Estudo de processos Fenton e biológico para remoção de corante Índigo Carmin

Abstract

The textile industry is characterized by high consumption of water in its production chain, and consequently, the generation of large volumes of highly colored effluents from dye molecules that did not adhere to fabric fibers in the dyeing process. When these dyes are improperly disposed, they act as "barriers" that interfere with the entry of sunlight into the riverbed, hindering the photosynthesis process of algae, as well as increase the COD of the effluent. There has been growing interest in the study of removing these substances through various methods. This work presents results of decoloration of the Indigo Carmine dye by the Fenton method applied under four different conditions, varying dye concentration (100 and 200 mg/L) and H2O2:Fe ratio (15,22:1; 5:1 and 3:1), achieving 90% removal under one condition (100 mg/L and 15,22:1) in 15 minutes of experiment. This work also evaluated the biological decoloration process using the cyanobacterium, Anabaena variabilis, and the yeast, Kluyveromyces marxianus. The assays were performed using the cyanobacterium Anabaena variabilis in decoloration with variations of pH (5, 8 and 11), dye concentration (100 and 200 mg/L), and controls without the biomass were prepared to verify the effect of medium under the presence and absence of light. At pHs 8.0 and 11.0, color removal reached 90% in 29 days, with decoloration favoring in these conditions. In the study using the yeast Kluyveromices marxianus, color removals greater than 90% were obtained for pHs 5 and 8, however, at pH 11 there was a decrease in cell concentration, and in general, decoloration reached its maximum between 10 and 20 days, depending on the medium pH. Although the long time of process in comparison with Fenton method, this work proved that the use of microorganisms (Anabaena variabilis como da Kluyveromyces marxianus) allowed to obtain the same removal percentage of indigo carmine. Further variables must be tested, mainly the increase of inoculum concentration in order to reduce the time of process.