Made available in DSpace on 2014-12-17T14:07:11Z (GMT). No. of bitstreams: 1 ThiagoC_TESE_PARCIAL.pdf: 936476 bytes, checksum: 8bf6e0f098d614d4feecc4fca3221123 (MD5) Previous issue date: 2013-03-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Different types of heterogeneous catalysts of the silicoaluminophosphate type, (SAPO-5, SAPO-11, SAPO-31, SAPO-34 and SAPO-41), molecular sieves with a: AFI, AEL, ATO, CHA and AFO structure, respectively, were synthesized through the hydrothermal method. Using sources such as hydrated alumina (pseudobohemita), phosphoric acid, silica gel, water, as well as, different types of organic structural templates, such as: cetyltrimethylammonium bromide (CTMABr), di-isopropylamine (DIPA), di-n- propylamine (DNPA) and tetraethylammonium hydroxide (TEOS), for the respective samples. During the preparation of the silicoaluminophosphates, the crystallization process of the samples occurred at a temperature of approximately 200 ? C, ranging through periods of 18-72 h, when it was possible to obtain pure phases for the SAPOs. The materials were furthermore washed with deionized water, dried and calcined to remove the molecules of the templates. Subsequently the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), absorption spectroscopy in the infrared region (FT-IR), specific surface area and thermal analysis via TG/DTG. The acidic properties were determined using adsorption of n-butylamine followed by programmed termodessorption. These methods revealed that the SAPO samples showed a typically weak to moderate acidity. However, a small amount of strong acid sites was also detected. The deactivation of the catalysts was conducted by artificially coking the samples, followed by n-hexane cracking reactions in a fixed bed with a continuous flow micro-reactor coupled on line to a gas chromatograph. The main products obtained were: ethane, propane, isobutene, n-butane, n-pentane and isopentane. The Vyazovkin (model-free) kinetics method was used to determine the catalysts regeneration and removal of the coke / Diferentes tipos de catalisadores heterog?neos do tipo silicoaluminofosf?tico, (SAPO-5, SAPO-11, SAPO-31, SAPO-34 e SAPO-41), peneiras moleculares com estrutura: AFI, AEL, ATO, CHA e AFO, respectivamente, foram sintetizados pelo m?todo hidrot?rmico. Utilizando-se de fontes como ? alumina hidratada (pseudobohemita), ?cido fosf?rico, s?lica gel, ?gua e diferentes tipos de direcionadores estruturais org?nicos, tais como o: brometo de cetiltrimetilam?nio (CTMABr), di-isopropilamina (DIPA), di-n-propilamina (DNPA) e hidr?xido de tetraetilam?nio (TEOS), nas respectivas amostras. Durante a prepara??o dos silicoaluminofosfatos o processo de cristaliza??o das amostras ocorreu ? temperatura de aproximadamente 200 ?C, durante per?odos que variaram de 18-72 h, quando foi poss?vel obter as fases puras dos SAPOs. Os materiais obtidos foram lavados com ?gua deionizada, secos e calcinados para a remo??o das mol?culas dos direcionadores. Posteriormente, as amostras foram caracterizadas por difra??o de raios-X (DRX), microscopia eletr?nica de varredura (MEV), espectroscopia de absor??o na regi?o do infravermelho (FT-IR), ?rea de superf?cie espec?fica e an?lise t?rmica via TG/DTG. As propriedades ?cidas foram determinadas usando adsor??o de n-butilamina seguida de termodessor??o programada. Esses m?todos revelaram que ?s amostras dos SAPOs apresentaram uma acidez tipicamente fraca a moderada. Entretanto, uma pequena quantidade de s?tios ?cidos fortes foi tamb?m detectada. A desativa??o dos catalisadores foi conduzida pelo coqueamento artificial das amostras, seguidas das rea??es de craqueamento do n-hexano em um microrreator catal?tico de leito fixo com fluxo cont?nuo acoplado em linha com um cromat?grafo a g?s. Como principais produtos foram obtidos: etano, propano, isobutano, n-butano, n-pentano e isopentano. Para determinar a regenera??o do catalisador e a remo??o do coque foi aplicado o m?todo cin?tico Vyazovkin (Model Free Kinetics) / 2020-02-01

