Irídio e rutênio isoladamente e em combinação com tungstênio, termicamente depositados na plataforma de um tubo de grafite com aquecimento transversal, foram investigados quanto a sua aplicabilidade como modificadores permanentes para a determinação de cádmio em suspensões de carvão por espectrometria de absorção atômica com forno de grafite. O modificador químico de Pd-Mg adicionado em solução na forma de nitratos também foi investigado, para comparação. Este apresentou a melhor performance para solução aquosa, enquanto a mistura de W-Ir e W-Ru como modificadores permanentes apresentou o menor poder de estabilização. Todos os modificadores investigados perdem parte do seu poder de estabilização quando aplicados a suspensões de carvão. O modificador químico Pd-Mg e os modificadores permanentes Ir e Ru bem como a mistura de 300 μg de W e 200 μg de Ir estabilizam cádmio a uma temperatura de pirólise de 600 ºC, enquanto que as demais combinações investigadas permitem temperaturas de pirólise máximas entre 500 e 550 ºC. Investigações a partir da fase líquida das suspensões demonstram que existe a possibilidade de que a alta concentração de ácido empregada no preparo das suspensões e/ou compostos que são extraídos do carvão para a fase líquida podem ser responsáveis pela redução no poder de estabilização dos modificadores. A temperatura máxima de pirólise de 600 ºC não foi suficiente para reduzir a absorção de fundo provocada por concomitantes de algumas das amostras testadas, enquanto que temperaturas de pirólise mais elevadas levam à perda de analito. Para o desenvolvimento deste estudo, foram utilizados os materiais de referência BCR No 180 Gas Coal, SARM 18 Coal Witbank, SARM 19 Coal O.F.S., SARM 20 Coal Sasolburg, NIST SRM 1635, NIST SRM 1630a e SRM 1632b. Foi investigado também um carvão brasileiro da mina de Candiota no Rio Grande do Sul. Foram determinadas as figuras de mérito e os valores obtidos para o limite de detecção e a massa característica estão entre 1,0 e 1,3 ng g-1 e 1,9 e 2,2 pg, respectivamente. Estudos por espectrometria de absorção atômica de alta resolução com fonte contínua foram realizados com o intuito de elucidar as possíveis interferências provenientes de diferentes matrizes de carvão na forma de suspensão. Estes estudos revelaram que o fundo contínuo apresenta uma absorção maior do que a capacidade de correção exibida pelo corretor de deutério e que o mesmo se sobrepõe ao sinaldo analito. Valores de 1,0 pg e 0,6 ng g-1 foram obtidos respectivamente, para massa característica e limite de detecção, empregando-se irídio como modificador permanente e temperatura de pirólise de 600 ºC. Apesar de a técnica corrigir esse fundo pronunciado, parte do analito é aparentemente perdida durante a volatilização da matriz, fazendo com que o método não possa ser considerado robusto. / Iridium and ruthenium, alone and in combination with tungsten, thermally deposited on the platform of a transversely heated graphite tube, were investigated for their suitability as permanent chemical modifiers for the determination of cadmium in coal slurries by graphite furnace atomic absorption spectrometry (GF AAS). The conventional mixed palladium and magnesium nitrates (Pd-Mg) modifier, added in solution, was also investigated for comparison. The latter one showed the best performance for aqueous solutions, and the mixed W-Ir and W-Ru permanent modifiers had the lowest stabilizing power. All of the investigated modifiers lost some of their stabilizing power when coal slurries were investigated. The Pd-Mg modifier, pure Ir and Ru, and a mixture of 300 μg W + 200 μg Ir could stabilize Cd at least to a pyrolysis temperature of 600 ºC, whereas all the other combinations already failed at temperatures above 500-550 ºC. Additional investigations of the supernatant liquid of the slurries supported the assumption that the high acid concentration of the slurries and/or a concomitant leaching out of the coal might be responsible for the reduced stabilizing power of the modifiers. The maximum applicable pyrolysis temperature of 600 ºC was not sufficient to reduce the background absorption to a manageable level in the majority of the coal samples and higher pyrolysis temperatures cause loss of analyte. The following reference materials were used in this work: BCR No. 180 Gas Coal, SARM 18 Coal witbank, SARM 19 Coal O.F.S, SARM 20 Coal Sasolburg, NIST SRM 1635, NIST SRM 1630a and SRM. In addition, a coal sample from the Candiota mine in Rio Grande do Sul, Brazil, was investigated. Figures of merit were established and the values obtained for detection limit and characteristic mass were between 1.0 and 1.3 ng g-1 and 1.9 and 2.2 pg, respectively. In order to further investigate the spectral interference caused by the coal slurries, additional investigations were carried out using high resolution continuum source atomic absorption spectrometry. High-resolution continuum source ET AAS revealed that the continuous background absorption was beyond the capabilities of background correction exhibit by the deuterium background correction system, and was overlapping with the analyte signal. A characteristic mass of 1.0 pg and a detection limit of 0.6 ng g-1 could be obtained with iridium as permanent modifier and a pyrolysis temperature of 600 ºC. Although the technique could correct for thisbackground absorption, some analyte was apparently lost with the rapidly vaporizing matrix so that the method could not be considered to be rugged.

