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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.
61

A Non-isolated Half Bridge Buck-based Converter For Vrm Application And Small Signal Modeling Of A Non-conventional Two Phase Bu

Batarseh, Majd 01 January 2006 (has links)
This dissertation is about treatment of the nonbiodegradable organic content of landfill leachate by chemical oxidation combined with biological treatment. It is divided into three parts. In the first part, ferrate was compared to Fenton's reagent for the purpose of removing non-biodegradable organic compounds from mature leachate. Oxidation conditions (time, pH, and dose) were optimized to yield maximum organic removal using two leachate samples from 20 and 12-year old solid waste cells. Results from this research demonstrated that ferrate and Fenton's reagent had similar optimum pH ranges (3-5), but different organic removal capacities, ranging from 54 to 79 % of initial leachate organic contents. An advantage of ferrate was that it was relatively effective over a wide pH range (Fenton's reagent lost its reactivity outside optimum pH range). Advantages associated with Fenton's reagent include a higher organic removal capacity, production of more oxidized organic compounds (measured as chemical oxygen demand/dissolved organic carbon), and production of more biodegradable byproducts (measured as 5-day biochemical oxygen demand/chemical oxygen demand). Finally, both treatments were found to oxidize larger molecules (>1000 dalton) and produce smaller molecules, as indicated by an increase in smaller molecule contribution to organic carbon. In part two, effects of Fenton's reagent treatment on biodegradability of three landfill leachates collected from a Florida landfill were evaluated using biochemical oxygen demand (BOD), biochemical methane potential (BMP), and tertamethylammonium hydroxide (TMAH) thermochemolysis gas chromatography/mass spectrometry (GC/MS). The hypothesis was that Fenton's reagent will remove refractory compounds that inhibit biodegradation and will produce smaller, more biodegradable organic molecules which will result in an increase in BOD and BMP values. Both BOD and BMP results demonstrated that Fenton's reagent treatment did not convert mature leachate to biodegradable leachate, as indicated by a low BOD5 expressed as C /dissolved organic carbon (DOC) ratio of almost 0.15 in treated samples and a low net methane production / theoretical methane potential (less than 0.15). Ultimate BOD only slightly increased. However the first-order BOD reaction rate increased by more than five fold, suggesting that Fenton's reagent removed refractory and inhibitory compounds. BMP results demonstrated that the ratio of CO2/CH4 produced during anaerobic biodegradation did not increase in treated leachate (compared to untreated), indicating that small biodegradable organic acids produced by oxidation were removed by coagulation promoted by Fenton's reagent. Finally, the TMAH thermochemolysis results showed that several of the refractory and inhibitory compounds were detected fewer times in treated samples and that carboxylic acids did not appear in treated samples. In the third part of this dissertation the application of flushing/Fenton's reagent oxidation to produce sustainable solid waste cells was evaluated. A treatment similar to pump and treat process utilizing Fenton's reagent on-site treated leachate combined with in-situ aeration was proposed. Treated leachate would be recycled to the landfill cell flushes releasable nonbiodegradable carbon from the cell and oxidizes it externally. This technique was demonstrated to have treatment cost and time benefits over other alternatives for producing completely stable solid waste cells such as anaerobic flushing and biological and/or mechanical pretreatment of solid waste (used in the EU).
62

Integrated processes for removal of persistent organic pollutants : soil washing and electrochemical advanced oxidation processes combined to a possible biological post-treatment

Mousset, Emmanuel, Mousset, Emmanuel 02 December 2013 (has links) (PDF)
Soils contaminated by hydrophobic organic pollutants like polycyclic aromatic hydrocarbons (PAHs) are a common concern since they are extremely difficult to remove and their potential toxicological impacts are significant. As an alternative to traditional thermal or physical treatments, soil washing and soil flushing processes appear to be conceivable and efficient approaches, especially for higher level of pollution. However, the treatment of highly loaded soil washing/flushing solutions is another challenge to overcome. In that way, a new integrated approach is suggested: soil washing/flushing processes combined to an electrochemical advanced oxidation process (EAOP) in a combination with a recirculation loop (to save extracting agents) and/or a biological post-treatment step (to minimize energy cost).Extraction efficiency of the extracting agent like hydroxypropyl-beta-cyclodextrin (HPCD) is compared to the traditional non-ionic surfactant Tween 80 in synthetic and real soil washing solutions. A new simple fluorescent sensitive and selective quantification method is developed to monitor Tween 80 oxidation. Two EAOPs were compared: electro-Fenton (EF) and anodic oxidation (AO). Platinum (Pt) (in EF process) and boron doped diamond (BDD) (in both treatment) anodes are the respective electrodes employed to recycle effluents and to consider a biological post-treatment, respectively. Regarding the extracting agent recovery, the biodegradability evolution of effluent and the energy consumption (in kWh (kgTOC)-1) during EAOP, HPCD is more advantageous than Tween 80. However, in terms of extraction efficiency, costs of extracting agents and impact on soil respirometry, Tween 80 is much more efficient. By considering all these advantages and drawbacks, Tween 80 could still appear to be the best option
63

