Especiação redox de crômio em amostras de solos contaminados
Autor(a) principal: | |
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Data de Publicação: | 2012 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFSCAR |
Texto Completo: | https://repositorio.ufscar.br/handle/ufscar/6522 |
Resumo: | Chromium and its compounds are employed in various industrial processes, and these activities are responsible for the disposal of significant amounts of materials containing this element in the environment. Due to the known toxic feature of Cr(VI) in biological systems, the determination of chromium species has acquired great importance in environmental chemistry. In this study three analytical strategies were combined, X-ray absorption spectroscopy, flame atomic absorption spectrometry and UV-Vis molecular absorption spectrophotometry, in order to identify and determine Cr(III) and (VI) in contaminated soil samples. The samples were collected around the Comandante Ferraz Antarctic Station, a Brazilian scientific station in Antarctica. For the pseudototal chromium analysis, acid digestion was employed for sample preparation and determinations were performed using a flame atomic absorption spectrometer. Na2CO3 0.28 mol L-1 - NaOH 0.5 mol L-1 extractor solution and heating were used for Cr(VI) extraction in the samples, and preliminary identification of this specie was performed using XANES and EXAFS techniques at the Brazilian Synchrotron Light Laboratory. For Cr(VI) determination, NaOH 0.1 mol L-1 and heating were employed for the extraction of the specie, and determinations were based on the reaction of Cr(VI) with the colorimetric reagent diphenylcarbazide in acid medium, using a flow injection analysis system coupled to a molecular absorption spectrophotometer. The quantification of Cr(III) was carried out by subtraction between the pseudototal chromium concentration and Cr(VI) concentration. Results obtained were compared with those calculated from the determination of Cr(VI) with diphenylcarbazide in batch mode. Chromium (VI) concentrations determined in soil samples using both methods were discordant, and these differences were originated from problems occurred in the developed flow injection analysis system. |
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Canevari, Natália TostesPereira Filho, Edenir RodriguesPEREIRA FILHO, E. Rhttp://lattes.cnpq.br/730968445609015966e5b52f-12a7-47ee-a896-97fb506652c92016-06-02T20:36:37Z2012-05-072016-06-02T20:36:37Z2012-03-21CANEVARI, Natália Tostes. Redox especiation of chromium in contaminated soil samples. 2012. 87 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2012.https://repositorio.ufscar.br/handle/ufscar/6522Chromium and its compounds are employed in various industrial processes, and these activities are responsible for the disposal of significant amounts of materials containing this element in the environment. Due to the known toxic feature of Cr(VI) in biological systems, the determination of chromium species has acquired great importance in environmental chemistry. In this study three analytical strategies were combined, X-ray absorption spectroscopy, flame atomic absorption spectrometry and UV-Vis molecular absorption spectrophotometry, in order to identify and determine Cr(III) and (VI) in contaminated soil samples. The samples were collected around the Comandante Ferraz Antarctic Station, a Brazilian scientific station in Antarctica. For the pseudototal chromium analysis, acid digestion was employed for sample preparation and determinations were performed using a flame atomic absorption spectrometer. Na2CO3 0.28 mol L-1 - NaOH 0.5 mol L-1 extractor solution and heating were used for Cr(VI) extraction in the samples, and preliminary identification of this specie was performed using XANES and EXAFS techniques at the Brazilian Synchrotron Light Laboratory. For Cr(VI) determination, NaOH 0.1 mol L-1 and heating were employed for the extraction of the specie, and determinations were based on the reaction of Cr(VI) with the colorimetric reagent diphenylcarbazide in acid medium, using a flow injection analysis system coupled to a molecular absorption spectrophotometer. The quantification of Cr(III) was carried out by subtraction between the pseudototal chromium concentration and Cr(VI) concentration. Results