El objetivo fundamental de esta Tesis es describir y monitorizar el efecto de diversas concentraciones de ácido nítrico en la degradación del color de once pigmentos de uso común en obras de arte pictóricas. Así mismo se busca conocer cuál es el efecto de los parámetros tiempo de exposición y temperatura ambiental. Finalmente se efectúa una comparación entre la degradación del color inducida por ácido nítrico y la que provocan el ozono y el ambiente real urbano. El cambio de color de los pigmentos se valora de manera cuantitativa, cualitativa y gráfica, siguiendo el sistema CIELAB. Para la consecución de estos objetivos se han efectuado una serie de experimentos de laboratorio y ensayos de campo. En el laboratorio se han recreado diferentes condiciones ambientales controladas de exposición por medio de un sistema dinámico de exposición para el ácido nítrico y el ozono respectivamente. Los resultados experimentales muestran que todos los pigmentos expuestos al ácido nítrico, al ozono y al ambiente real urbano sufren variaciones en su color original en dependencia del tiempo durante el que las muestras están sometidas a la acción del ácido nítrico, la concentración del ácido nítrico y la temperatura ambiental. El cambio es diferente según la naturaleza de cada uno de los pigmentos, por lo que es razonable pensar que otros colorantes estrechamente relacionados con los de este estudio sean sensibles al ácido nítrico de una manera similar. / The main objective of this Thesis is to describe and detail the effect of different concentrations of nitric acid in the fading of eleven pigments commonly used in art works. Likewise the study try to know what is the effect of the parameters time of exposure and environmental temperature on fading. Finally we made a comparison between color degradation induced by nitric acid and which cause the ozone and the real urban environment. Fading is valued using the CIELAB system quantitatively, qualitatively and graphically. Different laboratory experiments and field trials have been carried on for the achievement of these objectives. In the laboratory, several controlled environmental conditions of exposure have been recreated ,by the use of a dynamic system of exposure to nitric acid and ozone respectively. Results show that all the pigments exposed to nitric acid, ozone and to a real urban environment suffer variations in its original color, depending on time during the samples are exposed to the action of nitric acid, concentration of nitric acid and temperature. Fading is different according to the nature of each pigment, so it is reasonable to think that other pigments closely related of the ones studied are sensitive to nitric acid in a similar way.

El p-Nitrophenol (PNP) es un compuesto que tiene numerosas aplicaciones en la industria química; es empleado como materia prima en la industria farmacéutica, de pesticidas y en la manufactura de cuero. Sin embargo, es un compuesto dañino para los humanos, los animales y el medio ambiente. Exposiciones repetidas al PNP pueden causar daños en los glóbulos rojos, en el sistema nervioso central y efectos mutagénicos. La selección del tratamiento adecuado para la remediación de aguas residuales industriales que contengan compuestos recalcitrantes, como el PNP, depende de la naturaleza del compuesto, su concentración y su carga. Por consiguiente, en esta tesis se realizó un estudio comparativo de diferentes tecnologías para el tratamiento de aguas residuales que contienen altas concentraciones de PNP tomando en cuenta las características de dichas aguas. Primeramente, se estudió el tratamiento biológico de aguas contaminadas con PNP en un reactor aeróbico secuencial por lotes (SBR). La puesta en marcha del reactor fue realizada utilizando como inóculo biomasa no aclimatada, proveniente de una estación depuradora de aguas urbanas, y agua sintética que contenía una mezcla de PNP y glucosa – sacarosa como fuentes de carbono. Se aplicó una estrategia operacional específica con el objetivo de desarrollar lodos activos del tipo estrategas de la K. Durante todo el período de operación se obtuvo un 100% de eliminación del PNP. Se realizaron estudios respirométricos para caracterizar cinéticamente los degradadores de PNP. Los valores cinéticos obtenidos confirmaron que la biomasa obtenida es del tipo estrategas de la K, demostrando consecuentemente el éxito de la estrategia de operación. En segundo lugar, se empleó como tratamiento la bioaumentación utilizando una población microbiana aclimatada a consumir PNP en un reactor que recibió choques de carga de PNP transitorios o continuos. Se estudió el efecto de la cantidad de población microbiana añadida empleando dos dosis diferentes obteniéndose la eliminación total del PNP durante el choque. Se demostró