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Soilless substrates, such as peat, pine bark, and coir, are widely used as growing media in containerized crops for their favorable characteristics, including low bulk density, balanced air exchange and water retention, disease resistance, and low pH and salinity. However, improper irrigation of these media can have negative outcomes such as root asphyxia, pathogen development, and reduced plant growth. Understanding pore size distributions, water dynamics, and gas diffusivity of these substrates is essential to promote plant growth. The effects of different particle sizes of soilless media on processes such as infiltration, hydraulic conductivity, and gas diffusivity are also not well understood. The characterization of these effects is important for the overall improvement of container crop production. This thesis presents three studies that aimed to characterize the physical and hydraulic properties of pine bark substrates, both unamended and amended with peat or coir. The first study looked at three substrate types: unamended, unscreened pine bark, peat-amended pine bark, and coir amended pine bark. Three methods were employed to quantify pore distributions: non-equilibrium infiltration measurements, equilibrium water retention characterization, and scanning electron microscopy. We characterized pore distributions during wetting and drainage for the three substrates. Coir-amended bark had the largest water-conducting porosity, highest hydraulic conductivity, and most water retention. Unamended pine bark had the highest microporosity, and the addition of peat and coir lowered macroporosity, with peat having the greater effect. The total porosity inferred from the infiltration method was significantly smaller than that inferred from drainage experiments due to assumptions related to pore shape. The second study focused on defining hydraulic conductivity and water retention for pine bark substrates of five different particle sizes, <1 mm, 1-2 mm, 2-4 mm, 4-6 mm, and an unscreened fraction. We utilized the same methods from the first study. The resulting data showed that the smallest particle sizes (i.e., <1 mm and 1-2 mm) had the highest hydraulic conductivity and greatest water retention. The three larger sizes had lower hydraulic conductivity and poor water retention, including the unscreened fraction, which more closely followed the results of the 2-4 mm size. The final study examined gas diffusivity of the five pine bark particle sizes at different moisture levels: 60% moisture content (initial conditions), saturated at the bottom of the sample, near-saturated at the sample bottom, and drained from saturation to container capacity. We used a one-chamber gas diffusion setup to find gas diffusion coefficients (Ds). The results displayed an inverse relationship between Ds values and substrate water content. In addition, the larger particle sizes were less sensitive to changes in water content due to their well-draining large pores. Proper balance of aeration and water retention is necessary for the success of soilless growing media. Overall, the smaller particle size fractions had the best water retention and hydraulic conductivity rates while the larger fractions had the largest Ds coefficients. This work contributes valuable knowledge on the physical and hydraulic properties of different size fractions of pine bark substrates, which can assist nursery growers in optimizing water usage for sustainable container crop production. / Master of Science / Since the 1950's soilless substrates have been an important resource for growing a variety of fruits, vegetables, flowers, and ornamental plants. Soilless growing media have become more popular choices for containerized plant production compared to natural soils due to improved air exchange, increased disease resistance, and more plants per acre. They are also favored because they help conserve resources, reduce agricultural waste, and minimize transportation requirements as compared to traditional cropping methods. The most popular types of soilless media include peat, coir, compost, and pine bark. In the U.S., pine bark is the main substrate used, as it is renewable and widely available. Growers still face many issues when using containerized crop production. For example, pine bark is susceptible to water runoff which can cause environmental problems and increase costs from this loss of water and fertilizer. Further characterizing of water and gas dynamics in of pine bark growing media is important for conserving water and fertilizer resources while optimizing plant growth in this container cropping industry. Pore characteristics, aeration, and water movement are key factors of substrates to be described to solve these challenges. This project aimed to apply soil physics strategies to soilless media, focusing on describing pore sizes, water movement, water holding capacity, and air movement in pine bark substrates. We utilized three methods throughout this study. For the first method, we took infiltration