O estudo geoquímico orgânico de biomarcadores foi aplicado ao perfil estratigráfico da jazida de carvão fóssil de Candiota, Rio Grande do Sul, proporcionando a determinação do grau de maturação, ambiente de óxi-redução, paleoambiente deposicional, tipo de matéria orgânica constituinte do sedimento e principal classe de plantas que originaram o carvão. Somado a isto, comparações com os dados petrográficos também foram realizadas. Para tal, as amostras foram extraídas com diclorometano em aparelhagem Soxhlet. Os betumes (extratos), de todo o perfil estratigráfico, apresentaram-se ricos em enxofre elementar e compostos aromáticos e polares. Através do emprego das técnicas de cromatografia a gás com detector de ionização em chama (GC-FID) e detector de massas (GC-MS) as frações puras de alifáticos e aromáticos dos betumes foram analisadas, onde foram determinados parâmetros geoquímicos. Os resultados indicaram que todas as amostras estudadas são de baixo grau de maturação, formadas em ambiente altamente oxidante, compostas por querogênio predominantemente do tipo III, paleoambiente deposicional majoritariamente terrestre, com pequena possibilidade de contribuições estuária e de mar aberto e tendo plantas coníferas como principais organismos depositados para sua formação, coincidindo com os dados obtidos por análise petrográfica. / The organic geochemical study of biomarkers was applied to the stratigraphic profile of fossil coal from Candiota, Rio Grande do Sul leading to the determination of maturity degree, oxyreduction environment, depositional paleoenvironment, type of organic matter constituent of the sediment and main class of plants that originated the coal. Besides that, comparisons with petrographic data were also carried out. To that purpose, samples were extracted with dichloromethane in Soxhlet extractor. The bitumens (extracts) from the entire stratigraphic profile resulted rich in elemental sulphur and aromatic and polar compounds. Through the use of gas chromatography techniques employing flame ionization detector (GC-FID) and mass detector (GC-MS) the bitumen pure aliphatic and aromatic fractions were analized and geochemical parameters were determined. Results indicate that all studied samples present low maturation degree, they were formed in a high oxidant environment, they are composed predominantly by type III kerogen. The depositional environment was mainly terrestrial, presenting low possibility of estuarine and open sea contributions and having conifers plants as principal deposited organisms for their formation. These results obtained were coincident with data from petrographical analysis.

A análise do parâmetro TPH (Total de hidrocarboneto de petróleo) tem como objetivo verificar as concentrações de hidrocarbonetos de petróleo e afins em matrizes ambientais. Os hidrocarbonetos que resultam no TPH podem ser de origem biogênica ou antropogênica, portanto utilizam-se alguns indicadores para a verificação de indícios da origem da contaminação. Neste trabalho foi realizado um monitoramento no canal e na baia que faz margem ao bairro de Tapera, localizado no sul de Florianópolis, através das análises de TPH e seus indicadores em sedimento durante 7 meses em 11 pontos. As amostras foram extraídas por banho ultrassônico e analisadas por cromatografia gasosa com detector de ionização por chama (GC/FID) conforme as normas EPA 8015B e EPA 3550B, 1996. A variação das concentrações de TPH durante o monitoramento foi de 0,11a 1600 mg.kg-1, sendo que 21% das amostras apresentaram algum indício de contaminação antropogênica. Os dados do monitoramento foram tratados estatisticamente por Análise de Componentes Principais (PCA), Projeção às estruturas Latentes (PLS) e Projeção ortogonal às estruturas latentes (OPLS). O Ponto 2 do monitoramento apresentou altas concentrações de TPH e os maiores indícios de contaminação antropogênica comparado com os demais pontos. Portanto, nesse ponto foi realizada outra amostragem após o término do monitoramento, sendo analisado por GC/FID e cromatografia gasosa bidimensional com detector de espectrometria de massas com analisador de íons por tempo de voo (GC × GC-TOFMS). Nessa última técnica, foi possível identificar tentativamente 87 compostos de classes diferentes pela biblioteca do software Chroma TOF e pelo índice de retenção de Van Den Dool Kratz. / The analysis of the parameter TPH (Total petroleum hydrocarbon) aims to verify the concentrations of petroleum hydrocarbons and related in environmental matrices. The hydrocarbons that could be result in TPH may be of biogenic or anthropogenic origin, therefore some indicators are used to verify evidence of the origin of the contamination. In this work a monitoring was carried out in the canal and in the bay that borders the neighborhood of Tapera, located in the south of Florianopolis, through the analyzes of TPH and its indicators in sediment during 7 months in 11 points. The samples were extracted by ultrasonic bath and analyzed by gas chromatography with flame ionization detector (GC/FID) according to standards EPA 8015B and EPA 3550B, 1996. The variation of TPH concentrations during the monitoring was from 0.11 to 1600 mg.kg-1, and 21% of the samples showed some evidence of anthropogenic contamination. The monitoring data were statistically treated by Principal Component Analysis (PCA), Latent Structures Projection (PLS) and Latent Structures Orthogonal Projection (OPLS). Point 2 of the monitoring showed high concentrations of TPH and the highest evidence of anthropogenic contamination compared to the other points. Therefore, at this point another sampling was performed after the end of the monitoring, being analyzed by GC/FID and two-dimensional gas chromatography with mass spectrometry detector with time-of-flight ion analyzer (GC × GCTOFMS). In the latter technique, it was possible to tentatively identify 87 compounds of different classes by the Chroma TOF software library and the Van Den Dool Kratz retention index.

