Avaliação do processo foto-fenton na degradação do corante sintético alaranjado de metila

Abstract

This work aimed to assessment the performance of the solar-photo-Fenton process (PFP) on the Methyl Orange azo-dye degradation, commonly used at the textile industries. The photodegradation experiments were carried out, using a lab-scale reactor in bath-mode system. Natural solar lights were focused on the reactor as UV-Vis irradiation sources to increase the ion iron photoactivity. The main reactor operational parameters (ROP’s) such as pH of the solution, solar irradiation time and the H 2 O 2 , Fe 2+ and dye concentrations; were evaluated by applying a 3 3 complete factorial experimental design (FED), followed by statistical analysis of the data sets. The response variables were the decolourisation and azo- dye degradation values. A second polynomial order modeling was applied to reproduce the experimental data, enable the built of the 3-D responses surfaces, verify the effect of each coefficient and variance analysis (2-way ANOVA). The best results were achieved at the photoreactor operating with solution of pH 3, 2 mg H 2 O 2 L -1 , 1.85 Fe 2+ L -1 , leading to an complete decolourisation and azo-dye AM degradation after about 240 min. Dyes concentrations more than 40 mg L -1 may be cause the significant decrease on the PFP efficiencies operating at the optimal conditions determined. However, the PFP results show high efficiencies on the dye degradation and potential to achieve the limits of discharge in water bodies receptors imposed by the specific legislations. In addition, natural solar radiation show be an effective, viable and sustainable alternative when necessary the UV-Visible irradiation applications.