Removal of O-toluidine by fluidized-bed fenton process

Abstract

This research investigated the removal of o-toluidine by the fluidized-bed Fenton process using the two-level-factorial and Box-Behnken designs to find the key factors and optimum conditions. Results indicate that Fe2+ and H2O2 had positive effects on o-toluidine degradation whereas the amount of carriers was not the key factor. The optimal pH, initial Fe2+ and H2O2 concentrations for the maximum o-toluidine removal (90.2% from prediction) and COD removal (41.4% from prediction) were 3, 1 mM and 17 mM, respectively. In addition, The oxidation of o-toluidine was found to be a two-stage reaction. The first stage was under the influence of Fe2+/H2O2 reaction whereas the second stage was controlled by Fe3+/H2O2 reaction. Within the studied ranges of 0.1 to 2 mM Fe2+, 1 to 34 mM H2O2, 1 mM o-toluidine, 100 g SiO2 and pH 3, the rate law for the second stage reaction can be expressed by the following reaction: d[o-toluidine]/dt = -2.14×105[Fe2+]1.77[H2O2]0.79[OT]