Aplicação do processo oxidativo avançado \'H IND.2\'O IND.2\'/UV como pós-tratamento de reator anaeróbio em efluentes de indústrias de celulose kraft branqueada / Application of the advanced oxidative process \'H IND.2\'O IND.2\'/UV as post-treatment of anaerobic reactor in bleached kraft pulp mill effluents

Ruas, Diego Botelho 11 April 2008 (has links)
A proposta desta pesquisa foi avaliar a aplicação do processo oxidativo avançado (POA), peróxido de hidrogênio (\'H IND.2\'O IND.2\') e radiação ultravioleta (UV), como pós-tratamento de um reator anaeróbio utilizado para tratar efluentes de branqueamento de indústrias de celulose kraft. O principal objetivo do pós-tratamento químico foi aumentar a biodegradabilidade e a remoção de compostos recalcitrantes nos efluentes. O tratamento biológico foi realizado por meio de reator anaeróbio horizontal de leito fixo (RAHLF), em escala de bancada, seguido pelo tratamento \'H IND.2\'O IND.2\'/UV dos efluentes. As doses do agente oxidante variaram de 50 a 500 mg \'H IND.2\'O IND.2\'/L e as aplicações de energia pela lâmpada de radiação ultravioleta foram variadas, principalmente, de 3,8 a 15,0 kWh por \'M POT.3\' de efluente tratado. Desta forma, amostras de efluentes foram coletadas de duas indústrias brasileiras de celulose kraft branqueada, originando respectivamente duas fases experimentais. Na primeira fase, o RAHLF apresentou boa estabilidade de operação, obtendo adequadas eficiências de remoção de DQO (61 ± 3%), COT (69 ± 9%), \'DBO IND.5\' (90 ± 5%) e AOX (55 ± 14%). Todavia, não ocorreu boa remoção dos compostos de absorbância na \'UV IND.254\'. Além disso, houve aumento de constituintes da lignina do afluente para o efluente do RAHLF. Por sua vez, o pós-tratamento com \'H IND.2\'O IND.2\'/UV no efluente anaeróbio proporcionou eficiência de remoção variada nos parâmetros DQO (0 a 11%), \'UV IND.254\' (16 a 35%), lignina (0 a 29%) e AOX (23 a 54%). Em relação a melhoria da biodegradabilidade, todas as dosagens de \'H IND.2\'O IND.2\' estudadas promoveram aumento na relação \'DBO IND.5\'/DQO. Para uma relação \'DBO IND.5\'/DQO média inicial igual a 0,09, correspondente ao efluente do RAHLF, o maior aumento obtido foi de 131% aplicando 500 mg \'H IND.2\'O IND.2\'/L e 7,5 kWh/\'M POT.3\'. O tratamento conjugado biológico e químico foi necessário para atingir ao padrão europeu de emissão de AOX (< 0,4 kg AOX por tonelada de polpa de celulose seca produzida). Na segunda fase, o RAHLF apresentou alguns problemas operacionais, tais como entupimento nas conexões e quebras do reator de vidro, pelo possível aumento da carga orgânica volumétrica aplicada presente nos efluentes coletados na segunda indústria de celulose. O pós-tratamento com \'H IND.2\'O IND.2\'/UV mostrou menor desempenho nessa fase experimental, o que pode ser explicado também pelo maior teor de matéria orgânica residual, lignina, alcalinidade e íons cloretos ainda remanescentes nos efluentes tratados biologicamente. Visando complementar os estudos, testes em reatores aeróbios nos efluentes do RAHLF, tratados e não tratados pelos processos \'H IND.2\'O IND.2\'/UV, foram avaliados. Os resultados demonstraram que os melhores resultados (menor tempo de aeração necessário para atingir a mesma concentração dos parâmetros avaliados) foram alcançados pelos reatores que receberam efluentes previamente tratados pelo POA. Uma avaliação simplificada do custo operacional associado com a aplicação do tratamento \'H IND.2\'O IND.2\'/UV, em escala plena, indicou um custo de R$ 1,87 por \'M POT.3\' de efluente tratado. / The purpose of this research was to assess the application of the advanced oxidation processes (AOP), hydrogen peroxide (\'H IND.2\'O IND.2\') and ultraviolet radiation (UV), as post-treatment for an anaerobic reactor used to treat bleaching effluents from kraft pulp mills. The main objective of the chemical post-treatment was to increase the biodegradability and remove recalcitrant compounds from the wastewater. The biological treatment was performed in a fixed bed anaerobic horizontal reactor (FBAHR), in bench scale, followed by \'H IND.2\'O IND.2\'/UV treatment of the effluents. The oxidizer dosage varied from 50 to 500 mg \'H IND.2\'O IND.2\'/L while the energy applied by the UV lamp ranged, mainly, from 3.8 to 15.0 kWh per \'M POT.3\' of treated effluent. This way, wastewater samples were collected from two brazilian bleached kraft pulp mills thus the results were reported as two different experimental phases. In the first phase the FBAHR showed good operational stability and reached the expected removal efficiencies for COD (61 ± 3%), TOC (69 ± 9%), \'BOD IND.5\' (90 ± 5%) and AOX (55 ± 14%). However, the anaerobic treatment did not provide good removal of compounds indicated by \'UV IND.254\' absorbency. Furthermore, there was an increase of lignin from the affluent to effluent of the FBAHR. In its turn the \'H IND.2\'O IND.2\'/UV post-treatment provided a wide range of removal depending upon the dosage: COD (0 to 11%), \'UV IND.254\' (16 to 35%), lignin (0 to 29%) and AOX (23 to 54%). Regarding to the improvement in biodegradability, all dosages of \'H IND.2\'O IND.2\' applied in this work promoted an increase in the \'BOD IND.5\'/COD ratio. For an average initial \'BOD IND.5\'/COD ratio equal to 0.09, which corresponds to the FBAHR effluent, the greatest increase was 131% with 500 mg \'H IND.2\'O IND.2\'/L and 7.5 kWh/\'M POT.3\'. It was necessary to couple the anaerobic and the oxidative treatment to reach the current European allowable AOX emission load (< 0.4 kg AOX per ton of produced dried cellulose pulp). During the second phase of the experiments, the FBAHR had operational problems as plugging of the tubes and cracking of the reactor wall that may be partially attributed to the higher organic load applied, as the effluents from the second mill were stronger. The AOP post-treatment also had lower performance during this experimental phase, which may be explained by the higher concentration of the organic matter, lignin, alkalinity and chloride ions, still present in the biologically treated effluents. To complete the experiments samples from effluents of the FBAHR and AOP process were submitted to aerobic assays. By tests done in aerobic reactors in the FBAHR effluents, treated and non-treated by the processes \'H IND.2\'O IND.2\'/UV, it was verified that the best results, shorter aeration time requirement to reach the same concentration of the evaluated parameters, were obtained from reactors that received previously treated by AOP effluents. A simplified evaluation of the operational cost associated with the use of the tested AOP, in full scale, indicated a cost of R$ 1.87 per \'M POT.3\' of treated effluent.
64

