Orientador: Raquel Fernandes Pupo Nogueira / Banca: Andrew George Allen / Banca: Ian Castro-Gamboa / Banca: Eduardo Bessa Azevedo / Banca: Maria Lucia Arruda de Moura Campos / Resumo: Neste trabalho foi avaliada a fotodegradação dos fármacos amoxicilina (AMX), diclofenaco (DCF), paracetamol (PCT) e sulfametoxazol (SMX) por fotólise e por processos oxidativos avançados. A degradação dos compostos foi feita em água destilada (AD), água do mar (AM) e efluente de estação de tratamento de esgoto (ETE) utilizando fonte de irradiação artificial e solar. A concentração dos fármacos foi determinada por cromatografia líquida de alta eficiência (CLAE) e a remoção da carga orgânica por determinações de carbono orgânico total (COT). Os intermediários gerados durante a degradação foram determinados por CLAE acoplada à espectrometria de massas de alta resolução e a toxicidade das soluções por bioensaios com Daphnia magna e Vibrio fischeri. Foi observada uma pequena diferença na degradação de AMX e PCT variando o pH entre 2,5 e 9,0 e independência da concentração de H2O2 (170-3400 mg L-1) quando o processo H2O2/UV foi avaliado. Por outro lado, a espécie de ferro influenciou fortemente a degradação de AMX e PCT quando o processo foto-Fenton foi empregado. A degradação de ambos compostos foi favorecida na presença do complexo ferrioxalato de potássio (FeOx) quando comparado ao Fe(NO3)3. Contudo, na presença de sulfato ferroso, a degradação de PCT foi favorecida em comparação ao FeOx. A aplicação de ambos processos foi avaliada na degradação de AMX e PCT em efluente de ETE usando diferentes fontes de radiação e comparado aos resultados em AD. A eficiência de degradação de AMX usando o processo foto-Fenton foi prejudicada pela matriz ETE. Isso não foi observado usando o processo H2O2/UV. Com relação a eficiência de degradação de PCT, esta não foi influenciada pela matriz quando ambos os processos (H2O2/UV e foto- Fenton) foram empregados. A degradação de AMX e PCT foi favorecida na presença de radiação solar... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work the photodegradation of the pharmaceuticals amoxicillin (AMX), diclofenac (DCF), paracetamol (PCT) and sulfamethoxazole (SMX) by photolysis and advanced oxidation processes was studied. The degradation of the compounds was performed in distilled water (DW), seawater (SW) and sewage treatment plant (STP) using artificial and solar irradiation source. The pharmaceuticals concentrations were determined by high performance liquid chromatography (HPLC) and the organic matter by total organic carbon (TOC). The intermediates generated during degradation were determined by high performance liquid chromatography coupled to the high resolution mass spectrometry and the toxicity of the solutions by bioassays with Daphnia magna and Vibrio fischeri. It was observed a small difference on the AMX and PCT degradation varying the pH between 2.5 and 9.0 and independence of H2O2 concentration (170-3400 mg L-1) when the H2O2/UV was employed. On the other hand, a strong influence of the iron species was observed on the AMX and PCT degradation when the photo-Fenton process was evaluated. The degradation of both pharmaceuticals was favored in the presence of the potassium ferrioxalate complex (FeOx) when compared to Fe(NO3)3. However, at the presence of ferrous sulphate, the PCT degradation was favored in comparison to FeOx. Both processes were evaluated for the AMX and PCT degradation in STP effluent using different radiation sources and compared with the DW results. The AMX degradation efficiency by the photo- Fenton process was affected by the STP matrix, while no influence was observed by H2O2/UV process. In relation to PCT degradation efficiency, it was not influenced by the matrix using both processes, (H2O2/UV and photo-Fenton). The AMX and PCT degradation was favoured in the presence of solar radiation. After the photo-Fenton application to both compounds and iron species... (Complete abstract click electronic access below) / Doutor

