Avaliação e remoção de cobre em aguardentes de cana pela utilização dos aluminossilicatos: zeólita e bentonita

Abstract

RESUMOA cachaça, bebida genuinamente nacional, é um produto de grande aceitação nos mercados interno e externo. Durante o processo de produção há alguns pontos críticos, ocorrendo a formação de contaminantes que podem afetar a qualidade da bebida, sendo necessário o conhecimento de sua composição química. Com este trabalho, objetivou-se comparar o comportamento do cobre, quando presente em solução alcoólica 40% e uma aguardente comercial (utilizando sulfato de cobre pentaidratado como fonte desse mesmo metal), além de avaliar a remoção de cobre na bebida, utilizando dois aluminossilicatos (zeólita e bentonita) comumente empregados na adsorção de metais. A zeólita e bentonita adsorveram mais cobre quando estiveram presentes em solução alcoólica do que em aguardente. Esses resultados sugerem que o cobre em aguardente deva estar ligado a moléculas volumosas, dificultando sua entrada nos pequenos poros da argila bentonita e da zeólita ZSM-5. Quando os aluminossilicatos estiveram presentes na aguardente impregnada com cobre em alambique, a bentonita foi mais eficiente na remoção do cobre do que a zeólita; no entanto a zeólita é mais recomendada na remoção do cobre, pois a redução das concentrações dos componentes secundários foi menor, não descaracterizando a bebida.Termos para indexação: Aguardente, cobre, adsorção. ABSTRACTThe "cachaça", a genuinely national drink, is a product of great acceptance in the domestic and international markets. Therefore, we need to know its chemical composition, as in the production process a few critical points due to the presence of contaminants that can affect the quality of the drink. This work is aimed to compare the behaviour of copper, when present in a 40% alcohol solution and a "cachaça" trade (using copper sulfate pentahydrate as a source of the same metal), in addition to evaluating the removal of copper in the spirit, using two aluminosilikate (zeolite and bentonite) commonly employed in the adsorption of metals. The zeolite and bentonite adsorbed more copper when were present in alcoholic solution than in spirits. These results suggest that copper in spirits should be linked to large molecules, hampering its entry in the small pores of the bentonite clay and zeolite ZSM-5. When the aluminosilikate were present in spirit impregnated with copper still in the bentonite was more efficient in the removal of copper than zeolite, although the zeolite is recommended in the removal of copper in the spirit, because the reduction of concentrations of the components side was lower, not losing its peculiar feature.

Removal of copper in cachaças using clays

“…These results confirm those of other authors who used other matrices and even bentonite clay as an adsorbent medium for copper in cachaça (Lima et al, 2009;Cantão et al, 2010). However, it is known that the reduction in the concentrations of aldehydes, higher alcohols and esters with filtration, whatever the adsorbent, can often modify the bouquet of the cachaça because these elements impart a different bouquet to the beverage when present in appropriate concentrations.…”

“…This can be explained by the adsorption of the aldehydes through the contact with the clays, or to a lesser extent, by the oxidation of aldehydes to the corresponding carboxylic acids, as well as their possible loss through evaporation during the filtering process. Comparing the results obtained by Lima et al (2006;Cantão et al (2010), it can be concluded that the results obtained in our research are within the expected, presenting a slight decrease of this component.…”

“…However, Lima et al (2009) andCantão et al (2010) observed a reduction in the concentrations of higher alcohols, when comparing the control (226.54 and 224.10 mg per 100 mL of anhydrous ethanol) with the average values for the adsorbent media used by the authors after filtering the cachaça (199.29 and 166.03 mg per 100 mL of anhydrous ethanol, respectively).…”

“…There was a significant reduction in the concentration of copper from 8.51 mg L -1 in the control to concentrations of 0.29, 2.32, 0.39, 0.88, and 2.43 mg L -1 for kaolinite samples K01, K02, K03, K04 and K05, respectively. Cantão et al (2010) evaluated the removal of copper using zeolite and bentonite clays, starting with a control enriched with 6.63 mg L -1 of copper. The authors noted that bentonite (4.68 mg L -1 ) was more effective in adsorbing copper than zeolite (5.20 mg L -1 ), but they did not obtain a significant removal of this element.…”

“…Agrotec., Lavras, v.38, n.4, p.382-389, jul./ago., 2014 The introduction of clay as an adsorbent for extracting heavy metals such as copper from cachaça is a viable alternative. Cantão et al (2010) observed that the bentonite clay was more efficient than zeolite for the removal of metals.…”