que la dosis de lodos especializados es el factor clave para una estrategia de bioaumentación exitosa. Este hecho, fue confirmado monitorizando la población microbiana durante los experimentos mediante la hibridación fluorescente in-situ . Asimismo, la puesta en marcha del reactor bioaumentado fue más rápida y estable en comparación con el reactor no bioaumentado. Finalmente, en el caso de aguas residuales altamente concentradas en PNP que no pueden ser degradadas en un reactor biológico, se realizó la oxidación húmeda (WAO) y la oxidación húmeda catalítica (CWAO) con el objetivo de incrementar la biodegradabilidad de los efluentes. Se estudió la influencia de la temperatura, presión parcial de oxígeno, tipo de catalizador, pH y fuerza iónica. Se realizaron diversos experimentos con cuatro catalizadores basados en Pt y Ru. La mejora en la biodegradabilidad de los efluentes fue analizada mediante ensayos respirométricos. Los resultados muestran que la eliminación de PNP fue mayor a 90% en la mayoría de los casos, siendo la temperatura el factor más importante. Más aún, la biodegradabilidad de los efluentes mejoró en más de 50% en la mayoría de los casos y se incrementaba a medida que la fracción de ácidos carboxílicos en el efluente era mayor. Así pues, se determinó que la integración de CWAO con un tratamiento biológico permitiría la eliminación del PNP y de los intermediarios que se forman durante la primera etapa del tratamiento. En conclusión, esta investigación contribuye a una comprensión más profunda de la dinámica de degradación del PNP bajo diferentes tecnologías y provee de una herramienta para la selección de la mejor tecnología de tratamiento disponible. / p-Nitrophenol (PNP) is a compound with numerous applications in the chemical industry. PNP is mainly used in the manufacturing industry of pharmaceutical products, pesticides and leather-related products. PNP is highly toxic for humans, animals and the environment. Repeated exposure to PNP may cause injury to blood cells, damage to the central nervous system and mutagenic effects. Selecting the appropriate process to treat wastewaters containing recalcitrant compounds, such as PNP, is greatly dependent on the nature of the compound itself, its concentration and its loading rate. In this thesis, a comparative study on the treatment of high-strength wastewaters containing PNP is intended by taking different approaches according to the wastewater characteristics. Firstly, biological treatment in an aerobic Sequencing Batch Reactor (SBR) was studied. The start up of the reactor was performed using a non-acclimated biomass, coming from a municipal wastewater treatment plant as inoculum and a synthetic wastewater containing a mixture of PNP and glucose-sucrose as carbon source. A specific operational strategy was applied with the aim of developing a K-strategist PNP-degrading activated sludge. Total PNP removal was achieved in the whole operating period. Kinetic characterization of the PNP-degrading population was carried out using respirometry assays. The kinetic values obtained confirmed that the biomass was of K-strategist type, thus demonstrating the success of the operational strategy. The Ki value obtained in this work was higher than others reported in the literature, meaning that the sludge was more adapted to PNP inhibition. Afterwards, bioaugmentation with an enriched microbial population was applied as treatment for facing transient or continuous shock loads of PNP. The effect of the amount of enriched microbial population added for bioaugmentation was assessed using two different dosages. In the cases tested, total PNP removal was achieved during the transient PNP shock load. However, after a long PNP starvation period, total PNP removal during a second PNP shock load was achieved, when higher doses were applied. Therefore, the dosage of specialized bacteria was established as the key factor for a successful bioaugmentation strategy. This was confirmed with the microbial characterization through fluorescence in-situ hibridisation during experiments. In addition, the performance of a bioaugmented SBR receiving a continuous PNP shock load was enhanced when compared to a non-bioaugmented SBR. Finally, in the case of highly concentrated PNP wastewaters that cannot be degraded in a biological reactor, wet air oxidation (WAO) and catalytic WAO (CWAO) were performed with the aim of increasing the biodegradability prior to a biological remediation. The influence of temperature, oxygen partial pressure, pH, ionic strength and type of catalyst on PNP CWAO was studied. Four Pt and Ru-based catalysts have been tested in batch experiments. PNP elimination, total organic carbon abatement and intermediates distribution were monitored. Respirometric tests