Resumo: A nanociência e nanotecnologia são campos científico-tecnológicos empenhados em compreender como o controle estrutural da matéria ao nível molecular pode ser utilizado para a preparação de novos materiais com propriedades únicas e exclusivas. Um material muito promissor para aplicações nanotecnológicas é o dióxido de titânio (TiO2). Este trabalho descreve a síntese e caracterização de semicondutores nanoestruturados de TiO2 na forma de material nanoporoso e nanoparticulado pelo método sol-gel usando o tetra-isopropóxido de titânio [Ti(OPri)4] como precursor, empregados como fotoanodos de Ti/TiO2 no processo de fotoeletrocatálise visando a degradação do corante alimentício Índigo Carmim (IC) utilizado como modelo de poluente orgânico. Tais materiais se diferenciam pela etapa de hidrólise na síntese do sol-gel que foi feita tanto em meio aquoso (nanoporoso) quanto em meio alcoólico (nanoparticulado). Para a preparação dos fotoeletrodos placas de titânio de 25 cm2 foram recobertas com filmes de TiO2 obtidos pelo método sol-gel. A sequência de deposição por dip-coating, lavagem e calcinação a 450 o C por três horas, foi realizada por quatro vezes. A caracterização dos semicondutores nanoestruturados de filmes finos de Ti/TiO2 foi feita por difração de raios-X, microscopia eletrônica de varredura (MEV), microscopia de força atômica (AFM) e assim como caracterização voltamétrica como medidas de fotocorrente versus potencial, potencial de banda plana e determinação de constantes de adsorção. Foi possível determinar o tamanho de partícula de 20 nm o material nanoporoso e 10 nm o nanoparticulado, pela presença das fases anatásio e rutilo uniformemente dispersas, compactas, com alta cristalinidade do TiO2 e conseqüentemente maior fotoatividade. O desempenho do eletrodo nanoparticulado foi notável, principalmente pelo seu menor ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Nanoscience and nanotechnology are scientific-technological fields involved in understanding how structural control of molecular matter level can be used on the preparation of new materials with unique properties. A very promising material for nanotechnology applications is titanium dioxide (TiO2). This work describes the synthesis and characterization of nanostructured TiO2 semiconductor in nanoporous and nanoparticulated materials by the sol-gel method using titanium tetra-isopropoxide [Ti(OPri)4] as a precursor, used as Ti/TiO2 photoanodes in the photoelectrocatalytic process on the degradation of Indigo Carmine (IC) food dye used as a model of organic pollutant. Such materials differ in the hydrolysis step in the sol-gel synthesis that was made in aqueous medium (nanoporous) and in an alcoholic medium (nanoscale).For the preparation of the photoeletrodos titanium foils of 25 cm2 were coated with TiO2 films obtained by the sol-gel method. A sequence of diping, washing and firing at 450 o C for three hours, was performed four times. The characterization of nanostructured Ti/TiO2 semiconductor thin films was made by X-ray powder diffraction (DRX), scanning electron microscopy (SEM), atomic force microscopy (AFM) as well as voltammetric characterization measurements of photocurrent versus potential, flat band potential and determination of adsorption constants. It was possible to determine the particle size of both materials as 20 nm nanoporous and 10 nm nanoparticulated, through the presence of anatase and rutile phases uniformly dispersed, compact, highly TiO2 crystallinity and photoactivity. The best performance of nanoparticulated electrode was notable especially for their smaller particle size and increase in surface area, minimizing the recombination of electron/hole pairs. In photoelectrochemical oxidation the combination of UV irradiation with the application of ... (Complete abstract click electronic access below) / Orientador: Maria Valnice Boldrin Zanoni / Coorientador: Sandra Helena Pulcinelli / Banca: Christiane de Arruda Rodrigues / Banca: Adalgisa Rodrigues de Andrade / Mestre

Fluoreto presente em águas de abastecimento, pode ser determinado por titulação condutométrica, usando-se La(NO3)3 como titulante. O método proposto no presente trabalho exige a separação prévia de fluoreto da amostra, por destilação a 135ºC. O pH do destilado é ajustado entre 5,5 - 6,0; etanol é adicionado até atingir-se a proporção de 50%, titulando-se a solução resultante com La(NO3)3. Nessas soluções, fluoreto nas concentrações de 500 ppb e 2,0 ppm podem ser determinadas com precisões de 5% e 4%, respectivamente. Amostras naturais foram analisadas condutometricamente pelo método proposto, potenciometricamente com eletrodo íon seletivo de fluoreto, obtendo-se resultados compatíveis. / Fluoride ions in drinking water can be easily determined by condutometric titraction using La(NO3)3 as titrant. The sample must be destilled in H2S04 previously to separate the fluoride ions, at 1350 C. The destillated, in 50% ethanol is titrated with La(NO3)3 In these conditions, fluoride ions at the concentrations of 500 ppb and 2,0 ppm are determined with accuracy of, respectively, 5% and 4%. Natural samples of drinking water were analysed by this method and by the ion-selective method, with agreement among the results.

