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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.
171

Efeitos das condições de cultivo e desenvolvimento de um bioensaio de toxicidade com o fungo bioluminescente Neonothopanus gardneri / Effects of culture conditions and development of a toxicity bioassay with the bioluminescent fungi Neonothopanus gardneri

Fernanda de Freitas Ventura 12 June 2015 (has links)
Os fungos são decompositores primários e, portanto, ocupam uma posição estratégica na base da cadeia alimentar em diversos ecossistemas, incluindo os terrestres. Por tais características, estes organismos são de especial interesse na aplicação em bioensaios de toxicidade. As metodologias com espécies bioluminescentes são geralmente práticas, economicamente viáveis e de fácil aplicação. Ainda assim, os fungos naturalmente bioluminescentes são ainda pouco estudados para este propósito, em comparação com os organismos aquáticos, como as bactérias. Neste cenário, o presente trabalho apresenta os efeitos de diferentes condições de cultivo sobre o perfil de bioluminescência do fungo Neonothopanus gardneri, buscando o desenvolvimento de um bioensaio de toxicidade utilizando esta espécie. Estudos preliminares foram destinados à redução da variação experimental, à identificação de algumas das características intrínsecas do organismo em cultura e, ainda, à definição de procedimentos de análise e de inoculação do micélio. Em seguida, a emissão de luz foi monitorada variando as temperaturas de incubação, o pH dos meios de cultura e as concentrações das fontes de carbono e de nitrogênio, adotadas como nutrientes. Identificou-se que a incubação a 30ºC em meios com 2% de ágar, 1% de melaço de cana de açúcar, 0,02% de extrato de levedura e pH 6 resultou em um perfil de bioluminescência mais adequado ao propósito de interesse, apesar de não ter resultado na maior emissão de luz possível. Nestas condições de cultivo, foi possível desenvolver um bioensaio de toxicidade. Para isso, foi necessário avaliar o comportamento da luz emitida pelo micélio em contato tanto com ar atmosférico quanto com alguns potenciais diluentes, estabelecendo-se também o tempo de exposição necessário para uma resposta máxima do fungo N. gardneri em contato com soluções de Cu+2 (50 mM) e fenol (10 mM). Neste caso, uma solução aquosa de Triton X-100 na concentração de 0,01% (m:v) tamponada com ácido 2-(N-morfolino)etano sulfônico (MES, 50 mM, pH 5,7) foi adotada para diluir os agentes tóxicos, aos quais o micélio foi exposto durante 24 horas. Posteriormente, a metodologia foi aplicada para testar a toxicidade de dois metais e dois fenóis (Cu+2, Cd+2, fenol e 4-nitrofenol), obtendo-se respectivos valores de EC50 (concentração mediana efetiva) iguais a (0,53 ± 0,09) mM; (8,0 ± 0,5).10-3 mM; (1,7 ± 0,3) mM e (0,34 ± 0,04) mM. Entretanto, em experimentos paralelos, a quantificação espectrofotométrica de fenóis nos meios de cultura indicou que os mesmos são difundidos homogeneamente pelo ágar. Neste caso, os valores de EC50 seriam divididos por 6, para considerar a diluição dos compostos pelos meios. O bioensaio com a espécie N. gardneri possui vantagens, principalmente em relação ao comportamento reprodutível da emissão de luz, à alta intensidade da bioluminescência, ao crescimento rápido do micélio e à sensibilidade aos agentes tóxicos testados. Considerando tais características, a metodologia desenvolvida representa um procedimento viável em bioensaios de toxicidade. Assim, a mesma pode ser aperfeiçoada em trabalhos futuros e aplicada em complemento com outros métodos já desenvolvidos para outros organismos terrestres ou aquáticos. / Fungi are primary decomposers, thus occupying a strategic position at the base of the food chain in many ecosystems, including terrestrial ones. Due to such characteristics, these organisms are of special interest to toxicity bioassays. Bioluminescent-based methods are usually practical, economically viable and easy to perform. Nevertheless, naturally bioluminscent fungi are still poorly studied in this respect, compared to aquatic organisms like bacteria. In the above mentioned scenario, this work presents the effects of different culture conditions on the bioluminescence profile of the fungus Neonothopanus gardneri, aiming at the development of a toxicity bioassay using this species. Preliminary studies were intended to reduce experimental variation, identify some of the intrinsic characteristics of the organism in culture, and also to define the procedures for analysis and mycelium inoculation. Following this, light emission was monitored varying the incubation temperatures; the culture media pH and the concentrations of carbon and nitrogen nutrient sources. It was identified that the incubation at 30ºC in culture media containing 2% agar, 1% sugar cane molasses, 0.02% yeast extract and pH 6 resulted in the most appropriate bioluminescence profile for the purpose of interest, although it has not resulted in the higher light emission. Under these culturing conditions, it was possible to develop a toxicity bioassay. To this end, it was necessary to assess the behavior of light emission from the mycelium in contact with both atmospheric air and some potential diluents, also establishing the exposure time required for a maximum response of N. gardneri in contact with Cu+2 (50 mM) and phenol (10 mM) solutions. In this case, an aqueous solution of Triton X-100 in the concentration of 0.01% (w:v) buffered with 2-(N-Morpholino)ethanesulfonic acid (MES, 50 mM) was chosen to dilute the toxic agents, to which the mycelium was exposed for 24 hours. Thereafter, the methodology was applied to test the toxicity of two metals and two phenols (Cu+2, Cd+2, phenol and 4-nitrophenol), obtaining respective EC50 values (median effective concentration) equal to (0,53 ± 0,09) mM; (8,0 ± 0,5).10-3 mM; (1,7 ± 0,3) mM e (0,34 ± 0,04) mM. Meanwhile, in parallel experiments, the spectrophotometric quantification of phenols in culture media indicated that they are evenly diffused through agar. In this case, the EC50 values would be divided by 6, in order to consider the dilution of compounds by the media. The toxicity bioassay with N. gardneri species has advantages, manly in relation to the reproducible behavior of light emission, high intensity of bioluminescence, rapid growth of mycelium and sensitivity to the tested toxic agents. Considering these characteristics, the developed methodology represents a viable procedure for a toxicological bioassay. Accordingly, it can be improved in future work and performed in addition to other methods already developed for other terrestrial or aquatic organisms.
172

