Ce travail est consacré à l'étude de la sorption d'eau et du gonflement des argiles (bentonite MX80 et argilites du Bassin de Paris). On propose une nouvelle approche par microscopie électronique à balayage environnementale (ESEM) couplée à l'analyse digitale d'image pour estimer le gonflement en fonction du temps et de l'humidité relative. L'ESEM est un outil de nouvelle génération encore peu utilisé dans le domaine des argiles, qui permet d'étudier des matériaux hydratés dans différentes conditions d'humidités relatives. Dans ce travail on montre qu'il est possible d'obtenir des informations qualitatives et quantitatives sur le gonflement des argiles à l'échelle de l'agrégat. L'étude de la cinétique permet ainsi d'identifier trois étapes de gonflement, dont l'étape de gonflement proprement dite, décrite par un modèle cinétique de premier ordre. <br />L'étude de la sorption d'eau de la bentonite brute et échangée avec différents cations (Na+, Li+, K+, Ca++, Mg++) a permis d'aborder l'influence des cations sur le potentiel de gonflement. La cinétique d'adsorption, décrite par un modèle de deuxième ordre dépend directement de l'humidité relative, de la masse de l'échantillon et du cation compensateur. <br />L'étude de la texture en conditions sèches et humides de la bentonite MX80 compactée a permis d'observer l'évolution morphologique du réseau poreux (macroporosité) au cours de l'hydratation/ déshydratation. A partir de différentes approches analytiques on constate une diminution de la taille des macropores et/ou mésopores, et l'ouverture de pores inter- agrégats lorsque la densité apparente augmente. <br />L'étude de l'influence de la condensation/ évaporation instantanée d'eau sur les argilites montre que la sensibilité à l'eau augmente lorsque la proportion argileuse augmente; elle est marquée entre autres par une fissuration qui peut être partiellement réversible ou irréversible après quelques cycles de condensation/ évaporation.

Bentonite clays are exposed in Paleogene strata stretching over 650 km parallel to the Texas coastline. This study focuses on a white and blue and a yellow and brown commercial Ca-montmorillonite bentonite near the city of Gonzales, Gonzales county, Texas. The deposits have stratigraphic ages of Late Eocene (~36.7 - 32.7 Ma). The bentonites in these deposits have varying colors, purities and brightness affording them diverse industrial uses. The distribution and geologic character of the high purity white and blue bentonite suggests that the deposit represents an accumulation of volcanic ash in a secondary tidal channel during the ash-fall event. A low rate of terrigenous clastic sedimentation and rapid accumulation of fresh ash were critical to the formation of high purity clay. The lower purity yellow and brown bentonites appear to have a fluvial origin marked by higher rates of detrital sedimentation and episodic accumulation of clay and ash. The bentonite and associated strata were studied using optical microscopy, SEM, XRD and REE analyses to constrain their textural, mineralogic, and chemical character. vii Eocene pyroclastic volcanism is well documented from sources in southwestern North America, specifically in the Sierra Madre Occidental (Mexico), Trans-Pecos (Texas) and Mogollan-Datil (New Mexico) volcanic fields. Projected Eocene wind patterns support this region as a potential source for the Gonzales bentonites. A comparison of the trace and REE fingerprints of the white and blue bentonites and the yellow and brown bentonites with data available for Late Eocene volcanics in the North American Volcanic Database provides a couple of potential matches. The strongest potential match for the Late Eocene bentonite protolith is described as a sample of silicic tuff with an age range of 32.2 – 30.6 Ma, located in the southern Mexican state of Oaxaca. While the trace and REE match is strong, the tuff is somewhat young compared to the Jackson Group sediments. In addition, the sample location is due almost directly south of the Gonzales deposits, rather than the western location expected for a Gonzales bentonite source. The other potential matches are located in New Mexico, and the Mexican state of Chihuahua. These potential matches only have 6 REE available for comparison, and require further investigation. Many Paleogene volcanic units in southern North America are undocumented with regard to REE data or precise absolute ages. As additional geochemical analyses become available for a more extensive suite of Paleogene volcanic units, stronger matches with Gulf of Mexico Basin bentonites are expected to emerge. / text

