• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 39
  • 17
  • 6
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 73
  • 73
  • 73
  • 22
  • 21
  • 20
  • 20
  • 19
  • 15
  • 15
  • 13
  • 10
  • 10
  • 10
  • 10
  • 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.
41

Synthesis of Recyclable Magnetic Metal-ferrite Nanoparticles for the Removal of Contaminants of Emerging Concern in Water

Al Anazi, Abdulaziz H. January 2018 (has links)
No description available.
42

Solar concentration for the environment industry: photocatalytic materials and application technologies

Fendrich, Murilo Alexandre 14 January 2021 (has links)
This thesis presents the achievements pursued during the doctoral course. The work was carried out in the context of the project ERiCSol (Energia RInnovabile e Combustili SOLari), as part of the University of Trento strategic plan for the years 2017-2021. The project was conceived to establish an interdepartmental area to promote the challenge of developing scientific research and technological innovation to increase the competitiveness of Trento at national and international level in the areas of energy and environment. Among all the goals of the project, this work dedicates special attention to 1) development of novel materials for solar photocatalytic reactions and 2) use of renewable energy to push forward applications in water remediation. To accomplish these goals, the research brings a full collection of experimental activities regarding the employment of solar concentration for the environment industry and therefore this document is organized in 9 chapters. In chapter 1, it is presented the introduction outlining the overview of the environment industry, the employment of solar light as energy source and the general and specific objectives. Chapter 2 presents a literature review regarding the last 30 years of applications correlating the use of solar light towards wastewater purification. The chapter reviews the engineering features of solar collectors, photocatalyst materials employed and the panorama of the pollutants investigated up to the present date in solar photocatalysis, presenting comparisons between models and real wastewater approaches. Chapter 3 details the experimental techniques and characterizations employed to sustain the investigation proposed in the thesis. The first part of the chapter explains the features of parabolic dish solar concentrator designed and manufactured by the IdEA group at the physics department of the university of Trento. After, it is presented the pulsed laser deposition, a thin films fabrication technique employed to produce the photocatalysts used on water purification experiments. The second part of the chapter presents the description of the characterization techniques used to reveal the fabricated photocatalyst materials properties. Based on the review on the fundamentals of solar photocatalysis and the experimental techniques, chapters 4 and 5 present a discussion in the field of novel photocatalytic materials capable to operate under concentrated sunlight irradiation. Chapter 4 in special presents the investigation regarding the fabrication of tungsten trioxide (WO3) thin film coatings, bringing the novelty of using pulsed laser deposition as the fabrication method and the evaluation of this material in photocatalysis for the degradation of methylene blue dye model pollutant. Chapter 5 instead, presents the development on Zinc Oxide (ZnO) nanoparticles, bringing an innovative point of view on a “green-synthesis” approach and the material immobilization in film for heterogeneous photocatalysis routes. Chapters 6 and 7 discuss solar photocatalysis aiming to shift applications from model pollutants to real wastewater remediation conditions. Important comparisons are performed and discussed regarding the advantages and existing drawbacks. To fulfill this purpose, chapter 6 presents an application case of solar photocatalysis to the degradation of a surfactant-rich industrial wastewater whereas chapter 7 presents the approach focused on the remediation of organic lead contaminants present on a local water well site in the city of Trento. The last experimental approach of concentrated solar light is presented on chapter 8, dedicated to the application of concentrated sunlight towards waste biomass valorization. Conversely to the application on water previously described, this chapter presents the activity on designing, fabricating and coupling a hydrothermal reactor with concentrated sunlight using it as the driving force to promote degradation of grape seeds evolving into hydrochars with possible valorization of the carbonized material. Lastly, chapter 9 presents the conclusions and suggestions, this item expresses the final considerations on the results of the experimental investigations, advantages and limitations observed, and suggests possible actions for future works.
43

Ozonização catalítica de efluente de laticínio em processo semi-batelada com reciclo / Catalytic ozonation of dairy effluent in semi-batch process with recycle