Avaliação da toxicidade de diversos fenóis por meio de estudos teóricos e sua influência na determinação do dano ambiental / Evaluation of the toxicity of various phenols through theoretical studies and its influence in determining of the environmental damage

Gustavo Suzigan Leis 19 November 2014 (has links)
Os estudos de impacto ambiental em sistemas aquáticos são de grande importância, tanto no âmbito social quanto no econômico. Estes têm que contemplar a avaliação dos danos produzidos pelos mais variados tipos de substâncias, criando a necessidade de conhecer a ação destas ao sistema em questão. O resultado da interação de substâncias com o ambiente pode ser explorado por meio de experimentos envolvendo o coeficiente de partição octanol/água (Kow). A escolha do Kow se deve ao fato deste se relacionar a interação do composto escolhido com o meio, no que diz respeito à absorção e transporte. No caso deste trabalho, uma série de fenóis foi estudada em termos do coeficiente de partição. Cálculos teóricos foram realizados como alternativa para mensuração experimental do coeficiente de partição octanol/água. A elaboração de modelos QSAR (Quantitative Structure Activity Relationship) para a previsão de valores de coeficiente de partição octanol/água foi realizado por meio de cálculos envolvendo física quântica e quimiometria. Os dados das variáveis foram obtidos para o grupo de fenóis em questão utilizando os métodos de cálculos semiempíricos AM1, PM3, PM6 e PM7. A comparação dos modelos QSAR obtidos permitiu a conclusão de que, para os descritores selecionados, o conjunto de valores obtidos com o método PM7 proporcionou a criação dos melhores modelos. Utilizando como variáveis selecionadas energia eletrônica, área molecular, volume molecular, energia de repulsão core-core e massa molecular, obteve-se um modelo que acumulava aproximadamente 99,99% de toda a informação em três componentes, com um coeficiente de correlação externo (referente à calibração) em torno de 0,93, o que indica a força preditiva do modelo. A relação da toxicidade com o Índice de Qualidade das Águas também foi investigado por meio da relação dos valores LogKow obtidos e pH. Com o pKa de cada fenol proveniente de dados teóricos (e fazendo uso da relação de pKa e pH proposta por Henderson-Hasselbach), pode-se concluir que não existe influência intrínseca dos valores de LogKow nos valores de pH, verificado com o baixo coeficiente de correlação entre as variáveis, em torno de 0,15. / The environmental impact on aquatic systems are of great importance, both in the social sphere as the economic. These must include the assessment of the damage caused by all sorts of substances, creating the need to know the action of these to the system in question. The result of the interaction of substances with the environment can be explored through experiments involving octanol / water partition coefficient (Kow). The choice of Kow is due to relate the interaction of the compound with the chosen medium, as regards the absorption and transport. In the case of this work, a number of phenols was studied in terms of the partition coefficient. Theoretical calculations have been performed as an alternative to experimental measurement of octanol / water partition. The use of models QSAR (Quantitative Structure Activity Relationship) for predicting values of octanol / water partition was made by means of calculations involving quantum physics and chemometrics. The data for each variable were obtained for the group concerned phenols using the semi-empirical calculation methods AM1, PM3, PM6 and PM7. A comparison of the obtained QSAR models allowed the conclusion that, for the selected descriptors, a set of values obtained with the method provided PM7 the creation of the best models. Using as selected electronic energy, molecular area, molecular volume, core-core repulsion energy and molecular mass variables, we obtained a model that accumulated approximately 99.99% of all information in three components, with an external correlation coefficient (referring to the calibration) around 0,93, which shows the predictive power of the model. The relationship of toxicity with the Water Quality Index was also investigated by means of the relation of LogKow values obtained and pH. With the pKa of the phenol from each theoretical data (and using the relationship of pKa and pH proposed by Henderson-Hasselbach), it can be concluded that there is no influence of intrinsic values LogKow in pH checked with low coefficient correlation between the variables, around 0,15.
173

