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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.
341

Estudo da emissão de aldeídos e COV por óleos de dendê e soja em diferentes condições, sob aquecimento a temperatura de processos de fritura.

Silva, Thalita Oliveira da January 2007 (has links)
Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2013-04-23T14:07:51Z No. of bitstreams: 1 Thalita Silva.pdf: 824830 bytes, checksum: 144a9fb3d8d0b2ef49b28207c4f7d487 (MD5) / Made available in DSpace on 2013-04-23T14:07:52Z (GMT). No. of bitstreams: 1 Thalita Silva.pdf: 824830 bytes, checksum: 144a9fb3d8d0b2ef49b28207c4f7d487 (MD5) Previous issue date: 2007 / O consumo de frituras é significativo no hábito dos brasileiros e tem aumentado nos últimos anos, isto por ser este um método rápido de preparação e por conferir características agradáveis de aroma e sabor aos alimentos fritos. Durante o processo de fritura, os óleos vegetais são continuamente ou repetidamente expostos a temperaturas elevadas, na presença de oxigênio atmosférico, levando os mesmos à degradação por diferentes tipos de reação. Alguns dos produtos de degradação formados, como por exemplo compostos carbonílicos, como formaldeído, acetaldeído e acroleína, podem ter efeitos adversos sobre a saúde humana. Neste trabalho determinou-se as taxas de emissão de compostos carbonílicos (CC), produzidos por óleos de dendê e soja quando submetidos a aquecimento a 180°C e exposição ao ar por diferentes intervalos de tempo, em processos contínuo e descontínuo e diferentes razões superfície:volume (S/V). Os CC foram coletados e derivatizados em cartuchos de sílica funcionalizados com C18 e impregnados com solução ácida de 2,4-DNPH, sendo a seguir extraídos e analisados por CLAE-DAD e, em alguns casos, CLAE-EM com ionização por eletrospray. Dentre os CC identificados nas emissões, destacaram - se no óleo de dendê, formaldeído; acetaldeído; acroleína; propanal; butanal; pentanal; hexanal; (E)-2-heptenal; heptanal; (E)-2-octenal; octanal; nonanal e (E)-2-decenal, enquanto no óleo de soja destacaram-se formaldeído; acetaldeído; acroleína; hexanal e (E)-2-heptenal. Dentre os quantificados, o que apresentou as maiores taxas de emissão nos dois óleos, nas três relações S/V estudadas, foi a acroleína, emitida em maiores taxas pelo óleo de soja. Em seguida, vieram o hexanal e o (E)-2- heptenal. No estudo da influência da relação S/V, as taxas de emissão estiveram, em geral, diretamente relacionadas à razão superfície/volume de óleo utilizado, embora CC saturados e insaturados tenham se comportado de maneira diferente frente à oxidação. Durante aquecimento descontínuo, houve uma tendência ao aumento nas taxas de emissão, ao longo do tempo, para os aldeídos saturados. Aldeídos insaturados, ao contrário, tiveram uma diminuição ao longo do tempo, devida provavelmente à alta reatividade da dupla ligação presente nestes compostos. Outros compostos orgânicos voláteis (COV) foram avaliados qualitativamente por extração do headspace e análise por CGAR-EM. As principais classes de compostos identificadas foram, mais uma vez, aldeídos alifáticos saturados e insaturados, embora também álcoois insaturados, ácidos carboxílicos e o 2-pentil-furano, todos provenientes de degradação lipídica. Finalmente, esse estudo mostra que a relação superfície/volume, o tempo de fritura, a forma de aquecimento (contínua ou descontínua), o tipo de óleo utilizado e a presença ou não de antioxidantes são fatores importantes na degradação dos óleos vegetais. Vale ressaltar que embora as emissões de acroleína e de outros aldeídos possam ser elevadas mesmo após períodos curtos de aquecimento do óleo, isso não corresponde necessariamente à altas exposições pelos trabalhadores em cozinha, uma vez que essas vão ser afetadas por outros fatores, tais como o grau de ventilação/exaustão do ar no ambiente. Todavia, elas podem servir como alerta para ações de prevenção. / Salvador
342

Biofiltração de compostos orgânicos voláteis e gás sulfídrico em estações de despejos industriais de processamento de hidrocarbonetos. / Biofiltration of volatile organic compounds and hydrogen sulphide in an wastewater treatment plant of processing oil.

