Nanostructured, porous materials offer great promise for application in areas such as energy storage, photovoltaics, and catalysis. These materials are often difficult to characterize because they are structurally and compositionally inhomogeneous, and disordered with features to small to be resolved by scanning probe techniques such as atomic force microscopy (AFM) and scanning electron microscopy (SEM). These shortcomings require that new techniques be developed that can be applied to real world systems to elucidate how the interplay of material composition and structure alters their performance. Towards this end, the development of a hybrid quartz crystal microbalance/ ellipsometric porosimetry (QCM/EP) technique is being pursued to facilitate the determination of a number of material parameters such as porosity, pore size distribution, and surface area. Additionally, the use of adsorbate probe molecules of varying polarity gives further information about adsorbate-surface interactions and surface chemistry characteristics. Simultaneous acquisition of both mass-based and refractive index based adsorption isotherms fosters mechanistic understanding about the behavior of adsorbates confined in mesopores while at the same time reducing the uncertainty in the analysis of the optical parameters acquired via ellipsometry. To highlight the power of this approach, studies of TiO₂ and TiC, electrode materials as model systems will be presented that have helped us validate measurement and modeling protocols for extracting physical properties. / text

The aim of this thesis work was to investigate theadsorption of surfactants to different nonpolar interfaces.Particularly, the effects of the polar group and the nature ofthe hydrophobic interface were elucidated. The interfacialbehavior of the liquid-vapor interface was investigated bymeans of surface tension measurements. Here the effect of thepolar group and the hydrocarbon chain length was investigatedin a systematic manner. It was found that the shorter of thetwo chains examined, decyl, generated a larger surface pressurecontribution than the longer, dodecyl. Furthermore, the sugarbased surfactants behaved differently as compared to theethylene oxide based ones. The former could be modelled byassuming a hard disc behavior of the head group while thelatter displayed polymeric behavior. The influence of saltconcentration on the surface tension behavior of an ionicsurfactant, sodium dodecyl sulphate, was investigated. Theresult could be rationalized by employing the Gouy- Chapmanmodel to the polar region. Furthermore, mixtures of two sugarbased surfactants were investigated by surface tensionmeasurements and the adsorbed amount of the two components atthe interface atdifferent concentrations and fractions in thebulk were obtained by applying the Gibbs surface tensionequation. It was found that the molecule with the smaller headgroup adsorbed preferentially, and more so as the totalsurfactant concentration was increased. These findings could beexplained by considering the interactions generated by thedifferent head groups. The adsorption of sugar surfactants toan isolated hydrophobic surface was studied by means of wettingmeasurements and the behavior was similar to that at theliquid-vapor interface. Wetting isotherms were measured on twodifferent hydrophobic surfaces where the covalently attachedhydrophobic layers were in a crystalline and fluid state,respectively. The wetting results revealed that the sugarsurfactants anchored in the fluid hydrophobic layer. This had asignificant influence on the force profile. For example, at thecrystalline surface the surfactant monolayers were easilyremoved as the surface came into contact at relatively lowapplied loads. This was not the case when the hydrophobic layerwas in a fluid state. Here a significant fraction of thesurfactants remained between the surfaces. Disjoining pressureisotherms were measured using a sugar based surfactant thatwere thoroughly purified and compared to the as receivedsample. Even the purified sample showed a double-layer forcealthough lower as compared to the as received, one. Asignificant difference in foam stability was also observed. / <p>NR 20140805</p>

Les vapeurs organiques émises des solvants utilisés dans le produit chimique / la nourriture / les processus pharmaceutiques, ou des stations d'entreposage de combustible d'hydrocarbure aux terminus de pétrole, peuvent être efficacement capturées par l'adsorption sur les lits de charbon actif. L'objectif général du programme de recherche est les études expérimentales et les études de simulation de l'adsorption et des pas de régénération en cas de l'enlèvement COV qui estime dans les émissions industrielles par l'Adsorption (TSA – Température Swing Adsorption et VTSA -Vacuum Température Swing Adsorption). C'est accompli par les points suivants : établir les données d'équilibre d'isotherme pour 5 COV et 8 carbones activés à 293, 313, 333 et 353 K (complètement 120 expériences d'isotherme) et les utiliser ensuite dans le modèle