Submitted by Kátia Oliveira (katiadionisio@yahoo.com.br) on 2017-10-11T14:01:46Z No. of bitstreams: 1 Tese (Oliveira, KD).pdf: 7712617 bytes, checksum: c39a9ee83f33d05d99d354f6a524019f (MD5) / Rejected by Ronildo Prado (producaointelectual.bco@ufscar.br), reason: Faltou inserir a carta de aprovação on 2017-10-11T18:32:06Z (GMT) / Submitted by Kátia Oliveira (katiadionisio@yahoo.com.br) on 2017-10-11T18:41:31Z No. of bitstreams: 2 Tese (Oliveira, KD).pdf: 7712617 bytes, checksum: c39a9ee83f33d05d99d354f6a524019f (MD5) Carta comprovante.pdf: 149973 bytes, checksum: 67927f9413f2368fa8bac2ceb19f248d (MD5) / Approved for entry into archive by Ronildo Prado (bco.producao.intelectual@gmail.com) on 2018-01-18T18:52:09Z (GMT) No. of bitstreams: 2 Tese (Oliveira, KD).pdf: 7712617 bytes, checksum: c39a9ee83f33d05d99d354f6a524019f (MD5) Carta comprovante.pdf: 149973 bytes, checksum: 67927f9413f2368fa8bac2ceb19f248d (MD5) / Approved for entry into archive by Ronildo Prado (bco.producao.intelectual@gmail.com) on 2018-01-18T18:52:44Z (GMT) No. of bitstreams: 2 Tese (Oliveira, KD).pdf: 7712617 bytes, checksum: c39a9ee83f33d05d99d354f6a524019f (MD5) Carta comprovante.pdf: 149973 bytes, checksum: 67927f9413f2368fa8bac2ceb19f248d (MD5) / Made available in DSpace on 2018-01-18T19:04:18Z (GMT). No. of bitstreams: 2 Tese (Oliveira, KD).pdf: 7712617 bytes, checksum: c39a9ee83f33d05d99d354f6a524019f (MD5) Carta comprovante.pdf: 149973 bytes, checksum: 67927f9413f2368fa8bac2ceb19f248d (MD5) Previous issue date: 2012-09-14 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / This work aimed to apply the Design Of Experiment (DOE) methodology as an auxiliary tool to evaluate the conditions of synthesis of the aluminum-rich zeolite Beta. Bimetallic catalysts with 50% platinum and 50% nickel (50Pt50Ni) supported on zeolites with various Si/Al ratios were synthesized, characterized and evaluated in the isomerization of n-hexane. In the first part of this work, five variables related to the synthesis of zeolite Beta were evaluated by a series of statistical designs, in which the response variables were the relative intensities of the X-ray patterns and the yield of phase BEA. The results of the t-test showed that the ratio TEAOH/SiO2 is not significant for the formation and crystallization of zeolite Beta. However, the interaction of this variable with the Si/Al ratio was statistically significant. In order to obtain the aluminum-rich zeolite Beta, the samples were synthesized with partial substitution of cations TEA+ by cations Na+. The XRD patterns of these samples showed that BEA phase was formed using a Si/Al ratio of 5,0 and 7.5. These low values of Si/Al ratio were confirmed by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and energy-dispersive X-ray spectroscopy (EDS). Information about the main properties of the 50Pt50Ni catalysts such as activity, conversion and selectivity to di-branched isomers in the isomerization of n-hexane were obtained by performing catalytic tests. Concerning these properties, the catalysts supported on the synthesized zeolite Beta (Si/Al = 7.5) showed better catalytic performance compared with catalysts supported on commercial zeolite Beta (Si/Al = 9.0). Additionally to these tests, a study on the kinetics of reduction of ions Pt2+ and Ni2+ on these catalysts was conducted using X-ray absorption spectroscopy (XAS). The combination of XAS analysis and catalytic tests showed the importance of maintaining a bimetallic platinum and nickel system in order to obtain satisfactory performance of catalysts applied to the isomerization of n-hexane. The XAS results suggested that Pt2+ ions are reduced in lower temperatures compared to Ni2+ ions, and that the addition of platinum to the nickel-based samples promoted the reduction of Ni2+ ions. The catalytic results suggested that equilibrium between acid and metal sites exists during the isomerization of n-hexane. The understanding of this equilibrium is of major importance to increase the yield and selectivity to di-branched isomers. / Este trabalho teve como objetivo