Desempenho de reator anaeróbio de leito fluidificado operado sob condições de aumento progressivo da carga orgânica no tratamento de fenol / Performance of anaerobic reactor of fluidized bed operated under conditions of progressive increase of the organic load in the phenol treatment

Eduardo Lucena Cavalcante de Amorim 28 March 2007 (has links)
O fenol e seus derivados são poluentes comumente presentes nos efluentes industriais. Também são considerados poluentes orgânicos perigosos e difícieis de serem eliminados, quando presentes em altas concentrações. O processo de tratamento anaeróbio é uma alternativa para a degradação de despejos que possuem compostos persistentes, como fenóis. O objetivo deste trabalho foi estudar a viabilidade do uso de reator anaeróbio de leito fluidificado (RALF) operado sob condições de aumento progressivo da carga orgânica no tratamento de água residuária sintética contendo fenol como única fonte de carbono. O reator foi construído em acrílico com altura de 190 cm e diâmetro interno de 5 cm, e volume total de 4192 \'CM POT.3\'. O meio suporte foi constituído por partículas de poliestireno (2,2 mm). O inóculo utilizado foi lodo de abatedouro de suínos, o tempo de detenção hidráulica (TDH) foi 24 h, o RALF foi operado a 30 ± 1 ºC durante 182 dias. A adaptação do inóculo ocorreu no próprio reator, onde permitiu uma partida rápida, 14 dias, além de manter as condições de anaerobiose no reator. As concentrações de fenol tratadas foram de 50 mg/L, 100 mg/L, 200 mg/L, 300 mg/L, 400 mg/L, 500 mg/L, 600 mg/L e 700 mg/L, com taxas de carregamento orgânico real aplicadas de 0,09 a 1,29 kg fenol/\'M POT.3\'dia. O pH variou entre 6,59 e 8,21 para todo o sistema. As concentrações de alcalinidade a bicarbonato (AB) afluente e efluente foram 180 mg/L e 294 mg/L, respectivamente. Foram constatadas eficiências de remoção de fenol e de DQO superiores a 90% e 88%, respectivamente. De um modo geral, os resultados mostraram a potencialidade do sistema proposto em degradar efluentes líquidos contendo fenol. / The phenol and yours derived they are pollutant commonly presents in the industrial effluents. They are also considered pollutant organic dangerous and difficult of they be eliminated, when presents in high concentrations. The process of anaerobic treatment is an alternative for the degradation of spillings that possess composed persistent, as phenols. The objective of this work was to study the viability of the use of anaerobic fluidized-bed reactor (RALF) operated under conditions of progressive increase of the organic load in the treatment of synthetic wastewater containing phenol as only source of carbon. The reactor was built in acrylic with height of 190 cm and internal diameter of 5 cm, and total volume of 4192 \'CM POT.3\'. The half supports was constituted by particles of polystyrene (2,2 mm). The used sludge was the mud of slaughterhouse of swine, the time of hydraulic detention (TDH) it was 24 h, RALF was operated 30 ± 1 ºC for 182 days. The adaptation of the sludge happened in the own reactor, where it allowed a fast departure, 14 days, besides maintaining the anaerobic conditions in the reactor. The phenol concentrations treated were of 50 mg/L, 100 mg/L, 200 mg/L, 300 mg/L, 400 mg/L, 500 mg/L, 600 mg/L and 700 mg/L, where the taxes of real organic shipment applied varied from 0,09 to 1,29 kg fenol/\'M POT.3\'dia. The pH varied between 6,59 and 8,21 for the whole system. The alkalinity concentrations to bicarbonate (AB) influent and effluent were 180 mg/L and 294 mg/L, respectively. Efficiencies of phenol removal were verified and of superior DQO to 90% and 88%, respectively. In general, the results showed the potentiality of the system proposed in degrading liquid effluent containing phenol.
174