were done to assess the biodegradability enhancement of the CWAO effluents. PNP elimination was higher than 90% in most cases. Temperature was the most important operating parameter upon CWAO. Moreover, CWAO increased biodegradability by more than 50% for most of the conditions tested; the best biodegradability enhancement was observed when the carboxylic acids fraction was the highest. An integrated CWAO and biological treatment would allow an easy removal of highly concentrated PNP and the intermediates formed during CWAO step. In conclusion, this research contributed to a deeper understanding of the dynamics of PNP degradation under different technologies and provides an aid to propose a best available technology for the removal of recalcitrant compounds from industrial wastewaters.

Zugl.: Stuttgart, Univ., Diss., 2007

Thesis (D.A.)--Illinois State University, 1999. / Title from title page screen, viewed July 28, 2006. Dissertation Committee: L. Moody Simms (chair), M. Paul Holsinger, Dolores Kilgo, Lawrence W. McBride. Includes bibliographical references (leaves 333-346) and abstract. Also available in print.

No description available.

Le polyamide 66 est un polycondensat formé par condensation de l'acide adipique et de l'hexaméthylène diamine. La réaction a lieu sans catalyse. Cependant, elle peut être accélérée en présence de catalyseurs, les plus répandus étant les acides phosphorés organiques et minéraux. Aujourd'hui, on connaît peu de choses sur le mécanisme d'activation de la réaction. Dans un souci d'innovation et de compréhension, les recherches en catalyse de polycondensation du polyamide 66 se sont intensifiées ces dernières années. C'est dans cet optique que le travail de thèse a été réalisé. Les objectifs étaient de proposer et tester de nouveaux systèmes catalytiques et d'engager une recherche permettant de mieux comprendre le mécanisme de catalyse de polycondensation du polyamide 66. Nous avons mis en évidence une réelle spécificité du phosphore en catalyse. Des acides alkylphosphoniques porteurs de fonctions polaires se sont révélées particulièrement actifs en synthèse et en post condensation liquide. Grâce à des études sur des réactions modèles, l'hypothèse du passage par un intermédiaire réactionnel de type anhydride mixte, formé entre le catalyseur et l'acide adipique, a pu être confortée / Polyamide 6,6 is prepared by polycondensation of hexamethylene diamine with adipic acid The reaction occurs without catalyst. It can be accelerated using a catalyst, the most usual activators are organic and inorganic phosphorous acids. Today, we know little about the mechanism of activation of the reaction. To innovate and understand, researches in catalysis of polyamide 66 polycondensation have intensified in recent years. It is the reason for why thesis was done. The goal of the thesis was to propose and test new catalytic systems and to initiate a work to get a better understanding of the mechanism of polycondensation catalysis of polyamide 66. We have highlighted a real specificity of phosphorus in catalysis. Alkylphosphonic acids with polar functions were found to be particularly active in synthesis and post condensation liquid. Studies on model compounds have supported that the polycondensation may proceed through a reaction-typed mixed anhydride formed between the catalyst and adipic acid

Le dioxyde de chlore se positionne actuellement comme une alternative au chlore pour la désinfection de l'eau potable. Bien que son pouvoir biocide soit aujourd'hui bien connu, il existe peu de données bibliographiques sur ses effets sur les matériaux organiques dans les réseaux d'eau intérieurs. L'utilisation du PA66 pour des clapets anti-retour est récente : son comportement à long terme est donc méconnu. L'objectif de cette étude était de progresser dans la compréhension des mécanismes d'interaction entre le dioxyde de chlore et une matrice PA66 stabilisée par un mélange de deux antioxydants et chargée de fibres de verre, mais aussi de proposer une méthode « multi-échelle » de prédiction de la durée de vie de ce matériau composite en service. Tout d'abord, une meilleure description des réactions chimiques se produisant au sein du matériau (oxydation, hydrolyse, protection du polymère par les antioxydants, attaque chimique du polymère et des antioxydants par le désinfectant) a permis d'élaborer un schéma mécanistique général de dégradation. Des équations cinétiques ont été dérivées de ce schéma mécanistique pour prédire l'évolution des modifications chimiques, en considérant une répartition hétérogène des antioxydants dans la matrice PA66 et en prenant en compte la plupart des conditions d'exposition (température de l'eau, concentration en réactifs chimiques, temps). Ensuite, le matériau vieilli a été testé en