Seminario de Título entregado a la Universidad de Chile en cumplimiento parcial de los requisitos para optar al Título de Químico Ambiental. / El presente seminario de título se desarrolló en una empresa dedicada a la importación, exportación, fabricación y almacenaje, de productos agroquímicos. Orientada a entregar soluciones efectivas y rentables para la protección de los cultivos, por lo que dentro de sus líneas productivas se fabrican distintos productos para el uso agrícola que van desde fitosanitarios (como plaguicidas), a productos para una estimulación vegetal (como fertilizantes). Dichos productos generados por la empresa son distribuidos tanto de manera nacional como internacional. Por una parte, la seguridad industrial de las empresas es un área multidisciplinaria que se encarga de minimizar los riesgos en la industria. Uno de los supuestos de dicha área es que toda actividad industrial tiene peligros inherentes que necesitan de una correcta gestión. Es debido a esto y al compromiso de la empresa con el medio ambiente y sus trabajadores, que se realizó una matriz de riesgo y un plan de salud ocupacional acorde a las necesidades de la empresa, el cual era apremiante y de gran importancia para la compañía. Por consiguiente, este proyecto tuvo por finalidad desarrollar las medidas para la implementación de un plan de seguridad y salud ocupacional en una empresa química. Este plan abarcó a la totalidad de la empresa, tanto personal administrativo como de planta. Para esto, se evaluó la salud actual de los trabajadores, así como también sus puestos de trabajo y los riesgos a los que están expuestos, ya sean riesgos físicos o riesgos generados producto de la exposición a algún agente químico, así mismo se ix revisó las hojas de seguridad de todos los productos clasificándolos según la norma chilena oficial NCh382.Of2017. También, mediante la revisión de las declaraciones en el Sistema de Declaración de Residuos Peligrosos (SIDREP) y en el Sistema Nacional de Declaración de Residuos (SINADER) se determinó la cantidad de toneladas de residuos peligrosos y no peligrosos generados por la empresa, de acuerdo a esto se evaluó el manejo y gestión de los mismos. Por otro lado, se revisó los protocolos que el Ministerio de Salud (MINSAL) y la Asociación Chilena de Seguridad (ACHS) han desarrollado para la gestión del riesgo y la prevención de enfermedades profesionales en las empresas, identificándose los protocolos que por normativa ministerial inciden directamente en la empresa y son necesarios implementar. Finalmente, para la construcción de la matriz se evaluó todos los riesgos presentes en la empresa, registrados en el reglamento interno de higiene y seguridad junto con los riesgos recopilados y se determinó la probabilidad de ocurrencia (baja, media y alta) como también la consecuencia (ligeramente dañino, dañino y extremadamente dañino). Los resultados obtenidos en la matriz de riesgo permitieron valorar el nivel de riesgo presente en la empresa (triviales, tolerables, moderado, importante o intolerable), lo que forma la base para decidir si se requiere mejorar los controles existentes o implantar unos nuevos. x A raíz de lo anterior, se obtuvieron un total de 79 riesgos triviales, 135 riesgos tolerables, 143 riesgos moderados y 32 riesgos importantes, evaluándose estos últimos dos y entregándose las medidas preventivas para cada riesgo asociado. / The following seminar was developed in a company dedicated to the import, export, manufacturing and storage of agricultural chemicals. This company focuses on giving effective and profitable solutions in terms of the protection of agricultural chemicals crop. The productive chain includes the manufacturing of different chemicals for agricultural use from phytosanitaries (pesticides) to chemicals that improve the growth and productiveness of plants (fertilizers). These chemicals are nationally and internationally distributed by the company. The industrial security of the companies is a multidisciplinary area responsible of minimizing the industry risks. The industrial activity needs an appropriate management since it implies inherent danger. In consequence, a risk matrix and an occupational health and security plan were made, according to the company needs which was important and indispensable for the company. The purpose of this project was to develop measurements for the implementation of a security plan and occupational health in a chemical company. The plan covered all personnel of the company including the administrative personnel and the staff employee. All workers were evaluated in terms of health and also their workstation and the risks, physical or due to the exposition to a chemical agent, they might be exposed to. In addition, every product was checked and classified based on the official Chilean regulation NCh382.Of2017. After the review of Sistema de Declaración de Residuos Peligrosos (SIDREP) and Sistema Nacional de Declaración de Residuos (SINADER), the quantity of hazardous xii waste, in tons, and non-hazardous waste produced by the company were determined to evaluate their management. On the other hand, the Ministry of Health (MINSAL, Ministerio de Salud) and Chilean Security Association (ACHS, Asociación Chilena de Seguridad) protocols, developed for the risk management and the prevention of occupational disease in the company, were checked. The protocols that is important to apply, were identified since it is indispensable and directly influences the company and need to be according to the ministry regulatory. Finally, for the development of the matrix, all kind of risks in the company were evaluated, registered with the risks previously compiled in the internal regulatory policy of health and security and the probability of risk (low, medium or high) was stablished. The consequence of risk (slightly harmful, harmful and extremely harmful). The results obtained in the risk matrix allowed us to assess the level of risk present in the company (trivial, tolerable, moderate, important or intolerable), which forms the basis for deciding whether to improve existing controls or implement new ones. As a result of the above, a total of 79 trivial risks, 135 tolerable risks, 143 moderate risks and 32 major risks were obtained, evaluating the latter two and delivering the preventive measures for each associated risk.