Degradação anaeróbia de fenol sob diferentes condições nutricionais / Anaerobic degradation of phenol in different nutritional conditions

Sandra Imaculada Maintinguer 27 July 2004 (has links)
A tecnologia anaeróbia tem sido utilizada com sucesso no tratamento de água residuária contendo compostos fenólicos. Recentes pesquisas incluem tais compostos entre aqueles que podem ser degradados através desse processo. O objetivo desse trabalho foi avaliar a degradação do fenol em diferentes condições nutricionais, com ênfase na redução do sulfato. Os experimentos foram realizados com meio de cultura específico para esses microrganismos anaeróbios. Foram realizados ensaios de degradação em reatores em batelada alimentados nas seguintes condições: (1) fenol e sulfato, a diferentes concentrações, com inóculo previamente enriquecido; (2) fenol, sulfato e co-substratos e; (3) fenol, sulfato e extrato de levedura. Todos os ensaios foram realizados em temperatura de 30 graus Celsius, sob agitação de 150 rpm. Foi avaliado o consumo de fenol e sulfato e, produção de metano, em função do tempo, para diferentes concentrações iniciais de fenol e sulfato. Nos ensaios com reatores alimentados com fenol (329,3 mg/l); fenol (307,3 mg/l) e sulfato (160 mg/l); fenol (322.3 mg/l), sulfato (160 mg/l) e lactato (478,16 mg/l); fenol (332,1 mg/l), sulfato (150 mg/l) e etanol (129,76 mg/l), a remoção foi de, respectivamente, 99,8%, 98,2%, 98,8% e 98,8%. Os reatores alimentados com fenol (239,7 mg/l) obtiveram 100% de eficiência na degradação em apenas 11 dias e, os reatores alimentados com fenol (234,3 mg/l) e sulfato (162,5 mg/l) e fenol (256,0 mg/l) e sulfato (500 mg/l) tiveram eficiências de degradação de, respectivamente, 98,8% e 99,3% com 17 dias de operação. Tais eficiências foram obtidas pelo acréscimo de extrato de levedura nos reatores, no início dos ensaios. A caracterização morfológica foi realizada através de microscopia óptica. A diversidade microbiana referente aos Domínios Bacteria e Archaea, além do grupo de bactérias redutoras de sulfato foi avaliada através da técnica de PCR DGGE, onde foram observadas alterações nas populações microbianas, em função das condições nutricionais. Para o Domínio Archaea não foram observadas diferenças nos ensaios realizados. Para o Domínio Bacteria e Grupo das BRS essas diferenças foram, mais facilmente, percebidas com relação ao inóculo e entre os diversos reatores. A alteração na diversidade microbiana pode ter sido decorrente da composição do meio que, nesse caso, foi específico para BRS e a composição do inóculo que continha parte previamente adaptada às BRS. Essas condições adequadas puderam propiciar surgimento e desenvolvimento de populações microbianas capazes de degradar fenol, utilizando sulfato. / The anaerobic technology has been successfully used to treat wastewater containing phenolic compounds. Recent research includes such compounds among those that can be degraded through this process. The goal of this project was to assess phenol degradation in different nutritional conditions, focusing on sulfate reduction. The essays were carried out in a specific culture mean for these kinds of anaerobic microorganisms. Degradation essays were carried out in a batch reactor fed in the following ways: (1) phenol and sulfate, in different concentrations, with previously enriched inoculum; (2) phenol, sulfate and co-substrates and; (3) phenol, sulfate and yeast extract. All the essays were carried out at 30 Celsius degrees, under 150 rpm agitation. The consumption of phenol and sulfate and, methane production, in function of time, for different initial concentrations of phenol and sulfate was assessed. In the essays the reactors were fed with phenol (329.3 mg/l); phenol (307.3 mg/l) and sulfate (160 mg/l); phenol (322.3 mg/l), sulfate (160 mg/l) and lactate (478.16 mg/l); phenol (332.1 mg/l), sulfate (150 mg/l) and ethanol (129.76 mg/l), the removal was of, respectively, 99.8%, 98.2%, 98.8% and 98.8%. The reactors fed with phenol (239.7 mg/l) obtained 100% degradation efficiency in only 11 days. The reactors fed with phenol (234.3 mg/l) and sulfate (162.5 mg/l) and phenol (256.0 mg/l) and sulfate (500 mg/l) obtained degradation efficiency of 98.8% and 99.3%, respectively, in only 17 days of operation. Such efficiencies were obtained by the increase of yeast extract in the reactors, in the beginning of the essays. The morphological characterization was carried out by optical microscopy. The microbial diversity regarding the Bacteria and Archaea Domain, besides the sulfate reducing bacteria group was assessed through the PCR DGGE technique, where alterations were seen in the microbial population, due to nutritional conditions. For the Archaea Domain, no differences were seen in all the essays. For the Bacteria Domain and the SRB Group these differences were easily seen, noticed by the inoculum and the diverse reactors. The alteration in the microbial diversity might have occurred due to culture mean composition that, in this case, was specific for SRB and also due to inoculum composition that contained a part previously adapted to SRB. These adequate conditions could promote appearance and development of microbial population capable of degrading phenol, using sulfate.
175

