ABSTRACT The incorrect disposal of contaminated effluents from textile industries is a major contribution to their environmental impact. We aimed to use the chitosan biopolymer from industrial sources as a potential adsorbent agent. The experiments were performed in Jar-Test simulating an industrial scale treatment. Both pH and mass variations were analyzed. Our UV spectra results showed that all datasets fitted to the Langmuir model, indicating the formation of monolayers. Kinetics studies confirmed that adsorption follows a pseudo-second order model, in addition to a chemisorption pattern during adsorption. Kinetics studies also demonstrated intraparticle diffusion, which confirmed a strong adsorbate/adsorbent interaction with the dye. The Jar-Test proved to be an efficient system to simulate treatment of effluents on an industrial scale, thus ranking chitosan powder as a good adsorbent and eligible to future large-scale applications.

Abstract Microorganisms are the primary responsible for food poisoning and food spoilage. The purpose of this study was to evaluate different fruit washing methods with tap water, electrolyzed water and rhamnolipids solution produced by Pseudomonas aeruginosa LBI, in order to inhibit microbial growth. The tested organism was Eugenia uniflora. The fruits were washed and periodically inoculated into culture media to evaluate and count the colonies on the fruit surface. It was also observed the deterioration level of the fruits after each treatment. The results showed that treatment with rhamnolipids were the most efficient, inhibiting the growth of fungi and bacteria. The electrolyzed water proved to be very efficient in bacterial inhibition at the initial time, but in the final time it did not present any inhibitory effect. The electrolyzed water was also not effective in eliminating fungus. Washing with tap water was the less efficient treatment of all. The only treatment that showed an increased durability has been with rhamnolipids, increasing shelf life by up to two days. Thus rhamnolipids are the most recommended method for fruits sanitation.

RESUMO Os efluentes têxteis liberam grandes quantidades de resíduos de corantes no meio ambiente, poluindo e alterando todo o ecossistema aquático. Além da poluição visual os compostos possuem alta toxicidade, quando não tratado corretamente podem gerar bioacumulação na biota. A levedura Saccharomyces cerevisiae, comumente utilizada como biocatalizador nas indústrias, é um possível adsorvente, devido à estrutura química composta pela parede celular, contendo grupos amino sítio ativo de possíveis interações com os grupamentos sulfônicos pertencentes aos corantes reativos, cuja comercialização compreende em escala mundial. Para tanto, foi realizado um estudo de remoção do corante reativo Direct Orange 2GL pelo método de adsorção, utilizando analises em espectrofotômetro de UV-Vis, mediante a diferentes concentrações de biomassa de S. cerevisiae e valores de pH em solução. O experimento foi analisado a partir do gráfico de isotermas de adsorção, visando à capacidade máxima de adsorção do corante na parede celular da levedura a partir do tratamento matemático usando como modelo as equações de Langmuir e Freundlich e suas linearizações. Os experimentos ressaltaram os possíveis mecanismos de interações químicas, entre adsorbato/adsorvente, podendo apresentar formação em monocamadas ou multicamadas a partir do coeficiente de correlação relativo mediante a influência do valor de pH. As analises em espectrofotômetro UV-Vis, exibiram eficiência no decréscimo dos valores de absorvância em relação ao valor no pico de onda máximo, com resultados de 0,063 absorvância, sendo este um valor aceitável para o padrão de absorvância permitido no descarte de corante. Desse modo, a utilização de biomassa de S. cerevisiae propicia resultados relevantes mesmo a baixas concentrações desde que ajustado os valores de pH em solução.

ABSTRACT The textile effluents release large amounts of dye waste in the environment, polluting and altering the whole aquatic ecosystem. Besides the visual pollution compounds have high toxicity, if not treated properly can generate bioaccumulation in biota. The yeast Saccharomyces cerevisiae, commonly used as a biocatalyst in industries is a possible adsorbent due to the chemical structure composed of the cell wall containing amino groups, active site location of possible interactions with sulfonic groups belonging to reactive dyes, which marketing worldwide. This way, it was performed to removal study of reactive dye Direct Orange 2GL by adsorption method using a spectrophotometer analysis of UV-Vis to the different biomass concentrations ofS. cerevisiae and pH values in solution. The experiment was analyzed from the adsorption isotherms graphic, aiming at maximum capacity dye adsorption on the cell wall of the yeast by the mathematical treatment using as a model the equations of Langmuir and Freundlich and its linearization. The experiments pointed out the possible mechanisms of chemical interactions between the adsorbate/adsorbent may show forms of monolayers or multilayers by the correlation coefficient concerning on the influence of the pH. The analysis in UV-Vis spectrophotometer, showed efficiency in the decrease in absorbance values relative to the value at of maximum wavelength, with results of the 0.063 absorbance, which is an acceptable value for the standard absorbance allowed the dye disposal. So, the use of biomass S. cerevisiae provides relevant results even at low concentrations since the pH adjusted solution.