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5. Membranes for Heavy Metals Removal

Author

Marder, Luciano, Benvenuti, Tatiane, Giacobbo, Alexandre, Rodrigues, Marco Antônio Siqueira, Ferreira, Jane Zoppas, Bernardes, Andréa Moura, Lichtfouse, Eric, Series Editor, Schwarzbauer, Jan, Series Editor, Robert, Didier, Series Editor, Inamuddin, editor, Ahamed, Mohd Imran, editor, and Altalhi, Tariq, editor

Published
2021
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11. Membranes for Heavy Metals Removal

Author

Marder, Luciano, primary, Benvenuti, Tatiane, additional, Giacobbo, Alexandre, additional, Rodrigues, Marco Antônio Siqueira, additional, Ferreira, Jane Zoppas, additional, and Bernardes, Andréa Moura, additional

Published
2021
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17. General Aspects of Electrodialysis

Author

Moura Bernardes, Andréa, Rodrigues, Marco A. S., Ferreira, Jane Zoppas, Bergmann, Carlos P., Series editor, Moura Bernardes, Andréa, editor, Siqueira Rodrigues, Marco Antônio, editor, and Zoppas Ferreira, Jane, editor

Published
2014
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23. Influencia de Nb contenido en electrolito a base de oxalato en la anodización de aluminio en ácido oxalico

Author

Falavigna, Gleyson Silva, Kunst, Sandra Raquel, Ferreira, Jane Zoppas, Mueller, Luã Tainachi, Santana, Joseane de Andrade, Morisso, Fernando Dal Pont, and Oliveira, Cláudia Trindade

Subjects
AA7075-T6, Anodização, Oxalic acid, Niobil oxalate, Oxalato de niobil, Anodizing, Ácido oxálico, Oxalato de niobila, Anodizado
Abstract

The AA7075-T6 alloy is widely used in aviation due to its low weight characteristics and mechanical properties. To increase corrosion resistance, this alloy is generally protected by cladding and later anodized. Cladding coating, despite increasing the cost of the alloy, is necessary, as it allows the entire surface of the alloy to be anodized. Attempts to anodize AA7075-T6 alloys without cladding, showed that the precipitates region of the alloy is not anodized, originating cathode sites and, therefore, accelerating corrosion. Because of that, this work proposed anodizing in different electrolytes aiming the coating of the alloy precipitates by anodizing. For this purpose, AA7075-T6 aluminum samples were anodized in 0.3 M Oxalic Acid and 0.15 M Niobyl Oxalate with process variation. Anodized samples were evaluated for anodizing transients, morphology, cross section and corrosion resistance. Through the anodizing transients, it was possible to characterize that the samples anodized in 0.3 M of Oxalic Acid had a higher charge density than the samples anodized in 0.15 M of Niobyl Oxalate. All samples showed formation of pits and holes in the surface layer of the oxide film. Through analysis of the cross section by scanning electron microscopy (SEM), it was possible to verify that the unblasted samples obtained an oxide film of greater thickness than the samples that were pickled. However, it was not possible to state that the precipitates were covered. La aleación AA7075-T6 se usa ampliamente en la aviación debido a sus características de bajo peso y propiedades mecánicas. Para aumentar la resistencia a la corrosión, esta aleación generalmente se protege con un revestimiento y luego se anodiza. El revestimiento de revestimiento, a pesar de aumentar el costo de la aleación, es necesario, ya que permite anodizar toda la superficie de la aleación. Los intentos de anodizar aleaciones AA7075-T6 sin revestimiento, mostraron que la región de precipitados de la aleación no está anodizada, originando sitios de cátodos y, por lo tanto, acelerando la corrosión. Por eso, este trabajo propuso anodizar en diferentes electrolitos con el objetivo de recubrir los precipitados de aleación por anodización. Para este propósito, se anodizaron muestras de aluminio AA7075-T6 en ácido oxálico 0,3 M y oxalato de niobilo 0,15 M con variación del proceso. Las muestras anodizadas se evaluaron para determinar los transitorios anodizados, la morfología, la sección transversal y la resistencia a la corrosión. A través de los transitorios de anodización, fue posible caracterizar que las muestras anodizadas en 0,3 M de ácido oxálico tenían una densidad de carga más alta que las muestras anodizadas en 0,15 M de oxalato de niobilo. Todas las muestras mostraron formación de picaduras y agujeros en la capa superficial de la película de óxido. A través del análisis de la sección transversal por microscopía electrónica de barrido (SEM), se pudo verificar que las muestras no granalladas obtuvieron una película de óxido de mayor espesor que las muestras que fueron decapadas. Sin embargo, no fue posible afirmar que los precipitados estaban cubiertos. A liga AA7075-T6 é bastante utilizada em aviação devido as suas características de baixo peso e propriedades mecânicas. Para aumento da resistência à corrosão, esta liga geralmente recebe uma proteção por cladding e posterior anodização. O recobrimento por cladding, apesar de encarecer o custo da liga, é necessário, uma vez que possibilita que toda a superfície da liga seja anodizada. Tentativas de anodização em ligas AA7075-T6 sem cladding, mostraram que a região dos precipitados da liga não é anodizada, originando sítios catódicos e, portanto, acelerando a corrosão. Devido a isso, este trabalho propôs anodizações em eletrólitos diferentes visando o recobrimento dos precipitados da liga por anodização. Para tanto, amostras de alumínio AA7075-T6 foram anodizadas em 0,3 M Ácido Oxálico e 0,15 M Oxalato de Niobila com variação de processos. As amostras anodizadas foram avaliadas quanto aos transientes de anodização, morfologia, seção transversal e resistência à corrosão. Através dos transientes de anodização foi possível caracterizar que as amostras anodizadas em 0,3 M de Ácido Oxálico obtiveram uma carga de densidade maior que as amostras anodizadas em 0,15 M de Oxalato de Niobila. Todas as amostras apresentaram formação de pites e buracos na camada superficial do filme de óxido. Através de análises da seção transversal por microscopia eletrônica de varredura (MEV), foi possível verificar que as amostras não decapadas obtiveram um filme óxido de espessura superior as amostras que foram decapadas. No entanto, não foi possível afirmar que houve recobrimento dos precipitados.