a utilização da metodologia de planejamento experimental como uma ferramenta auxiliar para avaliar as condições de síntese da zeólita Beta rica em alumínio. Catalisadores bimetálicos com 50% de platina e 50% de níquel (50Pt50Ni) com teor de metal total de 130 μmol gcat-1 e suportados em zeólitas com diferentes razões Si/Al foram sintetizados, caracterizados e avaliados na reação de isomerização do n-hexano. Na primeira parte do trabalho, cinco variáveis da síntese da zeólita Beta foram avaliadas por uma série de planejamentos estatísticos, nos quais as variáveis respostas analisadas foram a intensidade de difração relativa dos difratogramas de raios X e o rendimento à fase BEA obtida. Os resultados obtidos a partir do teste t demonstraram que a razão TEAOH/SiO2 não foi significativa para o processo de cristalização e formação da zeólita Beta. No entanto, a interação desta variável com a razão Si/Al apresentou significância estatística. Para a obtenção da zeólita Beta rica em alumínio, amostras foram sintetizadas com a substituição parcial dos cátions TEA+ por cátions Na+. Nos difratogramas de raios X destas amostras foi possível identificar a fase BEA para valores de Si/Al de 5,0 e 7,5. Estes baixos valores de Si/Al nas amostras sintetizadas foram confirmados pelas técnicas de espectroscopia por emissão de plasma indutivo (ICP) e análise dispersiva de raios X (EDS). Informações a respeito das principais propriedades dos catalisadores bimetálicos 50Pt50Ni tais como atividade, conversão e seletividade a isômeros birramificados na isomerização do n-hexano, foram obtidas através da realização de testes catalíticos. Com relação a estas propriedades, os catalisadores suportados na zeólita Beta sintetizada (Si/Al = 7,5) apresentaram melhores desempenhos catalíticos quando comparados aos catalisadores suportados na zeólita Beta comercial (Si/Al = 9,0). Paralelamente, um estudo sobre a cinética de redução dos cátions metálicos Pt2+ e Ni2+ destes catalisadores foi realizado através da técnica de espectroscopia de absorção de raios X (XAS). As análises de XAS aliadas aos resultados dos testes catalíticos sugeriram a importância de se manter um sistema bimetálico de platina e níquel de maneira a se obter um desempenho satisfatório dos catalisadores aplicados à isomerização do n-hexano. Os resultados de XAS sugeriram que temperaturas menores são necessárias para reduzir os cátions metálicos Pt2+ quando comparados aos cátions Ni2+, e que a adição de cátions Pt2+ contribui consideravelmente para a redução dos cátions Ni2+, diminuindo a temperatura de redução deste último. Os resultados apresentados neste trabalho sugeriram a existência de um equilíbrio entre a proporção de sítios ácidos e metálicos durante a isomerização do n-hexano e que o entendimento deste equilíbrio é de fundamental importância para se tentar aumentar o rendimento e a seletividade a isômeros birramificados. / CNPq: 141042/2008-7

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-06-22T11:26:33Z No. of bitstreams: 0 / Made available in DSpace on 2016-06-22T11:26:33Z (GMT). No. of bitstreams: 0 / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-12-17T15:01:14Z (GMT). No. of bitstreams: 1 AdrianaKVG.pdf: 2228086 bytes, checksum: 5a5ddc6253972ac4ee82c43ae0f08d6c (MD5) Previous issue date: 2008-07-27 / The petroleum industry, in consequence of an intense activity of exploration and production, is responsible by great part of the generation of residues, which are considered toxic and pollutants to the environment. Among these, the oil sludge is found produced during the production, transportation and refine phases. This work had the purpose to develop a process to recovery the oil present in oil sludge, in order to use the recovered oil as fuel or return it to the refining plant. From the preliminary tests, were identified the most important independent variables, like: temperature, contact time, solvents and acid volumes. Initially, a series of parameters to characterize the oil sludge was determined to characterize its. A special