Gestão ambiental nos terminais de armazenagem de produtos químicos líquidos a granel no Porto de Santos / Environmental management of storage terminals of liquid chemicals in bulk at Santos Port

Rodrigues, Eleni Stark 12 August 2010 (has links)
O controle das águas residuárias nas indústrias e nos terminais de armazenagem de produtos químicos líquidos a granel é uma difícil tarefa, por conta da alta rotatividade e grande variedade de produtos químicos orgânicos armazenados e movimentados em suas atividades. Oito terminais e duas indústrias químicas localizadas no Porto de Santos foram avaliados por 10 anos. Foram realizadas mais de 2.500 análises químicas e ecotoxicológicas em 200 amostras de efluentes brutos e tratados. Nosso principal objetivo foi verificar se o teste de toxicidade aguda usando Vibrio fischeri poderia ser utilizado na gestão de águas residuais nas diferentes instalações dos terminais químicos e mostrar o seu papel como instrumento de prevenção a poluição, reduzindo a descarga de substâncias tóxicas persistentes nos ambientes aquáticos. Os índices de biodegradabilidade obtidos pela relação de Demanda Bioquímica de Oxigênio (DBO5) / Demanda Química de Oxigênio (DQO) dos efluentes brutos indicaram que 44% das amostras apresentaram matéria orgânica recalcitrante. Das 86 amostras do efluente final analisadas, 45 (52%) apresentaram resultados tóxicos para o teste com V. fischeri. Não houve correlação de DQO e ecotoxicidade, mostrando que efluentes com DQO baixa podem conter substâncias tóxicas com baixa capacidade de degradação. Foi possível recomendar a aplicação das melhores práticas operacionais, incluindo a segregação dos efluentes brutos ou um pré-tratamento com base nos resultados de ecotoxicidade e índice de biodegradabilidade. O reúso de água também foi abordado, indicando fontes e oportunidades de reutilização. Testes de ozonização também foram conduzidos nas águas pluviais dos terminais químicos e nos efluentes tratados das indústrias com resultados promissores. A integração da análise química e ecotoxicológica se mostraram uma excelente ferramenta para gestão de águas residuais nos terminais químicos, permitindo a tomada de decisão rápida para o controle da poluição e a adoção de medidas de prevenção / Wastewater control at industries and storage terminals of liquid chemical products in bulk is very difficult task due to the high turnover and great variety of organic chemicals handled and stored in their activities. Eight terminals and two chemical plants located in Santos Port, SP, Brazil had been evaluated for 10 years. More than 2,500 chemical and ecotoxicological analysis were performed in 200 samples of raw and treated effluents. Our main objective was to verify if the acute toxicity test using Vibrio fischeri could be used in the wastewater management of those facilities and show its role as a tool for pollution prevention by reducing the discharge of persistent toxic substances in estuarine systems. The indexes of biodegradability obtained by the ratio of Biochemical Oxygen Demand (BOD5) / Chemical Oxygen Demand (COD) of raw effluents indicated that 44% of the samples presented recalcitrant organic matter. Out of 86 final effluent samples analyzed, 45 (52%) presented toxic result for V. fischeri test. No correlation was observed of COD and ecotoxicity, showing that with low COD effluent may contain toxic substances with low degradation capacity. It was possible to recommend the use of best operational practices including segregation of influents or a pre-treatment based on toxicity results and index biodegradability. Water reuse was also discussed indicating sources and opportunities for reuse in these facilities. Ozonisation tests were also conducted on the rain waters collected at the terminals facilities and on the treated effluents of the industries, showing promising results. The integration of chemical and ecotoxicity analysis turned out to be an excellent tool for wastewater management in chemical terminals, allowing rapid decision making for pollution control and prevention measures
65