measurements to examine how water moved into the media, while the second utilized controlled drainage experiments to observe how water moved out of the media. The final method was characterizing gas movement through the substrates at different water contents and particle sizes. The results found showed that the smaller particle sizes and pine bark mixed with peat and coir had increased ability to retain water and allow water movement as compared to the larger particle sizes and unamended pine bark. In contrast, the larger particles had less water retention but improved gas movement. These results could be applied by stacking different particle sizes or mixes over one another could optimize water retention in the top of the container and drainage and gas movement in the bottom of the container. Overall, the application of this work is to create best management practices for growers to be able to balance water retention and gas movement in order to optimize plant growth.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / M.H. Hosni / Z.C. Zheng / In order to study the capability of computational methods in investigating the mechanisms associated with disease and contaminants transmission in aircraft cabins, the Computational Fluid Dynamics (CFD) models are used for the simulation of turbulent airflow, tracer gas diffusion, and particle dispersion in a generic aircraft cabin mockup. The CFD models are validated through comparisons of the CFD predictions with the corresponding experimental measurements. It is found that using Large Eddy Simulation (LES) with the Werner-Wengle wall function, one can predict unsteady airflow velocity field with relatively high accuracy. However in the middle region of the cabin mockup, where the recirculation of airflow takes place, the accuracy is not as good as that in other locations. By examining different k-ε models, the current study recommends the use of the RNG k-ε model with the non-equilibrium wall function as a Reynolds Averaged Navier Stokes (RANS) model for predicting the steady-state airflow velocity data. It is also found that changing the cabin air-inlet nozzle height has a significant effect on the flow behavior in the middle and upper part of the cabin, while the flow pattern in the lower part is not affected as much. Through the use of LES and species transport model in simulating tracer gas diffusion, very good agreement between predicted and measured tracer gas concentration data is observed for some monitoring locations, but the agreement level is not uniform for all the sampling point locations. The reasons for the deviations between predictions and measurements for those locations are discussed. The Lagrange-Euler approach is invoked in the particle dispersion simulations. In this approach, the equation of motion for the discrete phase is coupled with the continuous phase governing equations through the calculation of drag and buoyancy forces acting on particles. The continuous phase flow is turbulent and RANS is employed in order to calculate the continuous phase velocity field. A complete study on grid dependence for RANS simulation is performed through a controllable regional mesh refinement scheme. The grid dependence study shows that using unstructured grid with tetrahedral and hybrid elements in the refinement region are more efficient than using structured grid with hexahedral elements. The effect of turbulence on the particle dispersion is taken into account by using a stochastic tracking method (Discrete Random Walk model). One of the significant features of this study is the investigation of the effect of the number of tries on the accuracy of particle concentration predictions when Discrete Random Walk is used to model turbulent distribution of particles. Subsequently, the optimum number of tries to obtain the most accurate predictions is determined. In accordance with the corresponding experimental data, the effect of particle size on particle distribution is also studied and discussed through the simulation of two different sizes of mono-disperse particles in the cabin with straight injection tube, i.e., 3µm and 10µm. Due to the low particle loading, neglecting the effect of particles motion on the continuous phase flow-field seems to be a reasonable, simplifying assumption in running the simulations. However, this assumption is verified through the comparison of the results from 1-way and 2-way coupling simulations. Eventually through the simulations for the particle injection using the cone diffuser, the effects of cabin pressure gradient as well as the particle density on particles dispersion behavior are studied and discussed. In the last part of this dissertation, the turbulent airflow in a full-scale Boeing 767 aircraft cabin mockup with eleven rows of seats and manikins is simulated using steady RANS method. The results of this simulation cannot only be used to study the airflow pattern, but also can be used as the initial condition for running the tracer gas diffusion and particle dispersion simulations in this cabin mockup.

