Treatment of textile matrices using Fenton processes: influence of operational parameters on degradation kinetics, ecotoxicity evaluation and application in real wastewater.

Since conventional processes for treating textile effluents have limitations, this work aimed to investigate the application of advanced oxidation technology in this type of matrix. Initially, for a textile dyes mixture in solution, the photo-Fenton/sunlight process proved to be the most efficient among other systems tested. During the tests it was found that the degradation kinetics depends of the pH and catalyst and oxidant concentrations. After 60 min under optimized conditions, the color was reduced by 98.19%, with 92.52% organic matter conversion. Ecotoxicity tests with the Lactuca Sativa vegetable indicated that the dyes were not totally oxidized to inert compounds, although the treated solution did not cause a significant toxic effect for this species. In the second stage of the research, the photodegradation in real samples of textile wastewater was evaluated. The efficiency of the photo-Fenton/sunlight process was lower than that obtained for the dyes solution, a fact attributed to the greater complexity of the real matrix. However, the data also indicated that the combination of coagulation/flocculation and advanced oxidation processes is the most suitable methodology to reduce the fraction of biodegradable compounds. In summary, research has revealed that photocatalytic degradation of dyes through advanced oxidation is an efficient treatment.