Messias, Raquel de Aquino 20 July 2015 (has links)
O efluente lácteo é caracterizado pelo elevado teor de matéria orgânica. Os principais impactos ambientais causados pelas indústrias de laticínios estão relacionados ao lançamento dos efluentes líquidos, geralmente com ineficiente controle ou tratamento, sendo de fundamental importância a implementação de técnicas de tratamento eficazes e de baixo custo. Dentro desta proposta, os chamados Processos Oxidativos Avançados (POAs) são tecnologias eficientes para a oxidação (parcial ou total) de compostos orgânicos de difícil degradação. O presente trabalho de pesquisa objetivou a avaliação da potencialidade da ozonização catalítica, para a redução da carga orgânica do efluente proveniente da indústria de laticínio Cia de Alimentos Glória da cidade de Guaratinguetá, oriundos do processamento de beneficiamento de leite, utilizando-se Fe2+ como catalisador em processo semi-batelada com reciclo. A caracterização do efluente lácteo in natura foi realizada empregando-se métodos estabelecidos e otimizados de alguns parâmetros elencados nas legislações ambientais, destacando-se: DQO, COT, DBO5, Nitrogênio (orgânico e amoniacal), Fósforo total, Ferro, Sólidos (ST, STF, STV), surfactantes aniônicos, óleos e graxas e elementos metálicos. Através de planejamento fatorial fracionado 24-1, determinaram-se as melhores condições entre as variáveis potência do ozonizador, vazão de O2, concentração de Fe2+ e pH para a etapa de tratamento com POA, tendo como fator de resposta a redução da DQO e COT. Avaliou-se também uma nova configuração de reator em função de uma espuma formada durante o processo de tratamento. Os resultados obtidos para o conjunto de experimentos mostraram-se promissores, sendo que a redução média de COT com 63,95 % e de DQO com 70,50 % para o ensaio com as variáveis da reação otimizada, com o custo no valor de R$ 0,056 / L de efluente. Após o processo de ozonização catalítica, a amostra do melhor experimento: pH 4,0, concentração de Fe2+ 1,0 g L-1, potência 86 W, vazão de O2 0,5 L min-1, tendo como vazão mássica de O3 3,10 mg min-1, foi tratada por um processo biológico - Sistema Lodo Ativado (SLA), a fim de verificar a eficiência de degradação da matéria orgânica do efluente estudado através do sistema conjugado (POA - SLA). Os resultados para o tratamento híbrido apresentou percentuais de reduções para COT de 82,95 %, DQO de 95,60 % e DBO de 93,09 %. / Dairy effluent is characterized by the high content of organic material. The major environmental impacts caused by dairy industries are related to the release of liquid effluents, generally with an inefficient control or treatment, which makes it essential to implement effective treatment techniques, at a low cost. Within this proposal, Advanced Oxidation Processes (AOPs) are efficient technologies for oxidation (partial or total) of organic compounds of difficult degradation. This research study aimed at assessing the potential of catalytic ozonation for reduction of the effluent organic load from the dairy industry Cia de Alimentos Glória located in the city of Guaratinguetá, State of São Paulo, Brazil, derived from milk processing, using Fe2+ as catalyst in a semi-batch process with recycle. The characterization of milky effluent in natura was performed by using established and optimized methods of some parameters listed in environmental legislation, among them: COD, TOC, BOD5, Nitrogen (organic and ammoniacal), total Phosphorus, Iron, Solids (TS, FTS, VTS), anionic surfactants, oils and greases and metallic elements. Through fractional factorial design 24-1, the best conditions among the power variables of the power ozonator, O2 flow, Fe2+ concentration and pH were determined for the treatment stage with AOP, with a response factor of COD and TOC reduction. A new configuration of reactor was also assessed due to the presence of foam during the treatment process. The obtained results for the set of experiments were found to be promising, with an average reduction of TOC of 63.95 % and of 70.50 % for COD for the test with optimized reaction variables, with a cost of U$$ 0.02 / L of effluent. After the catalytic ozonation process, the sample of the best experiment was: pH 4.0, concentration of Fe2+ 1.0 g L-1, power of 86 W, flow of O2 0.5 L min-1, with mass flow of O3 3.10 mg min-1, was treated by a biological process in order to verify to verify the efficiency of degradation of the organic matter of the effluent studied through the conjugated (AOP - AS) system.The results for the hybrid treatment showed percentages of reductions for TOC of 82.95 %, COD of 95.60 % and BOD5 of 93.09 %.
44

Processos oxidativos com hidroperóxidos, persulfatos ou perácidos, catalisados por espécies de cobre e de ferro com potencial aplicação em química ambiental / Oxidation processes with hydroperoxides, persulphates or peracids catalyzed by copper and iron species with potential application in environmental chemistry