Seminario de Título entregado a la Universidad de Chile en cumplimiento parcial de los requisitos para optar al Título de Químico Ambiental / Iron (Fe) is a transition metal usually found in potable water at low concentrations, whose concentration limit is 0.3 mg / L according to NCh 409, and due to its common use mainly in pipelines and industries, it must be constantly monitored, in order to keep its concentration under the limits and guarantee the welfare of people. The aim of this work is to promote an easy method to identify and extract Fe from potable and natural waters through solid phase extraction. This was done both for acid and basic mediums. 0.4 mL of sulfosalicylic acid (SSA) at 2.5% w/v was used as a ligand, adding 3 mL of a monochloroacetic acid buffer for the samples in acid medium and 3 mL of concentrated NH3 (12,66 M) for samples in basic medium and form a complex, either Fe(III)-SSA or Fetotal-SSA, in 100 mL total solution. Then, an anion exchange solid resin was added, called AG 2-x8 from BIORAD, in order to preconcentrate the complex. Previous studies were conducted without the addition of resin to observe the formation of the complex and study its characteristics. The quantification limits were 0.56 ppm and 0.28 ppm, which are very high or too close to the concentration limit of Fe allowed in potable water, that is, 0.3 ppm (NCh 409). Solid phase studies were carried out in order to decrease the quantification limits of the method. Then the chemical variables involved in obtaining the complex were optimized, such as the amount of SSA, anionic resin, buffer and total volume. Thus obtaining the adequate amounts for each analyte, mentioned above. The extraction of the Fe-ASS complex was possible for both media. However, in a basic medium it requires much higher Fe concentrations for its formation and presented a constant turbidity in the form of a colloidal compound of gray tone mainly referred so the procedure was more thoroughly studied in acid medium. The Fe(III)-SSA complex presented good linearity throughout the measurement range with an DL of 7.32 x 10-3 ppm and an QL of 0.024 ppm achieving a good sensitivity and a recovery percentage of 99.7%. Only SO4-2 presented interference in the sample with a tolerance limit of only 100 ppm. The standard addition method was effective to eliminate this interference by treating the entire matrix in the same way throughout the measurement range. Potable water samples were taken from different sources, such as, from the Analytic Chemistry Laboratory (Ñuñoa), Quinta Normal and from a construction zone adjacent of the the Faculty of Sciences of the University of Chile. Fe is generally found at concentrations below the norm (23.38 ppb and 172 ppb), but is sensitive to climatic factors (522 ppb after a very rainy day) and construction places with little waste treatment (342.3 ppb), so it must be constantly monitored. Solid phase extraction is a simple, fast and efficient method and has a wide range of applications for different compounds or chemical substances.