de simulation; développer une simulation pose pour le processus de régénération et l'adsorption; concevoir et optimiser l' expérimentale de TSA qui a été établi dans Ecole des les Mines de Nantes; concevoir et optimiser l'expérimentale de VTSA qui a été établi dans GRL ARKEMA; la validation de simulation de résultats expérimentaux de le processus TSA et VTSA. Une fois après l'achèvement de tous les objectifs, le but est de se développer et le lancement un utile de simulation complet pour l'adsorption et les pas de régénération de COV avec la coopération de la Société PROSIM. / Organic vapors emitted from solvents used in chemical / food / pharmaceutical processes, or from hydrocarbon fuel storage stations at oil terminals, can be efficiently captured by adsorption onto activated carbon beds. The overall objective of the research program is the experimental and simulation studies of the adsorption and regeneration steps in the case of VOC removal which accounts into industrial emissions by Temperature Swing Adsorption (TSA) and Vacuum Temperature Swing Adsorption (VTSA) processes. This is achieved by the following steps : to establish the isotherm equilibrium data for 5 VOCs and 8 activated carbons at 293, 313, 333, and 353 K (totally 120 isotherm experiments) and then use them in the simulation model; to develop a simulation model for adsorption and regeneration process; to design and optimize the experimental setup of Thermal Swing Adsorption (TSA) which has been established in Ecole des Mines de Nantes; to design and optimize the experimental setup of Vacuum Temperature Swing Adsorption processes (VTSA) which has been established in GRL ARKEMA unit ; simulation validation of experimental results of TSA and VTSA process. Once after the completion of all the objectives, the goal is to develop and launch a complete simulation package for adsorption and regeneration steps of VOCs with the co-operation from PROSIM Corporation.

The adsorption of methylene blue onto two types of commercial activated carbons, a mesoporous type (Norit CA1) and microporous type (207C) was analysed. Powdered TiO2 was mixed with the carbon and added to the dye solution to determine the influence of the photocatalyst during the adsorption process. Equilibrium and kinetics experiments were done with and without any addition of photocatalytic titanium dioxide (TiO2). Changes in capacity, heterogeneity, and heat of adsorption were detected and related to changes in the quantity of TiO2 added by evaluating the equilibrium parameter from 13 isotherm models. The influence of TiO2 on the adsorption kinetics of the dye was correlated using simplified kinetic-type model as well as mass transfer parameters. Using a formal design of experiments approach responses such as the removal of the dye, variation of pH, external mass transfer rate (KF) and intraparticle rate constant (Ki) were evaluated. Results indicated that TiO2 increased the uptake of methylene blue onto CA1, increased Ki and CA1-TiO2 interactions had electrostatic nature. In contrast, TiO2 was seen to inhibit the equilibrium adsorption for 207C by reducing its capacity. The 207C-TiO2 interaction was attributed to a specific adsorption of TiO2 on the coconut-based adsorbent, as zeta potential and pH measurements seemed to suggest. The regeneration of activated carbon using UV-C/TiO2 heterogeneous photocatalysis in a novel bell photocatalytic reactor, and in a standard-type coiled-tube photoreactor was also studied. Initially, response surface methodology was applied to finding the optimum conditions for the mineralization of methylene blue in both reactors using methylene blue as model compound and TiO2 as photocatalyst performing direct photocatalytic decolourization. Methylene blue concentration, TiO2 concentration and pH were the variables under study. Complete mineralization of the dye was achieved in the coiled-tube reactor using 3.07 mg/L of methylene blue at pH 6.5 with 0.4149 g/L TiO2. The regeneration experiments in the coiled-tube photoreactor were done using One Variable at Time (OVAT) method. The effect of the mass of TiO2 was the only studied variable. The study indicated an increase in regeneration of CA1 and a decrease in the pH during the oxidation step at higher concentration of the photocatalyst. In the case of the regeneration of 207C, the addition of TiO2 lowered the regeneration and made the suspension more basic during the photocatalytic step. However these results were not statistically significant. Experiments using the bell photoreactor were performed applying the same response surface method used in direct photocatalytic decolourization (control). The variables under study were pH, concentration of dye-saturated carbon and TiO2 concentration. The regeneration percentage was the chosen response. Low regeneration percentages were achieved (maximum 63%), and significant differences (95% confidence interval) were found between the regeneration of the activated carbons, being higher in the case of powdered CA1 as compared with granular 207C.