conditions d'usage grâce à des essais de pression hydrostatique pour identifier son régime de rupture. / Nowadays, chlorine dioxide is an alternative of chlorine for the disinfection of drinking water. Although its biocide ability is well known, scientific literature lacks of knowledge about its effects on organic materials in domestic water networks. The use of PA 66 for valves is quite recent: its long term behaviour is thus unknown. The aim of this study was to improve the knowledge of the interaction mechanisms between chlorine dioxide and a PA 66 matrix stabilized by blend of two antioxidants and reinforced by glass fibres, but also to propose a multi-scale method for the lifetime prediction of this composite material in service. First of all, a better description of the chemical reactions occurring within the material (oxidation, hydrolysis, polymer protection by antioxidants, chemical attack of polymer and antioxidants by disinfectant) has allowed elaborating a general degradation mechanistic scheme. Kinetic equations were derived from this mechanistic scheme for predicting the chemical changes, considering a heterogeneous distribution of antioxidants within the PA 66 matrix and taking into account most exposure conditions (water temperature, concentration in chemical reactants, time). Then, the aged material was tested in use conditions thanks to hydrostatic pressure experiments in order to identify its failure regime.

Introduction A method based on neutron activation is being developed to assist in resolving discrepancies between the expected yield and actual yield of radionuclides produced with the vertical-beam target station (VBTS) at iThemba LABS. The VBTS is routinely employed for multi-Ci batch productions of the radionuclide pairs 22Na/68Ga and 82Sr/68Ga using standardized natMg/natGa and natRb/natGa tandem targets, respectively [1]. The metal-clad target discs are bombarded with a primary beam of 66 MeV protons at an intensity of nominally 250 µA. The encapsulation materials are either Nb (for Mg and Ga) or stainless steel (for Rb) which serve to contain the molten target materials during bombardment and act as a barrier to the high-velocity cooling water which surrounds the targets in a 4π geometry. The natRb/natGa targets are typically bombarded according to a two-week cycle while natMg/natGa targets are bombarded on an ad-hoc basis, depending on a somewhat unpredictable 22Na demand. A too-large deviation between expected yield and actual yield has at times plagued this programme. These deviations can manifest both as an apparent loss or an apparent gain (relative to the expected yield) by up to about 15% in either direction. The resulting uncertainty of up to 30% (in the worst case) from one production batch to another can be costly and is unacceptable in a large-scale production regimen. This phenomenon is believed to be brought about by two types of problems: (1) Production losses, e.g. during the radio-chemical separation process or incomplete recovery of activated target material during the decapsulation step. (2) Incorrect values obtained for the accumulated proton charge. A problem of type (1) will always result in a loss of yield. A problem of type (2) can manifest as an apparent loss or gain. In an effort to get a handle on this second type of problem, neutron activation of suitable material samples, embedded in a target holder, is being investigated as an independent indicator of the total yield. For this purpose, samples of Co, Mn, Ni and Zn were activated during production runs and Co was found to be the most appropriate. Preliminary results will be presented after first discussing why the determination of the accumulated pro-ton charge is a problem with the VBTS. Materials and Methods The VBTS consists of a central region in which a target holder is located during bombardment as well as two half-cylindrical radiation shields which completely surround the target. The shields can be moved away from the central region on dedicated rails, e.g. when repairs or maintenance is required. FIGURE 1 shows the VBTS with the shields moved to the “open” position. As some components of the station are located below the vault floor, with the target position near floor level, it proved difficult to electrically isolate the VBTS as was done for the two horizontal-beam target stations at iThemba LABS [1]. The VBTS does not act as a Faraday cup like the other target stations. Instead, the beam current and accumulated charge is measured by means of a calibrated capacitive probe [1,2]. There appears to be a variation in the response of the capacitive probe, sensitive to the beam microstructure, in particular a dependence on the beam packet length. This problem is not yet fully resolved. FIGURE 2 (a) shows