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
$\hbox{Fe}^{2+}$
concentrations ranging from 0 to 118
$\mu\hbox{mol/L}\ (\mu\hbox{M})$
. The decolorization rate and efficiency with
$\hbox{Fe}^{2+}$
addition were higher than those without
$\hbox{Fe}^{2+}$
and increased with the rise in
$\hbox{Fe}^{2+}$
concentrations. The optimal
$\hbox{Fe}^{2+}$
concentrations for decolorization rate and efficiency were 95 and 83
$\mu\hbox{M}$
, respectively. The pH effect was evaluated in the range of 2.3–11.3 values for the initial solution containing 71
$\mu\hbox{M}\ \hbox{Fe}^{2+}$
. The decolorization rate was approximately constant for pH ranging from 4.7 to 8.0. The increases in decolorization rate and efficiency with
$\hbox{Fe}^{2+}$
are attributed to a significant increase in hydroxyl radicals quantity, which is generated by Fenton's reaction of iron and hydrogen peroxide.