Currently, there is very little research available on nonpoint source pollution from rural watersheds. Government regulatory agencies are desperate for information regarding the causes of nonpoint source pollution, which includes the relationship between suspended soil particles and dispersion. Since soil dispersion is dependent on clay mineralogy, knowing the clay mineralogy of the soil in an area can help predict sediment loads entering the surrounding surface waters. This information is necessary to protect the resource value of our rivers, lakes, and estuaries, as well as to protect recreational activities such as fishing or hunting; but most importantly, this information is necessary to ensure the safety of our drinking water supply. Clay mineralogy and its influence on dispersion, as well as dispersion and its relation to water quality are the focus of this study. Soil mineralogy affects water quality in several ways: soil mineralogy determines the dispersivity of the clay portion of the soil and dispersive clays are likely to end up as suspended sediment in surface waters; weathering reactions contribute elements to water as dissolved load, and the sorption properties of clay minerals contribute to soils' ability to filter and carry pollutants. Through the use of X-ray diffraction, dispersivity, atomic absorption spectrometry, cation exchange capacity, and petrographic microscopy, this study shows that the clay mineral fraction of a soil determines the dispersivity, and that dispersed clay minerals contribute excess nutrients and metals as nonpoint source pollutants to surface waters.

Ce travail s’inscrit dans une problématique locale de teneur élevée en arsenic naturel dans le but d’améliorer la surveillance et la gestion de la qualité de la ressource en eau dans l’arrière-pays niçois. L’existence de grandes disparités géographiques des teneurs en arsenic font de la géologie la cause principale de cette contamination. L’intérêt de ce travail est d’appréhender les interactions solide/solution entre l’arsenic total dissous et les particules solides (matières en suspensions, sédiment de lit de rivière, solides naturels). Pour décrypter le comportement géochimique de l’arsenic, les trois objectifs principaux sont : de déterminer son état de conservativité dans le milieu naturel ; puis d’étudier les phénomènes d’adsorption en laboratoire sur des solides naturels (illite, oxydes de fer) ou de référence (kaolinite) ; puis enfin d’apporter une application directe au piégeage de l’arsenic par la création d’un pilote de traitement destiné à dépolluer une source d’eau destiné à la consommation humaine. La concentration en particule est le facteur influençant la conservativité de l’arsenic dans le système de confluence Tinée/Var selon les données des compartiments dissous et particulaire. La fraction colloïdale semble avoir une implication de premier ordre lors de la période de crue étudiée. Le piégeage de l’arsenic est favorisé par les oxyhydroxydes de fer, les argiles puis en moindre quantité par les solides acido-solubles. / This work aimed to solve a local problem of high water contamination with natural arsenic. In order to monitor and manage the water resource quality in French Riviera region. The different geographical repartition of arsenic content makes the consequences of this contamination to the geology. The interest of this work is to understand the interaction at solid/liquid interfaces between total dissolved arsenic and the solid particles (suspended particles matter, bed sediments and natural solids). To elucidate the geochemical behavior of arsenic, the three main objectives are: to determine the conservative states in the natural environment, then to study the adsorption phenomena under laboratory conditions onto the natural solids (illite and iron oxides) or reference materials (kaolinite); thirdly to apply the outcome of this work to establish a processing pilot for arsenic removal to decontaminate drinking water. The particle content is the main factor which influences the conservativity of arsenic in the confluence Tinée/Var. Colloids seems to have the main role in the arsenic removal in the studied flood period. Arsenic removal is favored by iron oxides, and clays, but less efficiently by acid-soluble compounds. The study of sorption mechanisms onto clays showed that adsorption of arsenic is strongly dependent on pH, quantity of aluminol reactive sites, influence of competitive anions such as carbonates and phosphates. Finally, the association of zeolites (high specific surface area) with coating of amorphous iron oxides (high affinity for arsenic) makes this adsorbent the most efficient, hence was studied and used in this work for arsenic adsorption.