Fonctionnalisation et caractérisation multi-échelle de films minces de chitosane : vers une utilisation en ingénierie tissulaire / Functionalization and multi-scale characterisation of chitosan films for tissue engineering application

Zhang, Hongyuan 16 December 2014 (has links)
Ce travail porte sur la fonctionnalisation en volume et/ou en surface et la caractérisation multi-échelle de films minces de chitosane utilisés en ingénierie tissulaire. L’ajout des nanoliposomes à base de lécithine naturelle (végétale ou marine) et un traitement plasma sont employés pour réaliser ces deux fonctionnalisations. De nombreuses analyses des caractéristiques physico-chimiques et « structurales » de films minces ont montré que lorsqu’on ajoute 10 % de nanoliposomes dans les films de chitosane, l’hydrophobicité de la surface s’améliore de 18 à 36 %, ce fait est attribué à la présence de composants polaires. La cristallinité est légèrement augmentée ; à 37 °C, le module d’Young diminue de 6 GPa environ jusqu’à près de 4 GPa ; aucune nouvelle liaison ne se crée entre le chitosane et les nanoliposomes ; une diminution de degré de déacétylation est observée, qui pourrait être associée à la conformation des nanoliposomes ajoutés en volume aux films de chitosane. Le traitement plasma a réussi à modifier la structure de surface du chitosane seul et du chitosane mélangé aux nanoliposomes par greffe de groupements actifs (groupes amine, C-O, COOH, -OH). En revanche, dans notre cas, les liaisons hydrogène entre les groupes polaires créés par le traitement plasma peuvent être éliminées partiellement après un temps donné, ce qui limite l’application du traitement. Ensuite, des études préliminaires sur la biocompatibilité in vitro et la biodégradabilité in vitro sont réalisées pour les films de chitosane et du chitosane mélangé aux nanoliposomes. Les cellules souches mésenchymateuses sont utilisées pour l’étude de la première, et une solution de PBS contenant 10 mg/L de lysozyme pour la seconde. Les propriétés physico-chimiques des films de chitosane mélangé aux nanoliposomes marines, leur faible cytotoxicité aux cellules et leur stabilité dans la solution de PBS contenant du lysozyme leur permettent d’être utilisés comme matrice de support dans le domaine de la médecine régénérative / This work focused on functionalized chitosan thin films in the bulk and/or on the surface by nanoliposomes based on natural lecithin (plant and marine) and plasma treatment. Various techniques were used for physicochemical properties analysis of functionalized thin films. The results showed that by adding the nanoliposomes into the chitosan scaffold, the surface wettability of thin films increased from 18 % to 36 %. The crystallinity degree was slightly improved in blend thin films. Any new bond was determined by fourier transform infrared spectroscopy (FTIR), which confirmed that there is no chemical interaction between the nanoliposomes and chitosan. The Young’s modulus of blend thin films deceased from 6 GPa to 5 GPa. The morphological, nanomechanical properties and adhesion force of each scaffold system determined by Scanning Probe Microscopy (HarmoniXTM mode) showed that the fish nanoliposomes/chitosan thin film had the most similar properties compared to the pure chitosan thin film. The surface of chitosane films and nanoliposomes/chitosane blend films were modified by the plasma treatment. Functional groups (amine groups, C-O, COOH, -OH) are grafted onto the surface enhancing thus the surface energy of the films. But the hydrogen bonds between the polar groups introduced by the treatment can be destroyed after a given time; the author proposed that the functionalization in the bulk by adding of nanoliposomes provided more stable and greater possibility of new materials producing than the functionalization at the surface by plasma treatment for potential tissue engineering application. Then, in vitro biocompatibility preliminary study was carried using human mesenchymal stem cells (hMSCs); and in vitro biodegradability study was tested in the phosphate buffered saline (PBS) mixed with 10 mg/L lysozyme. The films of chitosan functionalized by salmon nanoliposomes showed more interesting as matrix extracellular for regenerative medicine applications because of their physico-chemical properties, low cytotoxicity and the stability inside the PBS and lysozyme solutions.
66

Tratamento de efluentes do branqueamento da polpa celulósica por processos oxidativos avançados baseados em ozônio / Treatment of pulp and paper bleaching effluents by means of ozone advanced oxidation processes