the beamstop of a VBTS target holder with several Co samples mounted on the outside as well as one each of Ni, Mn and Zn. The samples are small “tablets” with a 10 mm diameter and 1 mm thickness. The reactions of interest are 59Co(n,γ)60Co, 59Co(n,3n)57Co, nat-Ni(n,X)60Co, natNi(n,X)57Co, natZn(n,X)65Zn and 55Mn(n,2n)54Mn. The relevant half-lives are 60Co(5.271 a), 57Co(271.8 d), 65Zn(244.3 d) and 54Mn(312.2 d). The half-life should be long compared to the two-week cycle in order to reduce the dependence on the exact beam history, which is very fragmented over any production period. In this respect, 60Co is considered to be particularly attractive as its long half-life of more than 5 years leads to a negligible effect by the beam history. Note that the tandem targets, shown in FIGURE 2 (b), are mounted just upstream of the beamstop – in fact, the targets and beamstop form a single unit before being fitted into the target holder. At the end of bombardment, all samples were assayed for their characteristic γ-emissions using standard off-line γ-ray spectrometry with an HPGe detector connected to a Genie 2000 MCA. Calculations of the neutron fluence density in the central sample volume on the beamstop were also performed using the Monte Carlo radiation transport code MCNPX. For these calculations, the entire VBTS, a Rb/Ga target and the vault walls were included in the model. Results and Conclusion All samples activated significantly – copious amounts of 60Co were detected in the Co discs after a two-week run. The neutron fluence density for the case of a 250 µA, 66 MeV proton beam on a natRb/natGa tandem target is shown in FIGURE 3. The dominance of low-energy neutrons is evident, which is in part due to the large amount of paraffin-wax shielding material in close proximity to the target. While reactions such as the (n,2n) and (n,3n) would be sensitive to the more energetic part of the neutron spectrum, the (n,γ) capture reaction benefits from the large low-energy component. This explains the copious amounts of 60Co formed. It was therefore decided to only retain the central Co sample for subsequent bombardments, as shown in FIGURE 4. The first results are shown in TABLE 1. The accumulated charge as obtained from the capacitive probe (Q), the specific 60Co activity (A) at the end of bombardment (EOB), and their ratio (A/Q) are presented in the table, together with the deviation of individual ratios relative to their average for the case of the Mg/Ga tandem tar-gets only. Note that all samples were counted until the statistical uncertainties were negligible. Any systematic uncertainties are ignored at this stage as they are considered to remain the same from one batch production to another. For the sake of argument, the average value of the ratio is taken as the expected value. A positive deviation of the A/Q value is then indicative of a too-small value of the accumulated charge obtained from the capacitive probe, leading to a corresponding overproduction. Likewise, a negative value is indicative of a too-large value of the accumulated charge, leading to a corresponding underproduction. It is certainly true that the data in TABLE 1 are currently very limited. It is envisaged, however, that with time the growing database of values will assist in reducing the uncertainty in determining the accumulated charge and reduce the discrepancies between predicted and actual yields significantly. TABLE 1 illuminates the underlying problem satisfactorily. The four Mg/Ga tandem target bombardments, on identical targetry, were performed successively. The neutron activation correlates well the with actual yields, pointing directly to the current integration as the main source of error. The method already proves to be useful. An indication of an over or underprediction can be obtained prior to the target processing by recovering and measuring the Co disc. This in-formation can be used to make a decision concerning the present batch production and/or the subsequent one. One can either add beam to the present production target and/or in-crease/reduce the total beam on the subsequent production target to compensate for an expected overproduction or shortfall. In conclusion, we would like to stress that the capacitive probes show great promise and that better understanding and/or possibly some development of their signal processing algorithm may improve their ability to measure the accumulated charge to the desired accuracy. Segmented capacitive probes used at iThemba LABS and elsewhere for beam position measurement [1,3] are not affected by beam microstructure as only the ratios of the signal strengths on the different sectors are important. In this case, changes in response affect all sec-tors equally and the ratios are unaffected.