Beatrix Nery Villa Martignoni 09 March 2007 (has links)
Neste trabalho foi estudado o tratamento simultâneo por biofiltração de emissões de compostos orgânicos voláteis, COV e gás sulfídrico, H2S, em estações de tratamento de despejos industriais, de refinaria de petróleo, ETDI. A biofiltração dos gases emanados da EDTI mostrou ser uma técnica de alta eficiência, atingindo valores de 95 a 99 % para tratamento simultâneo de COV e H2S em concentrações de 1000 e 100 ppmv, respectivamente. Foram realizados testes em 95 dias consecutivos de operação, em uma planta piloto instalada na Superintendência da Industrialização do Xisto, SIX, em São Mateus do Sul, Paraná, de março a agosto de 2006. O biofiltro foi do tipo fluxo ascendente, com 3,77 m3 de leito orgânico, composto de turfa, carvão ativado, lascas de madeira, serragem brita fina além de outros componentes menores. Foi realizada inoculação biológica com lodo filtrado de estação de tratamento de esgoto sanitário. As vazões de gás aplicadas variaram de 85 a 407 m3/h, resultando em taxas de carga de massa de 11,86 a 193,03 g de COV/h.m3 de leito e tempos de residência de 24 segundos a 6,5 minutos, com tempo ótimo de 1,6 minutos. A capacidade máxima de remoção do sistema encontrada, nas condições testadas, foi de 15 g de COV/h. m3, compatível com os valores encontrados na literatura para depuração biológica de COV na escala praticada. Também foi verificada a redução de componentes específicos de BTX, demonstrando boa degradabilidade dos compostos orgânicos. Finalmente o biofiltro demonstrou boa robustez biológica diante dos desvios operacionais intencionalmente provocados, tais como falta de umidade do leito, baixa temperatura, alta vazão, falta de carga de COV e baixo pH do leito. Depois de retomada a condição de operação estável, a biofiltração rapidamente atingiu o estado de equilíbrio, assegurando o uso eficiente e confiável da técnica no tratamento de gases de EDTI na indústria do hidrocarbonetos ou em refinarias de petróleo. / In this project the biofiltration technique was applied as air pollution control technology to treat simultaneously emissions containing volatile organic compounds, VOC and hydrogen sulfide, H2S, in hydrocarbon processing industries and oil refinery Waste Water Treatment Plant, WWTP. The technique demonstrated high biological efficiency up to 95 and 100 % of simultaneous biofiltration of VOC and H2S, with inicial concentration of 1000 and 100 ppmv, respectively. Tests were conducted at UN-SIX/ Petrobras Oil Shale Processing Unit facilities through 95 consecutives days, from March to August 2006. The chosen reactor model was an up stream system, pilot plant scale with volume of 3.77 m3 of an organic compost media made out a blend of peat, rotten wood chips, activated carbon, lime, among other minor components. The biological inoculation was done with sanitary sludge from WWTP. The pilot plant capacity was able to treat from 85 to 480 m3/h of WWTP off-gas, resulting COV application rate from 11.86 to 193.03 g VOC/ h. m3 of media, and residence time from 24 sec to 6.5 minutes, with optimum value at 1.6 minutes. The system maximum elimination rate was about 15 g VOC/h. m3, value comparable to ones presented in open literature. The specific BTX compounds depuration was observed, demonstrating relevant media specificity to treat organic compounds. Finally the biofiltration systems demonstrated good biological toughness considering the operational provoked upsets, as lack of media bed humidity, low biofiltration temperature, high flow rate, lack of VOC flow and acid pH. After normal operational conditions were retaken all process characteristics and efficiency [was] reached the correspondent values, showing reliable and efficient use of the technique to treat off gases in WWTP of hydrocarbon processing industries and Oil Refineries.
343

Biofiltração de compostos orgânicos voláteis e gás sulfídrico em estações de despejos industriais de processamento de hidrocarbonetos. / Biofiltration of volatile organic compounds and hydrogen sulphide in an wastewater treatment plant of processing oil.

