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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.
781

Étude des propriétés physiques et du comportement mécanique des Basaltes : étude cinétique, mécanistique et toxicologique de l'oxydation dégradante de l'Ibuprofène par l'oxydation avancée électrochimique et photochimique / Study of the physical proprieties and mechanical behavior of basaltic rocks : kinetic, mechanistic and toxicological study of the ibuprofen degradation by electrochemical and photochemical oxidation processes

Loaiza Ambuludi, Silvia 18 December 2012 (has links)
La première partie de ce travail de thèse s'inscrit dans le cadre de la dépollution des eaux contaminées par les polluants organiques persistants et plus en particulier par les résidus pharmaceutiques. Des techniques alternatives telles que les procédés d'oxydation avancée (POA) qui utilisent comme agent oxydant les radicaux OH, ont été appliquées à la dégradation et/ou à la minéralisation d'un polluant médicamenteux, l'Ibuprofène, en milieu aqueux. Il a été choisi comme molécule modèle en raison de son grand volume de prescription et de sa présence prouvée dans les effluents des stations d'épuration et dans les eaux naturelles. Notre étude a consisté notamment à la recherche d'optimisation des paramètres opératoires tels que la concentration de H2O2 et de Fe2+ ainsi que leur rapport pour générer les radicaux hydroxyles par le procédé photo-Fenton, et la concentration (et nature) de l'électrolyte de support et l'intensité du courant appliqué pour les procédés électrochimiques électro-Fenton et oxydation anodique. En outre, l'évolution de la toxicité de cette molécule a été suivie par la méthode Microtox au cours du traitement par le procédé d'oxydation anodique. La cinétique d'oxydation et de minéralisation de l'ibuprofène a été étudiée. La constante de réaction d'oxydation de l'ibuprofène avec les radicaux hydroxyles a été déterminée par la méthode de cinétique de compétition comme 3,84 109 M-1 s-1. Nos résultats montrent que l'application de ces procédés est efficace pour éliminer ce produit pharmaceutique de l'eau. On atteint la dégradation complète du polluant, et une minéralisation quasi-totale de la matière organique. La deuxième partie englobe une étude expérimentale sur les propriétés physiques (à différentes échelles) et le comportement mécanique des Basaltes. On a étudié le comportement mécanique et les modes de rupture d'un basalte poreux des Açores. Les résultats sont obtenus lors d'essais en contrainte triaxiale, en conditions totalement drainées et à température ambiante. Ce basalte présente deux modes de déformation. À faible pression de confinement, les échantillons présentent un comportement mécanique fragile et une déformation localisée (bande de cisaillement). Pour des pressions de confinement plus élevées, le basalte présente un comportement ductile et des compactions localisées (bandes de compaction). Les données mécaniques ont permis de déterminer l'enveloppe complète du domaine élastique. La quantification des propriétés physiques de deux types de basaltes des Galápagos a été effectuée à pression et température ambiante. Dans le but d'étudier l'effet de la fissuration sur les propriétés physiques, les échantillons on été soumis à des traitements thermiques. Enfin, pour étudier la réponse de la roche aux conditions de pression auxquelles elle est soumise en profondeur, des mesures de vitesses des ondes sous pression ont été acquises. Les résultats obtenus et l'utilisation de modèles théoriques ont permis de quantifier la densité de fissures initiales et de celles induites par les traitements thermiques, ainsi que le facteur de forme de celles-ci. L'ensemble des propriétés physiques ont permis de mieux comprendre le rôle du réseau poreux de la roche sur les propriétés physiques. Cette étude de laboratoire a été nécessaire pour l'interprétation des données recueillies in situ par sismique réfraction / The first part of this thesis is focused on the remediation of waters contaminated with persistent organic pollutants, in particular pharmaceutical products. Alternative technologies such as the advanced oxidation processes (AOPs), which based on the generation of hydroxyl radicals OH, were applied to the degradation and/or mineralization of a pollutant drug, ibuprofen, in aqueous medium. We chose this pollutant as a model molecule to study due to its large volume of prescription and to its proved presence in the effluents of sewage plants and natural waters. The main objective of this work was the optimization of operational parameters of the applied AOPs. The concentration of H2O2 and Fe2+ reagents ratio to generate hydroxyl radicals for photo-Fenton process, and supporting electrolyte concentration (and the nature) and the applied current for both electro-Fenton and anodic oxidation processes. The oxidation and mineralization kinetics of the ibuprofen were studied and the absolute rate constant for the oxidative degradation of ibuprofen was determined by the competition kinetic method, being 3,84 109 M-1s-1. Toxicity tests of the drug solutions during the anodic oxidation process were carried out by the Microtox method. Our results show that these methods are effective for the degradation of this pharmaceutical product from water. Ibuprofen was completely degraded and the organic matter was almost completely mineralized after the application of these processes. The second part of the thesis includes an experimental study of the physical properties (at different scales) and the mechanical behavior of basaltic rocks. We studied the mechanical behavior and the failure modes of a porous basalt from Azores. Results were acquired under triaxial compression experiments on water saturated samples at room temperature. This basalt presented two modes of deformation. At low confining pressure, the samples exhibited a brittle mechanical behavior and a localized deformation (shear band). For higher confining pressure, this basalt showed a ductile behavior and localized compactions (compaction bands). The mechanical data allows us to plot the full yield surface for the porous basalt. The quantification of the physical properties of two types of basalts from the Galapagos was performed at room temperature and pressure. In order to study the effect of cracking on the physical properties of these basalts, samples were subjected to thermal treatments to induce thermal crack damage. Finally for the less porous basalt, measures of wave velocities under the pressure at which it is subjected in depth were acquired. The obtained results and the following application of models with them allow quantifying the density of initial cracks and of those induced by thermal treatments, as well as quantifying the aspect ratio of cracks. The studied physical properties led to better understand the role of the pore network of the rock in these physical properties. This laboratory study was necessary for the interpretation of data collected in situ by seismic refraction method
782

