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SUMMARYThe present study aimed to assess the influence of the variation in the parameters concentration and contact time on the purification of raw ethanol from the fermentation of cassava starch and residues from the industrialization of biscuits during the process of adsorption in C-117 activated charcoal. Results of the physicochemical analyses of the raw ethanol were subjected to analysis of variance (ANOVA) and linear regression models of responses of interest were adjusted according to the adsorbent mass. The physicochemical characteristics of conductivity, acidity and Barbet of raw ethanol, before and after the process of adsorption in activated charcoal, did not show mean values within the maximal limits of conductivity (500 μS/m at 20ºC) and acidity (30 mg/L) established by ANP -"Agência Nacional do Petróleo, Gás Natural e Biocombustíveis" [National Agency for Oil, Natural Gas and Biofuels]. However, the process of adsorption in activated charcoal reduced the mean values of conductivity and acidity by around 30 and 40%, respectively; in addition, it led to a 20-fold increase in the mean time of potassium permanganate reduction.

RESUMO:O objetivo deste trabalho foi avaliar o efeito de massas de carvão ativado e terra diatomácea sobre as características físico-químicas de condutividade, acidez e Barbet de diferentes tipos de bioetanol originários da hidrólise e fermentação do amido de mandioca. Foram avaliados o etanol neutro, fortificado, de primeira e de segunda, submetidos às massas de 0; 25; 50; 75 e 100 mg de adsorventes. Doses crescentes de carvão ativado aumentaram o valor de Barbet, porém influenciaram negativamente nos resultados de condutividade e acidez, alterando a classificação comercial do etanol. O etanol fortificado e de segunda apresentaram aumentos mais expressivos de Barbet, superior a 460%, quando submetidos a 25 mg de carvão ativado. As massas de terra diatomácea não foram suficientes para alterar a categoria dos tipos de etanol quanto às características físico-quimicas de condutividade, acidez e Barbet. Conclui-se que o carvão ativado aumentou o valor do Barbet dos tipos de etanol, devendo ser avaliado os ganhos econômicos. A terra diatomácea não interferiu positivamente no Barbet, porém outros trabalhos devem ser realizados para verificar a interferência sobre outras características do etanol. PALAVRAS-CHAVE:etanol, carvão ativado, terra diatomácea. EFFECT OF ADSORBENTS ON THE CONDUCTIVITY, ACIDITY AND BARBET OF DIFFERENT TYPES OF BIOETHANOLABSTRACT: The objective of this study was to evaluate the physicochemical effects caused by activated charcoal and by diatomaceous soil on the conductivity, acidity and Barbet of different bioethanol types from hydrolysis and fermentation of cassava starch. We evaluated neutral, fortified, first and second generation ethanol types submitted to 0, 25, 50, 75 and 100 mg of adsorbent. Increasing doses of activated charcoal increased the value of Barbet, however influenced negatively the results of conductivity and acidity, changing the commercial classification of the ethanol. The doses of diatomaceous soil were not enough to change the category of ethanol types as the physicochemical characteristics of conductivity, acidity and Barbet. Fortified and second generation ethanol showed more significant increases of Barbet, exceeding 460% when subjected to 25 mg of activated charcoal. The activated charcoal increases the value of the different types of ethanol Barbet and it economic gains should be evaluated. The diatomaceous soil does not interfere positively on the Barbet, but other tests should be performed to verify the interference on other ethanol characteristics