Beatrix Nery Villa Martignoni 09 March 2007 (has links)
Neste trabalho foi estudado o tratamento simultâneo por biofiltração de emissões de compostos orgânicos voláteis, COV e gás sulfídrico, H2S, em estações de tratamento de despejos industriais, de refinaria de petróleo, ETDI. A biofiltração dos gases emanados da EDTI mostrou ser uma técnica de alta eficiência, atingindo valores de 95 a 99 % para tratamento simultâneo de COV e H2S em concentrações de 1000 e 100 ppmv, respectivamente. Foram realizados testes em 95 dias consecutivos de operação, em uma planta piloto instalada na Superintendência da Industrialização do Xisto, SIX, em São Mateus do Sul, Paraná, de março a agosto de 2006. O biofiltro foi do tipo fluxo ascendente, com 3,77 m3 de leito orgânico, composto de turfa, carvão ativado, lascas de madeira, serragem brita fina além de outros componentes menores. Foi realizada inoculação biológica com lodo filtrado de estação de tratamento de esgoto sanitário. As vazões de gás aplicadas variaram de 85 a 407 m3/h, resultando em taxas de carga de massa de 11,86 a 193,03 g de COV/h.m3 de leito e tempos de residência de 24 segundos a 6,5 minutos, com tempo ótimo de 1,6 minutos. A capacidade máxima de remoção do sistema encontrada, nas condições testadas, foi de 15 g de COV/h. m3, compatível com os valores encontrados na literatura para depuração biológica de COV na escala praticada. Também foi verificada a redução de componentes específicos de BTX, demonstrando boa degradabilidade dos compostos orgânicos. Finalmente o biofiltro demonstrou boa robustez biológica diante dos desvios operacionais intencionalmente provocados, tais como falta de umidade do leito, baixa temperatura, alta vazão, falta de carga de COV e baixo pH do leito. Depois de retomada a condição de operação estável, a biofiltração rapidamente atingiu o estado de equilíbrio, assegurando o uso eficiente e confiável da técnica no tratamento de gases de EDTI na indústria do hidrocarbonetos ou em refinarias de petróleo. / In this project the biofiltration technique was applied as air pollution control technology to treat simultaneously emissions containing volatile organic compounds, VOC and hydrogen sulfide, H2S, in hydrocarbon processing industries and oil refinery Waste Water Treatment Plant, WWTP. The technique demonstrated high biological efficiency up to 95 and 100 % of simultaneous biofiltration of VOC and H2S, with inicial concentration of 1000 and 100 ppmv, respectively. Tests were conducted at UN-SIX/ Petrobras Oil Shale Processing Unit facilities through 95 consecutives days, from March to August 2006. The chosen reactor model was an up stream system, pilot plant scale with volume of 3.77 m3 of an organic compost media made out a blend of peat, rotten wood chips, activated carbon, lime, among other minor components. The biological inoculation was done with sanitary sludge from WWTP. The pilot plant capacity was able to treat from 85 to 480 m3/h of WWTP off-gas, resulting COV application rate from 11.86 to 193.03 g VOC/ h. m3 of media, and residence time from 24 sec to 6.5 minutes, with optimum value at 1.6 minutes. The system maximum elimination rate was about 15 g VOC/h. m3, value comparable to ones presented in open literature. The specific BTX compounds depuration was observed, demonstrating relevant media specificity to treat organic compounds. Finally the biofiltration systems demonstrated good biological toughness considering the operational provoked upsets, as lack of media bed humidity, low biofiltration temperature, high flow rate, lack of VOC flow and acid pH. After normal operational conditions were retaken all process characteristics and efficiency [was] reached the correspondent values, showing reliable and efficient use of the technique to treat off gases in WWTP of hydrocarbon processing industries and Oil Refineries.
344

Poluição do ar por compostos orgânicos voláteis (COV) em ambiente interno hospitalar / Air pollution by volatile organic compounds (VOCs) inside hospital

Ivan Alexandre Petroni 07 August 2009 (has links)
A quantificação de 11 compostos carbonílicos (formaldeído, acetaldeído, acetona, acroleína, propionaldeído, crotonaldeído, butiraldeído, benzaldeído, isovaleraldeído, valeraldeído e 2,5-dimetilbenzaldeído) e a identificação de outros 43 compostos orgânicos voláteis (alcanos, alcenos, aromáticos, halogenados e nitrogenados) foram feitas em 9 ambientes diferentes de trabalho localizados em áreas internas do Hospital Universitário, USP, São Paulo. Dentre os compostos carbonílicos, os mais abundantes em ordem decrescente foram formaldeído, acetona, acetaldeído e acroleína. As maiores razões de mistura de formaldeído foram observadas nas salas de Macroscopia (169,9 e 90,2 ppbv) e Técnicas Histológicas (11,7 e 58,7 ppbv), em decorrência da atividade desenvolvida nos locais. Na sala de Macroscopia, os níveis de formaldeído encontrados foram acima do limite (100 ppbv) estabelecido por órgãos internacionais que controlam a qualidade do ar em ambientes internos não industriais. As razões de mistura entre o ambiente interno e o ambiente externo, razões I/E, permitiram indicar a predominância dos compostos carbonílicos nos ambientes internos. A acroleína foi encontrada na faixa de 6,4 a 9,3 ppbv nos ambientes internos estudados. Na área externa, entretanto, foram encontrados valores similares (6,4 e 6,8 ppbv) aos dos ambientes internos obtendo razões I/E próximas de 1. Os compostos podem ter sido emitidos por materiais de construção e acabamento, fumaça do tabaco, adesivos, via metabolismo microbiano e bacteriano ou podem ter sido transportados por correntes de ar do ambiente externo para o ambiente interno / The quantification of 11 carbonyl compounds (formaldehyde, acetaldehyde, acrolein, acetone, propionaldehyde, crotonaldehyde, butiraldehyde, benzaldehyde, isovaleraldehyde, valeraldehyde and 2,5-dimethylbenzaldehyde) and the identification of another 43 volatile organic compounds (alkanes, alkenes, aromatic, halogenated and nitrogenated compounds) have been done with samples of 9 different indoor places inside the University Hospital at USP in São Paulo. Among the carbonyl compounds, there where found higher quantities of formaldehyde, acetone, acetaldehyde and acrolein in this order. The highest ratios of formaldehyde mixture have been observed at the Macroscopic room (169.88 and 90.2 ppbv) and Histological Techniques (11.7 and 58.7 ppbv), due to the routine activities of these places. At the Macroscopy room, the level of formaldehyde identified (100 ppbv) was above the international limits established to non-industrial internal places. The ratios of the mixture of indoor and outdoor places, I/O, indicate the biggest presence of carbonyl compounds in internal places. Acrolein has been identified (6.4 to 9.3 ppbv) at indoor places. At the external area, there where found similar values (6,4 to 6,8 ppbv), and the ratio I/O obtained is near to 1. The origin of these compounds is possibly construction materials, smoke of cigarettes, adhesives, metabolism of microorganisms or they may have come from the outdoor to the indoor
345