Prions são definidos como partículas protéicas infecciosas compostas, quase que exclusivamente, por uma proteína conhecida como prion scrapie (PrPsc). O envolvimento dessas partículas na etiologia de doenças neurodegenerativas, tanto em homens como em animais, já está bem determinado. Acredita-se que o PrPsc seja sintetizado através de modificações pós-traducionais que ocorreriam na isoforma celular da proteína prion (PrPc), uma glicoproteína expressa constitutivamente na superfície de vários tipos celulares, principalmente de neurônios, ancorada na membrana plasmática por glicosil-fosfatidil inositol (GPI). Apesar de ser uma molécula conservada em várias espécies, a função de PrPc ainda permanece desconhecida. Interessados nos possíveis papéis fisiológicos desempenhados pelo PrPc, decidimos investigar certas interações que o PrPc poderia realizar com outras moléculas, na tentativa de se encontrar pistas sobre a função dessa proteína em células normais. Assim, nosso grupo identificou e vem caracterizando duas interações nas quais o PrPc está envolvido: com o seu receptor de 60-66 kDa e com a principal proteína não colagênica da matriz extracelular, a laminina (LN). Grande parte da caracterização dessas duas interações vem sendo desenvolvida graças ao uso de PrPc recombinante produzido em sistema heterólogo (em E.coli). O trabalho em questão trata principalmente da produção de PrPc recombinantes em sistema heterólogo e a utilização destes como importantes ferramentas para a melhor caracterização das interações identificadas. Alguns trabalhos na literatura vinham sugerindo a existência de um receptor para prions. Através da teoria da hidropaticidade complementar dos aminoácidos, nosso grupo foi capaz de identificar uma proteína de 60-66 kDa como sendo esse provável receptor. Ensaios de ligação in vitro utilizando PrPc recombinante, ou PrPc nativo (ancorado na superfície de células) confirmaram que a forma desse receptor presente na membrana (de 66 kDa) é capaz de se ligar ao PrPc. Com a ajuda de PrPc recombinante também foi possível verificar uma ligação específica, saturável e de alta afinidade (Kd da ordem de 10-8 M) entre PrPc e a LN. Através de ensaios de competição, utilizando peptídeos sintéticos correspondentes a domínios da LN já bem caracterizados e de funções estabelecidas, fomos capazes de mapear o sítio dessa molécula que se liga ao PrPc. A sequência identificada (RNIAEIIKDI) encontra-se na região C-terminal da cadeia γ1 da LN e, como demonstrado na literatura, esse domínio é responsável por estimular tanto a adesão celular, quanto o crescimento de neuritos em neurônios de cerebelo em cultura primária. De fato, resultados obtidos pelo nosso grupo indicam que a interação PrPc/LN participa no processo de neuritogênese. Experimentos de esquiva inibitória, realizados em colaboração com o grupo do Prof. Dr. Ivan Izquierdo (UFRGS) indicaram que a ligação PrPc/LN também desempenha um importante papel nos processos de memória e aprendizado. / Prions are defined as proteinaceous infectious particles that mediate the pathogenesis of certain neurodegenerative diseases, in humans and in animals. The prion particle is composed largely, if not entirely, by PrPsc (prion scrapie), a posttranslationaly modified isoform of the cellular host-encoded prion protein (PrPc). PrPc is a glycosylphosphatidylinositol anchored protein that is constitutively expressed by several cell types, mainly on neuronal cell surface. However, the physiological role of this conserved protein remains unclear. ínterested in this normal function of PrPc, our group decided to investigate some interactions that PrPc could be done with other molecules in order to find some clues about it. We have been identified and characterized two interactions that PrPc is involved: with its putative 60-66 kDa receptor and with laminin. In order to better characterize these interactions it was necessary to produce