Orientador: Juliana Heloisa Pinê Américo-Pinheiro / Resumo: Durante anos utilizou-se a coagulação, floculação, decantação, filtração e desinfecção para tratamento de água, contudo com a detecção dos Contaminantes Emergentes (CE’s) nos mananciais, como os fármacos, agregou-se aos métodos tradicionais o processo de adsorção, uma técnica avançada para a remoção dos CE’s. O objetivo do presente estudo foi desenvolver um material compósito de polietileno de tereftalato (PET) e cinza pesada de cana de açúcar (CPCA) funcionalizado com óxido de ferro (Fe3+) de baixo custo e avaliar a eficiência desse compósito na adsorção de diclofenaco de sódio (DIC) em solução sintética, simulando água de abastecimento para procedimento em batelada e em sistema de fluxo contínuo para aplicação em coluna de leito fixo. Utilizou-se para o procedimento em batelada uma concentração de 1000 µg.L-1 de DIC e 500 µg.L-1 de DIC para o ensaio em coluna de leito fixo. O processo adsorção em batelada iniciou-se com a determinação da massa do adsorvente, para obter a massa necessária para adsorver a quantidade analisada de DIC, seguido pela cinética de adsorção e isoterma de adsorção, avaliando a velocidade de reação e capacidade de adsorção, respectivamente. Por fim, verificou-se como o adsorvente se comportaria em fluxo contínuo por meio do ensaio de coluna em leito fixo. A determinação de massa permitiu concluir que a quantidade de 0,3 g de PETCPCA/Fe3+ é a que melhor se ajustaria à solução trabalho. O modelo de pseudo-segunda ordem (PSO) foi o que se ajustou ao estu... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: For years, coagulation, flocculation, decantation, filtration and disinfection for water treatment were used, however with the detection of the Emerging Contaminants (EC’s) in the springs, as the drugs, the traditional methods were added the adsorption process, a technique advanced for EC removal. The objective of the present study was to develop a low cost composite material of polyethylene terephthalate (PET) and sugarcane ash (SCA) with iron oxide (Fe3+) and to evaluate the efficiency of this composite in the adsorption of diclofenac sodium (DIC) in synthetic solution, simulating supply water for batch process and continuous flow system for fixed bed column application. A concentration of 1000 μg.L-1 of DIC and 500 μg.L-1 of DIC was used for the batch procedure for the fixed bed column assay. The batch adsorption process was started by determining the mass of the adsorbent to obtain the mass needed to adsorb the analyzed amount of DIC, followed by adsorption kinetics and adsorption isotherm, evaluating the reaction rate and adsorption capacity, respectively. Finally, it was verified how the adsorbent would conduct in a continuous flow through the fixed bed column test. The determination of mass allowed to conclude that the amount of 0.3 g PETSCSA/Fe3+ is the one that would best fit the work solution. The second-order model (SOM) was the one that fit the study, having a coefficient of determination (R²) equal to 0.97. The isotherms (Lagmuir and Freundlich) were adjusted to ... (Complete abstract click electronic access below) / Mestre

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-04-27T14:14:48Z No. of bitstreams: 1 PDF - Natássya Nyuska Cabral de Lima.pdf: 1817457 bytes, checksum: c20885f87efcfd4edcd9466b67b55e64 (MD5) / Made available in DSpace on 2016-04-27T14:14:48Z (GMT). No. of bitstreams: 1 PDF - Natássya Nyuska Cabral de Lima.pdf: 1817457 bytes, checksum: c20885f87efcfd4edcd9466b67b55e64 (MD5) Previous issue date: 2015-11-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The occurrence of cyanobacterial blooms in water sources used for public supply, is increasingly common. Some genera of cyanobacterial have species potentially producing cyanotoxins, which can affect human health by direct contact through the skin or by ingestion of contaminated water or food. Classified according to their pharmacological action, cyanotoxins, are known as hepatotoxins, neurotoxins and dermatotoxins. Among the hepatotoxins we found the microcystin, a cyclic heptapeptide which can lead to death in hours or days. During the treatment of water for human consumption it is important to consider a technique to remove intact cells of cyanobacteria, since the use of oxidizing agents promotes cell lysis which can cause the release of toxins into the water. The Activated Carbon (AC) is presented as one of the best alternatives to the removal of organic and inorganic compounds due to its high power of adsorption. Aimed the fulfillment the current drinkability ordinance, as the concentration of extracellular cyanotoxins the present study sought to evaluate on a bench scale, the microcystin-LR removal efficiency study of water by adsorption on Activated Carbon (AC). The