Published
2021

24. Removal of cadmium and cyanide from aqueous solutions through electrodialysis

Author

Marder Luciano, Sulzbach Guilherme O., Bernardes Andréa M., and Ferreira Jane Zoppas

Subjects
cadmium, cyanide, electrodialysis, wastewater, Chemistry, QD1-999
Abstract

The discharge of galvanic industry wastewaters containing heavy metals and cyanide is one of the largest sources of water pollution. The use of the electrodialysis technique for the treatment of a synthetic wastewater containing approximately 0.0089 mol L-1 cadmium and 0.081 mol L-1 cyanide was studied using a five-compartment electrodialysis cell. The results demonstrate that the removal of cadmium and cyanide depends on the applied current density and it is limited by the precipitation of cadmium on the cation-exchange membrane in the diluate central cell compartment.

Published
2003

34. Porous structure obtained by anodizing niobium in NaOH

Author

Rocha, Rafael Martins da, primary, Scheffel, Leonardo Felix, additional, Carone, Carlos Leonardo Pandolfo, additional, Morisso, Fernando Dal Pont, additional, Kunst, Sandra Raquel, additional, Ferreira, Jane Zoppas, additional, and Oliveira, Cláudia Trindade, additional

Published
2021
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35. Tratamento térmico em Zamac visando diminuir defeitos de porosidade

Author

Dienstmann, Fernando Konarzewski, primary, Fuhr, Luciane Taís, additional, Scheffel, Leonardo Felix, additional, Carone, Carlos Leonardo Pandolfo, additional, Morisso, Fernando Dal Pont, additional, Schneider, Eduardo Luís, additional, Kunst, Sandra Raquel, additional, Ferreira, Jane Zoppas, additional, and Oliveira, Cláudia Trindade, additional

Published
2021
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36. Avaliação da permeabilidade de luvas de látex utilizadas em laboratório para a manipulação de nanopartículas poliméricas

Author

Schmidt, Laís, primary, Mattos, Cristiane Bastos de, additional, Jahno, Vanusca Dalosto, additional, Carone, Carlos Leonardo Pandolfo, additional, Hoffmann, Luis Fernando, additional, Oliveira, Cláudia Trindade, additional, Kunst, Sandra Raquel, additional, Ferreira, Jane Zoppas, additional, and Morisso, Fernando Dal Pont, additional

Published
2021
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37. Computational image analysis as an alternative tool for the evaluation of corrosion in salt spray test