Medeiros, Daniel Reis 08 August 2008 (has links)
O impacto da oxidação com ozônio na transformação de compostos orgânicos de elevada massa molar (HMW) para o aumento da biodegradabilidade dos efluentes da indústria de celulose e papel foi investigado sob diferentes doses de ozônio. Os experimentos foram realizados utilizando-se os efluentes primário e de extração alcalina de duas indústrias de celulose sob dois valores iniciais de pH (12 e 7). Utilizou-se um reator em escala de laboratório equipado com um difusor de bolhas finas para a aplicação do ozônio. Os resultados revelaram o potencial da aplicação de ozônio como uma etapa de tratamento anterior ao processo biológico convencional. Para o efluente primário, a aplicação de 0,70 mg\'O IND.3\'/mL efluente elevou a razão DBO5/DQO de 0,18 para 0,35 e foi alcançada uma remoção de cor na ordem de 87%. Para o efluente de extração alcalina da indústria Howe Sound, a razão DBO5/DQO foi elevada de 0,07 para 0,15 (pH inicial 12) e para 0,20 (pH inicial 7) e obteve-se uma remoção de cor por volta de 44% com a aplicação de 0,80 mg\'O IND.3\'/mL efluente. Para o efluente de extração alcalina da indústria Catalyst Paper, obteve-se uma remoção de cor por volta de 78% e a razão DBO5/DQO foi elevada de 0,07 para 0,16 após a aplicação de uma dose de ozônio de 0,80 mg\'O IND.3\'/mL efluente. Essas modificações foram alcançadas por uma redução nas frações de elevada massa molar durante a aplicação de ozônio. Para o efluente primário, observou-se uma elevada redução da faixa de maior massa molecular ( > 2kDa) após a aplicação de 0,72 mg\'O IND.3\'/mL efluente. Alcançaram-se 85% e 61% de remoção da faixa superior a 5 kDa para os efluentes de extração alcalina da indústria Howe Sound sob pH inicial 7 e 12, respectivamente, com a aplicação de cerca de 0,72 mg\'O IND.3\'/mL efluente. A faixa de maior massa molar ( > 10 kDa) dos efluentes de extração alcalina da indústria Catalyst Paper foi removida com a aplicação de aproximadamente 0,80 mg \'O IND.3\'/mL efluente. O papel do ozônio molecular disponível sob pH neutro parece ser de fundamental importância quando o objetivo é a redução dos compostos de elevada massa molecular. / The impact of ozone oxidation in transforming high molecular weight (HMW) organic compounds in order to improve the biodegradability of pulp and paper effluents was investigated under different ozone doses. The experiments were conducted uppon a primary treated effluent and an alkaline bleach plant effluent taken from two pulp mills. The effluents were investigated under different initial pH (7 and 12). Ozone was applied using a semi-batch reactor equipped with fine bubble diffuser. The results showed the potential for using ozone as a pre-treatment to the conventional biological process. Applying 0.70 mg\'O IND.3\'/mLww to the primary treated effluent enhanced the ratio of BOD5/COD was from 0.18 to 0.35 and decreased the colour by 87%. The ratio of BOD5/COD was increased from 0.07 to 0.15 (initial pH 12) and to 0.20 (initial pH 7) and colour was reduced by 44% after applying 0.80 mg\'O IND.3\'/mLww to the alkaline bleach effluent from Howe Sound\'s mill. A similar behavior was observed after 0.80 mg\'O IND.3\'/mLww was applied to the alkaline bleach effluent from Catalyst\'s mill. The ratio of BOD5/COD was increased from 0.07 to 0.16 and the effluent colour decreased by 78%. These changes were primarily driven by reductions of the HMW fractions of the effluent during ozonation. Organics with molecular range higher than 2 kDa were completely removed from the primary treated effluent. Aproximately 85% and 61% of the organics higher than 5 kDa were removed from the Howe Sound\'s alkaline bleach effluent under initial pH 7 and 12, respectively, after applying 0.72 mg\'O IND.3\'/mLww. Organic compounds with molecular weight higher than 10 kDa were completely removed from the Catalyst\'s alkaline bleach effluent after applying 0.80 mg\'O IND.3\'/mLww. Molecular ozone available under neutral conditions seems to play an important role when the removal of the high molecular weight organic compounds is the main objective.
67

Integrated processes for removal of persistent organic pollutants : soil washing and electrochemical advanced oxidation processes combined to a possible biological post-treatment / Procédés intégrés pour l'élimination des polluants organiques persistants : lavages de sol et procédés d'oxydation avancée électrochimiques combinés à un possible post-traitement biologique