purified PrPc. In this work we will report the expression and the purification of mouse PrPc protein in heterologous system and its use as important tools to investigate the PrPc interactions. A specific cell surface receptor for PrPc has been predicted. Using the concept of complementary hydropathy, our group has identified a 60-66 kDa membrane protein in mouse brain, which seems to be a putative PrPc receptor. ln vitro binding assays using recombinant and native PrPc were able to confirm that the membrane receptor (66 kDa) binds PrPc. Recombinant PrPc was also useful to demonstrate a specific and high affinity (Kd around 10-8M) interaction between PrPc and laminin. In an attempt to map the PrPc binding site in this molecule, laminin peptides with established physiological functions were used in cornpetition binding assays. A peptide derived frorn C-terminal γ-1 chain of mouse laminin, RNIAEIIKDI, was the only one that was able to block the binding of laminin to PrPc, suggesting that this region comprises the PrPc binding site. It was reported in the literature that this peptide simulates the neurite outgrowth and cellular adhesion. In collaboration with Dr. Izquierdo\'s group (UFRGS) we demonstrated that the interaction characterized between this laminin\'s domain and PrPc is involved in the neuritogenesis process, as well as in learning and memory.

Os processos de separação por membrana (PSM) vêm ganhando destaque em aplicações industriais por conta de suas vantagens, principalmente o baixo custo de implementação e o baixo consumo de energia para sua operação. A utilização de subprodutos agrícolas na obtenção de materiais é uma tendência crescente, sendo os seus maiores atrativos a grande disponibilidade desses subprodutos e por serem uma matéria-prima barata. O presente trabalho teve como principais objetivos a produção de membranas sua utilização na detoxificação do hidrolisado hemicelulósico originado do tratamento ácido do bagaço de cana-de-açúcar. Para tanto foram produzidos dois tipos de membranas a partir de três polímeros diferentes, o acetato de celulose obtido a partir do bagaço de cana, o acetato de celulose comercial e a poliamida 66. Na produção de acetato a partir do bagaço foi realizado um estudo exploratório para extrair a celulose, matéria-prima do acetato, de uma maneira que se obtivesse um material com alto grau de pureza e que as perdas de celulose durante o processo fossem minimizadas. Para a produção das membranas foi utilizada a técnica de inversão de fases. No caso das membranas de acetato de celulose, foi realizada uma variação dos parâmetros utilizados no processo de confecção das membranas (tempo de evaporação do solvente, temperatura do banho de coagulação e tratamento térmico), com o intuito de se estabelecer as melhores variáveis do processo, enquanto que para a poliamida 66, foram utilizadas condições previamente determinadas por outros estudos. Depois de prontas, as membranas foram caracterizadas fisicamente e pelas suas propriedades de fluxo de água pura, fluxo de vapor de água, rejeição de sais, rejeição de açúcares e rejeição de compostos tóxicos. Finalmente, as membranas foram aplicadas no processo de detoxificação do hidrolisado hemicelulósico para testar sua capacidade de remoção de furfural, hidroximetilfurfural (HMF), ácido acético e compostos fenólicos. No estudo de extração da celulose do bagaço, as melhores condições produziram uma celulose com pureza de 84,01%. O acetato produzido apresentou um grau de substituição de 2,52, podendo ser classificado como um triacetato de celulose. Em comparação, o acetato comercial apresentou um grau de substituição de 2,85. Fisicamente, todas as membranas apresentaram uma morfologia que intercalava a presença de poros com regiões nodulares. As membranas de bagaço de cana apresentaram uma considerável fragilidade, por isso nos testes de permeação sob pressão, elas foram suportadas por uma