La série argileuse du Callovo-Oxfordien recouvre une transition minéralogique entre un interstratifié illite/smectite désordonné (R0 - partie supérieure) et un autre ordonné (R1 - partie inférieure. Or, la minéralogie de ces argiles conditionne les propriétés de rétention de la formation ainsi que leur réactivité en réponse à une perturbation physico-chimique potentiellement induite par le stockage. Dans une optique de caractérisation fine des minéraux argileux du Callovo-Oxfordien, les méthodes conventionnelles et simplificatrices d'identification comme l'utilisation d'abaques issus de la littérature ont été invalidées. La méthode retenue consiste à comparer directement des diffractogrammes de rayons X calculés avec ceux enregistrés sur un même échantillon après différents traitements et à en reproduire toutes les caractéristiques (positions des pics, rapports d'intensité, profils) à l'aide d'un modèle structural unique. Les minéraux argileux du forage EST104 peuvent ainsi être décrits comme un mélange de trois phases principales : une illite, une smectite et un interstratifié illite/expansible désordonné (R0) de composition fixe (35% exp.). Avec la profondeur les caractéristiques structurales de ces phases sont constantes. La transition minéralogique précédemment décrite traduit la modification des proportions relatives des différentes phases. Cette description diffère de celle classiquement proposée pour l'illitisation diagénétique des séries sédimentaires. Cependant, l'utilisation des mêmes outils sur une série diagénétique de référence conduit à une description similaire. Ces résultats novateurs impliquent de reconsidérer les mécanismes réactionnels proposés pour ces minéraux ainsi que leur modélisation cinétique. Enfin, la réactivité des minéraux argileux du Callovo-Oxfordien en réponse à une perturbation alcaline est très limitée par la présence de matière organique qui recouvre les particules argileuses et protège ainsi les sites réactifs des minéraux argileux.

O Brasil é produtor de argilas e conta com grandes reservas deste recurso natural. Porém, grande parte da sua produção é comercializada seca e moída. O desenvolvimento de argilas para seu uso como reforço em nanocompósitos poliméricos constitui uma opção para os produtores desta matéria prima que teriam assim um produto com maior valor agregado. Este trabalho visa avaliar o potencial uso como nanocarga de duas argilas nacionais provenientes da Bacia de Taubaté, São Paulo, denominadas ALIGRA e SANTA FÉ. As frações de tamanho de partícula médio menor de 0,02 mm, obtidas por peneiramento á úmido da argila homogeneizada e seca, foram utilizadas no desenvolvimento do trabalho experimental. Os estudos de caracterização, envolvendo análise granulométrica, química, mineralógica, morfológica, térmica e textural, revelaram características muito semelhantes em ambas às argilas. Fração argila, maior de 70% em massa. Composição química conforme a definição química de uma argila e os teores de seus componentes mostram valores intermédios entre as apresentadas pelas bentonitas e argila caulinítica usadas com fins de comparação. Ressaltamse boas propriedades adsorventes. Área superficial específica BET ao redor de 120 m2/g, valor maior do que o apresentado por muitas bentonitas naturais (74,5 m2/g). Predominantemente mesoporosas, com poros, maiormente em forma de fenda, característicos da estrutura em camadas das argilas. Baixa capacidade de troca catiônica, 12 meq/100g. Difratogramas de raios-X revelaram a predominância do estratificado ilita/esmectita, caulinita e quartzo na argila ALIGRA, e de ilita, caulinita e quartzo na argila SANTA FÉ. Prosseguiu-se com a argila ALIGRA a preparação da argila organofílica. A argila organofílica foi obtida por troca catiônica com o sal quaternário de amônio: cloro cetril trimetil amônio, depois de homogeneizada em sódio com cloreto de sódio. Análises FTIR e TGA indicaram que houve inserção dos cátions orgânicos. Testes preliminares foram feitas, preparando misturas das argilas com matriz de polipropileno e usando como agente compatibilizante polipropileno enxertado com anidrido maleico. Resultados de ensaios de tração reportam algumas melhoras nas propriedades testadas com as composições preparadas com as argilas purificadas. Com as composições com argilas organofílicas somente foi melhorado o alongamento na rotura. Estudos ais aprofundados são recomendados. / Brazil is a producer of clay and has large reserves of this natural resource. However, most of its production is sold dried and milled." The development of clays for use as reinforcement in polymer nanocomposites is an option for these raw material producers, who would thus have a product with higher added value. This study aims to evaluate the potential use as nanofiller of two national clays from Taubaté basin, São Paulo, called ALIGRA and SANTA FE. In this experiment, the fractions of particles with average size of less than 0.02 obtained through wet sieving were used. The characterization studies involving granulometric, chemical, mineralogical, morphological, thermal and textural analysis, revealed very similar characteristics in both the clays. Clay fraction (< 2&#956;m) is higher 70%. Chemical composition as the definition of clay and its components show intermediate values between those present by bentonite and kaolinitic clays used here for purposes of comparison. It should be underlined good adsorptive properties. Specific surface area BET (aBET) around of 120 m2/g, this value is higher than showed by many bentonites (74.5 m2/g). They are predominantly mesoporous, the pores predominantly in slit-shape in accordance to the characteristic layered structure of the clays. Low cationic exchange capacities (CEC), 12 meq/100 g. XRD results for samples saturated with ethylene glycol and heated revealed the predominance of illite/smectite, kaolinite and quartz in ALIGRA clay, and illite, kaolinite and quartz in the clay SANTA FE. Work continued with the clay ALIGRA the preparation of organoclay. The organoclay was obtained by ion exchange with the quaternary ammonium salt: cetril trimethyl ammonium chloride, after homogenized in sodium with sodium chloride. FTIR and TGA analyzes indicated that there was integration of organic cations Preliminary tests were performed by preparing mixtures of clays with a polypropylene matrix, and using polypropylene grafted with maleic anhydride as a compatibilizer. Results of tensile tests made in the polypropilene- purified clay compositions have reported some improvements in some tested properties. With polipropilene-organofilized compositions only improved elongation on break. More detailed studies are which would be required.

