PROCESSOS OXIDATIVOS AVANÇADOS: ESTUDO CINÉTICO DA DEGRADAÇÃO DE RESÍDUO QUÍMICO CONTENDO AZOCORANTE PELA REAÇÃO DE FENTON E FOTO-FENTON

Abstract

Accompanying the growing industrial increase, as well as the increase in research in teaching laboratories and research centers, is the increasing increase of chemical residues, becoming an environmental concern. Many of these chemical wastes, called emergent pollutants, are resistant to natural biodegradation and to conventional treatment methods. Among the new treatment alternatives studied are the Advanced Oxidative Processes (AOPs). They are processes with the potential to produce hydroxyl radicals (OH), highly oxidizing species capable of mineralizing organic matter. Thus, the objective of this work was to study the application of AOPs (Fenton and Photo-Fenton) in the treatment of the chemical residue containing Azo Dye, from a research already performed in the Laboratório de Química Analítica (LQA) of the Departamento de Química e Física (DQF), Centro de Ciências Agrárias (CCA), Campos II of the Universidade Federal da Paraíba (UFPB). The factors, concentration of Fe2+ and concentration of H2O2, were optimized by performing a factorial design and evaluated at two levels with a central point, maintaining the pH at 2.98 ± 0.07 and a mean temperature of 23.5 ± 2.6 °C. After 3.0 hours of experimentation, the degradation difference between Fenton and Photo-Fenton reactions was significant, with percentages of degradation being respectively 51.1% and 89.2%, using the central point parameters. With the use of factorial planning in the Photo-Fenton reaction, it was possible to determine the best experimental conditions (82.13 mg L-1 of Fe2+ and 5453.0 mg L-1 of H2O2) for the degradation of the dye. With the best conditions, after 1.5 hours of reaction, 58.49% of degradation of the residue was reached and in 5 hours, 96.08%. The maximum value of degradation was reached after 8 hours, with 98.96%.