Deisi Altmajer-Vaz

Ozone degradation of alkylbenzene sulfonate in aqueous solutions using a stirred tank reactor with recirculation

The degradation of linear alkylbenzene sulfonates (LAS) in aqueous solutions by ozone has been investigated. The ozonation process was performed in a stirred tank reactor with recirculation which simulates the clean-in-place process used in many industrial facilities. The gas-liquid mass transfer of ozone in a buffer solution at different temperatures (25–55°C) was also studied in the same device, revealing that ozone decomposition can be considered negligible under the experimental conditions assayed. The effect of the initial LAS concentration, temperature, and ozone concentration on the concentration of homologues and total LAS were analysed as a function of time. Both concentrations diminished with time, this effect being more significant when higher temperatures were assayed. The relative proportion of homologues shows that the homologues of higher chain length are degraded in a greater proportion than are the homologues with shorter chain lengths.

Treatment of the textile wastewater through fungi: a sustainable alternative

The decolorization of textile effluents represents a considerable challenge because it contains certain degradation resistant compounds, such us dyes. Chemical, physical and biological methods are used for the removal of dyes from wastewater; however, conventional treatments of these effluents do not appear effective in removing dyes compounds. It actually has several drawbacks such as the high cost of the chemicals used, the generation of hazardous secondary wastes or its disposal problem and limited applicability. A fungal culture has the capability to acclimate its metabolism to changing environmental conditions. This ability is vital for their existence. Here, intra and extracellular enzymes help in metabolic activity. These enzymes have the capacity to degrade various dyes present in the textile wastewater. Due to these enzymes, fungal cultures seem to be suitable for the degradation of dyes in textile wastewater. For these reasons, the purpose of this interdisciplinary approach review is to provide innovative solutions to environmental problems, particularly to improve the treatment of industrial textile effluents with the use of biomass generated in the agroindustry, like palm tree extraction.

Decolorization of textile industry wastewater in solid state fermentation with Peach-Palm (Bactris gasipaes) residue

In this work we have assessed the decolorization of textile effluents throughout their treatment in a solid-state fermentation (SSF) system. SSF assays were conducted with peach-palm (Bactris gasipaes) residue using the white rot fungus Ganoderma lucidum EF 31. The influence of the dye concentration and of the amounts of peach-palm residue and liquid phase on both the discoloration efficiency and enzyme production was studied. According to our results, independently of experimental conditions employed, laccase was the main ligninolytic enzyme produced by G. lucidum. The highest laccase activity was obtained at very low effluent concentrations, suggesting the existence of an inhibitory effect of higher concentrations on fungal metabolism. The highest percentage of color removal was reached when 10 grams of peach palm residue was moistened with 60 mL of the final effluent. In control tests carried out with the synthetic dye Remazol Brilliant Blue R (RBBR) decolorization efficiencies about 20% higher than that achieved with the industrial effluent were achieved. The adsorption of RBBR on peach-palm residue was also investigated. Equilibrium tests showed that the adsorption of this dye followed both Langmuir and Freundlich isotherms. Hence, our experimental results indicate that peach-palm residue is suitable substrate for both laccase production and color removal in industrial effluents.