Experimental and theoretical investigation of a homogeneous Fenton process for the degradation of an azo dye in batch reactor

The aim of this work was to study the homogeneous oxidation process of Fenton for the decolorization of methyl orange (MO) using experimental design methodology. The efficiency of this process was evaluated according to the effect of each of the most influential parameters such as concentrations of Fe2+, H2O2, MO and the pH, also their combined effects using three responses: the decolorization yield (R), the amount of dye removed per gram of catalyst (Q) and the time required to reach steady state (tss). The ANOVA showed that about 99% of the variations in R and Q responses and 92% of the tss response could be explained by these linear models with interactions. To ensure maximum yield of MO degradation (100%) with minimum residence time (less than 1 min) in the batch reactor, the Fenton process should be carried out in MO diluted medium ([MO] = 2 mg/L) and under the following optimal conditions: [H2O2] = 3.53 mM, [Fe2+] = 0.067 g/L and pH 2. These conditions were verified experimentally, enabling these three regression equations to be used for modeling the Fenton process and predicting future responses.