Ce travail est une contribution expérimentale à l'étude rhéologique et en écoulement de fluides complexes (à seuil et thixotropes) transitant dans un circuit hydraulique. Il s'agit notamment de suspensions de bentonite ainsi que des complexes bentonite/polymère. L'étude porte sur l'évolution des pertes de charge et des champs de vitesse et se situe en régime laminaire, transitoire et turbulent. L'étude a été réalisée en utilisant un vélocimètre ultrasonore Doppler pulsé développé au laboratoire. Dans la première partie expérimentale de la thèse, des mesures rhéologiques et en écoulement ont été effectuées sur des suspensions de bentonite pures (sans additifs) à différentes concentrations. A partir des essais sur boucle hydraulique, une étude détaillée est présentée sur l'évolution des coefficients de frottement et des profils de vitesse pour les différents régimes d'écoulement. Dans une seconde partie, une suspension de bentonite pure et des mélanges bentonite/CMC à différentes concentrations massiques ont été étudiées en termes de comportement rhéologique et hydrodynamique en écoulement en conduite. En ce qui concerne les mesures effectuées en boucle hydraulique, il a été montré que le polymère a des propriétés viscosifiantes en régime laminaire. Par contre, en régime turbulent, le polymère agit comme un réducteur de frottement. La dernière partie de la thèse a été consacrée à l'étude de l'influence de la température sur le comportement rhéologique des solutions de polymère et des mélanges argile/polymère. Les mesures rhéologiques à différents paliers de températures ainsi que les balayages en température ont mis en évidence le caractère thermodépendant des dispersions.

En France, le système de stockage profond de déchets radioactifs envisagé est constitué d'une barrière naturelle (roche hôte argileuse, argilite) et de barrières artificielles, comprenant des bouchons d'argile gonflante (bentonite)-sable pour son scellement. L'objectif de cette thèse est d'étudier l'efficacité du gonflement et du scellement des bouchons placés dans l'argilite, sous l'effet, à la fois, d'une pression d'eau et d'une pression de gaz (tel que formé dans le tunnel). Pour évaluer la capacité de scellement du bouchon bentonite/sable partiellement saturé en eau, on a évalué sa perméabilité au gaz Kgaz sous pression de confinement variable (jusqu'à 12MPa). L'étanchéité au gaz (Kgaz < 10-20m2) est obtenue sous confinement Pc≥9MPa si la saturation est d'au moins 86-91%. Par ailleurs, nous avons évalué le gonflement et l'étanchéité du bouchon de bentonite-sable imbibé d'eau dans un tube d'argilite ou de Plexiglas-aluminium lisse ou rugueux. La présence de gaz diminue la pression effective de gonflement (et la pression de percée de gaz) à partir d'une pression Pgaz= 4 MPa. Après saturation complète en eau, l'écoulement continu de gaz au travers du bouchon seul se fait à Pgaz=7-8MPa s'il dispose d'une interface lisse avec un autre matériau (tube métallique), alors que celui au travers de l'ensemble bouchon/argilite a lieu à Pgaz=7-7,5MPa. Le passage à travers le bouchon gonflé au contact d'une interface rugueuse se fait à une pression de gaz bien supérieure à la pression de gonflement du bouchon. Les essais de percée de gaz montrent que l'interface et l'argilite sont deux voies possibles de migration de gaz lorsque l'ensemble bouchon/roche hôte est complètement saturé

The potential use of Resadiye/Tokat bentonite as a reinforcement in polypropylene (PP) and linear low density polyethylene (LLDPE) polymer matrix nanocomposites filler was investigated. At first, organoclays (OC) were prepared by cation exchange reaction (CER) between the raw bentonite (RB) and three quaternary ammonium salts with long alkyl tails (QA): hexadecyl trimethyl ammonium bromide [HMA] [Br], tetrabutyl ammonium tetrafluoroborate [TBA] [BF4], tetrakisdecyl ammonium bromide [TKA] [Br] and one quaternary phosphonium (QP) salt: tetrabutyl phosphonium tetrafluroborate [TBP] [BF4]. Characterization of resulting materials by XRD, TGA, FTIR and chemical analysis confirmed the formation of organoclays. Ternary composites of PP/organoclay/ maleic anhydride grafted polypropylene (MAPP) were