Made available in DSpace on 2017-05-12T14:48:22Z (GMT). No. of bitstreams: 1 tatiane_texto.pdf: 2558616 bytes, checksum: c23ff4ce31df2fb07ce669109433709c (MD5) Previous issue date: 2011-08-08 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Swine wastewater application into soil to reuse water on cropping provides the addition of total and dissolved organic matter to soil, which interferes in the dynamics of pesticides in soil. This study aims at evaluating the effects of total and dissolved organic matter application from two systems of swine wastewater, biodigestor and lagoon treatments, in alachlor sorption, desorption, leaching and formation of bound residues into soil. The batch method was used to test sorption and desorption and the results were presented in Freundlich isotherms. The evaluation of miscible displacement of alachlor, in soil treated with total and dissolved organic matter, was performed by disturbed soil columns, by monitoring the concentration of alachlor in leachate, total organic carbon and pH. Extraction and quantification of desorption, extractable and bound residues were carried out. After that, it was registered the chemical fractionation of humic substances in extracts containing organic matter of low molecular weight, humic acids and fulvic acids, which were characterized by infrared spectroscopy and total organic carbon concentration. The swine wastewater addition promoted greater sorption and desorption of alachlor compared to Control. The dissolved organic matter promoted less sorption of alachlor in soil when compared to total organic matter, resulting in an increased leaching of alachlor. The dissolved organic matter did not show desorption residues, only extractable ones. The highest amount of total organic carbon was in organic matter of low molecular weight, spectroscope characterized, by the presence of carboxylate anions, which are important in sorption process. The total organic matter has contributed to the emergence of new sorption sites in soil column and the solids present in its composition blocked the movement of pesticide, resulting in lower leaching of alachlor. The dissolved organic matter interacted with alachlor and / or competed with the sorption sites of soil, promoting greater losses by leaching of this herbicide. / A aplicação de água residuária de suinocultura ao solo como reúso de água na agricultura resulta na adição de matéria orgânica total e dissolvida, que interferem na dinâmica dos pesticidas no solo. Objetivou-se avaliar o efeito da aplicação de matéria orgânica total e dissolvida proveniente de dois sistemas de tratamento de água residuária de suinocultura, biodigestor e esterqueira, na adsorção, dessorção, lixiviação e formação de resíduos ligados de alaclor no solo. O método do equilíbrio foi utilizado para o teste de adsorção e dessorção e os resultados foram apresentados em isotermas de Freundlich. A avaliação do deslocamento miscível do alaclor no solo tratado com matéria orgânica total e dissolvida foi realizada por ensaios em colunas de solo deformado, monitorando-se a concentração de alaclor no lixiviado, teor de carbono orgânico total e pH. Realizou-se a extração e quantificação dos resíduos dessorvíveis, extraíves e ligados do solo. Na sequência, fez-se o fracionamento químico das substâncias húmicas em extratos contendo matéria orgânica de baixo peso molecular, ácidos húmicos e ácidos fúlvicos, que foram caracterizados por espectroscopia infravermelha e pela concentração de carbono orgânico total. A adição de água residuária de suinocultura promoveu maior adsorção e dessorção do alaclor comparado ao Controle. A matéria orgânica dissolvida promoveu menor adsorção de alaclor ao solo comparada à total, resultando em maior lixiviação. A matéria orgânica dissolvida não apresentou resíduos dessorvíveis, apenas extraíveis. A maior quantidade de carbono orgânico total esteve presente na matéria orgânica de baixo peso molecular, caracterizada espectroscopicamente, pela presença de ânions carboxilatos, importantes no processo de adsorção. A matéria orgânica total contribuiu com o surgimento de novos sítios de sorção na coluna de solo e os sólidos presentes em sua composição bloquearam a passagem do pesticida, resultando em menores perdas de alaclor por lixiviação. A matéria orgânica dissolvida interagiu com o alaclor e/ou competiu com os sítios sortivos do solo, promovendo maiores perdas deste herbicida por lixiviação.