Almeida Filho, Saulo Afonso de 19 June 2015 (has links)
Neste trabalho, foram sintetizados complexos de cobre e ferro, com ligantes imínicos, obtidos a partir de 2-acetilpiridina e 2-(2-aminoetilpiridina) (apyepy), ou 2-acetilpiridina e 2-(aminometil)benzimidazol (apyambi), e com ligantes comerciais (ácido nitrilotriacético ou picolínico), capazes de catalisar a oxidação de poluentes, como benzeno, tolueno, etilbenzeno e xilenos (BTEX). Foi utilizado o tolueno como composto-modelo destes poluentes, que foi degradado com o uso de peróxido de hidrogênio, persulfato de sódio, ácido peracético ou peróxidos de metais alcalinos como agentes oxidantes. Os ligantes imínicos foram obtidos a partir de precursores carbonílicos e amínicos adequados, através de reações de condensação, e os correspondentes complexos metálicos de cobre(II), ferro(II) ou ferro(III) foram isolados utilizando métodos usuais de nosso laboratório. A caracterização dos compostos foi feita através de diversas técnicas analíticas e espectroscópicas: UV/Vis, infravermelho (IV) e de ressonância paramagnética eletrônica (EPR). Posteriormente, foi feita a inserção desses complexos de ferro e de cobre sintetizados em matrizes inorgânicas de niobatos e a verificação de sua reatividade em comparação com as mesmas espécies em solução. Monitorou-se a degradação do tolueno pelo peróxido de hidrogênio por cromatografia gasosa e os resultados obtidos indicaram boa atividade catalítica dos complexos, tanto em solução como inseridos em matrizes de niobato. Em solução, os complexos imínicos foram mais ativos que os de ligantes comerciais. Os compostos de ferro com ambos os ligantes imínicos mostraram-se melhores catalisadores que os correspondentes de cobre e um dos ligantes testados foi o mais eficiente (apyepy) com ambos os metais. A inserção em niobatos, aparentemente, preserva o catalisador e mantém sua atividade por mais tempo, mostrando que a inserção em niobatos beneficia o processo / In this work, iron and copper complexes were synthesized, with imine ligands obtained from 2-acetylpyridine and 2-(2-aminethylpiridine) (apyepy), or 2- acetylpyridine and 2- (aminomethyl)benzimidazole (apyambi) and commercial ligands (nitriletriacetic and picolinic acids) that are able to catalyze the oxidation of pollutant compounds as benzene, , ethylbenzene and xilenes (BTEX). Toluene was used as model compound of those pollutants, and its degradation was verified by using hydrogen peroxide, alkaline peroxide, sodium persulfate, or peracetic acid as oxidant agent. The imine ligands were obtained from adequate carbonyl and amine precursors, in condensation reactions, and the corresponding copper(II), iron(II) and iron(III) complexes were isolated by usual methods developed in our laboratory. Their characterization was carried out by analytical and spectroscopic techniques (UV/Vis, IR and EPR). Those complexes were then inserted in inorganic matrices (niobates) e its reactivity were compared to that of the analogous species in solution. Toluene degradation by hydrogen peroxide was monitored by gas chromatography, and the results showed good catalytic activity of all the complexes, both in solution and inserted into niobate matrices. In solution, the imine complexes were more efficient than the species with commercial ligands. The iron compounds with both imine ligands acted as better catalysts than the corresponding copper species, and for both metals those with the ligand apyepy were the most efficient in both cases. The insertion in niobates apparently preserves the catalyst and maintains its activity for longer, attesting that the insertion ameliorated the process.
45

Avaliação da remoção de cor e desinfecção de lixiviados de aterro sanitário utilizando ozônio e peróxido de hidrogênio / Evaluation of color and disinfection of landfill leachate using ozone and hydrogen peroxide