prepared with two different grades of PPs in a co-rotating twin screw extruder. Composites prepared with these organoclays and PPs showed microcomposite formation. In the second part of the study, raw bentonite was purified by sedimentation, and characterization of purified bentonite (PB) by XRD, cation exchange capacity (CEC) measurement and chemical analysis (ICP) confirmed the success of purification method. PB was then modified with two QA`s: dimethyl dioctadecylammonium chloride [DMDA] [Cl], tetrakis decylammonium bromide [STKA] [Br] and one QP: tributyl hexadecyl phosphonium bromide [TBHP] [Br]. Organoclays from PB were used with the PP with lower viscosity, and ternary nanocomposites (PP/Organoclay2/MAPP5) were prepared in the extruder followed by batch mixing in an intensive batch mixer. Use of DMDA and TBHP OCs resulted in nanocomposite formation, while STKA resulted in microcomposite formation as observed by XRD and TEM. Young`s modulus and yield stress of the samples were enhanced through nanocomposite formation. In the last part of the study, ternary composites of LLDPE/Organoclay/ compatibilizer, a random terpolymer of ethylene, butyl acrylate and maleic anhydride (E-BA-MAH, Lotader&reg / 3210), were prepared by melt compounding in the batch mixer at two different clay concentrations (2 and 5 wt %) and fixed compatibilizer/organoclay ratio (&alpha / =2.5). A commercial organoclay, I34, was also used in LLDPE based nanocomposites to make a comparison. XRD and TEM analyses of the compounds prepared by DMDA and TBHP showed mixed nanocomposite morphologies consisting of partially intercalated and exfoliated layers. Young`s modulus and tensile strength of nanocomposites prepared with DMDA and TBHP showed generally higher values compared to those of neat LLDPE, while results were the highest in the composites prepared with commercial organoclay I34. Parallel disk rheometry was used as a supplementary technique to XRD, TEM and mechanical characterizations, and it was shown to be a sensitive tool in assessing the degree of dispersion of clay layers in the polymer matrix.

Particles and macromolecular components, including biopolymers (protein and carbohydrate), are viewed as the main foulants in the complex feed submerged membrane filtration systems such as membrane bioreactor (MBR). This work focused on two aspects of fouling in complex fluids: 1- Assessing fouling propensity and mechanisms for various model solutions. 2- Using of two specific solutions modelling biomass found in MBR for a better understanding of the fouling mechanisms in submerged MBR processes. Filtrations were carried out with 0.22 ??m PVDF hollow fibre membrane. Alginate was used as a model for polysaccharide, bovine serum albumin (BSA) as a model for protein, (un)washed yeast and bentonite were representing suspended solid contents. According to the data obtained during this study the fouling propensity of each model solution was classified as follow in a decreasing order: Alginate &gt unwashed yeast &gt washed yeast &gt BSA &gt bentonite for one-component solutions; and Alginate-washed yeast &gt Alginate-BSA &gt Alginate-bentonite &gt Alginate-unwashed yeast for two-component solutions. Introducing the alginate increased the reversible fouling (except BSA). Passive adsorption had a significant effect on fouling of alginate even before the beginning of the filtration. Washed yeast and a mixture of washed yeast + BSA were then used as model solutions to simulate the activated sludge found in MBR. The concentration of washed yeast and BSA used in this study were calculated in order for the characterisations of the two model solution to match (in terms of biopolymer contents) those of MBR biomasses reported in the literature. By rinsing, backwashing and chemical cleaning of the membrane, three fouling layers of upper, intermediate and lower were defined respectively. Results obtained from the analysis of the biopolymers found in the cleaning solutions allow a better understanding of the fouling mechanisms occurring for the two model solutions used in this study: for washed yeast, the lower layer and for washed yeast + BSA , the upper and intermediate layers were found to have relatively high biopolymeric composition. This was explained by higher concentration of solids on the membrane surface and by higher biopolymer interactions when washed yeast was mixed with BSA.

