency of AO and H2O2 concentration without substrate was studied under different applied voltage, initial conductivity, hole diameter, hole number and anode material. Experimental results showed that 750 V was the optimal voltage for the AO decolorization and H2O2 formation. And the decolorization efficiency increased with the increase of the initial conductivity, hole number and hole diameter. With stainless steel as the anode, the decolorization efficiency was greatly improved. The iron ion from stainless steel anode played an important role as catalyst in Fenton-like reaction. Similarly, the addition of iron salts into solution also accelerated the decolorization of AO. The energy efficiency for H2O2 formation without substrate and AO decolorization was also calculated and compared with that in previous study.