Estudo de reação da resina fenolica sob pressão / Study of phenolic resin reaction under pressure

Lucchini, Carlos Eduardo 12 August 2018 (has links)
Orientador: Wagner dos Santos Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-12T09:30:52Z (GMT). No. of bitstreams: 1 Lucchini_CarlosEduardo_M.pdf: 5504371 bytes, checksum: d489cf9f3064f2f4afae8674e395758a (MD5) Previous issue date: 2008 / Resumo: Neste trabalho analisa-se de modo particular a resina fenol formaldeído para se obter uma redução do tempo de processamento nas condições de processo, além de melhorar as características de aplicação da resina em estudo. O trabalho se concentra principalmente na etapa de refluxo, onde ocorre a metilação do polímero. Faz-se a comparação da condução da reação da resina fenólica na etapa de refluxo, logo após a etapa exotérmica. Para o estudo considerou-se uma primeira fase, estando o reator aberto para a atmosfera, através do condensador e numa segunda etapa, mantendo reator fechado, obtendo a pressão de equilíbrio em 3 x104 N/m2. Os resultados mostram que é possível uma redução de aproximadamente meia hora estando o reator fechado durante a fase de refluxo, mantendo a pressão em 3 x104 N/m2. / Abstract: This study analyzes a phenol formaldehyde resin and to develop it in order to reach a time reduction in the cycle time and, in second plane, to evaluate if it improves the resin characteristics in the application. The study concentrated on the condensation step, where the formation of the chain of polymer occurs. The comparison between the reaction of the phenolic resin with the reactor opened to the atmosphere through the condenser during the reflux step and that same reaction with the vent closed to the atmosphere right after the exothermal phase, also in the reflux step. The results show that a reduction of approximately half an hour is possible when the reactor is closed during the reflux step, keeping the pressure in 3x104N/m2. / Mestrado / Ciencia e Tecnologia de Materiais / Mestre em Engenharia Química
176

Peeling de fenol pontuado no tratamento do fotoenvelhecimento: estudo clínico e histopatológico

Mendonça, Maria Cristina Cardoso de 26 August 2013 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-03-02T11:27:16Z No. of bitstreams: 1 mariacristinacardosodemendonca.pdf: 8315524 bytes, checksum: 5cb09e7f3009f401bfe32a402cc10858 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-03-03T14:47:04Z (GMT) No. of bitstreams: 1 mariacristinacardosodemendonca.pdf: 8315524 bytes, checksum: 5cb09e7f3009f401bfe32a402cc10858 (MD5) / Made available in DSpace on 2016-03-03T14:47:04Z (GMT). No. of bitstreams: 1 mariacristinacardosodemendonca.pdf: 8315524 bytes, checksum: 5cb09e7f3009f401bfe32a402cc10858 (MD5) Previous issue date: 2013-08-26 / O peeling de fenol é considerado um importante agente no tratamento do rejuvenescimento facial, porém sua utilização implica em limitações pelo seu grande potencial de efeitos colaterais. Com o avançar de novas técnicas, houve a introdução dos lasers na propedêutica dermatológica, técnica essa mais segura, porém com limitações tanto no pós-operatório quanto no custo de cada tratamento. O presente trabalho propõe uma nova técnica de aplicação do peeling profundo para tratamento do fotoenvelhecimento com o objetivo de avaliar clínica e histopatologicamente a eficácia de uma nova forma de aplicação de fenol 88%, com padrão pontuado. O procedimento foi realizado em ambiente ambulatorial, em pacientes do sexo feminino sobre rugas estáticas e áreas de maior flacidez da face, visando o rejuvenescimento facial, com acompanhamento fotográfico e obtenção de amostras cutâneas para análise histopatológica antes e ao final do tratamento. Essa nova forma de aplicação reduziu consideravelmente o afastamento do paciente de suas atividades habituais, além do baixo custo em relação ao procedimento convencional. De acordo com os resultados, o fenol a 88% aplicado topicamente com técnica pontuada é efetivo no rejuvenescimento cutâneo. Assim, sugerimos que, a partir desta nova proposta, outros estudos sejam realizados para melhor elucidar os mecanismos de ação do fenol 88%, em grupos maiores de pacientes. / Phenol peeling is considered an important agent in the treatment of facial rejuvenation; however, its use carries limitations due to its high potential for side effects. With the advance of new techniques, lasers were introduced into the dermatological workup, a technique that is safer, but with limitations both in post-operative terms and in the cost of each treatment. This paper proposes a new deep peeling application technique for the treatment of photoaging, aiming to evaluate, clinically and histopathologically, the efficacy of a new way of applying 88% phenol, using a punctuated pattern. The procedure was performed in an outpatient setting, with female patients, on static wrinkles and high flaccidity areas of the face, aiming for facial rejuvenation. Accompanying photographs and skin samples were taken for histopathological analysis before and after treatment. This new form of application considerably reduced patients' withdrawal from their regular activities, and lowered the cost as well, compared to the conventional procedure. According to the results, 88% phenol applied topically using a punctuated technique is effective in skin rejuvenation. We thus suggest, based on this new proposal, that further studies be conducted to better elucidate the action mechanisms of 88% phenol in larger groups of patients.
177