O objetivo desse projeto foi o de produzir sílica mesoporosa ordenada (SMO) do tipo SBA-15 com fósforos. A incorporação dos fósforos às paredes da sílica foi realizada através de um único processo de síntese. Os métodos experimentais utilizados para caracterização das amostras foram: RBS (Rutherford Backscattering Spectrometry) para a análise química, SAXS (Small Angle X Ray Scattering), XRD (X Ray Diffraction) e NAI (Nitrogen Adsorption Isotherms) para a análise estrutural destes materiais, além da fotoluminescência. Para a caraterização morfológica complementar das amostras, foi utilizado o SEM (Scanning Electron Microscopy). A incorporação de Eu na matriz de sílica preserva a estrutura de poros ordenada. Os resultados de XRD mostraram a formação de óxidos de európio. A partir dos resultados obtidos observaram-se diferentes efeitos da presença e ausência de sobrenadante durante o período de secagem nas amostras preparadas, como por exemplo, alterações de morfologia. As amostras preparadas com sobrenadante apresentaram menor área superficial e volume de poros. Materiais que mantiveram o sobrenadante apresentaram maior conteúdo de Eu e maior intensidade de luminescência. / The aim of this project was to synthesize ordered mesoporous silica (OMS) with phosphorus. The incorporation of phosphorus to the silica walls was performed by means of a one pot synthesis process. The experimental methods used to characterize the samples were: RBS (Rutherford Backscattering Spectrometry) for chemical analysis, SAXS (Small Angle X Ray Scattering), XRD (X Ray Diffraction) and NAI (Nitrogen Adsorption Isotherms) for structural analysis, besides fluorescence. SEM (Scanning Electron Microscopy) was used for complementary morphological characterization of the samples. The Eu incorporation in the silica matrix preserves the ordered mesoporous structure. The XRD results showed the presence of europium oxides. The presence and absence of the liquid solution during the drying process caused the formation of samples with different properties, as, for example, modification in morphology. Samples prepared in the presence of the liquid solutions showed smaller surface area and pore volume. Materials prepared with the liquid solution during the drying process presented larger Eu content and higher photoluminescence intensity.

The aim of this thesis is first and foremost to improve the fundamental knowledge of nonlinear and preparative separation theory by focusing on some of the remaining “white spots” on the theoretical chromatographic map. Secondly, the acquired knowledge is used to develop, validate and execute new methods for phase characterization in liquid chromatography. The methodology used in this thesis is a combination of experiments, fundamental nonlinear theory and systematic computer simulations. A fundamental knowledge of the molecular interactions between the compounds to be separated and the separation media requires the determination of adsorption isotherms over a broad concentration range to give a complete picture of all interactions in the separation system - weak as well as strong. In addition, such adsorption data is essential for optimization in preparative chromatography. For the first time, it has been experimentally shown that the injected molecules are not present in the detected peak when a small excess of molecules are injected into a chromatographic system equilibrated with a constant stream of identical molecules. Several experimental procedures for this method were developed such as (i) the optimal injection strategy and (ii) different labeling methods for visualizing the injected molecules. Remarkable phenomena in the single-component case, such as invisible peak deformation and deformed (invisible) frontal chromatograms, are reported, investigated, and explained. This phenomenon has asides from its future practical implementation, also a large didactic value. The accuracy of the ECP method is experimentally improved, and used to characterize the separation of protolytic compounds at different pH on modern commercially available silica and hybrid silica column packing materials. That investigation enables us to answer why basic compounds give a much more compact preparative peak profile at pH 11 than they yields at lower pH.