extractor was projected to work with oily waste. Two experimental designs were applied: fractional factorial and Doehlert. The tests were carried out in batch process to the conditions of the experimental designs applied. The efficiency obtained in the oil extraction process was 70%, in average. Oil sludge is composed of 36,2% of oil, 16,8% of ash, 40% of water and 7% of volatile constituents. However, the statistical analysis showed that the quadratic model was not well fitted to the process with a relative low determination coefficient (60,6%). This occurred due to the complexity of the oil sludge. To obtain a model able to represent the experiments, the mathematical model was used, the so called artificial neural networks (RNA), which was generated, initially, with 2, 4, 5, 6, 7 and 8 neurons in the hidden layer, 64 experimental results and 10000 presentations (interactions). Lesser dispersions were verified between the experimental and calculated values using 4 neurons, regarding the proportion of experimental points and estimated parameters. The analysis of the average deviations of the test divided by the respective training showed up that 2150 presentations resulted in the best value parameters. For the new model, the determination coefficient was 87,5%, which is quite satisfactory for the studied system / A ind?stria de petr?leo, em decorr?ncia de uma intensa atividade de explora??o e produ??o, ? respons?vel por grande parte da gera??o de res?duos, os quais s?o considerados t?xicos e poluentes ao meio ambiente. Dentre estes, encontra-se a borra oleosa formada durante as etapas de produ??o, transporte e refino de petr?leo. Este trabalho teve como prop?sito recuperar o ?leo presente na borra oleosa por processo de extra??o, a fim de que este pudesse ser utilizado como combust?vel ou retornar em alguma corrente do processo de refino. A partir dos ensaios preliminares foram selecionadas as vari?veis independentes que exercem maior influ?ncia no processo de extra??o, s?o elas: temperatura, volume de solvente, volume de ?cido e tempo de extra??o. Inicialmente, determinou-se uma s?rie de par?metros para caracterizar a borra oleosa. Posteriormente, projetou-se um extrator para operar com a borra de petr?leo. Foram aplicados dois planejamentos experimentais: fatorial fracionado e Doehlert. Os ensaios foram realizados em processo batelada, de acordo com as condi??es dos planejamentos experimentais aplicados. Atrav?s dos par?metros de caracteriza??o constatou-se que o res?duo oleoso ? constitu?do predominantemente de material org?nico (36,2% de ?leo), 16,8% de cinzas, 40% de ?gua e 7% de compostos vol?teis. A efici?ncia m?dia do processo de extra??o foi de 70%. Entretanto, a an?lise estat?stica mostrou que o modelo quadr?tico n?o se ajustou bem ao processo, indicando um baixo coeficiente de determina??o (60,6%). Isto ocorreu devido ? complexidade do material estudado. Para obter um modelo que melhor se ajustasse aos resultados obtidos experimentalmente, utilizou-se a ferramenta da modelagem matem?tica, redes neurais artificiais (RNA), a qual foi gerada, inicialmente, com 2, 4, 5, 6, 7 e 8 neur?nios na camada oculta, 64 dados experimentais e 10000 apresenta??es (intera??es), verificando-se menores dispers?es entre os valores experimentais e calculados para o n?mero de 4 neur?nios. Com base na an?lise dos desvios m?dios do teste e treinamento evidenciou-se que o n?mero de 2150 apresenta??es foi o melhor valor considerando a propor??o de pontos experimentais e par?metros estimados. Para o novo modelo, o coeficiente de determina??o foi de 87,5%, mostrando-se bastante satisfat?rio