Redução da concentração de fenol presente em águas residuárias utilizando sistema anaeróbio-aeróbio : desempenho e toxicidade residual / Phenol concentration reduction in wastewater using anaerobic-aerobic system : performance and residual toxicity

Carvalho, Luciana Vechi de 21 August 2018 (has links)
Orientador: Edson Aparecido Abdul Nour / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-21T10:47:29Z (GMT). No. of bitstreams: 1 Carvalho_LucianaVechide_M.pdf: 1975697 bytes, checksum: c889d2b763a156ae4029456cdc836b88 (MD5) Previous issue date: 2012 / Resumo: A grande utilização de compostos tóxicos e o descarte dos mesmos sem o devido tratamento fizeram com que o ecossistema aquático recebesse grande quantidade de contaminantes, os quais, com o passar do tempo, tendem a estar presentes em maiores concentrações no sedimento dos rios e mananciais que recebem o efluente in natura. O fenol é um dos compostos que tem sido utilizado de forma descontrolada tanto pelas indústrias como também para fins domésticos, aumentando ainda mais a concentração deste nos efluentes sanitários. Desta forma, estudou-se a capacidade de um sistema de tratamento biológico combinado, anaeróbio/aeróbio, em reduzir a concentração de fenol presente em efluentes sanitários. O sistema foi composto por um filtro anaeróbio (FA) seguido por um biofiltro aerado submerso (BAS), monitorado por meio de análises físicas, químicas e ensaios ecotoxicológicos. Para os ensaios ecotoxicológicos foi iniciado o cultivo de dois novos organismos - Chironomus xanthus e Eisenia sp. - viventes no sedimento, para avaliação da resposta de ambos ao fenol, sendo esta a parte dos rios em que há o maior acúmulo de contaminantes Também foi utilizado Daphnia similis. A pesquisa foi realizada em três etapas: Fase de adaptação, com duração de 106 dias, em que o sistema de tratamento recebeu o inóculo de um filtro anaeróbio testado para a remoção de formaldeído; Primeira Fase com a adição de 50 mg L-¹ de fenol, com duração de 207 dias, obtendo eficiências de remoção de fenol próximas a 100% com concentração média de fenol no efluente final de 0,16 mg L-¹ e eficiência de DQO acima de 90% e Segunda fase com duração de 115 dias em que a concentração de fenol aplicada foi gradualmente aumentada até o limite de 150 mg L-¹, determinado pela desestabilização do reator anaeróbio, Foram obtidas eficiências de remoção de fenol de 99,7% e de DQO 95,4% sem reduzir a nitrificação e resultando em um efluente final de acordo com as exigências para o lançamento segundo CONAMA 430/2011. O esgoto bruto contendo fenol foi tóxico para Chironomus xanthus e Daphnia similis com CL(50)/96h 60 mg L-¹ e CE(50)/48h 50 mg L-¹, respectivamente. Para o organismo Eisenia sp., os ensaios indicaram que não ocorreu toxicidade ao fenol. O efluente final tratado pelo sistema biológico combinado não apresentou e não causou toxicidade a nenhum dos organismos testes utilizados, indicando que a sua concepção e proposta de operação produziram um efluente que atende os padrões de lançamento para carga orgânica e fenol, sem prejudicar os índices para o nitrogênio amoniacal / Abstract: The great use of toxic compounds and its dispose without proper treatment, have caused a large concentration of contaminants on the aquatic ecosystem over the time, and the tendency is to be present in higher concentrations in the sediment of rivers and springs that hold the effluent in natura. The phenol, is one of the compounds which has been used in an uncontrolled fashion by both industry and also for domestic purposes, further increasing its concentration in the wastewater. This study shows the ability of a biological treatment system combined anaerobic/aerobic, reducing the concentration of phenol present in wastewater. The system consisted of an Anaerobic Filter (FA) followed by a Submerged Aerated Biofilter (BAS), monitored through physical chemical analysis and ecotoxicological tests. For ecotoxicological tests, the cultivation of two new organisms was started Chironomus xanthus and Eisenia sp. - living in the sediment, to assess the response of both to the phenol, being this the part of the rivers where there is greater accumulation of contaminants, was also used Daphnia similis. The study was performed in three phases: adaptation phase, lasting 106 days, where the Processing System received an inoculum of anaerobic filter, tested for the removal of formaldehyde, First stage with the addition of 50 mg L-¹ phenol, with duration of 207 days, obtaining phenol removal efficiencies close to 100%, with an average of phenol concentration in the final effluent of 0,16 mg L-¹ and efficiency of DQO higher than 90%. Second phase with duration of 115 days , where the phenol concentration applied was gradually increased to the limit of 150 mg L-¹ determined by the destabilization of the anaerobic reactor, were obtained efficiencies in phenol removal of 99.7% and 95.4% of DQO, without reduction the nitrification and resulting in an final effluent according to the requirements for launching as per CONAMA 430/2011. The raw sewage containing phenol was toxic to Chironomus xanthus and Daphnia similis with CL(50)/96h 60 mg L-¹ and CE(50)/48h 50 mg L-¹, respectively. For the organism Eisenia sp., the tests indicated that there was no toxicity to phenol. The final effluent treated by this combined biological system, did not show and did not cause toxicity to any of the test organisms used, thereby indicating that its design and proposed operation, were able to produce an effluent that meets discharge standards for organic load and phenol, while preserving the rates for ammonia nitrogen / Mestrado / Saneamento e Ambiente / Mestra em Engenharia Civil
178