Fármacos tem sido foco de diversas estudos e pesquisas devido à constatação de sua ocorrência em diversos compartimentos ambientais. Esses compostos, com destaque para os antibióticos, apresentam biodegradação limitada e contínua introdução nos sistemas hídricos devido ao descarte incorreto, eliminação por excreção de parte da dose ingerida e, principalmente, pelo processo de fabricação nas indústrias farmacêuticas. Como as formas convencionais de tratamento têm se mostrado pouco efetivas, a tecnologia eletroquímica associada aos processos oxidativos avançados (POA) têm se mostrado uma maneira eficiente na degradação desses compostos. Em diversos estudos, os eletrodos de difusão gasosa (EDG) são apresentados como uma opção promissora no que diz respeito à eletrogeração de peróxido de hidrogênio, uma das principais fontes de radical hidroxila utilizado nos POA. Nesse aspecto, surgem estudos sobre modificadores que podem atuar como catalisadores nesse processo. Neste trabalho estudou-se o comportamento eletroquímico de dois modificares orgânicos suportados em matriz condutora de carbono Printex 6L. Os compostos orgânicos escolhidos, pertencentes a classe das quinonas, foram a 2-terc-butil-9,10-antraquinona (TBA) e a 9,10 fenantraquinona (FQA). Os estudos foram realizados em um eletrodo de disco/anel rotatório (RRDE), depositando-se uma microcamada porosa, contendo ou não o modificador, sobre o carbono vítreo deste eletrodo. Através dos resultados de voltametria cíclica e linear pode-se avaliar a geração de peróxido de hidrogênio, que foi superior para as microcamadas com adição dos modificadores. O material com 0,5% (m/m) de FQA mostrou-se o mais eficiente entre todos, com 30% de rendimento a mais quando comparado à matriz Printex e 6% maior quando comparada a mesma quantidade de TBA na produção do peróxido. Estudou-se também a eficiência da FQA para a produção de peróxido de hidrogênio (H2O2) a partir da reação de redução do oxigênio gasoso (O2), em eletrodos de difusão gasosa (EDG). Considerando os cinco eletrodos estudados (Printex não modificado e modificado com 0,1, 0,5, 1,0 e 2,0% de FQA) foi realizada uma avaliação sobre qual eletrodo seria o mais apto a ser utilizado nos trabalhos de degradação dos fármacos. Para isso fez-se a análise da concentração de peróxido de hidrogênio eletrogerada, o consumo energético e a cinética envolvida no processo. Os resultados mostraram um aumento significativo na produção de peróxido para os eletrodos modificados com 0,5 e 1,0% de FQA. Sendo que o eletrodo sem modificação atingiu um máximo de 215 ppm de H2O2 em um potencial de -1,4 V com um consumo energético de 29 kWh kg-1 de H2O2. O eletrodo modificado com 0,5% de FQA alcançou 566 pmm de H2O2 em um potencial de -1,4 V com um consumo energético de 14 kWh kg-1 de H2O2. Estudou-se também a degradação dos antibióticos amoxicilina e ampicilina (AMX e AMP) com anodos condutores comerciais de diamante dopados com boro. A influência da densidade de corrente aplicada (15, 30 e 60 mA cm-2) para o mesmo eletrólito de suporte (3 g / L de Na2SO4) e a mesma concentração inicial de antibióticos (100 mg dm-3 cada) foi avaliada. A mineralização total dos antibióticos foi atingida. Além disso, o processo foi encontrado para ser mais eficiente na densidade de corrente de 30 mA cm-2. Os resultados demonstram a importância dos processos eletroquímicos mediados na degradação de AMX e AMP. Esta influência foi confirmada por alguns testes em que a eletrólise foi acoplada à radiação UV ou à radiação ultrassônica. O uso de radiação UV resulta em uma degradação menos eficiente, enquanto que o ultrassom melhora um pouco a taxa de mineralização quando comparado ao processo eletrolítico simples. / Drugs have been the focus of several studies and researches due to the finding of their occurrence in several environmental compartments. These compounds, especially antibiotics, present limited biodegradation and continuous introduction into water systems because of incorrect disposal, elimination by excretion of part of the ingested dose and, mainly, by the manufacturing process in the pharmaceutical industries. As conventional mode of treatment have been shown to be ineffective, electrochemical technology associated with advanced oxidative processes (POA) has been shown to be an efficient way of degradation of these compounds. In several studies, gas diffusion electrodes (EDG) are presented as a promising option with respect to hydrogen peroxide electrogeneration, one of the main sources of hydroxyl radical used in POAs. In this aspect, studies on modifiers appear that can act as catalysts in this process. In this work the electrochemical behavior of two organic modifiers supported in Printex 6L carbon matrix was studied. The organic compounds chosen, belonging to the class of quinones, were 2-tert-butyl-9,10-anthraquinone (TBA) and 9,10-phenanthraquinone (FQA). The studies were performed on a rotating disk / ring electrode (RRDE), depositing a porous micro-layer, containing or not the modifier, on the glassy carbon of this electrode. Through the results of cyclic and linear voltammetry the generation of hydrogen peroxide can be