Aplicação de processos oxidativos avançados no tratamento de águas contaminadas com efluentes têxteis

Abstract

In recent decades, the phenomenon of environmental contamination has reached global proportions. In this context, the industrial activity usually plays a major role due to the generation of a large amount of wastes, which have a high pollution potential if not properly treated. Textile industries are highlighted for their high water consumption and generation of large volumes of liquid waste containing high organic load and strong staining. In general, conventional treatments allow only partial removal of the load of pollutants present in such type of waste, which makes evident the need for new treatment systems. Based on new treatment technologies, focus is given on Advanced Oxidation Processes (AOP), which have a high efficiency of degradation face to several resistant pollutants, often allowing their full mineralization. This study aims to evaluate the applicability of oxidative processes in the treatment of synthetic textile wastewater. The method of hydrogen peroxide photolysis with ultraviolet radiation and the Photo-Fenton process using artificial radiation were employed. A 2 3 factorial design was performed to optimize the processes and evaluate the effect of discoloration. With this purpose, the following parameters were evaluated: concentration of iron (Fe 2+ ), dye and hydrogen peroxide (H 2 O 2 ) and the effect of pH. The concentration of dye ranged from 100 mgL to 500mgL -1 in the three phases; the concentration of hydrogen peroxide ranged from 500 mgL -1 to 1000 mgL -1 in the first and second phases, maintaining the initial pH (near neutral), and ranged from 1500 mgL -1 to 3000 mgL -1 in the third phase with pH variation of 4 and 5. Samples were treated for two hours with artificial radiation (germicidal lamp, 15W) and collected at 0, 15, 30, 45, 60, 90 and 120 minutes. The photodegradation of the samples was monitored by UV-Vis spectroscopy. Comparing these processes, Photo-Fenton with more acid pH (pH=4) showed the best results, followed by Photo-Fenton at pH=5 and H 2 O /UV process with initial pH.