Avaliação da qualidade do ar de cabines de veículos automotores recém-manufaturados / Evaluation of new vehicles cabin indoor air quality

Auzebio Valvassori Filho 23 September 2008 (has links)
Cabines de veículos automotores recém-manufaturados podem ser consideradas críticas quando se avalia a qualidade do ar interno, pois concentrações de compostos orgânicos voláteis encontram-se em níveis mais altos que os ambientes externos. Determinadas substâncias presentes no ar da cabine podem ser prejudiciais ao ser humano em função da sua toxicidade, pricipalmente nos grandes centros urbanos. A avaliação do ar da cabine automotiva se faz necessária. Nesse estudo, foi feita uma avaliação da qualidade do ar interno da cabine de 7 veículos populares recém-manufaturados contendo materiais de acabamento interno iguais. Um total de 46 compostos orgânicos voláteis foi identificado, sendo que 14 deles são compostos carbonílicos e 32 são hidrocarbonetos alifáticos e aromáticos, compostos halogenados e um nitrogenado. Os compostos carbonílicos foram identificados e quantificados por cromatografia a líquido e os outros VOCs apenas identificados por GC-MS. No ar interno da cabine dos veículos estudados, as concentrações médias encontradas para os compostos carbonílicos (µg/m3) em ordem decrescente foram: formaldeído (165,3); acetona (67,5); acetaldeído (56,8); isovaleraldeído (40,8); propionaldeído (21,1); butiraldeído (17,9); crotonaldeído (14,9); hexaldeído (14,9) valeraldeído (9,8); 2.5- dimetilbenzaldeído (9,3); otolualdeído (8,4); p/m tolualdeído (6,8); acroleína (4,2) e benzaldeído (3,8). Com relação aos outros VOCS foram identificados o metilbutano, que apresentou a maior porcentagem de abundância relativa, 8,5%, seguido de outros hidrocarbonetos com abundância relativa entre 5 e 2% , como, 2,7,10-trimetildodecano, 2,2,6-trimetildecano, ciclopentano, 2,3,4-trimetildecano, n-pentano, 3,6-dimetilundecano, 4-metildodecano, 4,6- dimetildodecano, 3,6-dimetildecano e 1,2-dimetilbenzeno. Dois derivados de hidrocarbonetos halogenados também foram encontrados, sendo que o triclorofluormetano foi o majoritário com 5,7%, e um composto nitrogenado, a acetonitrila com 5,4%. Os compostos derivados do benzeno identificados foram: 1,2-dimetilbenzeno, etilbenzeno, metilbenzeno, 1-etil-3- metilbenzeno, 1-etil-3-metilbenzeno e 1,3,5-trimetilbenzeno que perfazem 6,6 % de abundância relativa. O mais abundante entre os aromáticos foi o 1,2-dimetilbenzeno (2,5%). Os resultados experimentais revelaram também a liberação de VOCs pelos materiais de acabamento interno dos veículos automotores recém-manufaturados. / New motor vehicles cabins may be critical when considering the internal air quality, because concentrations of volatile organic compounds are at levels higher than the outdoors. Certain substances present in the cabin air can be harmful to humans according to their toxicity, mainly in the big cities. Assessment of the cabin air becomes necessary. In this study, cabin air quality was assessed and 7 popular new vehicles containing same interior trim materials were evaluated. A total of 46 volatile organic compounds were identified, with 14 of them were carbonylic compounds and 32 are aliphatic and aromatic hydrocarbons, halogenated compounds and a nitrogenated compound. The carbonylic compounds were identified and quantified by the liquid chromatography and other VOCs only identified by GC-MS. Cabin air vehicles studied showed the following average concentrations found for carbonylic compounds ( µg/m3) in a descending order: formaldehyde (165.3), acetone (67.5); acetaldehyde (56.8); Isovaleraldehyde ( 40.8); propionaldehyde (21.1); butyraldehyde (17.9); crotonaldeído (14.9); hexaldeído (14.9) Valeraldehyde (9.8); dimetilbenzaldeído-2.5 (9.3); the - tolualdeído (8.4), p / m - tolualdeído (6.8); acrolein (4.2) and benzaldehyde (3.8). Concerning the other VOCs the following compounds were identified: methylbutane, which had the highest percentage of relative abundance, 8.5%, followed by other hydrocarbons with relative abundance between 5 and 2%, 2,7,10-trimetildodecano, 2.2 ,6- Trimetildecano, ciclopentano, 2,3,4-trimetildecano, n-pentane, 3.6-dimetilundecano, 4- metildodecano, dimetildodecano-4.6, 3.6 and 1.2-dimetildecano-dimetilbenzeno. Two halogenated hydrocarbons were also found, and triclorofluormetano had the biggest relative abundance percentage 5.7%, and a nitrogen compound, the acetonitrile with 5.4%. The benzene compounds identified were: 1.2-dimetilbenzeno, ethylbenzene, methylbenzene, 1- ethyl-3-methyl, ethyl-1-and 3-methyl 1,3,5-trimethylbenzene which comprise 6.6% of relative abundance. 1.2-dimetilbenzeno was the most abundant aromatic compound with relative abundance 2.5%. Results also showed that VOCs were released by studied vehicles interior trim materials.
346