A titulação biamperométrica mostra possibilidades mais amplas que as relatadas em livros-texto, podendo-se analisar traços com elevadas precisão e exatidão. Duas aplicações foram demonstradas no presente trabalho: as determinações de SO2 e S-- inorgânico em efluentes, com enormes vantagens sobre os respectivos métodos espectrofotométricos. Em poucos minutos pode-se determinar 13 ppb de SO2 (recolhidos em TCM) com precisão de 7,7% e de 10 ppb de H2S (após separação do efluente) com precisão de 8,1%. Foram efetuadas anâlises de amostras naturais gentilmente cedidas pela CETESB e confrontadas com os métodos de referência, encontrando-se perfeita concordância nos resultados. / The biamperometric titration as studied, shows wider possibilities than classical interpretation reported in the text-books. This technique studied in this thesis shows tremendous applications in trace analysis, with higer accuracy and precision. In the present thesis, two applications of The technique were made: the determinations of SO2 in the atmosphere and inorganic S-- in waters, with advantages over the respective spectrophotometric methods. In few minutes one can determine 13 ppb the SO2 (absorved in TCM) with 7,7% accuracy and 10 ppb the S-- (after recovery in ZnAc2) with 8,1% accuracy. Natural samples offered by CETESB (Environmental Protection Agency of the State of São Paulo) and the results found were in good agreement with those obtained by the reference methods.

O monitoramento da poluição ambiental requer técnicas analíticas confiáveis e efetivas para analisar diferentes níveis de concentração de elementos metálicos. Com este objetivo, foi desenvolvido um método analítico para a determinação de metais presentes (Cd, Co e Cr) no particulado atmosférico, coletados em filtros de celulose, com a introdução direta da amostra sólida utilizando a espectrometria de absorção atômica com forno de grafite (GFAAS). As amostras foram cortadas utilizando um cortador de aço inoxidável com 2 mm de diâmetro e introduzidas no tubo de grafite por meio de pinça de aço inoxidável. Foi investigada a influência do pré - tratamento térmico do tubo com o modificador de matriz Pd/Mg no sinal de absorbância de alguns elementos como Cd, Pb, Sn, Se, Sb, Cr e Co. A calibração foi feita com curva analítica construída com soluções padrão. Concluiu-se que é possível determinar Cd e Co diretamente nas amostras de filtro de celulose com a introdução direta da amostra no forno de grafite. O Cr apresentou interferência, provavelmente do branco, na sua determinação direta por GFAAS. Uma combinação de métodos analíticos diferentes como ICP-AES (espectrometria de emissão atômica com fonte de plasma de argônio induzido); IC (cromatografia de íons), XRFS (espectrometria de fluorescência de Raios X), INAA (análise por ativação neutrônica instrumental) e PIXE (emissão de Raios X induzidos por partícula) foi utilizada para formar um banco de dados para utilização em modelo receptor e intercomparação dos resultados. A Análise de Componentes Principais (APC) foi aplicada para identificar as fontes poluidoras. Foram identificadas quatro fontes: o primeiro fator (Cd, Cu, K, Pb, Se, Sn, Sb) está associado às contribuições industriais (incluindo fundições) e incineradores municipais. O segundo fator com altos pesos para Al, Ca, Co, Fe, S, e também para Na+, NO3- e NH4+ pode ser associado à ressuspensão de partículas do solo e emissão biogênica. O terceiro fator (Cl- e As) pode estar associado a processos a altas temperaturas (indústria) e o quarto fator (SO4=) às emissões de uma fábrica de ácido sulfúrico existente nas imediações ou reações fotoquímicas do S e seus compostos. / Environmental monitoring requires reliable and effective analytical techniques for different concentration ranges. With this aim, an analytical method was developed for direct analysis of atmospheric particulate solid samples using graphite furnace atomic absorption spectrometry (GFAAS) to determine metalic elements (Cd, Co and Cr). The filters were subsampled using clean stainless steel punch (2 mm diameter) and this disc was inserted directly into the graphite tube using a stainless steel tweezer. It was also investigated the influence of the thermal pretreatment of Pd/Mg modifier in the absorbance signal of some elements such as Cd, Pb, As, Se, Sb, Cr and Co. A combination of different analytical methods like ICP-AES (Inductively Coupled Plasma - Atomic Emission Spectrometry); IC (Ion Chromatography), XRFS (X Ray Fluorescence Spectrometry), INAA (Instrumental Neutron Activation Analysis) and PIXE (Particle Induced X Ray Emission) were used to find the requeriments for receptor model analysis and intercomparison of the results. Principal Component Analysis (PCA) was applied to identify the particles sources. Four sources were identified: the first factor (Cd, Cu, K, Pb, Se, Sn, Sb) is associated to industrial emission and garbage burning. The second factor with high values to Al, Ca, Co, Fe, S, and also to Na+, NO3- e NH4+can be associated with resuspended soil dust and biogenic emission. The third factor (Cl- and As) is associated to high temperature process and the fourth factor (SO4=) to sulphuric acid emission from a factory near the sampling point or to photochemical reactions of S and their compounds.