La disponibilitat, qualitat i accés a l'aigua per al consum humà, per a l'ús domèstic, ramader, agrícola, industrial, etc. va lligat a la latitud, longitud i altura geogràfica, al nivell de desenvolupament i a la cultura pròpia d'una zona. En termes generals, el percentatge d'aigua dolça de fàcil disponibilitat a nivell mundial és del voltant del 0,6%. Una xifra baixa respecte al volum total d'aquest recurs natural. Com a conseqüència d'aquest fet, cal destacar l'augment dels esforços destinats a la reducció del seu ús, a la seva reutilització, al seu pre/post tractament, etc. És en aquest context en el qual s'emmarca aquesta tesi doctoral: el tractament d'aigües contaminades per fonts antropogèniques. S'estén més enllà del tractament dut a terme a les EDARs, i es situa front la problemàtica sorgida arran de la presència dels contaminants emergents al sistema aquàtic, com són els metabòlits d'alguns fàrmacs, determinats productes farmacèutics, productes per a la cura personal, etc. Alguns d'ells es caracteritzen per la seva baixa biodegradabilitat i/o ecotoxicitat. Conseqüentment, haurien de ser tractats mitjançant processos alternatius a la depuració convencional. L'ús dels anomenats processos químics i electroquímics d'oxidació avançada (AOP/AEOPs) és una solució potencial. Concretament, en aquesta tesi, determinats AOP/AEOPs han estat utilitzats per al tractament d'una aigua residual de baixa biodegradabilitat contaminada amb un producte provinent de la indústria farmacèutica, anomenat _-metil-fenilglicina (_-MPG). La comparació de diferents tipus d'AOP/AEOPs, sota varies condicions experimentals, és avaluat al llarg del treball duent a terme el seguiment i quantificació de les espècies majoritàries presents a l'aigua. L'augment de l'eficiència d'aquests processos, així com la reducció del seu impacte ambiental, és evidenciat fent ús de la radiació solar com a recurs renovable. Escollir el procés i condicions més adequades per al tractament d'aquest tipus d'aigües correspon a una situació de compromís entre el que proporciona una major eficiència i un menor impacte ambiental. És en aquest marc que, alternativament, s'ha avaluat i comparat la combinació d'un tractament d'oxidació avançada, que permeti l'obtenció d'aigua ràpidament biodegradable, amb un posterior tractament biològic de fangs activats. Així mateix, determinats AOP/AEOPs, sota condicions concretes, podrien ser proposats per a territoris on la salubritat de l'aigua és qüestionable i a on no es disposa dels recursos econòmics ni de la infraestructura suficients per a la construcció d'EDARs. mL'estudi en qüestió s'ha dut a terme a nivell de laboratori, de manera que cal tenir en compte que els resultats són vàlids per aquesta escala. / Water availability and quality assigned to human activities is linked to the geographic latitude, longitude and altitude, as well as to the level of development and the typical culture of a specific area. In general terms, only around 0.6% of total water volume of the Earth is easily available. Consequently, there is a rise of international efforts centred to reduce its use/abuse, to its reutilization, and its pre/post-treatment. In the above context, this doctoral thesis is centred in the anthropogenic wastewater treatment. Specifically, it pays special attention to current water contamination by emergent contaminants since as some pharmaceutical compounds, its secondary metabolites, some cure personal products, etc. Some of they are characterized by its non-biodegradability and eco-toxicity; consequently they should be eliminated to water by means of alternative treatment to activate sludge process that it is a conventional biological treatment in the Municipal Wastewater Treatment Plants (WWTPs). Advanced Oxidation Processes (AOPs) are a potential solution for bioremediation. In this work, some AOPs have been carried out to treat some water contaminated with _-methyl-phenylglycine, a non-biodegradable compound that comes from pharmaceutical industry. Several AOPs (Fenton, solar photo-Fenton, electro-Fenton and solar photoelectro-Fenton), under different conditions, are used to rise water biodegradability. Time evolution of total carbon organic (TOC), hydrogen peroxide, main inorganic nitrogenated species are followed during the treatment. Moreover, main intermediates aromatic compounds and carboxylic acids are detected, postulating a degradative pathway. Environmental impact associated to above processes have been evaluated using as a tool the Life Cycle Assessment (LCA). Efficiency and environment sustainability are raised with the use of solar light. Alternatively, processes with the minor environmental impact are been choose to carry out a chemical-biological coupling treatment: AOP allows rise water biodegradability and with the biological treatment water depuration is finished. In addition, some AOP, under specific conditions, could be suggested to territories where water healthiness is questionable and where there aren't enough economic resources either infrastructure to build some WWTPs. The study has been carried out at laboratory level, so that it is necessary to take that the results are valid for this scale.