Élaboration de matériaux catalytiques pour l'élimination de polluants organiques en phase gaz / Development of catalytic materials for the removal of organics pollutants in gas phase

Sedjame, Henri-Joël 28 October 2013 (has links)
Les travaux dont les résultats sont présentés dans ce manuscrit ont été menés dans le but de préparer des matériaux catalytiques à base de métaux nobles pour l'élimination de certains composés organiques volatils (COV). Différents catalyseurs à base de platine ont ainsi été préparés et leurs performances catalytiques évaluées pour l'oxydation de deux polluants : le n-butanol et l'acide acétique. Une première étude sur l'élimination oxydative et non-oxydative du n-butanol sur des catalyseurs à base de platine supportés sur alumine a été menée. Ce travail a porté essentiellement sur l'étude de l'effet des différents paramètres intervenant dans la réaction (oxygène, eau, métal). Le phénomène d'adsorption-désorption du polluant à la surface du catalyseur a également été étudié. S'inspirant des données de la littérature sur les propriétés redox particulières de la cérine, les travaux ont ensuite porté sur l'effet de l'ajout de CeO2 à des catalyseurs de type Pt/Al2O3 pour l'oxydation du n-butanol et de l'acide acétique. La modification des propriétés redox et acido-basiques ainsi que celle des performances catalytiques du matériau observées avec l'ajout de CeO2 a permis d'établir une corrélation entre activité catalytique en oxydation, capacité de stockage de l'oxygène et basicité. Cette corrélation a été confirmée dans la dernière étude menée sur des catalyseurs mis en forme de type monolithes enduits avec différents matériaux (Pt/Al2O3, Pt/CeO2, Pt/ZrO2, Pt/Al2O3-CeO2, Pt/Al2O3-ZrO2 et Pt/CeO2-ZrO2). / The results presented in this manuscript have aimed at preparing catalytic materials based on noble metals for the removal of volatile organic compounds (VOC). Thus, different platinum based catalysts have been prepared and their catalytic performances have been evaluated for n-butanol and acetic acid oxidation. A first study on oxidative and non-oxidative removal of n-butanol over alumina supported platinum based catalysts has been performed. This work focused on the study of the effect of the different parameters involved in the reaction (oxygen, water, metal). The adsorption-desorption phenomenon of the pollutant on the catalyst surface has also been studied.Inspired by the literature on the specific redox properties of ceria, the work was then focused on the effect of the addition of CeO2 to Pt/Al2O3 catalysts for n-butanol and acetic acid oxidation. The modification of the redox and acid-base properties as well as that of the catalytic performances of the material with the addition of CeO2 allowed to establish a relationship between catalytic oxidation activities, oxygen storage capacity and basicity. This correlation has been confirmed in the last study performed on the monolithic catalysts coated with different materials (Pt/Al2O3, Pt/CeO2, Pt/ZrO2, Pt/Al2O3-CeO2, Pt/Al2O3-ZrO2 and Pt/CeO2-ZrO2).
347

Caractérisation des interactions entre un plasma non-thermique et des matériaux / Characterization of interactions between a non-thermal plasma and materials