Author

Universitat Politècnica de Catalunya. Doctorat en Polímers i Biopolímers, Universitat Politècnica de Catalunya. Departament d'Enginyeria Química, Universitat Politècnica de Catalunya. IMEM-BRT- Innovation in Materials and Molecular Engineering - Biomaterials for Regenerative Therapies, Bonamigo Moreira, Vitor, Krummenauer, Alex, Ferreira, Jane Zoppas, Armelín Diggroc, Elaine Aparecida, Meneguzzi, Alvaro, Universitat Politècnica de Catalunya. Doctorat en Polímers i Biopolímers, Universitat Politècnica de Catalunya. Departament d'Enginyeria Química, Universitat Politècnica de Catalunya. IMEM-BRT- Innovation in Materials and Molecular Engineering - Biomaterials for Regenerative Therapies, Bonamigo Moreira, Vitor, Krummenauer, Alex, Ferreira, Jane Zoppas, Armelín Diggroc, Elaine Aparecida, and Meneguzzi, Alvaro

Abstract

The current standards for evaluating corrosion during salt spray tests rely on the visual analysis of the specimens, and this may be a limitation when higher resolution quantitative outputs are desired. In this work, computational image analysis was used to measure the area affected by corrosion during salt spray tests with aluminum alloy, copper, carbon steel and galvanized steel plates. The software ImageJ was used to select and measure the corroded areas differentiating the corrosion products from the metals uncorroded surfaces according to their different colors. With ten measurements for each selected exposure time, a 95 % confidence interval was calculated for each material and time of exposure, giving an indication of the precision of the estimated corroded area. These data were compared with a visual inspection carried out by an experienced technician. The results indicate that computational image analysis may be a powerful tool to obtain higher resolution in the results interpretation in comparison with the standard visual analysis, Postprint (published version)

Published
2020

41. Anodização porosa de nióbio com adição de glicerina

Author

Barreto, Aline Silveira, primary, Fuhr, Luciane Thaís, additional, Scheffel, Leonardo Felix, additional, Morisso, Fernando Dal Pont, additional, Carone, Carlos Leonardo Pandolfo, additional, Kunst, Sandra Raquel, additional, Ferreira, Jane Zoppas, additional, and Oliveira, Cláudia Trindade, additional

Published
2020
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44. ANÁLISE DE SOLDA EM ESTRUTURA METÁLICA

Author

Röhsig, Thomas, primary, Kunst, Sandra Raquel, additional, Scheffel, Leonardo Félix, additional, Fuhr, Luciane Taís, additional, Carone, Carlos Leonardo Pandolfo, additional, Morisso, Fernando Dal Pont, additional, Ferreira, Jane Zoppas, additional, and Oliveira, Cláudia Trindade, additional

Published
2019
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48. Removal of nitrates from copper-containing aqueous acidic leach solutions by electrodialysis.

Author

Riveros, Felipe, guajardo, Nicolas, Valenzuela, Marcelo Bravo, Bernardes, Andréa Moura, Ferreira, Jane Zoppas, and Cifuentes, Gerardo

Subjects
BACTERIAL leaching, ELECTRODIALYSIS, POTASSIUM nitrate, NITRATES, SODIUM nitrate, ACID solutions
Abstract

The north of Chile is characterised by a large content of caliche minerals which represent high amounts of sodium and potassium nitrates. The presence of these nitrates, in copper-containing aqueous acid leach solutions, are responsible for serious problems in the hydrometallurgical extraction of copper-from-ore. The main problems are: extractant losses due to nitration and/or hydrolysis and negative effects upon bioleaching microorganisms such as lower growth cell and higher microbial lag times. On the basis of these problems, the objective of this work was to evaluate electrodialysis (ED) as an alternative method for removal for nitrates from copper-containing aqueous acid leach solutions. For this purpose, ED experiments in a three-compartment cell using both real and synthetic solutions at different current densities, flow rate and temperature were studied. It was found that high temperature, high flow rate and low current densities favour the ED performance, under the range investigated. Thus, optimum operating conditions were found at 40 °C, 120 Lh-1 and 150 A m-2, where current efficiencies (CE) of 96.4% and 89.4% were obtained for synthetic and real catholyte, respectively. Likewise, the energy consumption (EC) was 25% lesser (0.75 kWh kg-1) with real catholyte versus 1.01 k Wh kg-1 consumed using synthetic catholyte. These results demonstrated that electrodialysis could be applied for removal of nitrates from coppercontaining aqueous acid leach solutions as an alternative technology. [ABSTRACT FROM AUTHOR]

Published
2021
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