La mesura de la radioactivitat es important en molts camps entre els que s’inclou el control mediambiental. En tots ells, es necessari conèixer les activitats dels diferents radionúclids presents a la mostra, degut al diferent comportament que presenten i al diferent dany biològic que poden produir. Existeixen diferent tècniques per a la determinació de la radioactivitat entre les que es troben les d’escintil•lació orgànica (líquida i plàstica) utilitzades per a la determinació d’emissors beta i també d’emissors alfa i gamma. Les tècniques de detecció per escintil•lació presenten limitacions de selectivitat que fan necessària una separació prèvia dels radionúclids per poder realitzar l’anàlisi. L’objectiu d’aquest treball és el desenvolupament de diferents mètodes per a la millora de la selectivitat en la mesura per escintil•lació plàstica. Per aquest motiu, la primera part de l’estudi ha estat la mesura de mostres d’elevada salinitat procedents de traçadors petrolífers que no poden ser mesurades per escintil•lació liquida, degut a que produeixen separació de fases. En aquesta part s’ha optimitzat el procés de mesura i s’han desenvolupat nous paràmetres de quenching i mètodes de calibratge que han sigut utilitzats en la següent part de l’estudi. La segona part d’aquest estudi ha estat l’aplicació de diverses estratègies de millora de la selectivitat en diferents etapes del procés de mesura: - classificant els senyals durant la seva adquisició en funció de la seva distribució temporal (PSA) - discriminant radionúclids en funció de l’energia de les seves desintegracions aplicant calibratge multivariant en els espectres obtinguts - incorporant l’etapa de separació a la de mesura extraient els radionúclids sobre les microesferes d’escintil•lador plàstic (immobilització i polímers impresos) / Radioactivity monitoring is important in many fields, especially in environmental protection. In this purpose it is necessary to determine the activities of the different radionuclides present on the sample due to their different behaviour and their different biological effects on humans. Different techniques are used for the detection of radioactivity, among them organic scintillation techniques (liquid and plastic) are applied to the determination of beta emitters but also for alpha and gamma emitters. The scintillation techniques show selectivity limitations that make necessary a previous chemical separation process before measurement. The objective of this work is to develop different methods for improving selectivity in plastic scintillation measurements. For this reason, the first part of the study was focused on the determination of high salt samples coming from oil radiotracers analysis. These samples cannot be measured by liquid scintillation because the salt content produces phase separation. In this case the measurement process was optimized and new quenching parameters and calibration procedures were developed. These parameters and procedures were used in the next part of the study. The second part of the study was the application of selectivity improvement strategies at different points of the measurement process: - classifying the signals during the data acquisition as a function of their temporary distribution (Pulse Shape Analysis, PSA) - discriminating radionuclides as a function of their disintegrations energy distribution using multivariate calibration to the spectra registered (Multivariate calibration – PLS Partial Least Square) - incorporating the chemical separation to the measurement step by extracting the radionuclides on the plastic scintillator microspheres (immobilization and imprinted polymers)

Orientador: Amauri Antonio Menegário / Banca: Carlos Renato Corso / Banca: Eduardo de Almeida / Banca: Marcelo Loureiro Garcia / Banca: Yadira Ansoar Rodríguez / Resumo: A técnica de difusão em filmes finos por gradiente de concentração (DGT) tem se consolidado como uma excelente ferramenta analítica capaz de fornecer concentrações lábeis por tempo, pré-concentração dos analitos e amostragem in situ, porém a aplicação desta técnica em águas de drenagem ácida de mina (DAM) é complicada devido à redução da adsorção do amostrador tradicional (resina ligante Chelex-100) para metais em baixo pH. Este estudo, avalia a utilização da técnica DGT para determinação das concentrações lábeis de Al, Cd, Cu, Mn, Ni, Pb U e Zn em águas de DAM, empregando novos agentes ligantes preparados a partir de biomassas (cascas de banana, borra de café e sementes de moringa) impregnadas em agarose. As medições DGT foram realizadas em soluções padrão em laboratório e in situ. Resultados laboratoriais mostram que os agentes ligantes podem ser empregados em águas com pH baixo (pH 3,5) para os íons Cd, Cu, Ni, Pb e Zn. Já os íons Al, Mn e U não apresentaram linearidade nas curvas de imersão para nenhuma biomassa pesquisada. Para a análise de amostras in situ de DAM, houve baixas recuperações dos íons Cd, Cu, Ni e principalmente para Zn com 5,7% da fração solúvel com o gel de agarose-moringa, podendo indicar a baixa eficiência dos agentes ligantes ou algum efeito matriz inerente durante a determinação por ICPOES. Por outro lado, houve recuperações satisfatórias para a imersão em amostras do Rio Corumbataí e do Rio Piracicaba, ressaltando o emprego destes agentes ligantes pesquisados em matrizes aquáticas diferentes das matrizes de DAM. Este estudo mostra que o uso da técnica DGT pode ser estendido para águas com pH baixo (desde que sejam avaliados as limitações e condições de contorno avaliadas neste estudo) podendo ser uma ferramenta útil para o monitoramento em tempo integrado de concentrações