Mousset, Emmanuel 02 December 2013 (has links)
Les sols contaminés par les polluants organiques hydrophobes tels que les Hydrocarbures Aromatiques Polycycliques (HAPs) constituent un problème majeur puisqu'ils sont difficilement éliminés et leurs impacts toxicologiques restent significatifs. Comme alternative aux procédés thermiques et physiques traditionnels, les procédés de lavages de sol in situ et ex situ apparaissent être une solution envisageable et efficace et particulièrement pour les fortes pollutions. Cependant, le traitement des solutions fortement chargées de lavages de sol est une autre barrière à surmonter. Une nouvelle approche combinée est proposée pour répondre à ce problème: les procédés de lavages de sol in situ/ex situ combinés à un Procédé Electrochimique d'Oxydation Avancée Electrochimique (PEOA) avec possibilité de recirculer l'effluent (pour réutiliser l'agent extractant) et/ou de combiner avec un post-traitement biologique (pour minimiser le coût énergétique).L'efficacité d'extraction de l'agent extractant tel que l'hydroxypropyl-beta-cyclodextrine (HPCD) est comparé au traditionnel tensioactif non-ionique dénommé Tween 80, dans les solutions synthétiques et réelles de lavages de sol. Une nouvelle méthode sensible d'analyse du Tween 80, basée sur la fluorescence, est développée pour suivre l'oxydation du Tween 80. Deux PEOAs sont comparés : l'électro-Fenton (EF) et l'oxydation anodique (OA). Les anodes de platine (Pt) (dans le procédé EF) et de diamant dopés au bore (BDD) (dans les deux procédés) sont respectivement utilisées pour étudier la recirculation des effluents et la possibilité d'une combinaison avec un post-traitement biologique. Concernant la réutilisation des agents extractants, l'évolution de la biodégradabilité des solutions et l'énergie consommée (en kWh (kg COT)-1) pendant les PEAOs testés, l'HPCD est trouvée être plus avantageuse que le Tween 80. En revanche, en terme d'efficacité d'extraction, de coût des agents extractants et d'impact sur la respirométrie du sol, le Tween 80 paraît être plus avantageux. En prenant en compte tous ces avantages et inconvénients, le Tween 80 pourrait être retenu comme la meilleure solution / Soils contaminated by hydrophobic organic pollutants like polycyclic aromatic hydrocarbons (PAHs) are a common concern since they are extremely difficult to remove and their potential toxicological impacts are significant. As an alternative to traditional thermal or physical treatments, soil washing and soil flushing processes appear to be conceivable and efficient approaches, especially for higher level of pollution. However, the treatment of highly loaded soil washing/flushing solutions is another challenge to overcome. In that way, a new integrated approach is suggested: soil washing/flushing processes combined to an electrochemical advanced oxidation process (EAOP) in a combination with a recirculation loop (to save extracting agents) and/or a biological post-treatment step (to minimize energy cost).Extraction efficiency of the extracting agent like hydroxypropyl-beta-cyclodextrin (HPCD) is compared to the traditional non-ionic surfactant Tween 80 in synthetic and real soil washing solutions. A new simple fluorescent sensitive and selective quantification method is developed to monitor Tween 80 oxidation. Two EAOPs were compared: electro-Fenton (EF) and anodic oxidation (AO). Platinum (Pt) (in EF process) and boron doped diamond (BDD) (in both treatment) anodes are the respective electrodes employed to recycle effluents and to consider a biological post-treatment, respectively. Regarding the extracting agent recovery, the biodegradability evolution of effluent and the energy consumption (in kWh (kgTOC)-1) during EAOP, HPCD is more advantageous than Tween 80. However, in terms of extraction efficiency, costs of extracting agents and impact on soil respirometry, Tween 80 is much more efficient. By considering all these advantages and drawbacks, Tween 80 could still appear to be the best option
68

Synthèse et caractérisation de capsules multicouches fonctionnelles à base de polysaccharides modifiés / Synthesis and characterization of functional multilayer capsules based on chemically modified polysaccharides

Cui, Di 26 May 2011 (has links)
This work focused on the design of functional capsules made of chemically modified polysaccharides. The layer-by-layer capsules have attracted great interest due to their Indeed, as an advanced multifunctionality which can be advantageously used for pharmaceutical and biomedical applications. Polysaccharides, which are generally biocompatible and biodegradable, are very attractive materials for the construction of bio-related multilayer systems. Considering the intrinsic antibacterial properties of chitosan (CHI), this polysaccharide was selected and quaternized to prepare in physiological conditions contact-killing capsules by combination with hyaluronic acid (HA). The relationship between the antibacterial activity of the quaternized chitosan derivatives (QCHI) and that of QCHI-based capsules was investigated. Then, in order to encapsulate small hydrophobic drugs within the wall of capsules, alkylated derivatives of HA were used as the negatively charged partner of QCHI for the capsules formation. The encapsulation of the hydrophobic dye, nile red (NR), in the hydrophobic shell of capsules was determined. At last, to release the payload under mild conditions was studied by synthesizing rapidly degradable capsules composed of hydrolysable cationic dextran derivatives and HA. The degradation of the layer-by-layer assemblies, both multilayer films and microcapsules is discussed. / Ce travail de thèse porte sur la conception de capsules fonctionnelles à base de polysaccharides chimiquement modifiés. Les capsules couche par couche connaissent actuellement un essor important lié à leur multifonctionnalité pouvant être avantageusement mise à profit dans les domaines pharmaceutique et biomédical. Les polysaccharides, généralement biocompatibles et biodégradables, constituent des matériaux de choix pour la construction de systèmes multicouches. Compte tenu des propriétés antibactériennes intrinsèques du chitosane (CHI), ce polysaccharide a été choisi puis quaternisé afin de préparer dans des conditions physiologiques des capsules par complexation avec l'acide hyaluronique (HA), capables de tuer les bactéries par simple contact. La relation entre l'activité antibactérienne des dérivés quaternisés du chitosane (QCHI) et celle des capsules préparées à partir de QCHI a été étudiée. En outre, afin d'encapsuler des médicaments hydrophobes dans la paroi des capsules, des dérivés alkylés du HA ont été utilisés en tant que partenaire chargé négativement du QCHI pour la formation des capsules. L'encapsulation d'une sonde fluorescente hydrophobe, le nile rouge (NR), dans le réservoir hydrophobe des capsules a été réalisée avec succès. Enfin, pour libérer des médicaments encapsulés dans des capsules dans des conditions douces, des capsules rapidement dégradables comprenant des dérivés cationiques hydrolysables du dextrane et de HA ont été préparées. La dégradation des assemblages couches par multicouches a été analysée par différentes approches à la fois à partir de capsules et de films plans.
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Tratamento de esgotos sanitários em sistema combinado anaeróbio/aeróbio utilizando lodo como fonte endógena de carbono / Wastewater treatment system for combined anaerobic / aerobic using sludge as a source of endogenous carbon