Abstract The chemical characteristics of spent wash, an effluent from the distillation of ethanol from molasses, can vary, depending on the initial feed stock and the operations of the factory. Spent wash from Australia contained large quantities of dissolved organic carbon (DOC), K, N and Cl with moderate to low concentrations of Ca, Mg, Na, and S, and small amounts of trace elements (Fe, Al, Mn, Cu, Zn). Spent wash from Thailand was obtained from whisky distillation and generally had similar chemical attributes to the spent wash from ethanol production, although the Zn concentration was much higher (399-974 mg Zn L-1). Large differences in EC and pH were found between Australian (pH: 4.08-4.49; EC: 40.4-42.2 dS m-1) and Thai spent wash (pH: 7.86-9.20; EC: 11.3-82.4 dS m-1). However, the high concentration of K in spent wash from both manufacturing processes indicates the unique chemical characteristic of wastewater produced from molasses-based distillation. While chemical characterisations of spent wash have shown its potential value as a fertilizer, its utility needs to be more practical than by direct application. This is due to its dilute nature, associated with the presence of organic carbon (OC) and nutrients in soluble form, thus making direct application susceptible to leaching losses of nutrients, especially in soils of low cation exchange capacity (CEC). It was hypothesized that capturing OC and nutrients on a high activity exchanger would overcome this problem. Since the charge on organic components in spent wash is important to the capturing process, pH manipulation is one of the major factors affecting the efficiency of this capture. The study of the influence of pH on development of charge on organic components in spent wash was undertaken using potentiometric titration. The potentiometric titration, and derived pH buffer curve, showed that the organic components in spent wash comprised a wide range of ionizable organic functional groups behaving like a mix of weak acids. While the inflection point (s) could not be obtained from the potentriometric titration, the absorbance of spent wash in the UV waveband (250 to 400 nm) confirmed the presence of phenolic groups in spent wash. The charge on organic components in spent wash was strongly pH dependent, and highest in the pH range of 4.0-5.0. The manipulation of pH and salt concentration (EC) was shown to have an effect on flocculation/dispersion and it is inferred that this was due to changes in the molecular arrangement of organic components in spent wash. A coiled configuration is suggested at acidic pH, whereas a linear flexible configuration and macromolecular structure tending to occur at neutral and alkaline pH respectively. Ca-saturated bentonite, originally sourced from Mantuan Downs, Central Queensland, was used in an investigation of the capture of OC and nutrients from Sarina spent wash at different pH values (4.5, 6.0, 8.0). This study demonstrated that manipulation of pH and electrolyte concentration had a small effect on adsorption of OC by the clay, probably the result of effects on the charge characteristics of both clay mineral surfaces and organic molecules and also on molecular sizes of the dissolved organic matter (DOM). The highest absorption of OC was only 28% for dewatered spent wash, suggesting Ca-saturated bentonite may not be a strong sorbent for DOM from a wastewater of high EC and which contains high concentration of DOC of the composition found in spent wash. The study of the adsorption of K by bentonite in a pure inorganic system (without DOM) indicated sufficiently high concentrations of K can compete with divalent Ca2+ for exchange sites on the clay surface. The adsorption of K in an organic system (the DOM component in spent wash) showed that DOM had a positive influence on adsorption of inorganic ions (e.g. K+). Characterisation of the spent wash/ clay mixture demonstrated its potential to be used as a soil ameliorant on the basis of the large quantity of OC and nutrients it contained (especially N and K). Wet and dry organic clays were produced and assessed as ameliorants in a glasshouse trial using forage oat (Avena sativa var. Coolobah) as test species. This pot study indicated a positive influence of application of either wet or dry organic clay on crop biomass at the high application rate (equivalent to 40 tonnes ha-1). The high proportional K recovery from this high application rate application suggests that organic clays can be used as K fertilizer. The crop nutrient uptake data also indicated its use as a source of S and Mn.