<p>Denna avhandling presenterar experimentella studier av polyelektrolytadsorption på motsatt laddade ytor, där substrat av både kiseloxid och blekt barrsulfatmassa har använts. Ett huvudsakligt syfte med denna forskning var att karaktärisera konformationen hos adsorberade skikt av katjonisk polyakrylamid (CPAM) i jämförelse med katjonisk dextran (Cdextran) och relatera denna information till inbindningskapaciteten av kolloidal kiselsyra. Ett andra syfte i denna avhandling var att studera kinetiken för sekventiell adsorption av polyamidamin epiklorhydrin (PAE) och karboxymetyl cellulosa (CMC) på massafibrer och att bestämma adsorptionsisotermer för deponering av polyelektrolyter skikt för skikt på massafibrer.</p><p>Adsorptionen av CPAM på kiseloxidytor studeras med stagnationspunkts-reflektometri och kvartskristalls-mikrogravimetri för att bestämma adsorptionskinetiken och mättnadsadsorptionens beroende av polyelektrolytens laddningstäthet, pH och NaCl koncentration. Konformationen hos adsorberade skikt av CPAM och Cdextran bestämdes både före och efter sekundär tillsats av kolloidal kiselsyra (CS) och adsorptionen av CS kvantifierades också som funktion av yttäckningen av polyelektrolyt.</p><p>Resultaten indikerar att laddningstätheten hos CPAM kontrollerar den adsorberade mängden på kiseloxidytor vid låga NaCl koncentrationer. Både adsorptionen av CPAM och Cdextran på kiseloxid visades vara effektiv i NaCl koncentrationer upp till 1 M, vilket indikerar ett signifikant bidrag av icke-jonisk interaktion mellan polyelektrolyterna och kiseloxid. Adsorptionen av CS var högre på föradsorberad CPAM än Cdextran. Konformationen hos de adsorberade skikten efter tillsats av CS sågs expandera signifikant för skikt baserade på CPAM medan skikt av Cdextran vid låga salthalter verkade återta sin konformation efter en temporär expansion.</p><p>I den andra delen av avhandlingen studerades sekventiell adsorption av PAE och CMC på massafibrer. Adsorptionsisotermer skikt för skikt på avkryllad massa visade att PAE adsorberade i större mängd än CMC, både i hänseende av massa och laddning. Adsorptionen av PAE var signifikant långsammare än CMC och adsorptionstiden till 90% av mättnadsadsorptionen bestämdes till 3 respektive 1 minut. Zetapotentialen för kryll bestämdes för adsorption av de två första polyelektrolytskikten och resultaten tydde på att kryllmaterialet omladdade inom en minut efter tillsatserna av polyelektrolyt. Reflektometriförsök inom sekventiell adsorption av PAE och CMC på kiseloxid antydde att den låga molekylviktsfraktionen av PAE störde uppbyggnaden av polyelektrolyt-multiskikten.</p> / <p>This thesis presents experimental studies of polyelectrolyte adsorption on oppositely charged surfaces, where substrates of both silica and bleached softwood kraft pulp were used. A major aim of this research was to characterise the conformation of adsorbed layers of cationic polyacrylamide (CPAM), in comparison to cationic dextran (Cdextran), and relate this information to the binding capacity of colloidal silica. A second aim in this thesis was to study the kinetics of the sequential adsorption of polyamide epichlorohydrine (PAE) and carboxymethyl cellulose (CMC) on pulp fibres, and to determine the adsorption isotherms for the layer-by-layer deposition of polyelectrolytes on pulp fibres.</p><p>The adsorption of CPAM on silica surfaces was studied using stagnation point adsorption reflectometry and quartz crystal microgravimetry to determine its adsorption kinetics as well as the dependencies of polyelectrolyte charge densities, pH, and NaCl concentration on saturation adsorption. The conformation of adsorbed layers of CPAM and Cdextran, analysed in terms of amount of water and layer thickness, was determined both before and after the secondary adsorption of colloidal silica (CS), and the adsorption of CS was also quantified as a function of the surface coverage of the polyelectrolyte.