Made available in DSpace on 2014-12-17T15:01:21Z (GMT). No. of bitstreams: 1 IaraMSC_partes autorizadas.pdf: 1463501 bytes, checksum: e015bfe96823e1650378fba54b280954 (MD5) Previous issue date: 2009-12-03 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Nowadays, the growing environmental worry leads research the focus the application of alternative materials from renewable resources on the industrial process. The most common vegetable oil extractant using around the world is the hexane, a petroleum derived, toxic and flammable. Based on this fact, the goal of this work was to test vegetable oil extractions from sunflower seeds cultivated on the Rio Grande do Norte State using two extraction process, the mechanical expelling and solvent extraction, this one using hexane and ethanol as a alternative solvent. The solvent extractions were carried out in the Soxhlet extractor in three different extraction times (4, 6, and 8 hours). The effect of solvent and extraction time was evaluated. The mechanical extraction was carried out in a expeller and the sunflower oil obtained was characterized by its physical-chemical properties and compared with sunflower refinery oil. Furthermore this work also explored the pyrolysis reaction carried out by thermogravimetry measurement as alternative route to obtain biofuel. For this purpose the oil samples were heated to ambient temperature until 900?C in heating rate of 5, 10, 20?C min-1 with the objective evaluated the kinetics parameters such activation energy and isoconversion. The TG/DTG curves show the thermal profile decomposition of triglycerides. The curves also showed that antioxidant presents on the refinery oil not influence on the thermal stability of sunflower oil. The total yield of the extraction s process with hexane and ethanol solvent were compared, and the results indicated that the extraction with ethanol were more efficient. The pyrolysis reaction results indicated that the use of unpurified oil required less energy to obtain the bio-oil / Atualmente, o aumento da preocupa??o com o meio ambiente, incentiva as pesquisas que buscam a aplica??o de materiais alternativos provenientes de fontes renov?veis em processos industriais. O extratante de ?leo vegetal mais utilizado no mundo ? o hexano, um derivado de petr?leo t?xico e inflam?vel. Considerando este fato, o presente trabalho teve por objetivo realizar extra??es do ?leo das sementes de girassol cultivadas no Estado do Rio Grande do Norte usando dois processos de extra??o, a extra??o mec?nica e a extra??o com solventes, utilizando hexano e etanol como solvente alternativo. As extra??es com solvente foram realizadas em um extrator Soxhlet utilizando tr?s tempos de extra??o (4, 6 e 8 horas). O efeito do solvente no rendimento da extra??o foi avaliado. O ?leo de girassol obtido da extra??o mec?nica foi caracterizado em rela??o as suas propriedades fisico-qu?micas e comparadas com as propriedades do ?leo de girassol refinado. Al?m disso, o presente trabalho explora as rea??es de pir?lise do ?leo de girassol como uma rota alternativa para a obten??o de biocombust?veis realizadas em um analisador termogravim?trico. Com essa finalidade as amostras de ?leo foram aquecidas da temperatura ambiente at? 900?C em raz?es de aquecimento de 5, 10, 20 ?C min-1 com o objetivo de avaliar os par?metros cin?ticos tais como energia de ativa??o e isoconvers?o. As curvas TG/DTG mostram o perfil t?rmico de decomposi??o dos triglicer?deos. As curvas mostraram tamb?m que o antioxidante presente no ?leo refinado comercial, n?o influencia a estabilidade t?rmica do ?leo de girassol. O rendimento dos processos de extra??o com hexano e etanol foi comparado e os resultados indicaram que a extra??o com etanol foi mais eficiente. Os resultados das rea??es de pir?lise indicaram que o uso do ?leo bruto requer menos energia para a obten??o de biocombust?veis que o ?leo refinado