The evaluation of an organophosphate thermosetting resin for use in a high temperature resistant composite and a study of chemistry of ionomer cements

Reader, A. L. January 1974 (has links)
Two different research projects were investigated for this thesis, which has consequently been presented in two parts. PART 1 An attempt has been made to improve the high temperature performance of phenol-formaldehyde thermosets by modification of their structure with inorganic phosphate groups. Transesterification of tri-phenyl phosphate with resorcinol has given a resorcinol phosphate resin, which cured with hexamethylenetetramine. A pilot scale batch of this resin has been made and used in high temperature stability studies. Post-cured resorcinol phosphate resin-chrysotile asbestos (30: 70) moulded bars retained 59.5% of their flexural strength after ageing at 523K for 1000 hr in air. Similar phenol-formaldehyde composite bars aged under identical conditions retained only 5.3% of their initial flexural strength. The utility of the resorcinol phosphate resin composite as a commercial product is limited, since the bars had a much lower initial flexural strength (30.85 MNm-2) than the phenol-formaldehyde resin composite bars (108.5 MNm-2). Thermogravimetry and isothermal heating studies have indicated that the degradation of resorcinol phosphate resin was greatly accelerated by chrysotile asbestos, which may catalyse a bond re-organisation process that has been tentatively proposed as a mechanism for the fragmentation of the resin. PART 2 Recently an ionomer dental cement (ASPA), prepared from aqueous poly(acrylic acid) and an ion-leachable aluminosilicate glass, has been developed. The system has been extended by studying other aqueous polymers. The factors influencing the gelation and the properties of the set cements have been examined. Poly(carboxylic acids) with hydrophobic, or no pendant substituents were found to be the most satisfactory polymers for preparing water stable cements. To study the influence of the nature of the cation and polymer structure on the gelation and water stability of ionomer cements, a wide range of metal oxide-polyacid products have been studied. The formation of water stable cements depended markedly on the type of oxide and polyacid employed and appeared to involve factors such as the co-ordination geometry and radius of the cation and the nature of the cation-polyanion bonding in the matrix. A comparison between the water stabilities of ASPA cement and poly(acrylic acid)-CaO, Al2O3, or Al(OH)3 cements has shown that the chemistry of ASPA cement is more complex than has been hitherto reported. Stability constants have been determined for Ca 2+ and Cd 2+ with poly(acrylic acid) and ethyl ethylene-maleic acid copolymer by a potentiometric titration method developed by Gregor and modified by Mandel and Leyte. The stability constants obtained in 1.0M NaNO3 at 298.2 ± 0.2K were: for poly(acrylic acid), with Cat2+, log b1 Ca2+ PAA ~ -3.35 with Cd2+, log Bav Cd2+ PAA = -2.30 for ethylene-maleic acid copolymer, with Cat2+, log b1 CA2+ EMA ~ -4.05 with Cd2+, log Bav Cd2+ EMA = -1.95 The log b1 values probably had little precise meaning, although to a first approximation, log b1 Ca2+ PAA > log b1 Ca2+ EMA The determined stability constants have been used with limited success in predicting the water stabilities of the corresponding metal oxide-polyacid cements.
179