</p><p>Results indicate that the charge density of CPAM controlled the amount of the polyelectrolyte adsorbed on silica surfaces at low NaCl concentrations. The adsorption of both CPAM and Cdextran on silica was shown to be effective at up to 1 M NaCl concentrations, which indicates that non-ionic interactions between the polyelectrolytes and silica contribute significantly. CS adsorption was higher on pre-adsorbed CPAM than on Cdextran. The conformation of the adsorbed layer after CS addition was seen to expand significantly in CPAM-based layers, while the Cdextran layer appeared to restore its conformation after a temporary expansion at low salt concentrations.</p><p>In the second part of the thesis, the sequential adsorption of PAE and CMC on pulp fibres was determined using the polyelectrolyte titration technique. Layer-by-layer adsorption isotherms derived on fractionated pulp showed that PAE adsorbed in higher amounts than CMC did, both in terms of adsorbed mass and adsorbed charge. The adsorption of PAE was significantly slower compared to CMC, and the adsorption times required to reach 90% of the saturation adsorption were 3 and 1 min, respectively. The zeta potential of pulp fines was determined for the adsorption of the two first polyelectrolyte layers, and data indicated that the fines recharge within one minute after the polyelectrolyte additions. Reflectometry experiments regarding the sequential adsorption of PAE and CMC on silica indicated that the low-molecular-weight fraction of PAE disturbed the formation of polyelectrolyte multilayers.</p>

This thesis examines the use of electrochemically treated viscose rayon based activated carbon cloth (ACC) for the removal of metal ions from aqueous effluent streams. Two types of treatment were performed: (i) electrochemical oxidation and (ii) electrochemical reduction to enhance cation and anion sorption capacities of the ACC, respectively. Electrochemical oxidation resulted in a loss of 61% BET surface area due to blockage of pores through formation of carboxylic acidic groups but its cation exchange capacity and oxygen content increased by 365% and 121%, respectively. The optimum constant current at which a combination of applied current and oxidation time at any extent of oxidation to produce ACC of maximum cation exchange capacity was found to be 1.1 A, with voltage of 4.2 V and current density of 0.8 mA/m2. Batch sorption experiments showed that the maximum copper and lead sorption capacities for electrochemically oxidised ACC increased 17 and 4 times, respectively, for noncompetitive sorption and 8.8 and 8.6 times, respectively for competitive sorption. Therefore, electrochemically oxidised ACC is an effective adsorbent for treating aqueous solution contaminated with copper/lead in both single component and multi-component systems. Industrial wastewaters are multicomponent systems, therefore, electrochemical oxidation of ACC is an efficient way of enhancing lead and copper ions sorptive capacity for industrial wastewater treatment. Electrochemical reduction resulted in a loss of 28% BET surface area due to formation of ether groups but its anion exchange capacity increased by 292%. The optimum constant current at which a combination of applied current and reduction time at any extent of reduction to produce ACC of maximum anion exchange capacity was found to be 5.5 A, with voltage of 9.8 V and current density of 6.4 mA/m2. Batch sorption experiments showed that the maximum chromium(VI) sorption capacity for electrochemically reduced ACC increased 2.12 times, with highest maximum chromium(VI) sorption capacity of 3.8 mmol/g at solution pH 4. Most industrial wastewaters contaminated with chromium(VI) are highly acidic, therefore, electrochemical reduction of ACC is an efficient way of enhancing chromium(VI) sorptive capacity for industrial wastewater treatment.