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-09T18:53:27Z No. of bitstreams: 1 CRISTIANE HENRIQUE DA SILVA - DISSERTAÇÃO PPG-CEMat 2014..pdf: 1882367 bytes, checksum: 61c1cc3ebbf9ac5089a587fe51bfa458 (MD5) / Made available in DSpace on 2018-04-09T18:53:27Z (GMT). No. of bitstreams: 1 CRISTIANE HENRIQUE DA SILVA - DISSERTAÇÃO PPG-CEMat 2014..pdf: 1882367 bytes, checksum: 61c1cc3ebbf9ac5089a587fe51bfa458 (MD5) Previous issue date: 2014-08-29 / Capes / Este trabalho apresenta um estudo sobre a influência da incorporação de argila bentonítica e carbonato de cálcio sobre as propriedades de um fluido de perfuração sintético n-parafina. Para tanto, a pesquisa utilizou argila bentonítica com tamanho de partícula de 45 µm e 75 µm e carbonato de cálcio com tamanhos de partículas nas faixas de 2-44 µm e 2-74 µm para analisar os efeitos da incorporação de sólidos. A análise da influência destes contaminantes foi realizada nas concentrações de 5%, 10% e 15% do volume da amostra de fluido (350 mL) considerados em massa. Para estudar a influência desses contaminantes foram determinadas, em laboratório, as propriedades: densidade, estabilidade elétrica, resistividade elétrica, comportamento de fluxo, viscosidade plástica, viscosidade aparente, limite de escoamento, força gel, volume de filtrado. Além desses ensaios, também foi realizada a caracterização dos contaminantes por meio da análise granulométrica e do teste de ângulo de contato. Os resultados obtidos demonstraram que o tipo de sólido contaminante exerce diferente influência sobre as propriedades do fluido, sendo a argila bentonítica responsável por maiores efeitos sobre as propriedades reológicas e o volume de filtrado, enquanto que, o carbonato de cálcio exerce maior influência sobre a densidade e a estabilidade elétrica. Mas, de maneira global a argila bentonítica exerce maior influência sobre todas as propriedades. Partículas mais finas causam maior efeito sobre as propriedades estudadas. Com relação aos teores dos contaminantes observou-se que o volume de filtrado é a propriedade que sofre maiores efeitos. Porém, o aumento ou a diminuição de uma ou outra propriedade não ocorre de maneira linear com relação ao aumento do teor de contaminante. / This work presents a study about the influence of the incorporation of bentonite clay and carbonate calcium in n-paraffin synthetic drilling fluids properties. Thus, the research uses bentonite clay with particle size of 45 µm and 75 µm, besides calcium carbonate with particle sizes in the ranges of 2-44 µm and 2-74 µm to simulate the effects of the solid incorporation. The analysis of the influence of such contaminants is performed in the concentrations of 5%, 10% and 15% of the volume of the fluid sample (350 mL) considered by mass. To study the influence of these contaminants the density, electrical stability, electrical resistivity, flow behavior, plastic viscosity, apparent viscosity, yield point, gel strength, and volume filtered properties of the n-paraffin synthetic fluids are measured in laboratory. In addition to these tests, the characterization of contaminants through granulometric analysis and contact angle test is also performed. The results show that the type of solid contaminant exerts different influence on the fluids properties. The bentonite clay is responsible for the greatest effect on the rheological properties and the volume of the filtrated, while the calcium carbonate is more influent on the density and electrical stability. However, globally the bentonite clay exerts greater influence on the all properties. Finer particles cause greater effect on the studied properties. With respect to the concentration of contaminants is observed that the volume of filtrated is the property that suffers the greatest effect. However, the increase or decrease of one or other property does not occur linearly with respect to increasing the amount of contaminant.