Seewald, Marina Medtler 28 February 2013 (has links)
Submitted by Maicon Juliano Schmidt (maicons) on 2015-07-06T19:15:18Z No. of bitstreams: 1 Marina Medtler Seewald.pdf: 3415895 bytes, checksum: a88885e13dc4a2b54ba496bc5a0fd0b7 (MD5) / Made available in DSpace on 2015-07-06T19:15:18Z (GMT). No. of bitstreams: 1 Marina Medtler Seewald.pdf: 3415895 bytes, checksum: a88885e13dc4a2b54ba496bc5a0fd0b7 (MD5) Previous issue date: 2013-02-28 / CNPQ – Conselho Nacional de Desenvolvimento Científico e Tecnológico / FINEP - Financiadora de Estudos e Projetos / Ministério da Ciência e Tecnologia / A degradação de resíduos dispostos em aterro sanitário gera um líquido com alto potencial poluidor caracterizado por sua coloração escura, alto teor de matéria orgânica e de nitrogênio amoniacal. O lixiviado de aterro sanitário pode ainda conter micro-organismos patogênicos provenientes de resíduos contaminados com excreções humanas, representando risco à saúde. Para o tratamento de lixiviado de aterro sanitário, processos biológicos tem mostrado eficiência, especialmente na remoção de matéria orgânica. No entanto, para que se atinja eficiência de remoção desejada para atendimento à legislação, especialmente em lixiviados antigos, um pós-tratamento se faz necessário. O emprego de processos oxidativos avançados (POAs) tem mostrado boa eficiência na remoção de cor, destruição de organismos patogênicos e aumento de biodegradabilidade em efluentes recalcitrantes. O objetivo deste trabalho foi avaliar a remoção de cor e desinfecção de lixiviado de aterro sanitário através do emprego de ozônio e peróxido de hidrogênio como agentes oxidantes. Para tanto, foram realizados doze ensaios no sistema POA instalado para tratar lixiviado bruto e tratado por sistema de lagoas. Seis ensaios foram realizados somente com ozônio e os outros seis com ozônio combinado com peróxido de hidrogênio. O sistema POA possuía volume útil de 460L e os ensaios tiveram a duraçãode 96h. A concentração de ozônio (gás) foi de 29 mg/L e a de peróxido de hidrogênio (adicionado em solução líquida) foi de 1000 mg/L no lixiviado. Com a caracterização do lixiviado, verificou-se alta variabilidade das características dos lixiviados gerados no aterro sanitário de São Leopoldo. Portanto, para a discussão dos resultados de remoção de cor, optou-se por dividir os ensaios realizados por grupos, utilizando como critério para a divisão a concentração inicial de cor verdadeira no lixiviado estudado. Embora inicialmente os resultados indiquem uma similiaridade entre os oxidantes testados a análise de variância de dois fatores realizada com medidas repetidas comprovou que houve diferença entre os agentes os oxidantes utilizados na remoção de cor, sendo observado que o peróxido de hidrogênio apresentou melhor desempenho. Foi observado que quanto menor a concentração inicial de cor verdadeira, mais rápida foi sua remoção. Na desinfecção do lixiviado, os ensaios utilizando ozônio e peróxido de hidrogênio apresentaram maiores taxas de inativação de coliformes termotolerantes, sugerindo que o acréscimo do segundo oxidante foi adequada. A turbidez e matéria orgânica presentes no lixiviado não impediram que a desinfecção ocorresse. Todos os ensaios realizados alcançaram mais de 90% de eficiência na remoção de cor verdadeira em 96h de ensaio e mais de 92% de eficiência na eliminação de coliformes termotolerantes em 24h. / Degradation of grounded waste in landfill generates a liquid with high pollution potential characterized by its dark color, high concentration of organic matter and ammonia nitrogen. Landfill leachate may still contain pathogenic microorganisms from wastes contaminated by human excreta, presenting health risk. For treating landfill leachate, biological processes have shown good performance, especially in organic matter removal. However, in order for the removal efficiency to attain local legislation, particularly in older leachate, a post treatment is necessary. Use of advanced oxidation processes has shown efficiency in color removal, destruction of pathogens and increased biodegradability of recalcitrant effluents. The purpose of this study is to evaluate color removal and disinfection of landfill leachate using ozone and hydrogen peroxide as oxidizing agents. Therefore, twelve experiments were performed in AOP system treating raw and treated leachate by pond system. Six tests were conducted with ozone only and six combining ozone and hydrogen peroxide. The POA was operated with volume of 460L and tests were carried out for 96h. The ozone (gas) concentration was 29 mg/L and hydrogen peroxide (liquid solution added) was 1000 mg/L in the leachate. Characterization of landfill leachate generated in São Leopoldo showed high variability. Therefore, to discuss results of color removal, groups of tests were created using like criteria true color concentration. Although attained results indicated similarity between tested oxidants, performed ANOVA two factors with repeated measures showed difference between oxidizing agents used in color removal. Hydrogen peroxide outperformed ozone alone. True color removal occured faster with smaller true color concentrations. The disinfection of the leachate, using ozone combined with hydrogen peroxide showed higher inactivation rates of fecal coliforms. Turbidity and organic matter in the leachate did not prevent the disinfection. All tests reached over 90% efficiency in true color removal at 96h and over 92% efficiency in disinfection within 24h.
46