evaluated, which was superior to the micro-layers with addition of the modifiers. The material with 0.5% (w / w) of FQA was the most efficient of all, with 30% more yield when compared to the Printex matrix and 6% higher when compared to the same amount of TBA in peroxide production . It was also studied the efficiency of the FQA for the production of hydrogen peroxide (H2O2) from the reduction reaction of gaseous oxygen (O2) in gaseous diffusion electrodes (EDG). Considering the five electrodes studied (Printex not modified and modified with 0.1, 0.5, 1.0 and 2.0% of FQA) an evaluation was made on which electrode would be the most suitable to be used in the degradation works of the drugs. For that, the analysis of the hydrogen peroxide concentration, the energy consumption and the kinetics involved in the process were analyzed. The results showed a significant increase in peroxide production for electrodes modified with 0.5 and 1.0% of FQA. Since the unmodified electrode reached a maximum of 215 ppm of H2O2 at a potential of -1.4 V with an energy consumption of 29 kWh kg-1 of H2O2. The electrode modified with 0.5% of FQA reached 566 pmm of H2O2 at a potential of -1.4 V with an energetic consumption of 14 kWh kg-1 of H2O2. The degradation of antibiotics amoxicillin and ampicillin (AMX and AMP) with commercial boron-doped diamond conducting anodes was also studied. The influence of the applied current density (15, 30 and 60 mA cm-2) for the same support electrolyte (3 g / L Na2SO4) and the same initial concentration of antibiotics (100 mg dm-3 each) was evaluated. Total mineralization of antibiotics was achieved. In addition, the process was found to be more efficient at current density of 30 mA cm-2. The results demonstrate the importance of the electrochemical processes mediated in the degradation of AMX and AMP. This influence was confirmed by some tests in which the electrolysis was coupled to UV radiation or to ultrasonic radiation. The use of UV radiation results in less efficient degradation, while ultrasound improves the rate of mineralization somewhat compared to the simple electrolyte process.

Neste trabalho foi estudado o comportamento eletroquímico de materiais à base de carbono Printex 6L, sem e com a adição de compostos orgânicos da classe das quinonas (2-terc-butil-9,10-antraquinona (TBA) e 2-etil-9,10-antraquinona (EA)) para a produção de peróxido de hidrogênio (H2O2) a partir da reação de redução do oxigênio gasoso (O2). Na primeira etapa, foi utilizada a técnica de microcamada porosa depositada sobre um eletrodo de disco/anel rotatório, sendo que a partir dos resultados obtidos foram confeccionados eletrodos de difusão gasosa (EDG) para a eletrogeração de H2O2. Os melhores resultados utilizando a microcamada porosa foram para os materiais com a adição dos modificadores, sendo que o material com 1,0% (m/m) de TBA na demonstrou ser o mais eficiente na geração de peróxido de hidrogênio, apresentando eficiência 20% maior comparado ao Printex 6L sem modificador. Com o eletrodo de difusão gasosa confeccionado com o composto orgânico escolhido, na melhor porcentagem de adição mássica de modificador, obteve-se a concentração de 301 mg L-1, sendo que com o eletrodo confeccionado com Printex 6L sem modificador obteve-se a concentração de 175 mg L-1, sob as mesmas condições experimentais. A eficiência cinética também apresentou os mesmos resultados quanto à eficiência dos materiais escolhidos, sendo de 5,94 mg L-1 min-1 para o material com 1,0% de TBA, no potencial de -1,0 V (vs. ECS), e de 3,05 mg L-1 min-1 para o eletrodo de difusão gasosa sem modificador, no potencial de -0,8 V (vs. ECS). / In this work, the electrochemistry behavior of the materials prepared with Printex 6L, with and without addition of organic compounds of the class of quinones, being the compounds: 2-tert-butyl-9,10-anthraquinone (TBA) and 2-ethyl-9,10-anthraquinone (EA). These materials were used to promote the electrogeneration of hydrogen peroxide through the oxygen reduction reaction. In the first phase, it was used the technique of porous microlayer deposited on the rotating ring/disk electrode, and after has been confectioned gas diffusion electrodes (GDE). The best results using the porous microlayer were for the materials with addition of modifiers, and the material with 1.0% (m/m) of 2-terc-butyl-9,10-anthraquinone was demonstrated to be the most efficient in generating hydrogen peroxide, presenting an efficiency 20% higher when compared to Printex 6L without the modifier. The gas diffusion electrode made with the chosen organic compound, in the best massic percentage of modifier, obtained the concentration of 301 mg L-1, and the electrode made with Printex 6L without the modifier obtained the maximum concentration of 175 mg L-1, under the same experimental conditions. The kinect efficiency also demonstrated the same results regarding the efficiency of the chosen materials, which means 5.94 mg L-1 min-1 for the material with 1.0% of 2-terc-butyl-9,10-anthraquinone, in the potential of -1.0 V(vs. SCE), and 3.05 mg L-1 min-1 for the gas diffusion electrode without the modifier, in the potential of -0.8 V (vs. SCE).