Submitted by Deyse Queiroz (deysequeirozz@hotmail.com) on 2018-06-13T13:49:19Z No. of bitstreams: 1 GILVANISE ALVES TITO - TESE PPGEA 2009..pdf: 11064945 bytes, checksum: bac5edce5a2a3875418ba29344312d3e (MD5) / Made available in DSpace on 2018-06-13T13:49:19Z (GMT). No. of bitstreams: 1 GILVANISE ALVES TITO - TESE PPGEA 2009..pdf: 11064945 bytes, checksum: bac5edce5a2a3875418ba29344312d3e (MD5) Previous issue date: 2009-09 / A contaminação dos solos por metais pesados tem sido um problema crescente ao meio ambiente e à saúde das pessoas em função da alta toxicidade, razão por que a ciência busca alternativas que possam impedir ou pelo menos minimizar os efeitos poluidores desses metais ou, ainda, remediar os ambientes já contaminados. Assim, vários estudos utilizando matérias adsorventes estão sendo conduzidos como forma de reduzir os efeitos poluidores desses metais. E importante conhecer o processo de adsorção de metais pesados por minerais de argila, uma vez que estes são capazes de imobilizar referidos metais. No presente trabalho avaliou-se, através de três experimentos, a capacidade da bentonita na remediação de solos contaminados com zinco e cobre. O primeiro experimento consistiu no estudo da adsorção desses metais pela bentonita, em pH 4; 5 e 6, utilizando-se os modelos matemáticos de Langmuir e Freundlich. A partir de experimentos tipo "batch" foram elaboradas isotermas de adsorção com quantidades crescentes de zinco e cobre (5; 10; 20; 30; 50; 100; 150 e 200 mg L"1); o segundo experimento consistiu no estudo da mobilidade de zinco e cobre em colunas de lixiviação, preparadas com solo e doses crescentes de bentonita (0; 30 e 60 t ha"1). Os parâmetros de transporte foram calculados através do modelo computacional DISP. No último experimento avaliou-se, em casa de vegetação, o efeito das doses de zinco e cobre (50; 250 e 450 mg kg"1) e de bentonita (0; 30 e 60 t ha"1), adicionados ao solo, na produção de fitomassa e composição mineral do feijoeiro. Terminado o experimento (65 dias), foram determinadas as concentrações do zinco e do cobre nas partes aéreas e nas raízes das plantas e no solo das unidades experimentais, cujos resultados permitiram concluir que a incorporação de bentonita ao solo aumentou a adsorção do zinco e do cobre e que esta adsorção é dependente do pH da solução; que os modelos de Langmuir e Freundlich se apresentaram adequados para descrever a adsorção desses metais; que o tamanho das partículas da bentonita não influenciou na adsorção e a incorporação de bentonita ao solo contribuiu para diminuir a concentração e o acúmulo dos metais zinco e cobre, nas plantas de feijão-macassar. / The contamination of soil by heavy metais has been a growing problem to the environment and to the people's health in function of their toxicity, that has induced the science to search alternatives to prevent, or at least, minimize the pollutant effects of those metais or still, remediate the already polluted environment. Thus, several studies using sorbent materiais are conducted aiming to reduce the pollution problems produced by the excess of heavy metais. It is important to know the process of adsorption of heavy metais by clay minerais, because these are capable to immobilize such metais. The present study was carried out aiming, through three experiments, to evaluate the ability of the bentonite clay on the remediation of soils contaminated with zinc and copper. The fírst experiment consisted in studying the adsorption of these metais by bentonite at pH 4; 5 and 6, using the mathematical models of Langmuir and Freundlich. Adsorption isotherms were elaborated from batch adsorption assays, with increasing zinc and copper concentrations (5; 10; 20; 30; 50; 100; 150 and 200 mg L"1); the second experiment consisted in