Performances des procédés physico-chimiques et membranaires pour l'élimination des ions fluorure dans les eaux de forage : application aux eaux tunisiennes / Performances of physico-chemical and membranes processes for the elimination of fluoride ions in drilling waters : application to tunisian waters

Ben Nasr, Anis 04 October 2013 (has links)
La problématique de l’élimination de l’excès d’ions fluorure présents dans les eaux de forage destinées à la consommation humaine peut être résolue en utilisant plusieurs méthodes. Dans cette thèse, les procédés testés sont : l’adsorption sur des particules d’os de seiche, l’adsorption sur des particules de calcite en présence d’acide acétique, la nanofiltration et l’échange d’ions. L’objectif est d’optimiser les différents procédés pour des solutions modèles en ions fluorure, puis de réaliser pour ces conditions optimales le traitement d’une eau de forage tunisienne. La concentration limite en ions fluorure imposée par la WHO est de 1.5 mg.L-1. Les essais d’adsorption en utilisant l’os de seiche, disponible en Tunisie, sont simples à mettre en œuvre et permettent des traitements à petite échelle avec des coûts très compétitifs en utilisant un matériau non toxique. La défluoration de l'eau souterraine avec l’os de seiche présente une concentration résiduaire en fluorure de 1,3 mg.L-1 (TR = 61,5%). Dans le cas de la précipitation des ions fluorures sous forme de fluorite suivi de microfiltration, l’addition d’acide acétique aux particules de calcite (CaCO3) favorise l’élimination des ions fluorure. La défluoration de l'eau souterraine montre que l’eau traitée présente une concentration résiduaire en fluorure de 1,24 mg.L-1 (TR = 53,7%). En utilisant une résine échangeuse d’ions Purolite A520E, la défluoration de l'eau souterraine montre que l’eau traitée présente une concentration résiduaire en fluorure de 1,2 mg.L-1 (TR = 54%). La nanofiltration permet de traiter des volumes importants d’eau et les taux de rétention des ions fluorure sont satisfaisants (88% et 57%) / The issue of the removal of excess fluoride ions present in well water for human consumption can be solved using several methods. In this PhD thesis, four processes have been tested: adsorption using cuttlefish bone particles, adsorption on calcite particles with acid acetic addition, nanofiltration and ion exchange. The aim is to optimize the different processes by using model solutions of fluoride ions, and to treat a Tunisian groundwater at these optimal conditions. The limiting concentration given by the WHO is 1,5 mg.L-1. The adsorption using cuttlefish bone, available in Tunisia, is simple to implement and provides treatment at small scale with very competitive costs by using a non-toxic material. Defluorination of groundwater shows that the water treated with cuttlefish bones has a residual fluoride concentration of 1.3 mg L-1 (TR = 61.5%). In the case of precipitation of fluoride ions in the form of fluorite followed by microfiltration, the addition of acetic acid to the particles of calcite (CaCO3) promotes the removal of fluoride. Defluorination groundwater shows that the treated water has a residual fluoride concentration of 1.24 mg L-1 (TR = 53.7 %). Using a ion exchange resin Purolite A520E, defluorination groundwater shows that water treated has a residual fluoride concentration of 1.2 mg L-1 (TR = 54%). Nanofiltration is particularly interesting as it allows the treatment of large volumes. The retention of fluoride ions are again satisfactory (88% and 57%)
783

Adsorpce nízkomolekulární složky organických látek produkovaných fytoplanktonem na aktivním uhlí při úpravě vody / Adsorption of low molecular weight algal organic matter onto activated carbon during water treatment

Fialová, Kateřina January 2019 (has links)
This diploma thesis deals with the study of adsorption of low-molecular components of organic substances produced by phytoplankton - AOM (Algal Organic Matter) on AC (Activated Carbon) during drinking water treatment. For the experimental purpose in this thesis, there were used selected amino acids as low molecular substances of AOM that are difficult to remove by conventional water treatment process by coagulation. As adsorbent, there was used a detailed characterized of granulated activated carbon (GAC) - Filtrasorb TL 830 (FTL830) which is intended directly for the purpose of water treatment. There were realizing the equilibrium batch adsorption experiments with three different model amino acids - arginine (Arg), phenylalanine (Phe) and aspartic acid (Asp). There was investigated the efficiency of removing amino acid depending on the solution temperature and pH. Results of the adsorption experiments have shown that the temperature affects the adsorption efficiency. Adsorption is essentially described as an exothermic process but the adsorption of Arg and Phe from an aqueous solution to GAC occurs more efficiently at higher temperatures. It means that the adsorption is the endothermic process. In the case of Arg adsorption, the temperature was found to influence adsorption efficiency less than...
784

