Pervaporação: uma técnica de separação contínua não-cromatográfica

Mattos, Ivanildo Luiz de; Queiroz, Roldão Roosevelt Urzedo de

doi:10.1590/s0100-40421998000200016

Cited by 4 publications

(4 citation statements)

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“…Such a methodology can also be classified as a nanofiltration, given the nature of the membranes employed and the size of the particles selected from the solution (Verhoef et al, 2008). Transport through the membrane occurs due to a difference in chemical potential between the substances separated by the membrane, where the molecules of alcohol permeate the membrane in the direction from the highest alcoholic concentration to the lowest (Mattos & Queiroz, 1998). This technology makes use of polymeric membranes usually constituted by Polydimethylsiloxane and Polyoctylmethylsiloxane (Verhoef et al, 2008).…”

Section: Pervaporationmentioning

confidence: 99%

Processes for alcohol-free beer production: a review

et al. 2020

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Since the invention of beer by the Sumerian people in 5000 BC, alcohol was the main reason of the interest of consumers on beer. Dnly in the beginning of the 20th century alcohol-free beer was demanded and since then technology has advanced dramatically in the production of those beverages. The aim on alcohol-free beer production is to have products that taste similarly to their alcoholic equivalents, the sole absence of alcohol and low concentrations of esters and higher alcohols and the higher concentration of aldehydes create a "worty" organoleptic impression of those products. Alcohol-free beers can be obtained by the restriction of alcohol formation during fermentation, the use of special yeast strains that consume or don't produce alcohol, the thermal removal of alcohol and by the removal of alcohol trough membrane processes. Membrane separated alcohol-free beers preserve more of the natural constituents of beer aroma and those products usually taste better than those obtained through other processes. Pervaporation techniques show a broad spectrum of use and can even be combined with other processes and perform the removal of undesired products or separation and recuperation of aromatic substances.

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Section: Pervaporationmentioning

confidence: 99%

Processes for alcohol-free beer production: a review

et al. 2020

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“…A pervaporação analítica pode ser definida como a integração da evaporação com a difusão gasosa em um único módulo, sendo uma alternativa viável à difusão gasosa, podendo ser utilizada nas amostras contendo suspensões e particularmente em amostras sólidas 9 . Quando o analito de uma amostra sólida ou líquida é transformado em um composto volátil, como no caso de CO 3 2-do solo acidificado em CO 2 , pode ser determinado em sistema de análise por injeção em fluxo (FIA), após separação por pervaporação 10 . A pervaporação é uma técnica que pode ser implementada em sistema FIA contribuindo com uma série de vantagens, tais como: pipetagem, adição de reagentes, dispensa extração do analito, não dilui o analito, menor número de etapas de análise e redução de contaminações.…”

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Determinação em fluxo do carbonatoresidual do solo empregando pervaporação

et al. 2002

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“…The analytical control of those species by flow injection analysis is commonly made with the employment of gas/liquid separation module that usually consists of two plates separated by a membrane that is permeable to the generated gas. Those diffusion modules can be bought commercially, 27,28 or can be home made, 26,[29][30][31][32] since they are easy to construct. However, the closedown of the diffusion system still consist a critical problem and little or no attention has almost been given to that subject.…”

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A new approach to construct diffusion/permeation cell for use in flow systems: application in the spectrophotometric determination of bicarbonate ions

Oliveira

Masini

Galhardo

et al. 2006

J. Braz. Chem. Soc.

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Este artigo descreve uma nova abordagem para construção de módulos de difusão/permeação de gás, baseado no perfeito encaixe entre dois blocos de acrílico. A cela foi empregada para determinação de íons bicarbonato, explorando a descoloração de uma solução 0,01% (m/v) de fenolftaleína em meio alcalino (pH 9,0). A variação da coloração do indicador foi monitorada em 552 nm. A curva analítica exibiu faixa linear entre 25,0 e 150,0 mg L -1 em NaHCO 3 . Os sinais obtidos a partir de injeções consecutivas (n=10) de uma solução padrão 5,0 mg L -1 resultaram em desvio padrão relativo menor que 1,0%. O coeficiente de correlação da curva analítica foi 0,9996 e o limite de detecção (3 x ruído/coeficiente angular) 4,41 mg L -1 de NaHCO 3 . O método proposto é rápido (até 50 amostras/hora) e os resultados estão em boa concordância com os obtidos por titulação clássica.This work describes a new approach for construction of gaseous diffusion/permeation module in a configuration based on the perfect fitting between two plaques of acrylic. It was employed to determine bicarbonate ions exploiting the discoloration of a 0.01% (m/v) phenolphthalein solution in medium of 1.0 x 10 -5 mol L -1 NaOH (pH 9.0). The variation in the indicator color was monitored at 552 nm. The analytical curve showed a working range between 25.0 and 150.0 mg L -1 in NaHCO 3 . Consecutive injections (n=10) of a standard 5.0 mg L -1 NaHCO 3 solutions exhibited less than 1.0% of relative standard deviation. The correlation coefficient of analytical curve was 0.9996 and the limit of detection (3 x noise/slope) is 4.41 mg L -1 in NaHCO 3 . The proposed method is rapid (50 sample/hour) and results were in good agreement with the ones obtained by classical titrimetry. Keywords: gas-diffusion device, flow injection analysis, bicarbonate ions IntroductionPhase separations associated to flow injection systems are strategies quite used to improve the selectivity of analytical methods, as well as to perform pre-concentration of chemical species.1-4 Phase separations involving liquid/ liquid, 5-7 gas/solid and gas/liquid extractions 8,9 are applied in many cases to eliminate chemical interferences and matrix effects. The applications of these approaches in flow injection systems reduce the time of analysis considerably, making possible the direct analysis of complex samples, and saving sample and reagents. 10,11 The uses of gaseous diffusion module for the analytical control of chemical species contained in many commercial products are of great interest. Among that species are sulfite, [12][13][14] and others. These substances can occur either naturally, as in the case of the presence of bicarbonate in mineral waters, or they can be intentionally added to confer especial properties to the product, increasing the 977 A New Approach to Construct Diffusion/Permeation Cell Vol. 17, No. 5, 2006 biochemical stability and chemical resistance to oxidation. The analytical control of those species by flow injection analysis is commonly made with the employment of gas/liquid...

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Pervaporação: uma técnica de separação contínua não-cromatográfica

Cited by 4 publications

References 14 publications

Processes for alcohol-free beer production: a review

Processes for alcohol-free beer production: a review

Determinação em fluxo do carbonatoresidual do solo empregando pervaporação

A new approach to construct diffusion/permeation cell for use in flow systems: application in the spectrophotometric determination of bicarbonate ions

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