This thesis studied the viability of recycling filter substrates as soil amendments after being used in on-site systems for phosphorus (P) removal from wastewater. Focus was put on the materials Filtra P and Polonite, which are commercial products used in compact filters in Sweden. A prerequisite for this choice was to review filter materials and P sorption capacity. The filter substrates (Filtra P, Polonite and wollastonite tailings) were recycled from laboratory infiltration columns as soil amendments to a neutral agricultural soil and to an acid meadow soil to study their impacts on soil properties and yield of barley and ryegrass. The amendments tended to improve the yield and showed a liming effect, significantly increasing soil pH and the availability of P. In another experiment, samples of Filtra P and Polonite were equilibrated in batch experiments with the two soils in order to study the P dynamics in the soil-substrate system.  Batch equilibrations confirmed the liming potential of Filtra P and Polonite and showed that improved P availability in soils was strongly dependent on substrate P concentration, phase of sorbed P, and soil type. Finally, samples of Polonite used for household wastewater treatment were recycled as soil amendments to a mountain meadow and to an agricultural field for wheat cropping. The liming effect of Polonite was confirmed under field conditions and the results were similar to those of lime for the mountain meadow soil. However, the results were quite different for the agricultural field, where Polonite did not affect soil pH or any other chemical and physical soil properties investigated and had no impact on wheat yield and quality. The results from field experiments suggested that Polonite can be safely recycled to meadows and cropping fields at rates of 5-10 ton ha-1 but long-term studies are needed to forecast the effects of accumulation. / QC 20100708

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.

La mise au point de nouveaux matériaux pour piéger les anions phosphate présents dans les eaux usées est une des clés pour lutter contre le phénomène d’eutrophisation des eaux de surface. Au cours de cette étude, les hydroxydes doubles lamellaires contenant des ions CaII et FeIII dans les feuillets cationiques et des anions chlorure et nitrate au sein de l’espace inter-feuillets (CaFe-HDL-Cl et CaFe-HDL-NO3) ont été utilisés pour piéger les phosphates. Ces deux variantes d’HDL ont été synthétisées par trois méthodes simples de co-précipitation. La capacité de piégeage de ces matériaux a été évaluée par des expériences de sorption en « batch » à l’équilibre et des mesures de cinétique dans une gamme de pH comprise entre 4 et 12. La cinétique de piégeage du phosphate par les HDL obéit à une loi du pseudo-second ordre. Les isothermes révèlent que les HDL synthétisés avec un rapport CaII : FeIII de 2 : 1 sont les plus efficaces pour piéger les phosphates. On mesure des capacités de piégeage très élevées de l’ordre de 385 et 402 mg g-1 pour les composés CaFe-HDL-Cl et CaFe-HDL-NO3, respectivement. Les données obtenues à l’équilibre ont pu être ajustées par des isothermes de type Langmuir et/ou Freundlich. Pour des concentrations en phosphate élevées ([PO43-] ≥ 100 mg L-1), la caractérisation des solides et des liquides par diverses techniques révèlent que la HDL se dissout et libèrent des cations solubles Ca2+ qui précipitent avec les phosphates pour former l’hydroxyapatite Ca5(PO4)3OH. A ce mécanisme principal s’ajoute un mécanisme de piégeage secondaire qui est l’adsorption des phosphates par un gel ferrique dopé en ions calcium qui est lui aussi issu de la transformation minéralogique de l’HDL. A faible concentration en phosphate ([PO43-] ≥ 100 mg L-1), l’hydroxyapatite ne se forme pas et l’adsorption des phosphates par ce gel ferrique dopé en ions calcium devient le mécanisme de piégeage principal. / The development of an efficient removal material for phosphate from wastewater to prevent the eutrophication in surface waters is very important. In this study, CaIIFeIII layered double hydroxide containing chloride and nitrate as intercalated anions (CaFe-LDH-Cl and CaFe-LDH-NO3) were used as removal materials for phosphate. Both forms were designed and synthesized at different CaII: FeIII molar ratios (2:1, 3:1, and 4:1) following three simple co-precipitation methods. The materials were evaluated for the removal of phosphate by batch equilibrium sorption experiments and kinetic measurements. The efficiency of the phosphate removal from aqueous solution was investigated in the range pH 4-12. As a result, it was found that pseudo-second-order kinetic model described well the phosphate removal. The isotherms of adsorption of PO43- ions showed that CaFe-LDH-Cl and CaFe-LDH-NO3 at CaII: FeIII molar ratio of 2:1 revealed the highest rate of phosphate uptake of 385 and 402 mg g-1, respectively, comparing to other CaII: FeIII molar ratios. Equilibrium data were well fitted with Freundlich and Langmuir isotherms. In