Innovative techniques for the quantification of waterborne microbial risks in field studies

Zimmer, Camille 30 August 2019 (has links)
In low-resource contexts, household-level point-of-use water treatment (POUWT) techniques are the final, and sometimes only, barrier against waterborne illnesses, and in these and other water-related applications, health risks can be quantified using one of two methods. Firstly, Escherichia coli (or other indicator organism) counts can be used to monitor water and determine adherence to a health-based limit (i.e. compliance monitoring). Secondly, E. coli can be used to conduct a quantitative microbial risk assessment (QMRA), indicating the level of protection conferred by a given POUWT device by spiking test water with E. coli to ascertain a reduction efficacy relative to that target organism, a process referred to as challenge testing, which is typically carried out in a laboratory context. Although both methods are well established, both have scope for improvement for effective field application in low-resource contexts. Regarding compliance monitoring, I assessed the performance of a new low-cost field kit for E. coli enumeration, which was designed by others. I also assessed the feasibility of re-using some disposable materials, in terms of sterility and mechanical wear. The use of the new low-cost field kit was successful during the fieldwork campaign; however, re-using disposable materials introduced a relatively high occurrence of false positive results during E. coli enumeration. Use of the new low-cost field kit can reduce financial barriers, thus enabling greater water quality testing coverage. Regarding challenge testing, the aim of this study was to adapt current protocols to assess the household performance (as opposed to laboratory performance) of POUWT techniques. I developed a conceptual framework to conduct Field Challenge Tests (FCT’s) on POUWT techniques, using a probiotic health supplement containing E. coli as the challenge organism. I successfully carried out a FCT in Malawi with limited resources, verifying FCT viability. Applications of such FCT’s include quality control practices for manufactured devices, guiding QMRA and recommendations by public health organizations regarding POU device selection, and assessing the impact of user training programmes regarding POUWT techniques. / Graduate
785

Efeito de algicidas sobre as cianobactérias e a microcistina-LR: implicações para o tratamento avançado de águas de abastecimento com carvão ativado / Effect of algaecides on cyanobacteria and microcystin-LR: implications for advanced drinking water treatment using activated carbon

Koshigoe, Amanda Sati Hirooka 14 May 2019 (has links)
Um grande desafio da atualidade é a crescente ocorrência, em ambientes aquáticos, de cianobactérias potencialmente tóxicas capazes de produzir cianotoxinas como a microcistina. Estratégias de controle de florações incluem a aplicação de algicidas. No entanto, esses produtos podem resultar na liberação de toxinas, que podem não ser removidas da água pelos processos convencionais de tratamento, sendo necessária uma etapa adicional como a adsorção com carvão ativado granular (CAG). A presente pesquisa avaliou com embasamento estatístico o efeito de cinco diferentes algicidas (à base de diuron, carbonato de sódio, polímero catiônico, sulfato de cobre e peróxido de hidrogênio), aplicados em três concentrações distintas, sobre a Microcystis aeruginosa, analisando-se a densidade celular, o biovolume, a concentração de potássio e de microcistina-LR extracelular/intracelular. Além disso, foram investigadas as implicações que esses produtos tiveram sobre a adsorção em dois CAGs, por meio de isotermas e modelos cinéticos. Todos os algicidas afetaram a integridade das células, resultando na liberação de microcistina. O último dia experimental (dia 7) foi o que apresentou maior concentração de microcistina extracelular, em que, em alguns casos, houve aumento de 10 vezes da concentração final de microcistina extracelular em relação à concentração inicial. O potencial de liberação de microcistina extracelular ocorreu na seguinte ordem de algicidas: polímero catiônico > sulfato de cobre > peróxido de hidrogênio > carbonato de sódio > diuron. Os algicidas também alteraram o comportamento de adsorção (de monocamada para multicamada), bem como pioraram os ajustes cinéticos. Além disso, enquanto o polímero catiônico praticamente triplicou a capacidade adsortiva dos carvões, o sulfato de cobre e o peróxido de hidrogênio pioraram o desempenho de ambos. Os algicidas possuem modos diferentes de ação e geraram consequências distintas para os indicadores avaliados, além de alterar a adsorção. Isso pode indicar a necessidade de se considerar a presença desses produtos na elaboração de projetos de estações de tratamento de água (ETAs). / A major challenge nowadays is the increasing occurrence in aquatic environments of potentially toxic cyanobacteria capable of producing cyanotoxins such as microcystin. Bloom control strategies include application of algaecides. However, these products may result in toxins release, which may not be removed from water by conventional treatment processes, requiring an additional step such as adsorption with granular activated carbon (GAC). The present study evaluated, using statistical methods, the effect of five different algaecides (diuron, sodium carbonate, cationic polymer, copper sulfate and hydrogen peroxide), applied on Microcystis aeruginosa in three different concentrations. We analyzed cell density, biovolume, potassium concentration and extracellular/intracellular microcystin-LR concentration. In addition, we investigated the implications these products had on two GACs adsorption, through isotherms and kinetic models. All algaecides affected cell integrity, resulting in microcystin release. The last experimental day (day 7) was the one that presented the highest extracellular microcystin concentration, in which, in some cases, there was a 10 times increase in the final extracellular microcystin concentration in relation to the initial concentration. The extracellular microcystin release potential occurred in the following order of algaecides: cationic polymer > copper sulfate > hydrogen peroxide > sodium carbonate > diuron. Algaecides also modified adsorption behavior (from monolayer to multilayer), as well as worsened kinetic adjustments. Furthermore, while cationic polymer almost tripled carbons adsorptive capacity, copper sulfate and hydrogen peroxide worsened the performance of both. Algaecides present different modes of action and caused distinct consequences for the evaluated indicator, besides modifying adsorption process. This may indicate the need to consider the presence of these products in water treatment plants (WTPs) designs.
786

