Spectrophotometric determination of hydrogen peroxide in water by oxidative decolorization of azo dyes using Fenton system

摘要

In this study, based on the oxidative decolorization of three azo dyes (Orange G (OG), Acid Orange 7 (AO7) and Reactive Black 5 (RB5)) with hydroxyl radicals generated in Fenton system, we have successfully established three types of azo dyes spectrophotometric methods for measuring aqueous hydrogen peroxide (H2O2) concentration. The decolorization extent of OG, AO7 and RB5 at the corresponding characteristic wavelengths of 478 nm, 484 nm and 597 nm are proportion to the concentration of H2O2 in aqueous solutions. Under the selected reaction conditions, three well linear correlations between the depletion of azo dyes and the H2O2 concentration are established in the range of 0.45-175 mu mol L-1 of OG, 036-120 mu mol L-1 of AO7 and 0.44-175 mu mol L-1 of RB5, respectively. These proposed spectrophotometric methods are enough accurate to measure low concentrations of H2O2 in practical water samples and monitor the variations of H2O2 concentration during the phenol degradation in the Cu(II)/HCO3-/H2O2 process. (C) 2019 Elsevier B.V. All rights reserved.