Oliveira, Marielle Ferreira de 23 March 2012 (has links)
Made available in DSpace on 2015-09-25T12:18:51Z (GMT). No. of bitstreams: 1 Marielle Ferreira de Oliveira.pdf: 1255416 bytes, checksum: 2938d36ef06506a40bbe2b05c9695f98 (MD5) Previous issue date: 2012-03-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The research aimed to treat sewage through combined anaerobic/aerobic system, using primary sludge and lysed excess sludge as an endogenous carbon source for removal of nutrients, aiming to produce effluent with low concentrations of organic material and nutrients and lower production excess sludge. The experiment was conducted in three phases. In the first, were performed respirometric tests as tool to assess the biodegradability of lysed biological sludge, through by techniques of cellular lysis induced: mechanical action, thermal and acid-base reaction. In the second phase, was monitored a Sequential Batch Reactor (SBR) together with Fermentation and Hydrolysis Reactor (FHR), which received excess sludge of SBR, tritured by mechanical action and primary sludge. SBR and FHR were operated with TRC of 3.36 and 10 days respectively. The third phase consisted of an anaerobic reactor followed by Immobilized Submerged with support Medium (polyurethane synthetic sponge) Aerated Reactor (ISMAR) operated in recirculation batch system. The results obtained from the respirometric tests found that the thermal sludge showed concentration biodegradable readily material greater than the tritured sludge and treated sludge by acid-base reaction. Values of the percentages of COD solubilized varied from 1.6% to 4.2%, with an average of 2.6%. The system presented promising results for the removal of nutrients, with removal efficiency of 85%, 93% and 98% for phosphorus soluble, nitrate and nitrite, respectively. However, the final effluent was maintained with concentration average of ammonia of 27 mgN-NH , considered out of the discharge standards. The combined system, anaerobic reactor and Immobilized Submerged with support Medium Aerobic Reactor (ISMAR), removed efficiently carbonaceous material (88%), TSS (86%), SSV (90%), TKN (94%) and N-NH4 - (96%). Producing effluent with average concentrations of nitrite and nitrate, respectively of 0.19 mgN-NO2-.L-1 and 2.52 mgN-NO3-.L. After addition of primary sludge the system, this presented a better performance with efficiency of COD removal gross and filtered 95%. However, the process of phosphorus removal was considered unsatisfactory since there was sludge disposal in the ISMAR reactor. Introducing an efficiency of removing just 20% for total phosphorus and 22% for the orthophosphate. / A pesquisa teve como objetivo principal tratar esgotos sanitários através de sistema combinado anaeróbio/aeróbio, utilizando lodo primário e lodo de excesso lisado como fonte endógena de carbono para remoção de nutrientes, buscando produzir efluente com baixas concentrações de material carbonáceo e de nutrientes e menor produção de lodo de excesso. O experimento foi realizado em três fases. Na primeira, foram realizados testes respirométricos como ferramenta para avaliar a biodegradabilidade de lodo biológico lisado, por meio de técnicas de lise celular induzida: ação mecânica, térmica e reação ácido-base. Na segunda fase, foi monitorado um Reator em Batelada Seqüencial (RBS) conjuntamente com Reator de Hidrólise e Fermentação (RHF), o qual recebia lodo de excesso do RBS, triturado por ação mecânica e lodo primário. O RBS e o RHF foram operados com TRC de 3,36 e 10 dias, respectivamente. A terceira fase foi constituída de reator anaeróbio seguido de reator aerado com meio suporte (esponja sintética de poliuretano) submerso imobilizado (RAMSI) operado em regime de bateladas com recirculação. Os resultados obtidos através dos testes respirométricos constataram que o lodo térmico apresentou concentração de material rapidamente biodegradável superior ao lodo triturado e ao lodo lisado por reação ácido-base. Os valores dos percentuais da DQO solubilizada variaram de 1,6% a 4,2%, com uma média de 2,6%. O sistema apresentou resultados promissores para a remoção de nutrientes, com eficiência de remoção de 85%, 93% e 98% para fósforo solúvel, nitrato e nitrito, respectivamente. Entretanto, o efluente final manteve-se com concentração média de nitrogênio amoniacal de 27 mgN-NH4.L-1, considerada fora dos padrões de lançamento. O sistema combinado, reator anaeróbio e reator aeróbio com meio suporte submerso imobilizado (RAMSI), removeram de forma eficiente material carbonáceo (88%), SST (86%), SSV (90%), NTK (94%) e N-NH4 -(96%). Produzindo efluente com concentrações médias de nitrito e nitrato, respectivamente de 0,19 mgN-NO e 2,52 mgN-NO3 -.L-1. Após a adição do lodo primário no sistema, este apresentou um melhor desempenho, com eficiência de remoção de DQO bruta e filtrada de 95%. No entanto, o processo de remoção de fósforo foi considerado insatisfatório, visto que não havia descarte de lodo no reator RAMSI. Apresentando uma eficiência de remoção de apenas 20% para o fósforo total e 22% para o ortofosfato.
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Tratamento de efluentes do branqueamento da polpa celulósica por processos oxidativos avançados baseados em ozônio / Treatment of pulp and paper bleaching effluents by means of ozone advanced oxidation processes