Métodos de recuperação e estimativa de viabilidade de cistos de Giardia spp. e oocistos de Cryptosporidium spp. em resíduos do tratamento de água de consumo / Recovery methods and viability assessment of Giardia spp. e oocistos cysts and Cryptosporidium spp. oocysts in water treatment residues

Silva, Kamila Jéssie Sammarro 25 February 2019 (has links)
Esta pesquisa comparou a incorporação de iodeto de propídio (IP) com a avaliação simultânea de corantes indicativos de danificação em membrana e atividade enzimática (Live/Dead Cell Assay®) para a estimar a viabilidade de cistos de Giardia muris e oocistos de Cryptosporidium parvum. Além disso, foram testados métodos de recuperação de (oo)cistos em amostras de lodo e água de lavagem de filtros (ALF) geradas em escala de bancada, simulando tratamento de água por ciclo completo com decantação. Dentre os métodos estudados para a detecção de G. muris e C. parvum inoculados em amostras de lodo, destacou-se a floculação com sulfato férrico, seguida de separação imunomagnética (IMS). Realizou-se, portanto, ensaio de qualidade analítica com ColorSeedTM, para este método, tendo atendido ao requerido pelo Método 1623.1 da USEPA (2012) para Giardia spp. (32,25%; CV=9,00%), mas não tendo sido suficiente para Cryptostoridium spp. (11,00%; CV=47,67%). O teste com ColorSeedTM em amostras de ALF reproduziu o procedimento de filtração em membrana (FM) com raspagem utilizando Tween® 80 (45°C, 0,1%) seguido de IMS, tendo atendido ao Método 1623.1 para Giardia spp. (13,00%, CV=19,61%), mas não tendo sido suficiente para Cryptostoridium spp. (2,00%; CV=93,54%). Optou-se por este procedimento na avaliação de qualidade analítica, pois o inóculo prévio de suspensões comerciais seguido de recuperação por FM sem IMS superou 100% para C. parvum, devido à utilização de fator de multiplicação. O desempenho do Live/Dead Cell Assay® sobre suspensões comerciais de (oo)cistos foi subjetivo, sobretudo para visualização de organismos enzimaticamente ativos, de modo que optou-se pela inclusão de IP como parâmetro para estimar o efeito dos métodos de recuperação sobre a viabilidade. Em função da baixa recuperação e fluorescência de G. muris, a incorporação de IP foi avaliada apenas em C. parvum. Os resultados reiteraram a dificuldade na recuperação de protozoários em lodo e ALF e o fato de que as particularidades destes procedimentos analíticos podem prejudicar a interpretação de dados de viabilidade. / This study compared the incorporation of propidium iodide (PI) with the simultaneous evaluation of dyes that indicate both membrane damage and enzymatic activity (Live/Dead Cell Assay®) to assess the viability of Giardia muris cysts and Cryptosporidium parvum oocysts. In addition, methods of recovering protozoan cysts and oocysts from sludge and filter backwash water (FBW) samples generated on bench scale, simulating conventional water treatment with decantation, were tested. Among the studied methods for detection of G. muris and C. parvum spiked into sludge samples, ferric sulphate flocculation followed by immunomagnetic separation (IMS) lead to higher recoveries. An analytical quality assay was therefore carried out with ColorSeedTM having met the USEPA Method 1623.1 (2012) recommendation for Giardia spp. (32.25%, CV=9.00%) but not for Cryptostoridium spp. (11.00%, CV = 47.67%). The quality assay test for FBW samples replicated the membrane filtration (MF) procedure using Tween® 80 (45 °C, 0.1%) followed by IMS, having complied with Method 1623.1 for Giardia spp. (13.00%, CV=19.61%) but again not for Cryptostoridium spp. (2.00%; CV=93.54%). This procedure was chosen for the analytical quality exam, since the previous inoculum of commercial suspensions followed by MF without IMS exceeded 100% recovery for C. parvum, due to the use of a multiplication factor. The Live/Dead Cell Assay® performance on commercial suspensions of cysts and oocysts was subjective, especially for visualizing enzymatically active organisms, thus PI inclusion was chosen as the parameter to estimate the effect of recovery methods on the organisms\' viability. Due to the low recovery and poor fluorescence of G. muris, IP inclusion was evaluated only in C. parvum. The results reiterated the difficulty in the recovery of protozoa from sludge and FBW and the possibility of these analytical procedures hinder the interpretation of cysts and oocysts viability.
787

Remoção de substâncias húmicas no processo de filtração em múltiplas etapas precedido de oxidação com ozônio / Humic substances removal in the multistage filtration system-MSF preceded rust with ozone