Fármacos tem sido foco de diversas estudos e pesquisas devido à constatação de sua ocorrência em diversos compartimentos ambientais. Esses compostos, com destaque para os antibióticos, apresentam biodegradação limitada e contínua introdução nos sistemas hídricos devido ao descarte incorreto, eliminação por excreção de parte da dose ingerida e, principalmente, pelo processo de fabricação nas indústrias farmacêuticas. Como as formas convencionais de tratamento têm se mostrado pouco efetivas, a tecnologia eletroquímica associada aos processos oxidativos avançados (POA) têm se mostrado uma maneira eficiente na degradação desses compostos. Em diversos estudos, os eletrodos de difusão gasosa (EDG) são apresentados como uma opção promissora no que diz respeito à eletrogeração de peróxido de hidrogênio, uma das principais fontes de radical hidroxila utilizado nos POA. Nesse aspecto, surgem estudos sobre modificadores que podem atuar como catalisadores nesse processo. Neste trabalho estudou-se o comportamento eletroquímico de dois modificares orgânicos suportados em matriz condutora de carbono Printex 6L. Os compostos orgânicos escolhidos, pertencentes a classe das quinonas, foram a 2-terc-butil-9,10-antraquinona (TBA) e a 9,10 fenantraquinona (FQA). Os estudos foram realizados em um eletrodo de disco/anel rotatório (RRDE), depositando-se uma microcamada porosa, contendo ou não o modificador, sobre o carbono vítreo deste eletrodo. Através dos resultados de voltametria cíclica e linear pode-se avaliar a geração de peróxido de hidrogênio, que foi superior para as microcamadas com adição dos modificadores. O material com 0,5% (m/m) de FQA mostrou-se o mais eficiente entre todos, com 30% de rendimento a mais quando comparado à matriz Printex e 6% maior quando comparada a mesma quantidade de TBA na produção do peróxido. Estudou-se também a eficiência da FQA para a produção de peróxido de hidrogênio (H2O2) a partir da reação de redução do oxigênio gasoso (O2), em eletrodos de difusão gasosa (EDG). Considerando os cinco eletrodos estudados (Printex não modificado e modificado com 0,1, 0,5, 1,0 e 2,0% de FQA) foi realizada uma avaliação sobre qual eletrodo seria o mais apto a ser utilizado nos trabalhos de degradação dos fármacos. Para isso fez-se a análise da concentração de peróxido de hidrogênio eletrogerada, o consumo energético e a cinética envolvida no processo. Os resultados mostraram um aumento significativo na produção de peróxido para os eletrodos modificados com 0,5 e 1,0% de FQA. Sendo que o eletrodo sem modificação atingiu um máximo de 215 ppm de H2O2 em um potencial de -1,4 V com um consumo energético de 29 kWh kg-1 de H2O2. O eletrodo modificado com 0,5% de FQA alcançou 566 pmm de H2O2 em um potencial de -1,4 V com um consumo energético de 14 kWh kg-1 de H2O2. Estudou-se também a degradação dos antibióticos amoxicilina e ampicilina (AMX e AMP) com anodos condutores comerciais de diamante dopados com boro. A influência da densidade de corrente aplicada (15, 30 e 60 mA cm-2) para o mesmo eletrólito de suporte (3 g / L de Na2SO4) e a mesma concentração inicial de antibióticos (100 mg dm-3 cada) foi avaliada. A mineralização total dos antibióticos foi atingida. Além disso, o processo foi encontrado para ser mais eficiente na densidade de corrente de 30 mA cm-2. Os resultados demonstram a importância dos processos eletroquímicos mediados na degradação de AMX e AMP. Esta influência foi confirmada por alguns testes em que a eletrólise foi acoplada à radiação UV ou à radiação ultrassônica. O uso de radiação UV resulta em uma degradação menos eficiente, enquanto que o ultrassom melhora um pouco a taxa de