Phenolic compounds in water and the implications for rapid detection of indicator micro-organisms using ß-D-Galactosidase and ß-D-Glucuronidase

Abboo, Sagaran January 2009 (has links)
Faecal contamination in water is detected using appropriate microbial models such as total coliforms, faecal coliforms and E. coli. Βeta-D-Galactosidase (β-GAL) and Beta-D-glucuronidase (β-GUD) are two marker enzymes that are used to test for the presence of total coliforms and E. coli in water samples, respectively. Various assay methods have been developed using chromogenic and fluorogenic substrates. In this study, the chromogenic substrates chlorophenol red β-D-galactopyranoside (CPRG) for β-GAL and p-nitrophenyl-β-D-galactopyranoside (PNPG) for β-GUD were used. Potential problems associated with this approach include interference from other organisms present in the environment (e.g. plants, algae and other bacteria), as well as the presence of certain chemicals, such as phenolic compounds in water. Phenolic compounds are present in the aquatic environment due to their extensive industrial applications. The USA Enviromental Protection Agency (EPA) lists 11 Priority Pollutant Phenols (PPP) due to their high level of toxicity. This study investigated the interfering effects of the eleven PPP found in water on the enzyme activities of both the β-GAL and β-GUD enzyme assays. The presence of these PPP in the β-GAL and β-GUD enzyme assays showed that over and underestimation of activity may occur due to inhibition or activation of these enzymes. Three types of inhibition to enzyme activities were identified from double reciprocal Lineweaver-Burk plots. The inhibition constants (Ki) were determined for all inhibitory phenolic compounds from appropriate secondary plots. Furthermore, this study presented a validated reverse phase high performance liquid chromatography (RP-HPLC) method, developed for the simultaneous detection, separation and determination of all eleven phenolic compounds found in the environment. This method demonstrated good linearity, reproducibility, accuracy and sensitivity. Environmental water samples were collected from rivers, streams, industrial sites and wastewater treatment plant effluent. These samples were extracted and concentrated using a solid phase extraction (SPE) procedure prior to analysis employing the newly developed HPLC method in this study. Seasonal variations on the presence of the PPP in the environment were observed at certain collection sites. The concentrations found were between 0.033 μg/ml for 2,4-dinitrophenol in a running stream to 0.890 mg/ml for pentachlorophenol from an tannery industrial site. These concentrations of phenolic compounds found in these environments were able to interfere with the β-GAL and β-GUD enzyme assays.
180

Phenol removal from saturated porous media using horseradish peroxidase mediated oxidative polymerization process

Kim, Wongee January 1900 (has links)
Doctor of Philosophy / Department of Civil Engineering / Alok Bhandari / Aquifers are frequently contaminated by phenolic compounds from spills, leaking underground storage tanks, or landfills. These compounds can be toxic to a variety of organisms including humans. Their disposal is restricted in many countries with strict limits for acceptable concentrations in drinking water. Phenols that are chlorinated have significantly greater toxicity and are resistant to aerobic biodegradation. Enzyme-mediated in situ stabilization has been advocated as an approach for the treatment of phenolic compounds in soils and groundwater. This research investigated the applicability of a luminol-based chemiluminescence assay to monitor transport of horseradish peroxidase (HRP) enzyme in saturated porous media. The chemiluminescence assay was optimized by varying solution conditions such as the concentration of luminol, p-iodophenol, hydrogen peroxide, ionic strength and pH. All assay components were found to affect the maximum chemiluminescene intensity. The study also evaluated the ability of HRP to mediate the removal of phenol from solution by catalyzing its oxidative polymerization in simulated aquifer conditions. HRP behaved as a conservative tracer in the column packed with Ottawa sand. The concentration of phenol in the column effluent was found to decrease by nearly 90% in the presence of HRP and H2O2 in the continuous flow system. HRP mediated oxidative polymerization of phenols resulted in the production of soluble and insoluble oligomeric products. Modification of porous media caused by the deposition of phenol polymerization products was studied and the impact of media modification on subsequent transport of phenolic contaminants was evaluated using 2,4-dichlorophenol (2,4-DCP) as a probe solute. The pore volume of the porous media was reduced due to the deposition of insoluble phenolic oligomers. The transport behavior of 2,4-DCP showed that the contaminant was retarded in the modified porous media.

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