Applicability of Coal Bottom Ash from Thermoelectric Power Plant as an Alternative Heterogeneous Catalyst in Photo-Fenton Reaction

In this work, coal bottom ash, a residue generated in thermoelectric power plant, was employed as an alternative catalyst in photo-Fenton reaction for the degradation of sunset yellow dye from liquid solution under visible irradiation. The residue was characterized by techniques such as XRD, XRF, N-2 adsorption/desorption isotherms, SEM/EDS, and. FT-IR. The influence of reaction parameters such as solution pH, catalyst dosage, and H2O2 concentration on dye removal was analyzed by a central composite rotatable design 2(3). According to the characterization results, the presence of iron in the material was confiimed by analysis of chemical composition by XRF, presenting 5.5 wt% in terms of iron oxide. Through the response surface methodology, it was possible to adjust the polynomial model and determine the optimum region of dye removal. The regression model was predictive and significant, with a coefficient of determination (R-2) equivalent to 91%, showing a good fit between the experimental and theoretical values. The optimum region reaching a color removal of 91% has a pH level of 2.7, catalyst dosage of 0.9 g L-1, and. H2O2 concentration of 10 mmol L-1. Therefore, coal bottom ash, an abundant residue with low cost, showed to be a potential catalyst in a photo Fenton process for the removal of organic contaminant from liquid solution.