the case of high phosphate concentration ([PO43-] ≥ 100 mg L-1), the comprehensive analysis of the phosphate-uptake products with different techniques revealed that CaFe-LDH dissolve first and then released Ca2+ ions reacting with PO43- anions to form Ca5(PO4)3OH (hydroxyapatite) which is the main mechanism for phosphate removal. Also, phosphate was removed partially via a subsidiary process other than precipitation of hydroxyapatite. The excess in phosphate removal was attributed to the formation of a disordered Ca doped ferrihydrite which removed phosphate via simple surface adsorption. In the case of initial low phosphate concentration ([PO43-] < 100 mg L-1), the analysis showed that PO43- removed mainly via simple surface adsorption over disordered Ca doped ferrihydrite which was the main component in the residual solid after partial Ca2+ releasing from LDH

Les minéraux argileux gonflants tels que les smectites sont omniprésents à la surface de la Terre et possèdent d'importantes capacités d'hydratation et d'absorption/rétention de contaminants. Ainsi, ces dernières exercent une influence clé sur les transferts d'éléments dans les environnements de surface. Ces propriétés sont particulièrement importantes quand les smectites sont utilisées comme barrières ouvragées ou géologiques pour les installations de contrôle des déchets. Les molécules d'eau dans l'interfoliaire représentent plus de 80% de l'eau en contact avec les smectites, dans des conditions non saturées. La caractérisation de l'organisation et de la dynamique de l'eau dans les smectites est donc essentielle pour prédire la mobilité des contaminants, dont le principal vecteur est l'eau. Dans ce cadre général, les présents travaux décrivent, dans un premier temps, la structuration interfoliaire eau/cations dans des conditions saturées, jusqu'alors méconnue. Puis, dans un second temps, nous avons examiné l'influence des paramètres structuraux (tels que la quantité et l'emplacement des charges, la composition chimique et plus particulièrement la présence de groupements fluors/hydroxyles) sur les propriétés d'hydratation des smectites. Une série d'échantillons couvrant toute la gamme de composition des smectites a donc été synthétisée et caractérisée structurellement. Une attention particulière a été accordée à la détermination du montant (isothermes vapeur d'eau de sorption) et la distribution (de diffraction des rayons X) de l'eau dans l'espace interfoliaire. La modélisation moléculaire a permis d'aller plus loin dans la compréhension de l'origine des comportements contrastés observés expérimentalement, et de déterminer l'influence des différents paramètres cristallochimiques sur l'hydratation de la smectite. Cette étape est essentielle pour la prédiction de la réactivité des smectites dans l'environnement sur la base d'un nombre limité de paramètres cristallochimiques. / Swelling clay minerals such as smectites are ubiquitous at the Earth surface and possess major hydration ability and contaminant uptake/retention capacity. As a consequence smectites exert a pivotal influence on elemental transfers in surficial environments. These properties are especially relevant also when smectites are used as sealant in engineered or geological barriers for waste disposal facilities. As interlayer H2O molecules account for more than 80% of smectite water in undersaturated conditions, characterization of H2O organization and dynamics in smectites interlayers is essential to determining the geometrical and dynamical properties of clay barriers for waste disposal and to predicting the mobility of contaminant whose principal vector is water. Within this general framework, the present works describe, in a first time, the structuration of interlayer water/cations in saturated conditions. Then, in a second time, review the influence of structural parameters such as the amount and location of layer charge deficit and the chemical composition (and more especially the presence of structural fluorine/hydroxyl) on smectite hydration properties. A set of samples covering the whole compositional range of swelling phyllosilicates has thus been synthesized and characterized chemically and structurally. Special attention was paid to determining the amount (water vapor sorption isotherms) and the distribution (X-ray diffraction) of interlayer water. Molecular modeling allowed unraveling the origin of the contrasting behaviors observed experimentally and to determine the influence of the different crystal-chemical parameters on smectite hydration. This step is essential for the prediction of smectite reactivity in the environment from a limited number of crystal-chemical parameters. Molecular modeling allowed unraveling the origin of the contrasting behaviors observed experimentally and to determine the influence of the different crystal-chemical parameters on smectite hydration. This step is essential for the prediction of smectite reactivity in the environment from a limited number of crystal-chemical parameters.