Integração entre os processos foto Fenton e lodo ativado no tratamento de efluentes contendo compostos orgânicos recalcitrantes. / Integration of photo-Fenton and activated sludge processes on the treatment of wastewater containing recalcitrant organic compounds.

Sassano, Fernando Carlos Nascimento 24 October 2008 (has links)
O Fenol e compostos fenolicos foram classificados como poluentes primarios pela Environmental Protection Agency (EPA USA). Eles sao geralmente encontrados em efluentes industriais como: poupa e papel; madeireiras; plasticos e polimeros sinteticos; farmaceuticos, pesticidas, oleo e petroquimicas. Os tratamentos de agua convencionais tem mostrado ineficiencia em altas concentracoes de fenol. Este trabalho visa o tratamento de solucao aquosa de fenol via Processos Oxidativos Avancados (POAs) com o objetivo de aumentar a biodegradabilidade possibilitando a aplicacao de um processo convencional (lodos ativados) como pos-tratamento. O pre-tratamento e usado para modificar a estrutura do fenol levando-o a seus subprodutos como substancias aromaticas e acidos carboxilicos. Os experimentos mostraram a eficiencia do pre-tratamento atraves do parametro de biodegradabilidade (DBO5/DQO) apresentando 0,19 em 30 min de reacao foto- Fenton, com concentracao inicial de fenol de 1000 mg.L-1 de Carbono Organico Total (TOC), 1 mmol.L-1 de FeSO4 e 100 mmol.L-1 de H2O2, dosado durante 2 horas de reacao. Apos pre-tratada fotoquimicamente, esta mesma solucao foi utilizada como fonte de carbono em um sistema continuo de lodos ativados para remocao da materia organica residual, apresentando reducao de 92% do TOC inicial. Estes resultados evidenciam a eficiencia da integracao entre os processos foto-Fenton e lodo ativado no tratamento de efluentes contendo compostos recalcitrantes. / Phenol and phenolic compounds have been listed as priority-pollutants by the Environmental Protection Agency (EPA USA). They are often found in industrial effluents such as from pulp and paper, timber, plastics and synthetic polymer, pharmaceutical, pesticide, oil and petrochemical industries. Most of the traditional wastewater treatments have shown inefficiency against high phenol concentrations. This work aims to treat phenol solution via Advanced Oxidation Processes (AOP´s) to enhance medium biodegradability and using it as an effluent in a continuous activated sludge process. The purpose of the pre treatment is to modify the phenol structure leading it to its byproducts such as aromatics compounds and carboxylic acids. The experiments have shown the effectiveness of the pre-treatment by the biodegradability parameter BOD5/COD which was achieved 0,19 at 30 min of photo- Fenton reaction with a initial phenol concentration of 1000 mg.L-1 of TOC, 1 mmol.L-1 of FeSO4 and 100 mmol.L-1 of H2O2, added with a peristaltic pump along 2 hours of reaction. After the photochemical pre treatment, the same solution was used as a carbon source in a continuous activated sludge system for removing residual organic matter, with a reduction of 92% of the TOC initial. Those results have shown the efficiency when integrating photo-Fenton and activated sludge processes on the treatment of effluents containing recalcitrant organic compounds.
47

Ozonização catalítica de efluente de laticínio em processo semi-batelada com reciclo / Catalytic ozonation of dairy effluent in semi-batch process with recycle