water study of was prepared with addition of lysed cells Microcystis aeruginosa cultivation. Were evaluated different pH values and the results confirmed that MC-LR adsorption was more efficient at acidic pH close to 5,0. Kinetic studies of adsorption were performed, analyzed according to the models of pseudo-first and pseudo-second order, getting the best fit the model of pseudo-first order, and adsorption isotherms to determine the adsorptive capacity of CA in relation to microcystins. The data of the isotherms were modeled according to the Langmuir isotherm and Freundlich, with best fit to the Langmuir model.The analytical method used during research to determine the concentration of microcystin-LR, after completion of kinetic experiments and isotherm was the High Performance Liquid Chromatography Coupled with Mass Spectrometry (HPLC-MS). The adsorption by AC palm coconut shell proved to be an efficient process for the removal of MC-LR, since averages toxin removal efficiencies above 90% were observed. / A ocorrência de florações de cianobactérias, em mananciais utilizados para abastecimento público, é cada vez mais frequente. Alguns gêneros de cianobactérias possuem espécies potencialmente produtoras de cianotoxinas, que podem afetar a saúde humana pelo contato direto através da pele ou por ingestão de água ou alimento contaminado. Classificadas de acordo com sua ação farmacológica, as cianotoxinas, são conhecidas como hepatotoxinas, neurotoxinas e dermatotoxinas. Dentre as hepatotoxinas encontramos a microcistina, um heptapeptideo cíclico que pode levar a morte em horas ou dias. Durante o tratamento de água para consumo humano é importante considerar uma técnica que remova células intactas de cianobactérias, pois o uso de agentes oxidantes promove a lise celular a qual pode causar a liberação de toxinas na água. O Carvão Ativado (CA) se apresenta como uma das melhores alternativas para a remoção de compostos orgânicos e inorgânicos devido a seu alto poder de adsorção. Visando o cumprimento da portaria de potabilidade vigente, quanto à concentração de cianotoxinas extracelulares o presente trabalho buscou avaliar em escala de bancada, a eficiência de remoção de microcistina-LR da água de estudo por meio de adsorção em Carvão Ativado (CA). A água de estudo foi preparada com adição de cultivo de células lisadas de Microcystis aeruginosa. Foram avaliados diferentes valores de pH e os resultados confirmaram que a adsorção de MC-LR se mostrou mais eficiente em pH ácido próximo a 5,0. Foram realizados estudos cinéticos de adsorção, analisados de acordo com os modelos de pseudo-primeira e pseudo-segunda ordem, obtendo-se melhor ajuste ao modelo de pseudo- primeira ordem, e isotermas de adsorção para determinar a capacidade adsortiva do CA em relação às microcistinas. Os dados das isotermas foram modelados segundo as isotermas de Langmuir e Freundlich, com melhor ajuste ao modelo de Langmuir. O método analítico utilizado durante a pesquisa para determinação da concentração de microcistina-LR, após a finalização dos experimentos de cinética e isoterma foi o Cromatógrafo Líquido de Alta Eficiência Acoplado a Espectrometria de Massas (CLAE-EM). A adsorção por CA de casca de coco de dendê se mostrou um processo eficiente para a remoção de MC-LR, visto que eficiências médias de remoção da toxina acima de 90% foram observadas.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-09-12T19:05:23Z No. of bitstreams: 1 2017 - Amanda de Paula Alves.pdf: 2949048 bytes, checksum: 68f405efb8be6119401dfd85e1d5768a (MD5) / Made available in DSpace on 2017-09-12T19:05:23Z (GMT). No. of bitstreams: 1 2017 - Amanda de Paula Alves.pdf: 2949048 bytes, checksum: 68f405efb8be6119401dfd85e1d5768a (MD5) Previous issue date: 2017-02-23 / The large amount of glycerol, produced in the last decades, generated as a by product of biodiesel production is object of inumerous studies searching for different technologies for its purification. Crude glycerol obtained as a by-product in the transesterification process is composed of alcohol, water, inorganic salts, free fatty acids, mono-, di-, triglycerides, among other organic materials and wastes in different concentrations. It is of extreme importance the purification of glycerol in order to reduce environmental problems due to its accumulation. There are current effective technologies in purifying and refining crude glycerol. However, they are considered unfeasible for small and medium production units due to the high cost and high energy demand. In this way, it is essential that new purification routes of low cost and high efficiency, as well as new markets, be developed. The adsorption process is promising and very favorable technique to remove the contaminants from glycerin due to its low cost, simplicity of design and operation. In