mineralização quando comparado ao processo eletrolítico simples. / Drugs have been the focus of several studies and researches due to the finding of their occurrence in several environmental compartments. These compounds, especially antibiotics, present limited biodegradation and continuous introduction into water systems because of incorrect disposal, elimination by excretion of part of the ingested dose and, mainly, by the manufacturing process in the pharmaceutical industries. As conventional mode of treatment have been shown to be ineffective, electrochemical technology associated with advanced oxidative processes (POA) has been shown to be an efficient way of degradation of these compounds. In several studies, gas diffusion electrodes (EDG) are presented as a promising option with respect to hydrogen peroxide electrogeneration, one of the main sources of hydroxyl radical used in POAs. In this aspect, studies on modifiers appear that can act as catalysts in this process. In this work the electrochemical behavior of two organic modifiers supported in Printex 6L carbon matrix was studied. The organic compounds chosen, belonging to the class of quinones, were 2-tert-butyl-9,10-anthraquinone (TBA) and 9,10-phenanthraquinone (FQA). The studies were performed on a rotating disk / ring electrode (RRDE), depositing a porous micro-layer, containing or not the modifier, on the glassy carbon of this electrode. Through the results of cyclic and linear voltammetry the generation of hydrogen peroxide can be evaluated, which was superior to the micro-layers with addition of the modifiers. The material with 0.5% (w / w) of FQA was the most efficient of all, with 30% more yield when compared to the Printex matrix and 6% higher when compared to the same amount of TBA in peroxide production . It was also studied the efficiency of the FQA for the production of hydrogen peroxide (H2O2) from the reduction reaction of gaseous oxygen (O2) in gaseous diffusion electrodes (EDG). Considering the five electrodes studied (Printex not modified and modified with 0.1, 0.5, 1.0 and 2.0% of FQA) an evaluation was made on which electrode would be the most suitable to be used in the degradation works of the drugs. For that, the analysis of the hydrogen peroxide concentration, the energy consumption and the kinetics involved in the process were analyzed. The results showed a significant increase in peroxide production for electrodes modified with 0.5 and 1.0% of FQA. Since the unmodified electrode reached a maximum of 215 ppm of H2O2 at a potential of -1.4 V with an energy consumption of 29 kWh kg-1 of H2O2. The electrode modified with 0.5% of FQA reached 566 pmm of H2O2 at a potential of -1.4 V with an energetic consumption of 14 kWh kg-1 of H2O2. The degradation of antibiotics amoxicillin and ampicillin (AMX and AMP) with commercial boron-doped diamond conducting anodes was also studied. The influence of the applied current density (15, 30 and 60 mA cm-2) for the same support electrolyte (3 g / L Na2SO4) and the same initial concentration of antibiotics (100 mg dm-3 each) was evaluated. Total mineralization of antibiotics was achieved. In addition, the process was found to be more efficient at current density of 30 mA cm-2. The results demonstrate the importance of the electrochemical processes mediated in the degradation of AMX and AMP. This influence was confirmed by some tests in which the electrolysis was coupled to UV radiation or to ultrasonic radiation. The use of UV radiation results in less efficient degradation, while ultrasound improves the rate of mineralization somewhat compared to the simple electrolyte process.

