Effect of hydrogen peroxide on aniline oxidation by electro-Fenton and fluidized-bed Fenton processes

In this study, the electro-Fenton and fluidized-bed Fenton processes under the given conditions were used to oxidize aniline. Factors such as feeding mode and concentration of the hydrogen peroxide were explored. Results showed that the feeding mode of H2O2 did not significantly affect the aniline oxidation in the electro-Fenton process. However, the aniline oxidation slightly decreased with the two-step addition of H2O2 in the fluidized-bed Fenton process. Presumably the decline of remaining Fe2+ led to destitute hydrogen radicals from the Fe2+-catalyzed H2O2. In addition, the removal efficiency of aniline was maintained at a maximum as H2O2 concentration was higher than 0.04 M in the electro-Fenton process. Meanwhile, the almost exhausted H2O2 would increase the amount of Fe2+ in the solution for the electro-Fenton process. This is because the Fe2+ is regenerated through the reduction of Fe3+ on the cathode. The electro-Fenton process has a stronger oxidative ability with regard to the production of the oxalic acid than fluidized-bed Fenton process which was attributed to a higher consumption of H2O2. Therefore, in the aspect of H2O2 depletion, the mineralization efficiency of the fluidized-bed Fenton process was higher than that of the electro-Fenton process. (C) 2010 Elsevier B.V. All rights reserved.