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-06-22T11:26:33Z No. of bitstreams: 0 / Made available in DSpace on 2016-06-22T11:26:33Z (GMT). No. of bitstreams: 0 / Este trabalho apresenta uma nova metodologia, simples e de baixo custo, para quantificação direta de urânio em compostos do ciclo do combustível nuclear, baseada na espectroscopia no infravermelho com transformada de Fourier (FTIR), utilizando a técnica de pastilhamento em KBr. Diferentes matrizes foram utilizadas para o desenvolvimento e validação analítica: nitrato de uranilo complexado com TBP (UO2(NO3)2.2TBP) em fase orgânica e nitrato de uranilo (UO2(NO3)2) em fase aquosa. O método para matriz de urânio em fase orgânica (UO2(NO3)2.2TBP em hexano/incorporado em KBr) apresentou linearidade (r = 0,9980) dentro da faixa analítica de 0,20% 2,85% de urânio na pastilha de KBr, LD de 0,02% e LQ de 0,03%, exatidão com recuperações acima de 101,0%, robustez e precisão (DPR < 1,6%). O método para matriz de urânio em fase aquosa (UO2(NO3)2/incorporado em KBr) apresentou linearidade (r = 0,9900) dentro da faixa analítica de 0,14% 0,29% de urânio na pastilha de KBr, LD de 0,01% e LQ de 0,02%, exatidão com recuperações acima de 99,4%, robustez e precisão (DPR < 1,6 %). Amostras de processo do ciclo do combustível nuclear foram submetidas a avaliação intralaboratorial e os resultados foram comparados estatisticamente por outras técnicas: Espectrometria de Fluorescência de Raios-X (FRX) e gravimetria. Os testes estatísticos (t-Student e Fischer) indicaram que a técnica por FTIR e as de referência são equivalentes, demonstrando que a nova metodologia pode ser empregada com sucesso nas análises de rotina para o controle de qualidade dos compostos nucleares. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

O n-hexano é um solvente usado industrialmente, e pode causar neuropatia periférica. O indicador biológico da exposição ocupacional ao n-hexano é a 2,5-hexanodiona (2,5HD). O objetivo deste estudo foi validar um método para determinação da 2,5HD urinária por cromatografia em fase gasosa, com detetor de ionização de chama. A validação do método levou em consideração dois tipos de tratamento da amostra, com hidrólise ácida e sem hidrólise ácida. Foi utilizada coluna HP1 (15m x 530&#181;m e espessura do filme 1,5&#181;m), gás de arraste He:4,2mL/min. e ciclohexanona como padrão interno. O método apresentou limites de detecção e quantificação, respectivamente 0,05 e 0,1 mg/L, linearidade de 0,1-20mg/mL, r = 0,999, recuperação entre 98-102%, com precisão e exatidão. Para verificar a aplicação do método foram analisadas 87 amostras de trabalhadores de indústrias de calçados (52 do grupo exposto e 35 do grupo controle). As amostras com hidrólise apresentaram níveis de 2,5HD cerca de dez vezes maiores quando comparados com as amostras sem hidrólise, esta diferença foi estatisticamente significante (p<0,0001), mas os níveis de 2,5HD não ultrapassaram o índice Biológico Máximo Permitido (IBMP) de 5mg/g de creatinina, em nenhuma das amostras analisadas. Os resultados indicam que o método validado mostrou aplicação prática para monitorização biológica, e as amostras que passaram pelo tratamento de hidrólise ácida apresentaram maiores níveis de detecção. / N-hexane is a solvent used in industries, and can cause peripheral neuropathy. The bioindicator in the biological monitoring of workers exposed to n-hexane is the 2,5-hexanedione (2,5HD). This study was developed in order to validate a method for 2,5HD analysis in urine by gas chromatography with flame ionization detector considering two types of sample preparing with and without acid hydrolysis. The chosen technique was performed with HP1 column measured 15m by 530&#181;m inner bore. Helio was used as the carrier gas at a flow rate of 4,2mL/min. The detection and quantification limits were respectively 0,05 and 0,1 mg/L. A linear relationship (r = 0,999) was observed in the range from 0,1-20mg/mL. The average recovery was 98-102%, with precision and accuracy. To apply this method, 87 samples from shoe factory workers were analyzed (52 exposed group and 35 control group). The samples with acid hydrolysis show levels ten times higher than samples without acid hydrolysis. This difference was statistically significant (p<0,0001), but this levels weren\'t higher than the Biological Exposure Index (BEI) were recommended value is 5mg/g creatinine, in any of the analyzed samples. These results reveal that the validated method has application for biological monitoring, and the samples with acid hydrolysis showed rates higher than the samples without hydrolysis.