Rodrigues, Anthony 08 November 2013 (has links)
L'étude des interactions entre les espèces actives générées par un plasma non thermique et diverses surfaces de matériaux font l'objet de ce travail.Dans un premier temps, des polymères provenant de la biomasse ont été le sujet de nos recherches. Ils représentent une source importante de molécules plateforme telle que le glucose à partir desquelles peuvent être générés des produits de haute valeur ajoutée. Plus précisément, les effets d'un plasma à décharge à barrière diélectrique sur la structure et la dépolymérisation de l'inuline, de la cellulose et de l'amidon ont été étudiés. Une variation des paramètres électriques et chimiques de la décharge plasma a été effectuée et leurs effets sur les biopolymères évalués afin de comprendre les mécanismes de réaction. Nos résultats ont montré qu'un traitement initial par le plasma permettait d'augmenter considérablement le rendement final en sucre monomère (fructose ou glucose) par rapport au même produit de départ non traité par le plasma (84 et 54% de glucose à partir réciproquement de l'amidon et de la cellulose traités par plasma, au lieu de 65 et 1 % pour les mêmes produits non traités). Cet effet pourrait être du en partie à une dépolymérisation par attaque acide induite au sein du plasma sur les zones amorphes des biopolymères.Dans un second temps, l'étude a porté sur l'élimination des COV par couplage plasma non-thermique et catalyseur. Pour cette étude, nous avons conçu et mis en oeuvre un appareillage original formé par un réacteur plasma-catalyseur permettant une analyse sous atmosphère contrôlée de la surface du catalyseur par spectroscopie IR (DRIFT). Cet appareillage a permis d'étudier la décomposition de quatre COV (isopropanol, acétone, éthanol et toluène) adsorbé sur différents oxydes métalliques (g-Al2O3, CeO2 et TiO2) placés dans la zone de décharge en temps réel (in-situ). Les premiers résultats ont permis d'élucider certaines voies de décomposition de ces différents COV. / The interactions between the active species generated by a non thermal plasma and various material surfaces have been studied in this work. In a first part, biopolymers coming from biomass have been the subject of our investigations as they offer a great reservoir for a platform molecule, glucose, from which valuable chemicals can be generated. More specifically, the effects of a dielectric barrier discharge plasma on the structure and depolymerization of inulin, cellulose and starch were evaluated. For that purpose, the electrical and chemical characteristics of the plasma discharge were varied and their effects on the biopolymers evaluated in order to understand the reaction mechanisms. Our results showed that a plasma pre-treatment increased considerably the final monomer yield (in glucose and fructose) compared to the untreated starting material (84 and 54 % yield in glucose from plasma treated starch and cellulose, instead of 65 and 1 % for the same untreated samples). This effect could be partly explained by the depolymerization of the amorphous areas of the polymers by and acid attack within the plasma discharge.In a second part, the study focused on the removal of VOCs by coupling non-thermal plasma and inorganic materials. For this purpose, we designed and implemented an innovative apparatus. It consists of a plasma-catalyst reactor with controlled atmosphere that allows the analysis of the catalyst surface by IR spectroscopy (DRIFT). The decomposition of four VOCs (isopropanol, acetone, ethanol and toluene) adsorbed on different metallic oxides (y-Al2O3, CeO2 and TiO2) placed within the discharge area have been studied in situ using this method. The first results have enlightened the decomposition pathways of the different VOCs.
348

Traitement combiné de polluants atmosphériques par filtration et adsorption pour limiter leur transfert dans l'habitat urbain / Combined treatment of outdoor air pollutants by filtration and adsorption for transfer limitation in urban dwelling