Raquel de Aquino Messias 20 July 2015 (has links)
O efluente lácteo é caracterizado pelo elevado teor de matéria orgânica. Os principais impactos ambientais causados pelas indústrias de laticínios estão relacionados ao lançamento dos efluentes líquidos, geralmente com ineficiente controle ou tratamento, sendo de fundamental importância a implementação de técnicas de tratamento eficazes e de baixo custo. Dentro desta proposta, os chamados Processos Oxidativos Avançados (POAs) são tecnologias eficientes para a oxidação (parcial ou total) de compostos orgânicos de difícil degradação. O presente trabalho de pesquisa objetivou a avaliação da potencialidade da ozonização catalítica, para a redução da carga orgânica do efluente proveniente da indústria de laticínio Cia de Alimentos Glória da cidade de Guaratinguetá, oriundos do processamento de beneficiamento de leite, utilizando-se Fe2+ como catalisador em processo semi-batelada com reciclo. A caracterização do efluente lácteo in natura foi realizada empregando-se métodos estabelecidos e otimizados de alguns parâmetros elencados nas legislações ambientais, destacando-se: DQO, COT, DBO5, Nitrogênio (orgânico e amoniacal), Fósforo total, Ferro, Sólidos (ST, STF, STV), surfactantes aniônicos, óleos e graxas e elementos metálicos. Através de planejamento fatorial fracionado 24-1, determinaram-se as melhores condições entre as variáveis potência do ozonizador, vazão de O2, concentração de Fe2+ e pH para a etapa de tratamento com POA, tendo como fator de resposta a redução da DQO e COT. Avaliou-se também uma nova configuração de reator em função de uma espuma formada durante o processo de tratamento. Os resultados obtidos para o conjunto de experimentos mostraram-se promissores, sendo que a redução média de COT com 63,95 % e de DQO com 70,50 % para o ensaio com as variáveis da reação otimizada, com o custo no valor de R$ 0,056 / L de efluente. Após o processo de ozonização catalítica, a amostra do melhor experimento: pH 4,0, concentração de Fe2+ 1,0 g L-1, potência 86 W, vazão de O2 0,5 L min-1, tendo como vazão mássica de O3 3,10 mg min-1, foi tratada por um processo biológico - Sistema Lodo Ativado (SLA), a fim de verificar a eficiência de degradação da matéria orgânica do efluente estudado através do sistema conjugado (POA - SLA). Os resultados para o tratamento híbrido apresentou percentuais de reduções para COT de 82,95 %, DQO de 95,60 % e DBO de 93,09 %. / Dairy effluent is characterized by the high content of organic material. The major environmental impacts caused by dairy industries are related to the release of liquid effluents, generally with an inefficient control or treatment, which makes it essential to implement effective treatment techniques, at a low cost. Within this proposal, Advanced Oxidation Processes (AOPs) are efficient technologies for oxidation (partial or total) of organic compounds of difficult degradation. This research study aimed at assessing the potential of catalytic ozonation for reduction of the effluent organic load from the dairy industry Cia de Alimentos Glória located in the city of Guaratinguetá, State of São Paulo, Brazil, derived from milk processing, using Fe2+ as catalyst in a semi-batch process with recycle. The characterization of milky effluent in natura was performed by using established and optimized methods of some parameters listed in environmental legislation, among them: COD, TOC, BOD5, Nitrogen (organic and ammoniacal), total Phosphorus, Iron, Solids (TS, FTS, VTS), anionic surfactants, oils and greases and metallic elements. Through fractional factorial design 24-1, the best conditions among the power variables of the power ozonator, O2 flow, Fe2+ concentration and pH were determined for the treatment stage with AOP, with a response factor of COD and TOC reduction. A new configuration of reactor was also assessed due to the presence of foam during the treatment process. The obtained results for the set of experiments were found to be promising, with an average reduction of TOC of 63.95 % and of 70.50 % for COD for the test with optimized reaction variables, with a cost of U$$ 0.02 / L of effluent. After the catalytic ozonation process, the sample of the best experiment was: pH 4.0, concentration of Fe2+ 1.0 g L-1, power of 86 W, flow of O2 0.5 L min-1, with mass flow of O3 3.10 mg min-1, was treated by a biological process in order to verify to verify the efficiency of degradation of the organic matter of the effluent studied through the conjugated (AOP - AS) system.The results for the hybrid treatment showed percentages of reductions for TOC of 82.95 %, COD of 95.60 % and BOD5 of 93.09 %.
48