Almeida, Hélio da Silva 30 November 2001 (has links)
No presente trabalho foi investigada a remoção de substâncias húmicas na Filtração em Mútiplas Etapas - FiME, com aplicação de ozônio antecedendo o processo de filtração lenta. A instalação piloto era constituída de um pré-filtro dinâmico operado com taxa de 18 m/dia, um pré-filtro de escoamento vertical ascendente operado com taxa de 12 m/dia e dois filtros lentos trabalhando com taxas de filtração iguais a 4 m/dia, com diferentes composições dos leitos filtrantes, sendo um somente de areia e o outro de areia e carvão ativado granular disposto como camada \"sanduíche\" entre duas camadas de areia, e sistema de ozonização. Foi injetada solução de substância húmica na água efluente do pré-filtro vertical ascendente, preparada a partir da turfa retirada de uma área localizada no município de Luís Antônio, para proporcionar aumento de cor verdadeira na água. A eficiência das unidades filtrantes, na remoção de matéria orgânica foi avaliada pela determinação de cor verdadeira, carbono orgânico dissolvido, absorvância a 254 nm e oxigênio consumido. O resultados obtidos mostraram que o filtro lento 1, com carvão ativado, foi superior na remoção de matéria orgânica nas duas carreiras desenvolvidas e que não houve diferença entre os filtros lentos quanto a remoção de Escherichia coli, bactérias heterotróficas, sólidos suspensos totais e ferro total. Fortes correlações entre cor verdadeira e absorvância foram identificadas na carreiras de filtração. O mesmo ocorreu só na carreira 3 entre carbono orgânico dissolvido e absorvância e entre COD e oxigênio consumido. / The current research was carried out investigate the removal of humic substances in the multistage filtration system - MSF, with ozone application upstream slow sand filters. The pilot plant was compose by one dynamic roughing filter operated at a filtration rate of 18 m/day, one upflow roughing filter with filtration rate of 12 m/day and two slow sand filters, both operated with filtration rate of 4 m/day, with different \"filtering beds\"; one with sand only and another with sand and granular activated carbon, disposed as a \"sandwich\" layer between two sand layers, and the ozonation system. Solution of humic substance was injected in the effluent water from the upflow roughing filter, which was prepared using turf extracted from Luís Antônio County, to provide a raise in the real color of the water. The efficiency of the filtering units in the remotion of organic matter was evaluated by using the following parameters: true color, dissolved organic carbon, Uv - absorbance at 254 nm and the consumed oxygen. The results show that the slow sand filter 1, with activated carbon, was better for the removal of organic matter in the two runs carried out and that there were no differences between the slow sand filters in the removal of Escheyichia Coli, heteroph bacteria, total suspended solids. Strong correlation between true color and UV - absorbance was identified in run 1. The same occurred in run 3, relating the dissolved organic carbon and UV - absorbance and between DOC and consumed oxygen.
788

Influência da porosidade do leito e do diâmetro das fibras na eficiência da filtração com filtro de fibras flexíveis aplicado ao tratamento de água / Influence of the porosity and diameter of the fibers in filtration efficiency with flexible fibers filter applied to water treatment