Morisseau, Kevin 26 October 2016 (has links)
Avec le développement des bâtiments basse consommation de plus en plus hermétiques, la nécessité de renouveler l’air intérieur à l’aide de système de ventilation mécanique s’est accrue. Or, les concentrations en polluants dans les environnements urbains augmentent continuellement, favorisant ainsi le transfert de polluants atmosphériques dans l’air intérieur. Ces travaux de thèse porte sur l’étude de procédés pour l’élimination combinée des principaux polluants de l’air extérieur urbain entrant dans les logements individuels via les systèmes de ventilation. A l’issue d’un état de l’art des polluants de l’air, des systèmes de ventilation et des procédés de traitement, les procédés de filtration par médias fibreux et d’adsorption ont été choisis pour traiter l’air urbain caractérisé par les PM₁₀, les PM₂ ₅, les aérosols microbiens, les BTEX et les NOₓ. Une méthodologie a été mise en œuvre pour sélectionner parmi différents matériaux étudiés et selon des critères de performances la solution de traitement la mieux adaptée, à savoir un filtre F7-combiné en fibres de verre et contenant des grains de charbon actif. Après étude, une stratégie de chauffage journalier du filtre à 70°C durant 1h30 a été proposée pour régénérer partiellement l’adsorbant afin de prolonger sa durée de vie et pour limiter la croissance microbienne sur le filtre notamment par dessiccation de ce dernier. Une campagne expérimentale en conditions de génération multi-polluants contrôlées a permis de quantifier les performances de traitement du filtre F7-combiné. Le traitement thermique utilisé a permis de maintenir une efficacité d’adsorption du toluène de 40% et de limiter la prolifération microbienne sur le filtre. Des interactions entre les polluants ont été observées, notamment une augmentation de l’efficacité de filtration des PM₁₀ par la présence de PM₂ ₅ qui permettent rapidement le passage à la phase de filtration en surface. En outre, le mélange toluène/NO₂ entraine une diminution de l’adsorption du NO₂ au profit du toluène. Enfin, une campagne expérimentale en conditions réalistes a été menée pendant 3 mois afin notamment d’étudier les performances du traitement thermique. Les niveaux de concentration des polluants dans la zone péri-urbaine de l’étude étaient faibles. Le traitement thermique appliqué au filtre F7-combiné, pour les conditions opératoires étudiées et après 3 mois de suivi, a permis de limiter significativement la croissance fongique sur le filtre mais pas d’améliorer de façon significative l’adsorption des COV et des NOₓ. / The development of low energy buildings, which are more and more hermetic, leads to the necessity of indoor air renewal with mechanical ventilation system. However, the concentration of pollutants in urban environments increases continually, which promotes the pollutant transfer from the outdoor to the indoor air. This PhD thesis consists in the study of processes for the combined purification of the main urban outdoor air pollutants coming in individual dwellings through the ventilation systems.Out of a state of the art of the air pollutants, the ventilation systems and the treatment processes, filtration with fibrous media and adsorption were the two processes chosen to treat the urban air characterized by PM₁₀, PM₂ ₅, microbialaerosol, BTEX and NOₓ. A methodology was setup to select, through the different studied materials and with some performance criterion, the most suitable treatment solution i.e. a combined-F7 filter with glass fiber and granular activated carbon. A daily heating strategy of the combined-F7 filter at 70°C for 1h30 was proposed to partially regenerate the adsorbent in order to improve its lifetime and to limit the microbial growth on the filter, inparticular by desiccation.An experimental campaign in controlled conditions with multi-pollutant generation permitted to quantify the performances of the combined-F7 filter. The thermal treatment permitted to maintain the adsorption efficiency of the toluene at 40% and to limit the microbial proliferation. Competitions within pollutants were observed, in particular an increase of the filtration efficiency of PM₁₀ with the presence of PM₂ ₅ by promoting the cake filtration stage. Moreover the mix toluene/NO₂ leads to a decrease of the NO₂ adsorption in favor of the toluene.Finally, an experimental campaign in realistic conditions was conducted for 3 months in particular to study the performances of the thermal treatment. Concentration levels of the pollutants in the suburban area of the study were low. The thermal treatment applied to the combined-F7 filter, with the operating conditions studied and after 3month of follow-up, permitted to significantly limit the fungal growth on the filter but it did not permit to improve significantly the VOC and NOₓ adsorption.
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Étude cinétique de la dégradation photocatalytique de composés organiques volatils (COV) et modélisation par une approche numérique de la mécanique des fluides / Kinetic study of VOC photocatalytic remediation and modelling with a computational fluid dynamics approach

Queffeulou, Amélie 05 November 2009 (has links)
Les COV présents en air intérieur sont une source d’inconfort pour les occupants et peuvent être nocifs pour la santé. La photocatalyse apparaît comme un procédé prometteur pour l’abattement de ces polluants. ArcelorMittal Liège Research développe à cet effet des films minces de TiOB2B déposé sur acier qui peuvent être intégrés dans des systèmes de purification d’air. Les objectifs de cette recherche sont, d’une part, identifier les paramètres influençant la dégradation photocatalytique de ces COV avec ce type de catalyseur et d’autre part, valider la possibilité de prédire les performances d’un réacteur photocatalytique par un modèle couplant l’écoulement et la réaction photocatalytique. Pour réaliser l’étude cinétique à des teneurs de quelques ppm, un dispositif expérimental adapté a été conçu ; il utilise un réacteur annulaire continu. L’acétaldéhyde a été choisi comme polluant modèle. La conversion dépend de la concentration en polluant, du taux d’humidité, de la température, de l’intensité lumineuse en UV et de la présence d’autres COV. La réaction est modélisée avec un modèle théorique surfacique de la réaction photocatalytique. Afin de prédire les performances d’un réacteur photocatalytique utilisant des films minces de TiOB2B, une méthodologie consistant à coupler l’écoulement et la réaction photocatalytique a été développée et validée. La distribution spatio-temporelle de la concentration en polluant est alors déterminée par une approche de mécanique des fluides numériques. La comparaison des résultats expérimentaux et des simulations obtenus avec un réacteur photocatalytique de laboratoire et un autre à l’échelle semi-pilote est très satisfaisante / VOCs are a source of discomfort for occupants and can have harmful effects on health. Photocatalysis is a promising process to remove these compounds. ArcelorMittal Liège Research has indeed developed TiOB2 Bthin film coated on steel which can be easily integrated into purification air systems. Objectives of this research are firstly, identifying parameters which influence the photocatalytic degradation of these VOCs using of such catalyst. Secondly, validate the possibility to predict performances of the photocatalytic reactor by combining fluid flow and photocatalytic reaction. An experimental set-up including an annular reactor has been designed and realized in order to conduct kinetic studies. Acetaldehyde has been chosen as a pollutant model and studied mainly with concentrations of few ppm ranges. Its conversion yield depends on pollutant concentration, relative humidity, temperature, UV light intensity and presence of others VOCs. Based on a theoretical surface model of the photocatalytic reaction, and using experimental data, this reaction is modelled. In order to predict performances of the photocatalytic reactor packed thin film of TiOB2B, a methodology which consists to combine fluid flow and photocatalytic reaction has been developed and validated. Space-time distribution of pollutant concentration is then determined with a computational fluid dynamics approach. Comparison between experimental data and numerical simulations obtained with a photocatalytic reactor at the laboratory scale and another one in semi-pilot scale are well satisfactory
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Elaboration d’un microsystème d’analyse de l’air destiné à la détection rapide d’un développement fongique dans les espaces clos / Elaboration of a rapid and continuous air analyzing macrosystem for fungal contamination detection in enclosed spaces