Atualmente a classe dos antibióticos se destaca pelo grande consumo e também pelo risco à saúde quando administrado de forma equivocada, esse aumento deve-se ao destaque cada vez maior da indústria de produtos farmacêuticos. Outra questão a ser levantada é a contaminação do meio ambiente por essa classe substâncias, pois após o uso pelo ser humano ocorre a eliminação natural de parte da concentração administrada, assim sendo liberadas nos esgotos e, posteriormente, contaminando os corpos d\'água, a fauna e flora local. Assim, foi proposto um métodos diferente para a degradação desses compostos, utilizando a eletrodos de difusão gasosa (EDG) capazes de gerar peróxido de hidrogênio in situ e em meio ácido, precursores dos radicais hidroxila, responsáveis pela degradação. Foram estudados EDG\'s não catalisados e catalisados, com diferentes porcentagens de ftalocianina de ferro II, com relação à quantidade de peróxido produzido, melhor potencial de produção e cinética do processo. Os resultados revelaram que a incorporação de 0,5% de Ft-Fe no eletrodo apresentou os melhores resultados. Esse eletrodo foi escolhido então para realizar as degradações dos antibióticos sulfametoxazol e trimetoprim. Na célula eletroquímica utilizou-se o processo Fenton, as reações ocorreram em uma faixa de potencial (-0,4 V &le; E &le; -1,4 V) e no reator foi utilizado um potencial fixo (-1,75 V) mas utilizando processos de Fenton e Foto-Fenton. As amostras degradadas foram avaliadas por técnicas analíticas de espectroscopia no ultravioleta (UV), cromatografia líquida de alta eficiência (HPLC) e teor de carbono orgânico total (TOC). Os resultados mostraram que, na célula eletroquímica, o melhor potencial de degradação foi de -1,1 V, com uma taxa de redução de 25,5% para o trimetoprim e 96,0% do sulfametoxazol e uma diminuição do teor de carbono orgânico total de 10,4%. Para o reator o melhor resultado foi obtido para o processo de Foto-Fenton onde houve uma redução de 16,9% do teor de carbono orgânico total e uma redução de 99,7% do sulfametoxazol e 11,3% do trimetoprim, em um potencial de -1,75 V. Considerando a formação de subprodutos foi elaborada uma rota de degradação com os possíveis compostos formados. / Currently the class of antibiotics is notable for the large consumption and also the risk to health when administered in error, this increase is due to the growing prominence of the pharmaceutical industry. Another issue to be addressed is the environmental contamination by substances that class, because after use by humans part of the concentration administered is naturally eliminated, thus being released into sewers and subsequently contaminating water bodies, the local fauna and flora. Thus, different methods has been proposed for the degradation of these compounds, using gas diffusion electrodes (GDE) capable of generating hydrogen peroxide in situ and in acid medium, precursors of hydroxyl radicals, responsible for degradation. We studied GDE\'s not catalyzed and catalyzed with different percentages of iron phthalocyanine II, with respect to the amount of peroxide produced better yield potential and kinetic process. The results revealed that the incorporation of 0.5% of Ft-Fe in the electrode showed the best results. This electrode was then chosen to perform the degradation of the antibiotic sulfamethoxazole and trimethoprim. In the electrochemical cell used in the Fenton process, the reactions occurred in a potential range (-0.4 V &le; E &le; -1.4 V) and in the reactor was used a fixed potential (-1.75 V) but using Fenton and photo-Fenton processes. Degraded samples were analyzed by analytical techniques, ultraviolet spectroscopy (UV), high performance liquid chromatography (HPLC) and total organic carbon content (TOC). The results showed that in the electrochemical cell, the best degradation potential was -1.1 V, with a reduction rate of 25.5% for trimethoprim and 96.0% for sulfamethoxazole and a decreased carbon content total of 10.4%. For the reactor the best result was obtained for the photo-Fenton process where there was a reduction of 16.9% of the total organic carbon content and a reduction of 99.7% of sulfamethoxazole and 11.3% of trimethoprim, in a potential of -1.75 V. Considering the formation of byproducts was drafted a route with the possible degradation compounds formed.