Daniel Reis Medeiros 08 August 2008 (has links)
O impacto da oxidação com ozônio na transformação de compostos orgânicos de elevada massa molar (HMW) para o aumento da biodegradabilidade dos efluentes da indústria de celulose e papel foi investigado sob diferentes doses de ozônio. Os experimentos foram realizados utilizando-se os efluentes primário e de extração alcalina de duas indústrias de celulose sob dois valores iniciais de pH (12 e 7). Utilizou-se um reator em escala de laboratório equipado com um difusor de bolhas finas para a aplicação do ozônio. Os resultados revelaram o potencial da aplicação de ozônio como uma etapa de tratamento anterior ao processo biológico convencional. Para o efluente primário, a aplicação de 0,70 mg\'O IND.3\'/mL efluente elevou a razão DBO5/DQO de 0,18 para 0,35 e foi alcançada uma remoção de cor na ordem de 87%. Para o efluente de extração alcalina da indústria Howe Sound, a razão DBO5/DQO foi elevada de 0,07 para 0,15 (pH inicial 12) e para 0,20 (pH inicial 7) e obteve-se uma remoção de cor por volta de 44% com a aplicação de 0,80 mg\'O IND.3\'/mL efluente. Para o efluente de extração alcalina da indústria Catalyst Paper, obteve-se uma remoção de cor por volta de 78% e a razão DBO5/DQO foi elevada de 0,07 para 0,16 após a aplicação de uma dose de ozônio de 0,80 mg\'O IND.3\'/mL efluente. Essas modificações foram alcançadas por uma redução nas frações de elevada massa molar durante a aplicação de ozônio. Para o efluente primário, observou-se uma elevada redução da faixa de maior massa molecular ( > 2kDa) após a aplicação de 0,72 mg\'O IND.3\'/mL efluente. Alcançaram-se 85% e 61% de remoção da faixa superior a 5 kDa para os efluentes de extração alcalina da indústria Howe Sound sob pH inicial 7 e 12, respectivamente, com a aplicação de cerca de 0,72 mg\'O IND.3\'/mL efluente. A faixa de maior massa molar ( > 10 kDa) dos efluentes de extração alcalina da indústria Catalyst Paper foi removida com a aplicação de aproximadamente 0,80 mg \'O IND.3\'/mL efluente. O papel do ozônio molecular disponível sob pH neutro parece ser de fundamental importância quando o objetivo é a redução dos compostos de elevada massa molecular. / The impact of ozone oxidation in transforming high molecular weight (HMW) organic compounds in order to improve the biodegradability of pulp and paper effluents was investigated under different ozone doses. The experiments were conducted uppon a primary treated effluent and an alkaline bleach plant effluent taken from two pulp mills. The effluents were investigated under different initial pH (7 and 12). Ozone was applied using a semi-batch reactor equipped with fine bubble diffuser. The results showed the potential for using ozone as a pre-treatment to the conventional biological process. Applying 0.70 mg\'O IND.3\'/mLww to the primary treated effluent enhanced the ratio of BOD5/COD was from 0.18 to 0.35 and decreased the colour by 87%. The ratio of BOD5/COD was increased from 0.07 to 0.15 (initial pH 12) and to 0.20 (initial pH 7) and colour was reduced by 44% after applying 0.80 mg\'O IND.3\'/mLww to the alkaline bleach effluent from Howe Sound\'s mill. A similar behavior was observed after 0.80 mg\'O IND.3\'/mLww was applied to the alkaline bleach effluent from Catalyst\'s mill. The ratio of BOD5/COD was increased from 0.07 to 0.16 and the effluent colour decreased by 78%. These changes were primarily driven by reductions of the HMW fractions of the effluent during ozonation. Organics with molecular range higher than 2 kDa were completely removed from the primary treated effluent. Aproximately 85% and 61% of the organics higher than 5 kDa were removed from the Howe Sound\'s alkaline bleach effluent under initial pH 7 and 12, respectively, after applying 0.72 mg\'O IND.3\'/mLww. Organic compounds with molecular weight higher than 10 kDa were completely removed from the Catalyst\'s alkaline bleach effluent after applying 0.80 mg\'O IND.3\'/mLww. Molecular ozone available under neutral conditions seems to play an important role when the removal of the high molecular weight organic compounds is the main objective.

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