Sá, Aline Beatriz Carvalho de 07 October 2016 (has links)
Os filtros de fibras flexíveis são unidades de filtração direta, compostos por leito de microfibras. São operados com altas taxas de filtração, garantindo alta eficiência de remoção de sólidos suspensos. Neste estudo avaliou-se a influência dos diâmetros das fibras, da porosidade do leito e da taxa de filtração na eficiência de clarificação de uma água sintética, utilizando filtro de fibras de poliamida. Foram construídos três filtros com diâmetro interno de 28mm e porosidade de 84%, cada um com leito de 100 cm de comprimento e diâmetro de fibra de 0,03, 0,11 e 0,32 mm e um filtro de mesmo diâmetro e comprimento, composto por fibras de 0,03 mm e porosidade 93%. A distribuição de água na entrada do filtro foi composta por 4 orifícios periféricos de 3,5 mm e um orifício central de 8 mm (Fundo de filtro Tipo 1 – FTipo1). Essa mesma entrada foi utilizada para a distribuição de água e ar na lavagem. Em um segundo momento, avaliou-se outra distribuição de água na entrada do filtro, com apenas quatro orifícios periféricos (Fundo de filtro Tipo 2 – FTipo2). Nessa nova configuração de filtro, foram avaliados os filtros de fibras de 0,03 mm, em duas porosidades: 84% e 93%. A água sintética possuía turbidez de 9,51 ± 0,22 uT e cor aparente de 86,4 ± 4,5 uC. A coagulação foi realizada in-line com sulfato de alumínio na dosagem de 22,5 mg.L-1. Em todos os filtros foram avaliadas três taxas de filtração: 60, 80 e 100 m h-1 e estabeleceu-se os limites de turbidez na água filtrada de 0,5 e 2,0 uT para o final da carreira de filtração. A distribuição de água na entrada do filtro mostrou-se de extrema importância para o bom funcionamento do mesmo, pois, dependendo da sua configuração, podem ocorrer emaranhamentos das fibras, comprometendo a eficiência de remoção de cor e turbidez. O filtro com fundo FTipo1 apresentou qualidade satisfatória para o filtro de fibras com diâmetro 0,11 mm, produzindo água filtrada com turbidez abaixo de 2,0 uT. O filtro de fibras de 0,03 mm de diâmetro conseguiu produzir qualidade dentro do limite estabelecido em alguns ensaios, entretanto não houve repetibilidade devido ao emaranhamento ocorrido no leito. Já o filtro de fibras de diâmetro 0,32 mm não atingiu turbidez satisfatória. Os dois filtros de fibras com fundo FTipo2 e porosidades 93% e 84%, respectivamente, conseguiram atingir os valores impostos para a turbidez da água filtrada em todas as taxas estudadas (60, 80 e 100m h-1) , com exceção do filtro de 93% de porosidade que não atingiu a turbidez mínima de 0,5 uT quando operado uma taxa de 100 m h-1. Ao final estimou-se os volumes de água filtrada produzidos no intervalo de um dia (24h) para cada filtro que atingiu os limites de turbidez pré-estabelecidos. Dentre as variações testadas em FTipo1 e FTipo2, concluiu-se que o volume diário de água produzida aumenta proporcionalmente ao aumento da taxa de filtração. Esse estudo demonstrou que o diâmetro da fibra, a porosidade e o fundo do filtro são características essenciais para o bom funcionamento do filtro, influenciando na eficiência de remoção de turbidez e cor aparente da água afluente. / The flexible fiber filters are direct filtration module, made of microfibers filter media. They are operated with high filtration rates ensuring high solids removal efficiency. This study evaluated the influence of diameters of fibers, porosity and filtration rates in the clarification efficiency of synthetic water. Three filters have been constructed with internal diameter of 28 mm and porosity of 84%, each with a filter medium of 100 cm length and fiber diameter of 0.03, 0.11 and 0.32 mm, and a filter of the same diameter and length, comprises fibers of 0.03 mm and porosity of 93%. The water distribution at the filter inlet was composed by four peripheral holes of 3.5 mm and a central hole of 8 mm (filter bottom Type 1 - FType1). That same input was used for water and air distribution in the wash. In a second step, was evaluated other water distribution in the filter inlet, with only four peripheral holes (filter bottom Type 2 - FType2). In this new filter configuration were evaluated 0.03 mm fiber filters with two porosity values: 84% and 93%. The synthetic water had turbidity of 9.51 ± 0.22 NTU and apparent color of 86.4 ± 4.5 uC. The coagulation was performed in-line with aluminum sulfate at a dosage of 22.5 mg.L-1. In all three filters were evaluated three filtration rates: 60, 80 and 100 m / h and fixed the limits of the filtered water turbidity of 0.5 and 2.0 NTU at the end of the career filter. The water distribution in the filter inlet proved to be extremely important for the proper functioning of the same, because, depending on your configuration, entanglements can occur, compromising the color and turbidity removal efficiency. The bottom filter FType1 presented a satisfactory quality for the fiber filter diameter 0.11 mm, producing filtered water with turbidity below 2.0 NTU. The filter of 0.03 mm diameter fibers could produce water quality within the limit in some tests, however there was no repeatability due to entanglement occurred in the bed. Other way, the 0.32 mm diameter fiber filter has not reached satisfactory turbidity. The two fibers filters FType2 and porosity 93% and 84%, respectively, were able to achieve values imposed to the turbidity of the filtered water in all studied rates (60, 80 and 100 m.h-1), except 93% porosity filter witch not reached the minimum turbidity of 0.5 NTU when operated a 100 m.h-1 rate. At the end was estimated the volumes of the filtered water produced within one day (24h) for each filter that has reached the limits of predetermined turbidity. Among the variations tested FType1 and FType2, can be concluded that the daily water volume produced increases with the filtration rate increasing. This study demonstrated that the fiber diameter, porosity and filter bottom characteristics are essential for the proper functioning of the filter, influencing the apparent color and turbidity removal efficiency of influent water.
789

Síntese de membranas planas compostas de PVDF e nanopartículas de argila. / Synthesis of flat sheet membrane using PVDF and clay nanoparticles.