obtained were compared with those calculated from the determination of Cr(VI) with diphenylcarbazide in batch mode. Chromium (VI) concentrations determined in soil samples using both methods were discordant, and these differences were originated from problems occurred in the developed flow injection analysis system.O crômio e seus compostos são empregados em diversos processos industriais, sendo estas atividades responsáveis pelo descarte de quantidades significativas de materiais contendo este elemento no meio ambiente. Devido ao reconhecido caráter tóxico do Cr(VI) em sistemas biológicos, a determinação de espécies de crômio vem adquirindo grande importância em química ambiental. Neste trabalho foram combinadas três estratégias analíticas, a espectroscopia de absorção de raios X, a espectrometria de absorção atômica com chama e a espectrofotometria de absorção molecular no UV-Vis, visando à identificação e determinação de Cr(III) e (VI) em amostras de solos contaminados. As amostras foram coletadas ao redor da Estação Antártica Comandante Ferraz, estação científica brasileira na Antártica. Para as análises de crômio pseudototal, empregou-se a digestão ácida no preparo das amostras e as determinações foram realizadas utilizando-se um espectrômetro de absorção atômica com chama. Solução extratora Na2CO3 0,28 mol L-1 - NaOH 0,5 mol L-1 e aquecimento foram empregados para a extração de Cr(VI) nas amostras, e a identificação preliminar desta espécie foi realizada com o uso das técnicas XANES e EXAFS no Laboratório Nacional de Luz Síncrotron. Para determinação de Cr(VI), NaOH 0,1 mol L-1 e aquecimento foram utilizados na extração da espécie, e as determinações foram baseadas na reação do Cr(VI) com o reagente colorimétrico difenilcarbazida em meio ácido, através do uso de um sistema de análise por injeção em fluxo acoplado a um espectrofotômetro de absorção molecular. A quantificação de Cr(III) foi realizada pela subtração entre o teor de crômio pseudototal e o teor de Cr(VI). Os resultados obtidos foram comparados com aqueles calculados a partir da determinação de Cr(VI) com difenilcarbazida em batelada. As concentrações de Cr(VI) determinadas nas amostras de solos com emprego dos dois métodos foram discordantes, sendo estas diferenças provenientes de problemas ocorridos no sistema de análise por injeção em fluxo desenvolvido.Financiadora de Estudos e Projetosapplication/pdfporUniversidade Federal de São CarlosPrograma de Pós-Graduação em Química - PPGQUFSCarBRQuímica analíticaEspeciação química redoxSolosEspectrofotometriaAnálise por injeção de fluxoEspectroscopia de absorção de raios XCIENCIAS EXATAS E DA TERRA::QUIMICAEspeciação redox de crômio em amostras de solos contaminadosRedox especiation of chromium in contaminated soil samplesinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesis-1-1cc86aeec-dd0e-4a5e-9ae0-d3a038091433info:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINAL4287.pdfapplication/pdf6056081https://repositorio.ufscar.br/bitstream/ufscar/6522/1/4287.pdffdfc8634dd718dd73cd0d1f9f8e103caMD51TEXT4287.pdf.txt4287.pdf.txtExtracted texttext/plain0https://repositorio.ufscar.br/bitstream/ufscar/6522/4/4287.pdf.txtd41d8cd98f00b204e9800998ecf8427eMD54THUMBNAIL4287.pdf.jpg4287.pdf.jpgIM Thumbnailimage/jpeg9030https://repositorio.ufscar.br/bitstream/ufscar/6522/5/4287.pdf.jpgabb9a28b52de8fb9869bfa64fd72b3f8MD55ufscar/65222023-09-18 18:30:39.569oai:repositorio.ufscar.br:ufscar/6522Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-09-18T18:30:39Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Especiação redox de crômio em amostras de solos contaminados |
dc.title.alternative.eng.fl_str_mv |
Redox especiation of chromium in contaminated soil samples |
title |
Especiação redox de crômio em amostras de solos contaminados |
spellingShingle |
Especiação redox de crômio em amostras de solos contaminados Canevari, Natália Tostes Química analítica Especiação química redox Solos Espectrofotometria Análise por injeção de fluxo Espectroscopia de absorção de raios X CIENCIAS EXATAS E DA TERRA::QUIMICA |
title_short |
Especiação redox de crômio em amostras de solos contaminados |
title_full |
Especiação redox de crômio em amostras de solos contaminados |
title_fullStr |
Especiação redox de crômio em amostras de solos contaminados |
title_full_unstemmed |