lábeis ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The diffusive gradients in thin films (DGT) technique has consolidated as an excellent analytical tool capable of providing labile concentrations by time, analytical preconcentration and in situ sampling, but the application of this technique in acid mine drainage waters (AMD) is limited by the reduction of adsorption of the traditional binding layer (Chelex-100 chelating resin) to metals at low pH. This study proposes the use of the DGT technique to determine the concentrations of Al, Cd, Cu, Mn, Ni, Pb U and Zn in AMD using new binding agents prepared from biomass (Musa cavendishi banana peel, spent coffee grounds and shelled Moringa Oleifera seeds) impregnated with agarose. DGT measurements were performed in laboratory standard solutions and in situ. Laboratory results showed that the binding agents can be used in waters with low pH (pH 3.5) for Cd, Cu, Ni, Pb and Zn. Al, Mn and U ions did not present linearity in the deployment curves for any biomass studied. For the analysis of in situ AMD samples, there were low recoveries of the Cd, Cu, Ni, and mainly Zn ions with 5.7% of the soluble fraction with the agarose-moringa gel, indicating the low efficiency of the binding agents at low values pH or some inherent matrix effect during determination by ICP-OES. On the other hand, there were satisfactory recoveries for deployment in samples from the Corumbataí River and the Piracicaba River, highlighting the use of these binding layers in aquatic matrices other than AMD matrices. This study shows that the use of the DGT technique can be extended to waters with low pH (provided that the limitations and contour conditions evaluated in this study are evaluated) and can be a useful tool for the integrated time monitoring of labile concentrations in different aquatic systems / Doutor

Orientador: Denise Bevilaqua / Orientador: Oswaldo Garcia Júnior (in memorian) / Banca: Luis Gonzaga Santos Sobral / Banca: Domingo Cantero Moreno / Resumo: Neste trabalho foram realizados ensaios para o estudo da viabilidade da conversão de lavadores químicos (tecnologia química muito utilizada para a remoção de H2S) em biofiltros percoladores para a remoção de H2S. Foi investigado o efeito inibitório da concentração de sulfato no meio de recirculação de nutrientes, o efeito do pH, da vazão de recirculação de nutrientes, da concentração de alimentação de H2S na corrente gasosa e do tempo de residência na eficiência de remoção de H2S em dois biofiltros percoladores, um recheado com espuma de poro aberto de poliuretano e o outro com anéis de Pall de polipropileno. Durante a etapa de imobilização dos micro-organismos foi observado, experimentalmente, que o anel de Pall de polipropileno não é um bom suporte para a imobilização de Thiobacillus denitrificans e, portanto, no caso da conversão de um lavador químico constituído por um leito de recheio de anéis de Pall em um biofiltro percolador, seria apropriada a substituição deste suporte por espuma de poro aberto de poliuretano, por exemplo, que demonstrou ser um bom suporte para a formação do biofilme. Durante o estudo do efeito do pH observou-se que o aumento de pH aumenta a porcentagem de remoção de H2S, sendo que nas condições utilizadas, o intervalo de pH ótimo ficou entre 7,6 - 8,5. O efeito inibitório da concentração de sulfato foi observado a partir de 16,5 g L-1 no biofiltro de espuma de poro aberto de poliuretano e de 13,0 g L-1 no biofiltro de anéis de Pall de polipropileno. Os efeitos da vazão de recirculação de nutrientes e do tempo de residência do gás foram mais evidentes no biofitro de anéis de Pall comparado a espuma de poro aberto, devido, provavelmente, às características do suporte. No biofiltro de espuma de poro aberto, a diminuição do tempo de residência afetou a... (Resumo completo, clicar acesso eletrônico baixo) / Abstract: In this work experiments were carried out in order to study the viability of conversion of chemical scrubbers (current technology) to biotrickling filter for removing H2S. Many parameters were investigated, such as, the inhibitory effect of sulfate concentration in the nutrient recirculation, the effect of the pH, the flow rate of recirculating nutrient, the inlet H2S concentration and the gas stream residence time in the H2S removal capacity in two biotrickling filter. One of them was packaged with open pore polyurethane foam and other with polypropylene Pall rings. During and after the immobilization stage it was observed, experimentally, that polypropylene Pall rings is not a good support for immobilizing Thiobacillus denitrificans. Thus, in the case of a chemical packaged scrubber conversion using such support in a biotrickling filter, it would be appropriate to replace it by open pore polyurethane foam, for instance, which demonstrated to be a better support to the biofilm to establish. It was shown that increasing the pH an increase in the H2S removal was detected. In this experimental work conditions, the optimum pH range was from 7.6 to 8.5. The inhibitory effect of the sulfate concentration was observed from 16.5 g L-1 in the open pore polyurethane foam biofilter and 13.0 g L-1 in the polypropylene Pall rings biofilter. The effects of the flow rate of the recirculating nutrient and the gas residence time were more evident in the Pall ring biofilter when compared with the open pore foam, probably due to the support characteristics. In the open pore foam biofilter, decreasing the residence time the H2S removal percentage was affected only for less than 9 s, whereas in the Pall rings biofilter, before 33 s. In both biofilters as lower the residence time, lower the H2S removal percentage. In the open pore polyurethane foam... (Complete abstract click electronic access below) / Mestre