Joblin, Yaël 12 May 2011 (has links)
Les champignons sont des biocontaminants courants des environnements intérieurs. De nombreuses études ont démontré leur rôle dans la dégradation des supports que ces microorganismes colonisent tels que les matériaux de construction, les ouvrages ou les œuvres d'art. De plus, ces biocontaminants sont susceptibles d'induire des allergies, des infections, des toxi-infections ou encore des irritations. Depuis 2005, une technique de détection de la croissance fongique, basée sur la recherche de traceurs chimiques spécifiques dans l'air, et un indice de contamination fongique (ICF), ont été développés et validés au cours de différentes campagnes de mesures dans l'habitat, les bureaux, les écoles, les crèches… L'objectivation d'une croissance fongique dans un environnement s'appuie sur des prélèvements par adsorption, une analyse chromatographique au laboratoire (GC/MS) et le calcul de l'ICF. Dans le cadre de la surveillance de la qualité microbiologique de l'air des environnements intérieurs, cette thèse a pour ambition de prolonger ces travaux en développant notamment un système de microcapteurs chimiques adapté à la mesure in situ. Cette recherche repose à la fois sur la méthode de détection fongique développée au CSTB et sur l'expertise scientifique et technique de l'ESIEE en matière de miniaturisation d'instruments de mesure, grâce à l'apport des microtechnologies. Le premier axe de cette étude a consisté à identifier expérimentalement les COV du métabolisme fongique spécifiques d'un développement sur des matériaux du patrimoine. Ces molécules ont permis de consolider l'ICF et de définir deux indices spécifiques à la problématique des sites patrimoniaux, validés dans des châteaux, musées, bibliothèques, grottes ornées… Le second axe porte, d'une part, sur la conception la réalisation et la caractérisation des briques élémentaires du microsystème d'analyse, à savoir un module de préconcentration (adsorption TENAX), un module de séparation (microGC) et un module de détection (capteurs polymères) et d'autre part sur les intégrations et pilotage de ces briques / Fungi are common microbial contaminants of indoor environments. Many studies have demonstrated their role in the partial or total degradation of materials they colonize such as building materials, or works of art. Moreover, those microbial contaminants are likely to lead to allergies, infections, poisoning or irritation. Since 2005, a new technique based on researching specific chemical tracers in the air, was developed and validated during different measurement campaigns. This approach is now applied to various indoor environments (houses, offices, schools, child care centers…) and allows the detection of recent and/or hidden contamination. The purpose of this work is to study and characterize a rapid and continuous air analysing microsystem for detection of fungal contamination in closed spaces. This study falls within the field of monitoring air microbiological quality in indoor environments. In addition to the time saved by the absence of any laboratory analysis, this system must provide a permanent monitoring of environments frequented by people, such as museums, schools, hospitals... This research is based both on the fungal detection method developed by CSTB and on scientific and technical expertise of ESIEE : specialised in design and manufacturing of miniaturized analysis systems obtained using microtechnology. The first step of this study was to define the compounds' nature to be detected for different cases of contamination along with the sampling strategy for the system. The second step focuses on the microstructures design and fabrication to be used in microanalytical system based on gas chromatography and the development of a miniaturised analysis system. So the first part of the study consisted in defining specific fungal contamination tracers for heritage conservation sites. This list allowed to reinforce a fungal contamination index for indoor environments and to define two specific indexes designed for heritage conservation sites. The validation of these different indexes allowed checking their compliance with those types of environments (castles, museums, libraries, decorated caves...) by detecting all cases of contamination, along with the control remediation of former contaminated environments. The second part of the study enabled the design and validation of three main modules constitutive of the microanalytical system based on gas chromatography. A miniaturised analysis system based on three modules has been developed

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