Aplicação de catálise heterogênea com TiO2 fotoirradiada por luz solar como pré-tratamento da vinhaça para posterior tratamento biológico / Application of Heterogeneous Catalysts with TiO2 Photoirradiated by Solar Energy as Pre-Treatment of Vinasse for Biological Treatment

Carrocci, Juliana Sanches 16 December 2009 (has links)
A vinhaça é o principal resíduo obtido na produção de álcool, açúcar e aguardente, sendo considerado um efluente de alto poder poluente e fertilizante. Sem o devido tratamento, quando lançada nos rios compromete a sobrevivência de diversos seres aquáticos e quando utilizada como fertilizante, o efluente não tratado pode contaminar lençóis freáticos e afetar os seres terrestres. O objetivo deste trabalho consistiu em avaliar a eficiência e aplicação da fotocatálise heterogênea com TiO2, seguido por um tratamento biológico (lodo ativado) para a redução da carga orgânica do efluente em questão. A caracterização da vinhaça in natura e tratada foi realizada empregando-se métodos estabelecidos e otimizados [DQO, NPOC, DBO5, Análise de Elementos via Absorção Atômica, Fenol, Nitrogênio (orgânico e amoniacal) e Sólidos (ST, STF, STV)]. Por meio de planejamentos fatoriais completos foram determinadas as melhores condições experimentais posterior aos tratamentos fotocatalítico e biológico, tendo como variável resposta a redução de NPOC. Uma caracterização morfológica (DRX, BET e MEV-EDS) da estrutura de TiO2 anatase e rutilo também foi realizada. Após o processo fotocatalítico, a amostra do melhor experimento foi tratada por um processo biológico, a fim de verificar a eficiência de degradação da matéria orgânica do efluente estudado através do sistema híbrido (POA - SLA). Este sistema apresentou maior eficiência tendo como fatores do tratamento fotoquímico 180 minutos de reação, com aeração, pH 9 e efluente in natura; e pH 8 e concentração do lodo de 5 g L-1 no tratamento biológico. A redução de DBO alcançada foi superior a 80 %. / Vinasse is the main residue obtained by the production of alcohol, sugar and blue rum. It is considered a high power pollutant effluent and fertilizer. Untreated vinasse into ponds and rivers make the environment unsafe, especially, to different aquatic species and, when used as a fertilizer, the untreated effluent may contaminate freatic water beds and affect terrestrial species. The aim of this work consists of evaluating the efficiency and application of heterogeneous photocatalysis with TiO2, followed by a biological treatment (activated sludge system) to reduce organic load in the referred effluent. The characterization of vinasse in natura is carried out by the use of established and optimized methods [DQO, NPOC, DBO5, Elemental Analysis by Atomic Absorption, Phenol, Nitrogenium (organic and ammoniacal) and Solids (TS, FTS, VTS)]. Complete factorial designs indicated the best experimental conditions subsequent to photacatalytic and biological treatments providing a reduction of NPOC as a variable response. A morphological evaluation (XRD, B.E.T and SEM-EDS) of anatase and rutile phase of TiO2 structure was also performed. After the photocatalytic process, the sample of the best experiment was treated by a biological process in order to verify the degradation efficiency of the effluent organic matter studied according to the hybrid system (AOP - Activated Sludge System). This system, which presented more efficiency, had a photochemical treatment of 180 minutes carried out in aerated solutions, pH 9 and effluent in natura, while the biological treatment was performed at pH 8 and sludge concentration of 5 g L-1. The reduction of BOD was more than 80%.
49