Irídio e rutênio isoladamente e em combinação com tungstênio, termicamente depositados na plataforma de um tubo de grafite com aquecimento transversal, foram investigados quanto a sua aplicabilidade como modificadores permanentes para a determinação de cádmio em suspensões de carvão por espectrometria de absorção atômica com forno de grafite. O modificador químico de Pd-Mg adicionado em solução na forma de nitratos também foi investigado, para comparação. Este apresentou a melhor performance para solução aquosa, enquanto a mistura de W-Ir e W-Ru como modificadores permanentes apresentou o menor poder de estabilização. Todos os modificadores investigados perdem parte do seu poder de estabilização quando aplicados a suspensões de carvão. O modificador químico Pd-Mg e os modificadores permanentes Ir e Ru bem como a mistura de 300 μg de W e 200 μg de Ir estabilizam cádmio a uma temperatura de pirólise de 600 ºC, enquanto que as demais combinações investigadas permitem temperaturas de pirólise máximas entre 500 e 550 ºC. Investigações a partir da fase líquida das suspensões demonstram que existe a possibilidade de que a alta concentração de ácido empregada no preparo das suspensões e/ou compostos que são extraídos do carvão para a fase líquida podem ser responsáveis pela redução no poder de estabilização dos modificadores. A temperatura máxima de pirólise de 600 ºC não foi suficiente para reduzir a absorção de fundo provocada por concomitantes de algumas das amostras testadas, enquanto que temperaturas de pirólise mais elevadas levam à perda de analito. Para o desenvolvimento deste estudo, foram utilizados os materiais de referência BCR No 180 Gas Coal, SARM 18 Coal Witbank, SARM 19 Coal O.F.S., SARM 20 Coal Sasolburg, NIST SRM 1635, NIST SRM 1630a e SRM 1632b. Foi investigado também um carvão brasileiro da mina de Candiota no Rio Grande do Sul. Foram determinadas as figuras de mérito e os valores obtidos para o limite de detecção e a massa característica estão entre 1,0 e 1,3 ng g-1 e 1,9 e 2,2 pg, respectivamente. Estudos por espectrometria de absorção atômica de alta resolução com fonte contínua foram realizados com o intuito de elucidar as possíveis interferências provenientes de diferentes matrizes de carvão na forma de suspensão. Estes estudos revelaram que o fundo contínuo apresenta uma absorção maior do que a capacidade de correção exibida pelo corretor de deutério e que o mesmo se sobrepõe ao sinaldo analito. Valores de 1,0 pg e 0,6 ng g-1 foram obtidos respectivamente, para massa característica e limite de detecção, empregando-se irídio como modificador permanente e temperatura de pirólise de 600 ºC. Apesar de a técnica corrigir esse fundo pronunciado, parte do analito é aparentemente perdida durante a volatilização da matriz, fazendo com que o método não possa ser considerado robusto. / Iridium and ruthenium, alone and in combination with tungsten, thermally deposited on the platform of a transversely heated graphite tube, were investigated for their suitability as permanent chemical modifiers for the determination of cadmium in coal slurries by graphite furnace atomic absorption spectrometry (GF AAS). The conventional mixed palladium and magnesium nitrates (Pd-Mg) modifier, added in solution, was also investigated for comparison. The latter one showed the best performance for aqueous solutions, and the mixed W-Ir and W-Ru permanent modifiers had the lowest stabilizing power. All of the investigated modifiers lost some of their stabilizing power when coal slurries were investigated. The Pd-Mg modifier, pure Ir and Ru, and a mixture of 300 μg W + 200 μg Ir could stabilize Cd at least to a pyrolysis temperature of 600 ºC, whereas all the other combinations already failed at temperatures above 500-550 ºC. Additional investigations of the supernatant liquid of the slurries supported the assumption that the high acid concentration of the slurries and/or a concomitant leaching out of the coal might be responsible for the reduced stabilizing power of the modifiers. The maximum applicable pyrolysis temperature of 600 ºC was not sufficient to reduce the background absorption to a manageable level in the majority of the coal samples and higher pyrolysis temperatures cause loss of analyte. The following reference materials were used in this work: BCR No. 180 Gas Coal, SARM 18 Coal witbank, SARM 19 Coal O.F.S, SARM 20 Coal Sasolburg, NIST SRM 1635, NIST SRM 1630a and SRM. In addition, a coal sample from the Candiota mine in Rio Grande do Sul, Brazil, was investigated. Figures of merit were established and the values obtained for detection limit and characteristic mass were between 1.0 and 1.3 ng g-1 and 1.9 and 2.2 pg, respectively. In order to further investigate the spectral interference caused by the coal slurries, additional investigations were carried out using high resolution continuum source atomic absorption spectrometry. High-resolution continuum source ET AAS revealed that the continuous background absorption was beyond the capabilities of background correction exhibit by the deuterium background correction system, and was overlapping with the analyte signal. A characteristic mass of 1.0 pg and a detection limit of 0.6 ng g-1 could be obtained with iridium as permanent modifier and a pyrolysis temperature of 600 ºC. Although the technique could correct for thisbackground absorption, some analyte was apparently lost with the rapidly vaporizing matrix so that the method could not be considered to be rugged.