Especiação redox de crômio em amostras de solos contaminados |
title_sort |
Especiação redox de crômio em amostras de solos contaminados |
author |
Canevari, Natália Tostes |
author_facet |
Canevari, Natália Tostes |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://lattes.cnpq.br/7309684456090159 |
dc.contributor.author.fl_str_mv |
Canevari, Natália Tostes |
dc.contributor.advisor1.fl_str_mv |
Pereira Filho, Edenir Rodrigues |
dc.contributor.advisor1Lattes.fl_str_mv |
PEREIRA FILHO, E. R |
dc.contributor.authorID.fl_str_mv |
66e5b52f-12a7-47ee-a896-97fb506652c9 |
contributor_str_mv |
Pereira Filho, Edenir Rodrigues |
dc.subject.por.fl_str_mv |
Química analítica Especiação química redox Solos Espectrofotometria Análise por injeção de fluxo Espectroscopia de absorção de raios X |
topic |
Química analítica Especiação química redox Solos Espectrofotometria Análise por injeção de fluxo Espectroscopia de absorção de raios X CIENCIAS EXATAS E DA TERRA::QUIMICA |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::QUIMICA |
description |
Chromium and its compounds are employed in various industrial processes, and these activities are responsible for the disposal of significant amounts of materials containing this element in the environment. Due to the known toxic feature of Cr(VI) in biological systems, the determination of chromium species has acquired great importance in environmental chemistry. In this study three analytical strategies were combined, X-ray absorption spectroscopy, flame atomic absorption spectrometry and UV-Vis molecular absorption spectrophotometry, in order to identify and determine Cr(III) and (VI) in contaminated soil samples. The samples were collected around the Comandante Ferraz Antarctic Station, a Brazilian scientific station in Antarctica. For the pseudototal chromium analysis, acid digestion was employed for sample preparation and determinations were performed using a flame atomic absorption spectrometer. Na2CO3 0.28 mol L-1 - NaOH 0.5 mol L-1 extractor solution and heating were used for Cr(VI) extraction in the samples, and preliminary identification of this specie was performed using XANES and EXAFS techniques at the Brazilian Synchrotron Light Laboratory. For Cr(VI) determination, NaOH 0.1 mol L-1 and heating were employed for the extraction of the specie, and determinations were based on the reaction of Cr(VI) with the colorimetric reagent diphenylcarbazide in acid medium, using a flow injection analysis system coupled to a molecular absorption spectrophotometer. The quantification of Cr(III) was carried out by subtraction between the pseudototal chromium concentration and Cr(VI) concentration. Results obtained were compared with those calculated from the determination of Cr(VI) with diphenylcarbazide in batch mode. Chromium (VI) concentrations determined in soil samples using both methods were discordant, and these differences were originated from problems occurred in the developed flow injection analysis system. |
publishDate |
2012 |
dc.date.available.fl_str_mv |
2012-05-07 2016-06-02T20:36:37Z |
dc.date.issued.fl_str_mv |
2012-03-21 |
dc.date.accessioned.fl_str_mv |
2016-06-02T20:36:37Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
CANEVARI, Natália Tostes. Redox especiation of chromium in contaminated soil samples. 2012. 87 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2012. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/6522 |
identifier_str_mv |
CANEVARI, Natália Tostes. Redox especiation of chromium in contaminated soil samples. 2012. 87 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2012. |
url |
https://repositorio.ufscar.br/handle/ufscar/6522 |
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por |
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info:eu-repo/semantics/openAccess |
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openAccess |
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Universidade Federal de São Carlos |
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Programa de Pós-Graduação em Química - PPGQ |
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UFSCar |
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BR |
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Universidade Federal de São Carlos |
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