Oxidation Of Acid Red 151 Solutions By Peroxone (o3/h2o2) Process

Acar, Ebru 01 September 2004 (has links) (PDF)
Wastewaters from textile industry contain organic dyes, which cannot be easily treated by biological methods. Therefore, pretreatment by an advanced oxidation process (AOP) is needed in order to produce more readily biodegradable compounds and to remove color and chemical oxygen demand (COD) simultaneously. In this research, ozone (O3) is combined with hydrogen peroxide (H2O2) for the advanced oxidation of an azo dye solution, namely aqueous solution of Acid Red 151, which is called as &ldquo / Peroxone process&rdquo / . The aim of the study is to enhance the ozonation efficiency in treating the waste dye solution. The effects of pH, initial dye and initial ozone concentrations and the concentration ratio of initial H2O2 to initial O3 on color and COD removals were investigated. Also, the kinetics of O3-dye reaction in the presence of H2O2 was approximately determined. As a result of the experimental study, it was seen that an increase in the initial dye concentration at a constant pH and initial ozone concentration did not change the COD % removal significantly, from a statistical analysis of the data. The results obtained at pH values of 2.5 and 7 gave higher oxidation efficiencies in terms of color and COD removals compared to those at pH of 10. The best initial molar ratio of H2O2 to O3 was found to be 0.5, which yielded highest treatment efficiency for each pH value studied. The results of the excess dye experiments suggest that the ozonation of Acid Red 151 follows an average first order reaction with respect to ozone at pH=2.5 and pH=7 whereas it is around 0.56 at pH=10. By Initial Rate Method, the orders with respect to individual reactants of O3 and dye were determined as one, the total order of the reaction being two for all the studied pH. As a conclusion, a further study of the peroxone process at a pH of 10 can be recommended to determine the reaction kinetics and mechanism at this pH, where radicals play an important role.
50

Étude du rôle d’adsorbants alumino-silicatés dans un procédé d’ozonation d’eaux usées pétrochimiques / Study of the alumino-silicate adsorbents role in a petrochemical wastewater ozonation process

Aboussaoud, Wael 17 July 2014 (has links)
Les eaux usées issues de l’industrie pétrochimique contiennent des composés organiques peu ou pas biodégradables dont le traitement nécessite de faire appel à des nouvelles techniques de traitement sophistiquées. L’objectif de ce travail est d’étudier le rôle d’adsorbants alumino-silicatés dans un procédé d’oxydation avancée associant, dans un même réacteur, adsorption et oxydation à l’ozone pour le traitement de ce type d’effluents. Dans un premier temps, l’étude s’est centrée sur l’évaluation des performances du procédé pour l’élimination d’une molécule modèle, le 2,4-diméthylphénol, dans un réacteur agité semi-batch. Avant de coupler l’ozonation et l’adsorption, chacun des phénomènes mis en jeu a été étudié indépendamment, ce qui a permis la compréhension des mécanismes qui régissent le couplage. Deux modes de couplage ont été testés, un traitement simultané ozonation/adsorption et un traitement séquentiel ozonation puis adsorption. Dans les deux configurations, l’ajout des matériaux alumino-silicatés a eu un effet très limité sur la cinétique globale de dégradation de la molécule modèle. Par contre, l’ajout des matériaux a un effet très marqué sur la cinétique d’élimination du COT, principalement dû à un effet d’adsorption de sous-produits d’oxydation spécifiques. Il a aussi été démontré que la restauration des propriétés du solide est possible, permettant ainsi sa réutilisation. Dans un second temps, le procédé a été appliqué au traitement d’un effluent réel rejeté par une usine pétrochimique chinoise, en suivant la même démarche que celle adoptée lors de l’étude réalisée sur la molécule modèle et en utilisant un réacteur à lit fluidisé semi-batch. Les mêmes phénomènes ont été observés, confirmant l’efficacité de ce procédé pour le traitement des eaux usées pétrochimiques. / Petrochemical wastewaters often contain hardly biodegradable organic compounds requiring the use of sophisticated treatment techniques to be eliminated. The aim of this work is to study the role of alumino-silica adsorbents in an advanced oxidation process combining, in the same reactor, adsorption and ozonation for the treatment of such effluents. Initially, the study focused on the evaluation of process performance for the removal of a target molecule, 2,4-dimethylphenol, in a stirred semi-batch reactor. Before coupling adsorption and ozonation, each of these techniques has been studied independently, which allowed the well understanding of the mechanisms taking place during the combined process. Two process configurations were tested; a simultaneous ozonation/adsorption process and a sequential process including a first ozonation step followed by an adsorption step. In both cases, the addition of alumino-silica materials had a very limited effect on the overall kinetics of degradation of the target molecule. However, the use of the materials had a beneficial effect on TOC removal, mainly due to an adsorption effect of specific oxidation by-products. It was also shown that the restoration of the material properties is possible, allowing its reuse. In a second time, the process has been applied to the treatment of a real effluent discharged by a Chinese petrochemical plant, following the same approach adopted in the study of the target molecule and using a semi-batch fluidized bed reactor. Similar phenomena were observed, thus confirming the efficiency of the process on petrochemical wastewater treatment.

Page generated in 0.2741 seconds