La contribution de l’inhalation et de la voie percutanée à l’exposition totale à des composés organiques volatils (COV) présents dans l’eau potable est une problématique qui suscite un intérêt grandissant en santé publique et au niveau réglementaire. Jusqu’à tout récemment, seule l’ingestion était considérée dans l’évaluation du risque des contaminants de l’eau. L’objectif de ce projet était de caractériser l’impact de l’exposition multivoie sur la pharmacocinétique et la dose interne de trois COV : le toluène (TOL), le n-hexane (HEX) et le cyclohexane (CYCLO). À cette fin, un modèle expérimental animal a été utilisé et un modèle toxicocinétique à base physiologique (TCBP) a été adapté pour le TOL. Des rats Sprague-Dawley ont été exposés par voies uniques (inhalation, orale et percutanée) ou simultanées (multivoie) aux solvants. Pour le TOL, les trois voies ont été expérimentées, alors que la voie percutanée n’a pas été retenue pour le HEX et le CYCLO. Des prélèvements sanguins ont permis de caractériser les cinétiques sanguines. Les niveaux sanguins, obtenus lors des expositions multivoies, étaient généralement plus élevés que la somme des niveaux associés aux expositions par voies uniques, fait illustré par le rapport des surfaces sous la courbe expérimentale versus les prédictions (TOL : 1,30 et 2,19 ; HEX : 1,55 ; CYCLO : 0,98 et 0,99). Le modèle TCBP prédit bien la cinétique du TOL lors d’expositions par voies uniques et par multivoies. Les données expérimentales obtenues suggèrent que la dose interne résultant d’une exposition multivoie ne peut pas toujours être prédite par la somme des doses internes obtenues lors d’expositions par voies uniques. Ce phénomène serait explicable par la saturation du métabolisme. La modélisation TCBP est un outil efficace pour l’estimation du risque relatif à l’exposition multivoie aux COV présents dans l’eau potable. / The contribution of dermal and inhalation routes of exposure to volatile organic chemicals (VOCs) in drinking water is increasingly drawing attention. Until recently, ingestion was the only route considered in risk assessment of drinking water contaminants. The general objective of this study was to characterize multi-route exposures on the pharmacokinetics and internal dose of three VOCs: toluene (TOL), n-hexane (HEX) and cyclohexane (CYCLO). Towards this goal, an experimental animal model was developed and a physiologically-based toxicokinetic (PBTK) model was adapted in order to take account route-specific absorption parameters of TOL. Sprague-Dawley rats were given a single dose of VOCs by oral ingestion, inhalation or dermal route. Additional groups of rat were exposed by the three routes simultaneously. In the case of HEX and CYCLO, dermal route was not considered. Blood samples were collected in order to compare kinetics following simple and multiroute exposures. Blood levels obtained following multiroute exposures were generally higher than predictions (i.e., the sum of the blood levels obtained for single route exposures) (as revealed by area under curve ratio: TOL :1,30 et 2,19; HEX : 1,55; CYCLO : 0,98 et 0,99). The PBTK model described adequately the kinetics of TOL in rats following single and multiroute exposures. The results suggest that internal dose arising from multiple routes is not necessarely comparable to the sum of the blood levels obtained for single route exposures. This phenomenon would be attributable to degree of saturation during aggregate exposures. Furthermore, the present study demonstrated that PBTK model can be used to predict/interpret blood levels associated with multiroute exposures to VOCs in drinking water, using toluene as a model substance.