Atualmente a classe dos antibióticos se destaca pelo grande consumo e também pelo risco à saúde quando administrado de forma equivocada, esse aumento deve-se ao destaque cada vez maior da indústria de produtos farmacêuticos. Outra questão a ser levantada é a contaminação do meio ambiente por essa classe substâncias, pois após o uso pelo ser humano ocorre a eliminação natural de parte da concentração administrada, assim sendo liberadas nos esgotos e, posteriormente, contaminando os corpos d\'água, a fauna e flora local. Assim, foi proposto um métodos diferente para a degradação desses compostos, utilizando a eletrodos de difusão gasosa (EDG) capazes de gerar peróxido de hidrogênio in situ e em meio ácido, precursores dos radicais hidroxila, responsáveis pela degradação. Foram estudados EDG\'s não catalisados e catalisados, com diferentes porcentagens de ftalocianina de ferro II, com relação à quantidade de peróxido produzido, melhor potencial de produção e cinética do processo. Os resultados revelaram que a incorporação de 0,5% de Ft-Fe no eletrodo apresentou os melhores resultados. Esse eletrodo foi escolhido então para realizar as degradações dos antibióticos sulfametoxazol e trimetoprim. Na célula eletroquímica utilizou-se o processo Fenton, as reações ocorreram em uma faixa de potencial (-0,4 V &le; E &le; -1,4 V) e no reator foi utilizado um potencial fixo (-1,75 V) mas utilizando processos de Fenton e Foto-Fenton. As amostras degradadas foram avaliadas por técnicas analíticas de espectroscopia no ultravioleta (UV), cromatografia líquida de alta eficiência (HPLC) e teor de carbono orgânico total (TOC). Os resultados mostraram que, na célula eletroquímica, o melhor potencial de degradação foi de -1,1 V, com uma taxa de redução de 25,5% para o trimetoprim e 96,0% do sulfametoxazol e uma diminuição do teor de carbono orgânico total de 10,4%. Para o reator o melhor resultado foi obtido para o processo de Foto-Fenton onde houve uma redução de 16,9% do teor de carbono orgânico total e uma redução de 99,7% do sulfametoxazol e 11,3% do trimetoprim, em um potencial de -1,75 V. Considerando a formação de subprodutos foi elaborada uma rota de degradação com os possíveis compostos formados. / Currently the class of antibiotics is notable for the large consumption and also the risk to health when administered in error, this increase is due to the growing prominence of the pharmaceutical industry. Another issue to be addressed is the environmental contamination by substances that class, because after use by humans part of the concentration administered is naturally eliminated, thus being released into sewers and subsequently contaminating water bodies, the local fauna and flora. Thus, different methods has been proposed for the degradation of these compounds, using gas diffusion electrodes (GDE) capable of generating hydrogen peroxide in situ and in acid medium, precursors of hydroxyl radicals, responsible for degradation. We studied GDE\'s not catalyzed and catalyzed with different percentages of iron phthalocyanine II, with respect to the amount of peroxide produced better yield potential and kinetic process. The results revealed that the incorporation of 0.5% of Ft-Fe in the electrode showed the best results. This electrode was then chosen to perform the degradation of the antibiotic sulfamethoxazole and trimethoprim. In the electrochemical cell used in the Fenton process, the reactions occurred in a potential range (-0.4 V &le; E &le; -1.4 V) and in the reactor was used a fixed potential (-1.75 V) but using Fenton and photo-Fenton processes. Degraded samples were analyzed by analytical techniques, ultraviolet spectroscopy (UV), high performance liquid chromatography (HPLC) and total organic carbon content (TOC). The results showed that in the electrochemical cell, the best degradation potential was -1.1 V, with a reduction rate of 25.5% for trimethoprim and 96.0% for sulfamethoxazole and a decreased carbon content total of 10.4%. For the reactor the best result was obtained for the photo-Fenton process where there was a reduction of 16.9% of the total organic carbon content and a reduction of 99.7% of sulfamethoxazole and 11.3% of trimethoprim, in a potential of -1.75 V. Considering the formation of byproducts was drafted a route with the possible degradation compounds formed.