The body of work in this dissertation focuses on the properties of an environmental thin film system, including the roughness and composition of the surface. The deposition of particles, such as airborne soil and plant pollen, from the atmosphere creates a thin film known as “environmental film” or “urban film” that covers virtually all of Earth’s solid surfaces. Environmental films have been shown to accumulate a variety of chemicals, including toxic pollutants. To investigate the means by which environmental films uptake chemicals, model films are made in the lab and real films are collected outside. Model films serve to mimic the properties of native films and allow for a simple analysis of a complex system. Native films serve to provide real field samples to analyze. The properties of model and native films are characterized using reflected light to determine what the film is made of and microscopes capable of imaging small particles. The results of the model film study indicate a model capable of reproducing the surface roughness and other properties of native films. This study serves as a platform with the goal of making model films that better mimic native films. The results of the native film study indicate successful imaging using microscopes capable of revealing the structure and chemical composition of the films. This imaging adds an important contribution to the field that has not previously been performed.

Atmospheric aerosols encapsulate a wide variety of particles with different compositions, sizes and sources of origin. They also directly and indirectly affect climate by their interactions with sunlight, clouds, atmospheric chemical species, and even other suspended particles. To understand the atmospheric aerosol processes and the effects they have in global and regional climate is of utmost importance for the future establishment of environmental regulations and emission policies that affect aerosol precursor compounds in an effective and beneficial manner. In particular, aerosols are known to be formed from emissions from human activities, such as fossil fuel burning, agriculture, or concentrated animal feeding operations (CAFOs). Secondary organic aerosols (SOA) constitute a type of atmospheric aerosols that are formed from the atmospheric oxidation of organic compounds that are released from various sources into the atmosphere. Due to the complexity of the atmosphere and variability of its conditions, the direct study of SOA formation is a challenging task, but the implementation of atmospheric chamber facilities to study aerosol formation and growth under controlled conditions has provided a way to study the formation and growth of SOA. However, chamber experiments cannot study specific reactions or individual compounds from the aerosol formation mechanisms in isolation, they can only provide insight on what is produced and what it is produced from, and under what conditions. Thus, kinetic modeling of the mechanisms of gas-phase atmospheric oxidation of the compounds of interest is used to develop reliable and accurate chemical models that will help have precise estimations and determine the mechanisms by which volatile organic compounds interact to produce aerosol particles. Dimethyl sulfide (DMS), dimethyl disulfide (DMDS) and trimethylamine (TMA) are three relevant atmospheric compounds, due to their emissions from many natural and anthropogenic sources and recent studies on emissions of these compounds from animal waste from CAFOs has triggered the interests on the study of SOA formation from these and other similar compounds. In this study, kinetic modeling of the atmospheric oxidation mechanisms of DMDS, DMS and TMA is used to simulate atmospheric chamber studies of aerosol formation to develop accurate models and help determine the mechanisms of aerosol formation.

ABSTRACT Current glove guides attempt to assist in recommending which type of glove is appropriate for handling chemicals; however, they include information on less than 1% of the 89 million chemical products available today. This study offers a solution by testing five durable polymer materials against 50 chemicals, using two rapid chemical degradation assessment techniques. The first technique involves gravimetric analysis of the weight change following constant immersion against the chemical mixture. The second method uses tensile strength to assess molecular changes in the polymer structure. This study is focused on addressing three issues of concern. First, this study examines if current degradation testing methods are adequate to determine chemical resistance against complex mixtures. Secondly, this study will be used to determine if current degradation information on pure chemicals is effective in predicting degradation of complex chemical mixtures, based on the major ingredient(s). Lastly, this study will start a chemical resistance index for complex mixed chemicals. The results of this study clearly show that glove recommendations of pure and mixed chemicals are frequently different. In more than 58.4% of the cases, the mixed chemical requires a different glove than that of its pure chemical components. Results also show that glove recommendations based solely on weight change and/or permeation results are missing important information on tensile test performance. There are several instances (15.2%) in which the initial glove recommendation would be changed to a lower recommendation rating if the results of a tensile test were included.

Photoacoustic spectroscopy was used to analyze the transport of ozone through the air/water interface. Experimental results showed that the ozone transport rate is similar to rates measured for other gases of low solubility and low reactivity. The transport rate increases with increasing pH. The decomposition rate of ozone was studied in solutions. The decomposition rate also depends on the pH of the solution, and in high pHs both the deposition velocity and the decomposition rate constant of ozone have larger values. The value of the deposition velocity (Kd) is 3.7 ± .9 x 10-3 cm/sec and the decomposition rate constant is 5.3 ± 0.6 x 10-5 sec-l for distilled water. For ocean water, the respective values are 5.2 ± 0.4 x 10-3 sec-l and 7.8 ± 0.4 x 10-4 cm/sec respectively.

This treatise is a recapitulation of the theoretical and experimental study of hysteresis in atmospheric kinetics. The original problem arose from a theoretical study of a series of reactions for clean air. Upon evaluation a bistable equilibrium was predicted. The steady-state analysis had delineated a metastable region for the set of reactions. This bounded region is the hysteresis that this research project evaluated.