Morihama, Ana Carolina Daniel 30 March 2016 (has links)
Esta pesquisa foi desenvolvida no laboratório do Centro Internacional de Referência em Reúso de Água (CIRRA), vinculado ao Departamento de Engenharia Hidráulica e Ambiental da Escola Politécnica da Universidade de São Paulo (USP). O projeto de pesquisa teve como objetivo principal a síntese de membranas planas compostas, utilizando o polímero fluoreto de polivinilideno (PVDF), nanopartículas inorgânicas de argila (montmorilonita hidrofílica) e óxido de polietileno (PEO). As membranas foram sintetizadas pelo processo de inversão de fases, utilizando 18% em massa de PVDF, n-metil-pirrolidona como solvente e água como o não solvente. Avaliou-se a influência da introdução de diferentes concentrações de nanopartículas de argila e PEO. As membranas sintetizadas foram submetidas a testes de avaliação de desempenho (permeabilidade, capacidade de separação, potencial de depósitos) e de caracterização (morfologia e características físicas). Os resultados obtidos indicam que a adição de nanopartículas inorgânicas de argila e o formador de poros PEO melhoraram o desempenho e as características físicas das membranas. As membranas Kynar 761 6% argila 0% PEO (K6-0), Kynar 761 0% argila 4% PEO (K0-4) e Kynar 761 6% argila 4% PEO (K6-4) apresentaram as melhores permeabilidades com um aumento, respectivamente, de 520%, 1.250% e 1.100%, em relação à membrana pura. Além disso, observa-se uma melhora de 55%, 60% e 41% na redução do potencial de depósito, respectivamente, para as membranas K6-0, K0-4 e K6-4, quando comparada a membrana de controle. A melhora da permeabilidade e do potencial de depósito das membranas compostas está relacionada à melhoria da hidrofilicidade e da carga superficiail. A morfologia interna das membranas sintetizadas com argila pode ser caracterizada com uma camada superficial com poros conectados verticalmente aos poros em formas de canais da camada intermediária. A camada inferior possui uma morfologia esponjosa com micro-poros. O aumento da quantidade e tamanho dos poros superficiais é proporcional ao aumento da concentração de argila, assim como a diminuição de bloqueios horizontais entre a camada superficial e os poros em formas de canais da camada intermediária. A morfologia interna das membranas sintetizadas com PEO pode ser caracterizada por uma camada superficial densa com poros e uma camada inferior com uma morfologia esponjosa densa com micro-poros. A camada intermediaria tem uma morfologia densa com poros em forma de canais com diâmetros maiores se comprado às membranas sem adição de PEO. A adição de PEO diminui o tamanho médio dos micro-poros, se comparado com as membranas onde apenas argila é adicionada. Foi constatado que a melhoria da permeabilidade está associada à alteração na morfologia interna das membranas compostas. O aumento dos poros superficiais conectados aos poros em forma de canais mais longos e uma camada inferior menor, proporciona uma redução da resistência interna da membrana, devido à formação de caminhos livres, facilitando a passagem da água. Pelas análises de espectrômetro de raios X por dispersão de energia (EDS), foram identificadas nanopartículas de argila dispersas na superfície e na matriz transversal da membrana. Os resultados indicam que a introdução de nanopartículas de argila na solução polimérica é uma técnica de modificação da membrana promissora no melhoramento do desempenho da membrana para o tratamento de água e efluentes. / This research was developed in the International Reference Center for Water Reuse (IRCWR) laboratory inside to the Departamento de Engenharia Hidráulica e Ambiental da Escola Politécnica da Universidade de São Paulo (USP). The main objective of this research is the synthesis of ultrafiltration flat sheet membrane, using polyvinylidene fluoride (PVDF) polymer, clay (montmorillonite hydrophilic) inorganic nanoparticles and polyethylene oxide (PEO). Membranes were synthesized by phase inversion process, using 18% PVDF, mass based, in n-methylpyrrolidone as solvent and water as the non-solvent in the coagulation bath. The influence of different concentrations of clay nanoparticles and PEO was evaluated. Permeability, separation capability, and foulling potential tests were conducted to evaluate membranes performance and morphology analysis and physical characteristics were used for membranes characterization. Results indicated that clay nanoaprticles and PEO addiction can improve membrane permeability and morphology. The Kynar 761 6% clay 0% PEO (K6-0), Kynar 761 0% clay 4% PEO (K0-4) and Kynar 761 6% clay 4% PEO (K6-4) membranes showed the best permeability results, with an increase, respectively of 520%, 1,250% and 1,100%, compared to pure membrane. Furthermore, there is an improvement of 55%, 60% and 41% in the foulling potential reduction, respectively, for K6-0, K0-4 and K6-4 membranes, compared to the control membrane. It was verified that membrane permeability improvement and fouling potential reduction with the addition of clay nanoparticles is related with the improvement of membranes hydrophilicity and surface charge. The internal morphology of the membranes synthesized with clay can be characterized by a surface layer with pores interconnected with finger-like pores in the intermediate layer. The bottom layer has a sponge-like morphology with micro-pores. The increasing number and size of surface pores and also the reduction of horizontal blocks between the surface layer and the finger-like pores in the intermediate layer, is observed with increasing dosage of clay. The internal morphology of the membranes synthesized with PEO can be characterized by a dense surface layer and a bottom layer with dense sponge morphology with micro-pores. The intermediate layer has a dense morphology with finger-like pores with larger diameters if compared to the membranes without addition of PEO. The PEO addition decreases the average size of micro-pores, compared with membranes only clay is added. It was observed that change in composite membranes internal morphology, resulted in the water permeability improvement. The increasing superficial pores connected to longer finger-like pores and a thin bottom layer resulted in an internal pore structure with a lower resistance due to free paths formation, facilitating the flow passage. Using Energy Dispersive X-ray Spectroscopy (EDS) analysis it was possible to observed clay nanoparticles dispersed on membrane surface and in its cross-section matrix. These preliminary results indicate that clay nanoclay addiction in polymeric solution is a promising membrane modification technique for improving membrane performance for water and wastewater treatment.
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Avaliação da remoção de diclofenaco e formação de subprodutos em tratamento de água / Evaluation of the removal of diclofenac and formation of by-products in water treatment

