Effect of Iron Addition on the Decomposition of Dye by Pulsed Discharge in Air With Water Droplets Spray

The effect of iron addition in the treated solution on the decomposition of indigo carmine is reported. The effect of iron addition was evaluated for various Fe²⁺ concentrations ranging from 0 to 118 μmol/L (μM). The decolorization rate and efficiency with Fe²⁺ addition were higher than those without Fe²⁺ and increased with the rise in Fe²⁺ concentrations. The optimal Fe²⁺ concentrations for decolorization rate and efficiency were 95 and 83 μM, respectively. The pH effect was evaluated in the range of 2.3-11.3 values for the initial solution containing 71 μM Fe²⁺. The decolorization rate was approximately constant for pH ranging from 4.7 to 8.0. The increases in decolorization rate and efficiency with Fe²⁺ are attributed to a significant increase in hydroxyl radicals quantity, which is generated by Fenton´s reaction of iron and hydrogen peroxide.