studying the zinc and copper mobility through leaching columns, prepared with soil and increasing bentonite leveis (0; 30 and 601 ha"1). The transport parameters were calculated using the computer model DISP. Finally, a greenhouse experiment was conducted to evaluate the effects of zinc and copper (50; 250 and 450mg kg"1) and bentonite (0; 30 and 60 t ha"1) added to the soil, on the phytomass production and mineral composition of a bean plant (Vigna unguiculata.h). At the end of the experiment (65 days) the phytomass and the content of zinc and copper in the aerial part, in the roots and in the soil were determined. It was observed that the adsorption of the elements increased with the bentonite application being dependent of the pH of the solution; the two studied models are appropriate to describe the zinc and copper adsorption for the bentonite; the granulometric size of the bentonite does not influence the metais adsorption and that the application of bentonite to the soil contributed to the decrease the concentration and accumulation of the heavy metais in the bean plant.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-14T20:08:14Z No. of bitstreams: 1 TATIARA GOMES DE ALMEIDA – DISSERTAÇÃO (PPG-CEMat) 2015.pdf: 3847734 bytes, checksum: 33a29fced4bd93aef9e1714ea5787ad1 (MD5) / Made available in DSpace on 2018-06-14T20:08:14Z (GMT). No. of bitstreams: 1 TATIARA GOMES DE ALMEIDA – DISSERTAÇÃO (PPG-CEMat) 2015.pdf: 3847734 bytes, checksum: 33a29fced4bd93aef9e1714ea5787ad1 (MD5) Previous issue date: 2015-02-12 / Capes / O efeito da incorporação, purificação e organofilização de uma carga mineral nanoparticulada (argila bentonítica), nas propriedades mecânicas, térmicas e morfológicas de sistemas PHB poli(3-hidroxibutirato)/bentonita com concentrações de argila variando de 1 a 3% em massa foi avaliado. As argilas bentoníticas nas suas formas natural, purificada por ultrassom e organofílica com sal Cetremide, foram caracterizadas por FTIR e DRX antes de serem incorporadas ao PHB. As composições obtidas foram caracterizadas por difração de raios X (DRX), calorimetria exploratória diferencial (DSC), análise dinâmico-mecânica (DMA), microscopia eletrônica de varredura (MEV) e propriedades mecânicas. Os resultados mostraram que a purificação e organofilização da argila foram eficientes. A incorporação da argila organofílica ao PHB provocou um aumento no módulo de elasticidade e armazenamento. As resistências à tração e ao impacto diminuíram com a adição das nanocargas. As propriedades mecânicas dos compósitos foram significativamente afetadas pela exposição prolongada a temperaturas elevadas. Os resultados obtidos sugerem que a incorporação da argila organofílica ao PHB acelera o processo de degradação térmica da matriz. / The influence of addition, purification and organophilization of a nanoparticulate mineral filler (bentonite clay) on the mechanical, thermal and morphological properties of PHB (polyhydroxybutyrate)/bentonite with concentrations ranging from 1 to 3% w/w was investigated. Pristine, purificed (sonication) and organophilic (Cetremide) bentonite clays, were characterized by FTIR and XRD before being incorporated into the PHB. The compositions were characterized with X-ray diffraction (XRD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM) and mechanical properties. Results showed that the purification and organophilization clay were effective. The incorporation of the organoclay to PHB caused an increase in tensile and storage modulus, while tensile and impact strength decreased with clay addition. Mechanical properties were significantly affected by prolonged exposure to elevated temperatures. Results suggest that the incorporation of the organoclay to PHB accelerates the thermal degradation of the polymer.