Rigobello, Eliane Sloboda 14 May 2012 (has links)
A presença de resíduos de fármacos em águas superficiais e de abastecimento público tem preocupado a comunidade científica devido principalmente à sua persistência na água e aos efeitos adversos causados à comunidade aquática e aos possíveis riscos à saúde humana. Dentre os fármacos comumente identificados em águas de abastecimento público, encontram-se os anti-inflamatórios, como o diclofenaco (DCF), um dos fármacos mais consumidos no Brasil e no mundo. Nesse contexto, o presente trabalho, teve como objetivo principal estudar a eficiência das etapas de tratamento de água em ciclo completo (coagulação, floculação, sedimentação, filtração em areia e desinfecção com cloro) com e sem pré-oxidação com cloro e com dióxido de cloro e adsorção em carvão ativado granular (CAG) na remoção de DCF. Também foram determinados os trialometanos (THM) e identificados os principais subprodutos do DCF formados na oxidação com cloro e dióxido de cloro. Para a determinação do DCF nas amostras de água antes e após as etapas de tratamento de água foram desenvolvidos e validados métodos analíticos de extração em fase sólida (SPE) e cromatográfico por cromatografia líquida de alta eficiência (HPLC) com detecção no ultravioleta (UV). A validação do método foi feita de acordo com a resolução n&ordm; 899 de 2003 da Agência Nacional de Vigilância Sanitária (ANVISA), considerando os requisitos para métodos bioanalíticos. Os procedimentos analíticos empregados foram efetivos e confiáveis para a identificação e quantificação do DCF nas amostras de água antes e após os processos de tratamento de água. Os ensaios de tratamento de água foram feitos em equipamento de reatores estáticos (jarteste) e filtros de escala laboratorial empregando-se água de poço artesiano não clorada preparada com substâncias húmicas aquáticas (SHA) para conferir cor verdadeira de 20 uH, caulinita para conferir turbidez de 70 uT e fortificada com 1 mg L-1 de DCF. Os resultados indicaram que as etapas de coagulação com sulfato de alumínio, floculação, sedimentação e filtração em areia não removeram o DCF. Nas etapas de préoxidação com cloro e dióxido de cloro e de pós-cloração houve remoção parcial do DCF, porém verificou-se a formação de subprodutos provenientes da oxidação do DCF. Dentre os THM, foi quantificado apenas o clorofórmio na etapa de pré-oxidação com cloro. Em geral, os resultados indicaram que o dióxido de cloro foi mais eficiente na redução do DCF e formou menos subprodutos. Entretanto, o tratamento em ciclo completo seguido da adsorção em CAG foi eficiente na remoção de DCF, com remoção maior que 99,7%. Os subprodutos formados na oxidação com cloro e dióxido identificados por cromatografia líquida acoplada a espectrometria de massas em série (LC-MS/MS) consistiram na descaboxilação/hidroxilação e substituição aromática de átomos de hidrogênio por cloro. Os subprodutos identificados na oxidação com cloro apresentaram as seguintes fórmulas moleculares: C14H11</subCl2NO3, C13H10Cl3N e C14H10Cl3NO2. Com o dióxido de cloro foi identificado o subproduto de fórmula molecular igual a C14H11Cl2NO3. / The presence of pharmaceutical residues in surface waters and in drinking water supply has concerned the scientific community, mainly in which regards their persistence in water, adverse effects on the aquatic community and possible risks to human health. Antiinflammatory drugs, as diclofenac (DCF), are among those drugs commonly identified in drinking water supply. In this context, the main objective of this study was to assess the efficiency of the different stages of the conventional drinking water treatment (coagulation, flocculation, sedimentation, sand filtration and chlorine disinfection) with and without preoxidation with chlorine and chlorine dioxide and adsorption on granular activated carbon (GAC) in the removal of DCF. The trihalomethanes (THMs) were also determined and the main by-products of DCF formed by oxidation with chlorine dioxide and chlorine were identified. For the DCF determination in water samples before and after water treatment stages analytical methods of solid phase extraction (SPE) and chromatographic method by high performance liquid chromatography (HPLC) with detection in the ultraviolet (UV) were developed and validated. The method validation was based on Resolution n&ordm; 899 of the 2003 of the Brazilian National Health Surveillance Agency (ANVISA), considering the requirements for bioanalytical methods. The analytical procedures used were effective and reliable for the identification and quantification of DCF in the water samples before and after the water treatment stages. The water treatment tests were carried out in jar test equipment and filters on laboratory scale employing non chlorinated water of artesian well prepared with aquatic humic substances (AHS) to yield 20 uH true color, kaolin turbidity of 70 NTU and DCF concentration of 1 mg L-1. The results indicated that the stages of coagulation with aluminum sulphate, flocculation, sedimentation and filtration sand did not remove DCF. In the stages of pre-oxidation with chlorine and chlorine dioxide and chlorine disinfection the DCF was partially removed, however by-products were formed from the DCF oxidation. Among the THMs, only chloroform was quantified in the pre-oxidation with chlorine. In general, the results showed that chlorine dioxide was more effective to reduce the DCF and fewer by-products were formed. Nevertheless, the complete cycle treatment followed by GAC adsorption was effective to remove DCF (&gt; 99.7%. removal). The by-products of the oxidation of DCF with chlorine and chlorine dioxide identified by liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) consisted in the descaboxylation/hydroxylation and aromatic substitution of hydrogen atoms by chlorine. The compounds identified in the oxidation with chlorine showed the following molecular formulas: C14H11</subCl2NO3, C13H10Cl3N e C14H10Cl3NO2. The by-product identified using chlorine dioxide was C14H11Cl2NO3.

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