O conhecido histórico de contaminação por passivos da mineração de galena (PbS) da região do Vale do Ribeira (SP) faz com que seja de grande importância o estudo da adsorção de Pb com a finalidade de determinar a capacidade de sorção de materiais inconsolidados do município de Eldorado Paulista (SP) para serem empregados como barreira selante na contenção da lixiviação de metais por resíduos de mineração (com destaque para o Pb). O objetivo do presente trabalho foi avaliar a adsorção de Pb por meio de ensaios de equilíbrio em lote. Para realizar tal objetivo, foram coletadas 4 amostras de materiais inconsolidados (3 transportados e 1 residual) no município de Eldorado Paulista, anteriormente caracterizadas. Foram realizados ensaios de caracterização dos materiais (MO, \'delta\'pH, compactação e permeabilidade) visando determinar as principais características que influenciam na retenção de metais, assim como ensaios de equilíbrio em lote para avaliar a capacidade de adsorção de Pb. O ensaio BET foi realizado com amostras triplicatas dos 4 solos, empregando concentrações iniciais de Pb aproximadas de 30, 60, 90 e 120 mg L-1, massa de solo de 20 g, tempo de contato de 24 horas e razão massa/solução de 1/5. Com os resultados obtidos foram confeccionadas isotermas de sorção segundo os modelos Linear, de Freundlich e Langmuir I e II. Os resultados indicaram que os materiais inconsolidados transportados T2 e T3 são os mais adequados para o emprego em barreira selante para contenção de Pb, sendo suas capacidades de adsorção influenciadas, principalmente, pelo teor de óxidos de ferro e fração argila. As melhores sorções foram obtidas para os solos T2 e T3 para concentrações iniciais aproximadas entre 30 e 120 mg L-1. Desta forma, conclui-se que o ensaio BET foi adequado para determinação da adsorção por metais. / The known history of contamination by galena (PbS) mining liabilities from Ribeira Valley region (SP) provides importance to the Pb adsorption study in order to determine the sorption by unconsolidated materials from Eldorado Paulista city (SP) to be employed as liners to contain metals leaching derived from mining (with emphasis on Pb). The objective of the current work was assess the Pb adsorption by Batch Equilibrium Tests. To accomplish this objective, 4 unconsolidated materials samples were collected in Eldorado Paulista, previously characterized. Characterization tests were performed (MO, \'delta\'pH, compaction and permeability) to determine the main characteristics that influence the retention of metals, and Batch Equilibrium Tests to assess soils capacities of Pb adsorption. BET was performed with triplicate samples of the 4 materials, applying initial Pb concentrations around 30, 60, 90 and 120 mg L-1, mass of soil about 20 g, mass/solution rate of 1/5 and 24 hours of contact time. the results provide sorption isotherms modeled by Linear, Freundlich and Langmuir I and II equations. The results indicated that unconsolidated materials T2 and T3 are the best suited for use in liners to retain Pb, and their sorption capacities are mainly influenced by iron oxides content and clay content. Best sorption were obtained to soils T2 and T3 with initial concentrations about 30 to 120 mg L-1. Thus, it is concluded that BET is appropriated to determine metals adsorption.