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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An?lise qu?mica de produtos de incrusta??o em dutos de petr?leo por espectometria de fluoresc?ncia de raios X

Sena, Caio Patr?cio de Souza 28 July 2008 (has links)
Made available in DSpace on 2014-12-17T15:41:46Z (GMT). No. of bitstreams: 1 CaioPSSpdf.pdf: 3119135 bytes, checksum: 46f81d35762fa5844ea534c57d40d0b2 (MD5) Previous issue date: 2008-07-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The quantitative chemical characterization of the inorganic fraction of scale products is very relevant in studying, monitoring and controlling corrosive processes of oil pipelines. The X-ray fluorescence spectrometry (XRF) is a very versatile analytical technique, which can be used in quantitative analysis in solid samples at low concentrations of the chemical element, in the order of few ppm. A methodology that involves sample preparation diluted in the proportion of 1:7 (one portion of the sample for seven of wax), pressed as pellets was used in the XRF calibration for chemical analysis of scale products from oil pipelines. The calibration involved the preparation of reference samples from mixtures of P.A. reagents, aiming to optimize the time consumed in the steps of sample preparation and analysis of Al, Ba, Ca, Fe, K, Mg, Mn, Na, P, S, Si, Sr and Ti, using the same pressed pellet for trace and major elements analysis / A caracteriza??o qu?mica quantitativa da fra??o inorg?nica de produtos de incrusta??o ? de grande relev?ncia no estudo, monitoramento e controle de processos corrosivos em dutos de petr?leo. A espectrometria por fluoresc?ncia de raios X (EFRX) ? uma t?cnica anal?tica muito vers?til, que pode ser utilizada na obten??o de resultados quantitativos de amostras s?lidas em baixas concentra??es do elemento qu?mico, da ordem de alguns ppm. Uma metodologia de prepara??o de amostras dilu?das na propor??o de 1:7 (uma por??o de amostra para sete de cera), posteriormente prensadas na forma de pastilhas foi utilizada na calibra??o do EFRX para an?lise de produtos de incrusta??o de dutos de petr?leo. O processo de calibra??o envolveu a confec??o de amostras de refer?ncia a partir de misturas de reagentes P.A., onde se buscou a otimiza??o do tempo envolvido nas etapas de prepara??o de amostras e an?lise dos elementos Al, Ba, Ca, Fe, K, Mg, Mn, Na, P, S, Si, Sr e Ti, utilizando-se as mesmas pastilhas para dosagem de elementos tra?os e maiores
2

Avalia??o da influ?ncia da mat?ria org?nica, na determina??o quantitativa de metais em amostras de sedimento, por espectrometria de absor??o at?mica e an?lise de metais tra?os por fluoresc?ncia de raios-X

Martins, Ilton S?vio Batista 21 February 2011 (has links)
Made available in DSpace on 2014-12-17T15:41:54Z (GMT). No. of bitstreams: 1 IltonSBM_DISSERT.pdf: 1681110 bytes, checksum: cc6a556fbd04c8fc33747969d0ee11f6 (MD5) Previous issue date: 2011-02-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The proposal of this work is to evaluate the influence of the organic matter on the results of the analyses of the metals (Zn, Pb, Al, Cu, Cr, Fe, Cd e Ni) for Atomic Absorption Spectrometry (AAS), so much in the extraction stage as in the reading using for that the chemometrics. They were used for this study sample of bottom sediment collected in river Jundia? in the vicinity of the city of Maca?ba-RN, commercial humus and water of the station of treatment of sewer of UFRN. Through the analyses accomplished by EAA it was verified that the interference of the organic matter happens in the extraction stage and not in the reading. With relationship to the technique of X Ray Fluorescence Spectrometry (XRFS), the present work has as intended to evaluate the viability of this technique for quantitative analysis of trace metals (Cr, Ni, Cu, Zn, Rb, Sr and Pb) in having leached obtained starting from the extraction with acqua regia for an aqueous solution. The used samples constitute the fine fraction (<0.063 mm) of sediments of swamp of the river Jundia?. The preparation of tablets pressed starting from the dry residue of those leached it allowed your analysis in the solid form. This preliminary study shows that, in the case of the digestion chemistry partially of the fine fractions of bottom sediments used for environmental studies, the technique of applied EFRX to the analysis of dry residues starting from having leached with acqua regia, compared her it analyzes of the leached with ICP-OES, it presents relative mistakes for Cu, Pb, Sr and Zn below 10% / A proposta deste trabalho ? avaliar a influ?ncia da mat?ria org?nica sobre os resultados das an?lises dos metais (Zn, Pb, Al, Cu, Cr, Fe, Cd e Ni) por Espectrometria de Absor??o At?mica (EAA), tanto na etapa de extra??o quanto na leitura utilizando para isso a quimiometria. Foram utilizados para este estudo amostra de sedimento de fundo coletadas no Rio Jundia? nas imedia??es da cidade de Maca?ba-RN, h?mus comercial e ?gua da esta??o de tratamento de esgoto da UFRN. Atrav?s das an?lises realizadas por EAA verificou-se que a interfer?ncia da mat?ria org?nica ocorre na etapa de extra??o e n?o na leitura. Com rela??o ? t?cnica de Espectrometria de Fluoresc?ncia de Raio-X (EFRX), o presente trabalho tem como proposta avaliar a viabilidade desta t?cnica para an?lise quantitativa de metais tra?os (Cr, Ni, Cu, Zn, Rb, Sr e Pb) em lixiviados obtidos a partir da extra??o com ?gua r?gia para uma solu??o aquosa. As amostras utilizadas constituem a fra??o fina (< 0.063 mm) de sedimentos de mangue do Rio Jundia?. A prepara??o de pastilhas prensadas a partir do res?duo seco dos lixiviados permitiu sua an?lise na forma s?lida. Este estudo preliminar mostra que, no caso da digest?o qu?mica parcial das fra??es finas de sedimentos de fundo utilizadas para estudos ambientais, a t?cnica de EFRX aplicada ? an?lise de res?duos secos a partir de lixiviados com ?gua r?gia, comparada a analise do lixiviado com ICP-OES, apresenta erros relativos para Cu, Pb, Sr e Zn abaixo de 10%

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