O Brasil é produtor de argilas e conta com grandes reservas deste recurso natural. Porém, grande parte da sua produção é comercializada seca e moída. O desenvolvimento de argilas para seu uso como reforço em nanocompósitos poliméricos constitui uma opção para os produtores desta matéria prima que teriam assim um produto com maior valor agregado. Este trabalho visa avaliar o potencial uso como nanocarga de duas argilas nacionais provenientes da Bacia de Taubaté, São Paulo, denominadas ALIGRA e SANTA FÉ. As frações de tamanho de partícula médio menor de 0,02 mm, obtidas por peneiramento á úmido da argila homogeneizada e seca, foram utilizadas no desenvolvimento do trabalho experimental. Os estudos de caracterização, envolvendo análise granulométrica, química, mineralógica, morfológica, térmica e textural, revelaram características muito semelhantes em ambas às argilas. Fração argila, maior de 70% em massa. Composição química conforme a definição química de uma argila e os teores de seus componentes mostram valores intermédios entre as apresentadas pelas bentonitas e argila caulinítica usadas com fins de comparação. Ressaltamse boas propriedades adsorventes. Área superficial específica BET ao redor de 120 m2/g, valor maior do que o apresentado por muitas bentonitas naturais (74,5 m2/g). Predominantemente mesoporosas, com poros, maiormente em forma de fenda, característicos da estrutura em camadas das argilas. Baixa capacidade de troca catiônica, 12 meq/100g. Difratogramas de raios-X revelaram a predominância do estratificado ilita/esmectita, caulinita e quartzo na argila ALIGRA, e de ilita, caulinita e quartzo na argila SANTA FÉ. Prosseguiu-se com a argila ALIGRA a preparação da argila organofílica. A argila organofílica foi obtida por troca catiônica com o sal quaternário de amônio: cloro cetril trimetil amônio, depois de homogeneizada em sódio com cloreto de sódio. Análises FTIR e TGA indicaram que houve inserção dos cátions orgânicos. Testes preliminares foram feitas, preparando misturas das argilas com matriz de polipropileno e usando como agente compatibilizante polipropileno enxertado com anidrido maleico. Resultados de ensaios de tração reportam algumas melhoras nas propriedades testadas com as composições preparadas com as argilas purificadas. Com as composições com argilas organofílicas somente foi melhorado o alongamento na rotura. Estudos ais aprofundados são recomendados. / Brazil is a producer of clay and has large reserves of this natural resource. However, most of its production is sold dried and milled." The development of clays for use as reinforcement in polymer nanocomposites is an option for these raw material producers, who would thus have a product with higher added value. This study aims to evaluate the potential use as nanofiller of two national clays from Taubaté basin, São Paulo, called ALIGRA and SANTA FE. In this experiment, the fractions of particles with average size of less than 0.02 obtained through wet sieving were used. The characterization studies involving granulometric, chemical, mineralogical, morphological, thermal and textural analysis, revealed very similar characteristics in both the clays. Clay fraction (< 2&#956;m) is higher 70%. Chemical composition as the definition of clay and its components show intermediate values between those present by bentonite and kaolinitic clays used here for purposes of comparison. It should be underlined good adsorptive properties. Specific surface area BET (aBET) around of 120 m2/g, this value is higher than showed by many bentonites (74.5 m2/g). They are predominantly mesoporous, the pores predominantly in slit-shape in accordance to the characteristic layered structure of the clays. Low cationic exchange capacities (CEC), 12 meq/100 g. XRD results for samples saturated with ethylene glycol and heated revealed the predominance of illite/smectite, kaolinite and quartz in ALIGRA clay, and illite, kaolinite and quartz in the clay SANTA FE. Work continued with the clay ALIGRA the preparation of organoclay. The organoclay was obtained by ion exchange with the quaternary ammonium salt: cetril trimethyl ammonium chloride, after homogenized in sodium with sodium chloride. FTIR and TGA analyzes indicated that there was integration of organic cations Preliminary tests were performed by preparing mixtures of clays with a polypropylene matrix, and using polypropylene grafted with maleic anhydride as a compatibilizer. Results of tensile tests made in the polypropilene- purified clay compositions have reported some improvements in some tested properties. With polipropilene-organofilized compositions only improved elongation on break. More detailed studies are which would be required.

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No description available.