Research on the electrocoagulation (EC) of hexane extractable materials (HEM) has been conducted at the University of New Orleans using a proprietary bench-scale EC reactor. The original reactor configuration forced the fluid to follow a vertical upward-downward path. An alternate electrode arrangement was introduced so that the path of flow became horizontal. Both configurations were evaluated by comparing the residence time distribution (RTD) data generated in each case. These data produced indication of internal recirculation and stagnant water when the fluid followed a vertical path. These anomalies were attenuated when the fluid flowed horizontally and at a velocity higher than 0.032 m s-1 . A series of EC experiments were performed using a synthetic emulsion with a HEM concentration of approximately 700 mg l-1. It was confirmed that EC of HEM follows first-order kinetics, and kinetic constants of 0.0441 s-1 and 0.0443 s-1 were obtained from applying both the dispersion and tanks-in-series (TIS) models, respectively. In both cases R2 was 0.97. Also, the TIS model indicated that each cell of the EC behaves as an independent continuous-stirred-tank reactor.

La contribution de l’inhalation et de la voie percutanée à l’exposition totale à des composés organiques volatils (COV) présents dans l’eau potable est une problématique qui suscite un intérêt grandissant en santé publique et au niveau réglementaire. Jusqu’à tout récemment, seule l’ingestion était considérée dans l’évaluation du risque des contaminants de l’eau. L’objectif de ce projet était de caractériser l’impact de l’exposition multivoie sur la pharmacocinétique et la dose interne de trois COV : le toluène (TOL), le n-hexane (HEX) et le cyclohexane (CYCLO). À cette fin, un modèle expérimental animal a été utilisé et un modèle toxicocinétique à base physiologique (TCBP) a été adapté pour le TOL. Des rats Sprague-Dawley ont été exposés par voies uniques (inhalation, orale et percutanée) ou simultanées (multivoie) aux solvants. Pour le TOL, les trois voies ont été expérimentées, alors que la voie percutanée n’a pas été retenue pour le HEX et le CYCLO. Des prélèvements sanguins ont permis de caractériser les cinétiques sanguines. Les niveaux sanguins, obtenus lors des expositions multivoies, étaient généralement plus élevés que la somme des niveaux associés aux expositions par voies uniques, fait illustré par le rapport des surfaces sous la courbe expérimentale versus les prédictions (TOL : 1,30 et 2,19 ; HEX : 1,55 ; CYCLO : 0,98 et 0,99). Le modèle TCBP prédit bien la cinétique du TOL lors d’expositions par voies uniques et par multivoies. Les données expérimentales obtenues suggèrent que la dose interne résultant d’une exposition multivoie ne peut pas toujours être prédite par la somme des doses internes obtenues lors d’expositions par voies uniques. Ce phénomène serait explicable par la saturation du métabolisme. La modélisation TCBP est un outil efficace pour l’estimation du risque relatif à l’exposition multivoie aux COV présents dans l’eau potable. / The contribution of dermal and inhalation routes of exposure to volatile organic chemicals (VOCs) in drinking water is increasingly drawing attention. Until recently, ingestion was the only route considered in risk assessment of drinking water contaminants. The general objective of this study was to characterize multi-route exposures on the pharmacokinetics and internal dose of three VOCs: toluene (TOL), n-hexane (HEX) and cyclohexane (CYCLO). Towards this goal, an experimental animal model was developed and a physiologically-based toxicokinetic (PBTK) model was adapted in order to take account route-specific absorption parameters of TOL. Sprague-Dawley rats were given a single dose of VOCs by oral ingestion, inhalation or dermal route. Additional groups of rat were exposed by the three routes simultaneously. In the case of HEX and CYCLO, dermal route was not considered. Blood samples were collected in order to compare kinetics following simple and multiroute exposures. Blood levels obtained following multiroute exposures were generally higher than predictions (i.e., the sum of the blood levels obtained for single route exposures) (as revealed by area under curve ratio: TOL :1,30 et 2,19; HEX : 1,55; CYCLO : 0,98 et 0,99). The PBTK model described adequately the kinetics of TOL in rats following single and multiroute exposures. The results suggest that internal dose arising from multiple routes is not necessarely comparable to the sum of the blood levels obtained for single route exposures. This phenomenon would be attributable to degree of saturation during aggregate exposures. Furthermore, the present study demonstrated that PBTK model can be used to predict/interpret blood levels associated with multiroute exposures to VOCs in drinking water, using toluene as a model substance.