OTIMIZAÇÃO DA DEGRADAÇÃO ELETROQUÍMICA DE COMPOSTOS ORGÂNICOS E A ECOTOXICIDADE DO EFLUENTE GERADO

Abstract

Industrial wastewater contains a wide range of emerging pollutants, whose presence in the environment poses a significant risk to public health and aquatic ecosystems. Conventional treatments often fail to effectively eliminate these contaminants. In this context, electrochemistry emerges as a promising technology, capable of degrading persistent organic pollutants. This thesis emphasizes the optimization of electrochemical processes for the treatment of effluents containing textile dyes and surfactants, specifically Procion Yellow (PY) dye and Linear Alkylbenzene Sulfonate (LAS) surfactant. The main objectives were to investigate the efficacy of electro-oxidation using Boron-Doped Diamond (BDD) electrodes in the degradation of emerging pollutants, to evaluate operational variables for treatment optimization, and to examine the effects on the toxicity of the treated effluents. The methodology encompasses detailed experimental studies in five chapters, using experimental designs such as Taguchi and Box-Behnken for optimization, as well as ecotoxicity analyses to assess the environmental safety of the treatments. Chapter 2 presents the application of electro-oxidation, which resulted in 91.4% removal of PY and significant reductions in Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC). Chapter 3 demonstrates the efficiency of optimizing operational variables, achieving 97.06% removal of the dye. Chapter 4 stands out for the degradation of 98% of LAS and 71.36% of PY in the presence of surfactants, with the degradation kinetics following a second-order model. This work deepens the understanding of the interaction between surfactants and electrochemical processes, presenting an efficient methodology to eliminate textile dyes in matrices containing Linear Alkylbenzene Sulfonate (LAS). The research emphasizes the importance of environmental sustainability and public health protection, demonstrating that the treatment significantly reduces the toxicity of the effluents. This result underlines the potential of electro-oxidation techniques not only in the removal of pollutants but also in mitigating their harmful impacts on the environment. Furthermore, it provides a scientific basis for the application of such technologies on a pilot scale, encouraging their adoption by the industry. Keywords: Electrochemistry, Industrial Effluents, Electro-oxidation, Boron-doped Diamond, Emerging Pollutants, Textile Dyes, Surfactants, Procion Yellow, Alkylbenzene Sulfonate Linear, Process Optimization, Ecotoxicity, Effluent Treatment