membrana de polissulfona comercial. Todas as membranas de acetato de bagaço e membrana de poliamida apresentaram fluxo de água pura, enquanto que apenas algumas membranas de acetato comercial conseguiram permear água pura. As membranas apresentaram diferentes resultados nos experimentos de rejeição de compostos, resultado das diferenças estruturais entre elas. No ensaio de detoxificação, a membrana que alcançou o melhor desempenho foi a membrana obtida a partir do acetato comercial. Essa membrana conseguiu remover 89,92% de HMF, 91,99% de furfural, 51,52% de ácido acético e 8,35% de compostos fenólicos. As membranas produzidas a partir do bagaço de cana alcançaram uma remoção de 71,66 de HMF, 60,87% de furfural, 91,79% de ácido acético e 10,86% de fenólicos. / Membrane separation processes (MSP) have been highlighted at industrial processes because of their advantages, mainly the low cost of implementation and the low energy consumption during their operation. The utilization of agriculture co-products for the obtainment of material is a increasing trend, wherein the main attractive are the high availability and the low cost of these co-products. The aims of this work were to produce membranes and to investigate their utilization in the detoxification of the hemicellulosic hydrolisate originated from the acid treatment of sugarcane bagasse. For that, two types of membranes were produced from three different types of polymers, cellulose acetate obtained from sugarcane bagasse, commercial cellulose acetate and polyamide 66. For the production of the sugarcane bagasse cellulose acetate it was conducted an exploratory study in order to extract cellulose, raw-material of the acetate, in a manner that the final material possessed high purity degree and the losses of cellulose during the process were minimized. The technique of phase inversion was utilized to produce the membranes. In the case of cellulose acetate membranes, the variation of the membrane production parameters (time of solvent evaporation, temperature of coagulation bath and thermical treatment) was performed for the purpose of establishing the best process parameters, whereas it was utilized previously established conditions found in the literature for the polyamide membrane production. The membranes were characterized physically and for their properties of pure water flux, vapor water flux, salt rejection, sugar rejection and toxic compound rejection. Finally, the membranes were applied in the process of hemicellulosic hydrolysate detoxification for testing their capacity of furfural, hydroxymethylfurfural (HMF), acetic acid and phenolic compound removal. The best conditions of cellulose extraction from sugarcane bagasse were able to produce cellulose with 84.01% of purity. The sugarcane cellulose acetate presented a substitution degree of 2.52, being classified as cellulose triacetate. In comparison, commercial cellulose acetate presented a substitution degree of 2,85. Physically, all membranes possessed a morphology that interspersed the presence of porous and nodular regions. Due to their fragility, sugarcane bagasse membranes were supported by a polysulfone commercial membrane in the tests of permeation under pressure. All sugarcane bagasse membranes and polyamide membrane achieved pure water flux. Nevertheless, just some commercial cellulose acetate membranes could permeate pure water. In the assays of compound rejection, the membranes reached different results, on behalf of their structural differences. The membrane that obtained the best performance in the detoxification process was the membrane produced form commercial cellulose acetate. This membrane was able to remove 89.92% of HMF, 91.99% of furfural, 51.52% of acetic acid and 8.35% of phenolic compounds. The membranes produced from sugarcane bagasse reached a removal of 71.66 of HMF, 60.87% of furfural, 91.79% of acetic acid and 10,86% of phenolics.