this point of view, the objective of this work was to select an adsorbent for the purification of crude glycerol obtained from the transesterification reaction of residual oil. The evaluation of the efficiency and the best operacional conditions were studied using three types of adsorbents: Pure-Flo Supreme B81 clarifying clay, activated charcoal and diatomaceous earth. Preliminary adsorption experiments were carried out using a synthetic solution of glycerin and soybean oil, in order to verify the influence of glycerin concentration in the solution, as well as the behavior of the glycerol contaminants in the adsorption process. In order to reach the objective, the influence and optimization of the process variables as temperature (298.15, 305.65 and 313.15 K), amount of adsorbent (1.2, 1.8 and 2.4 g) and glycerol concentration (30, 50 and 70% v/v) were evaluated through an experimental design. The most significant variable was glycerol concentration, and results indicated high glycerol content after purification: 97.25% for diatomaceous earth, 95.59% for activated carbon and 90.26% for clay. Through the optimization of these variables, experiments were carried out to study the thermodynamics and kinetics of the reaction. The equilibrium time was less than 60 minutes for the three adsorbents. The negative values of Gibbs free energy (?G) showed that the adsorption of the contaminants is a spontaneous process. The negative values for enthalpy change (?H) and positive entropy (?S) values for clay and activated carbon indicate an exothermic nature and that the contaminant molecules are more randomnless in the adsorbed state than in solution. The positive value of ?H for diatomaceus earth indicates that the adsorption process for this adsorbent is endothermic. The adsorption results obtained at 298.15, 305.65 and 313.15 K showed that the experimental data were well correlated with the Langmuir, Freundlich and Redlich-Peterson isotherms models. The purification of crude glycerol using the same adsorbents did not show an effective result. The results showed that the adsorbents were not able to adsorb the impurities, but rather a small amount of glycerol. The adsorption carried out for purification did not clarify the glycerin, concluding that only the adsorption process is not suitable for purification of the crude glycerol, and a pre-purification step is necessary for the previous removal of the contaminants. / O excedente de glicerol produzido nas ?ltimas d?cadas, gerado como subproduto da produ??o de biodiesel, est? associado a constantes pesquisas por fontes alternativas de energia e vem criando uma demanda na busca de diferentes tecnologias para sua purifica??o. A glicerina bruta obtida como subproduto no processo de transesterifica??o ? composta por ?lcool, ?gua, sais inorg?nicos, ?cidos graxos livres, mono-, di-, triglicer?deos, entre outras mat?rias org?nicas e res?duos em diferentes quantidades. ? de extrema import?ncia a purifica??o do glicerol, a fim de reduzir problemas ambientais devido ao seu ac?mulo. Existem tecnologias atuais eficazes na purifica??o e refino do glicerol bruto. Por?m, s?o consideradas invi?veis para pequenas e m?dias produ??es, devido ?s restri??es de custos e alta demanda energ?tica. Dessa forma, ? indispens?vel que novas rotas de purifica??o de menor custo e maior efici?ncia, assim como novos mercados, sejam desenvolvidos. A adsor??o desponta como uma t?cnica promissora e muito favor?vel para a remo??o dos contaminantes da glicerina, devido ao seu baixo custo, simplicidade de projeto e opera??o. Diante do exposto, o objetivo deste trabalho foi selecionar um adsorvente para a purifica??o do glicerol bruto obtido da rea??o de transesterifica??o de ?leo residual. Para a avalia??o da efici?ncia e escolha das melhores condi??es de purifica??o, foram avaliados tr?s tipos de adsorventes: argila clarificante Pure-Flo Supreme B81, carv?o ativado e terra diatom?cea. Experimentos de adsor??o foram realizados utilizando uma solu??o sint?tica de glicerina P.A. e ?leo de soja, com o intuito de verificar a influ?ncia da concentra??o da glicerina na solu??o, assim como o comportamento dos contaminantes do glicerol no processo de adsor??o. Para atingir o objetivo, avaliou-se a influ?ncia e otimiza??o das vari?veis de processo como temperatura (298,15, 305,65 e 313,15 K), quantidade de adsorvente (1,2, 1,8 e 2,4 g) e concentra??o de glicerol (30, 50 e 70% v/v) atrav?s de um planejamento experimental. A vari?vel mais significativa foi a concentra??o de glicerol, e resultados indicaram alto teor de glicerol ap?s a purifica??o: 97,25% para terra diatom?cea, 95,59% para carv?o e 90,26% para argila. Al?m disso, foram realizados experimentos para o estudo da termodin?mica e cin?tica da rea??o e o tempo necess?rio para o sistema alcan?ar o equil?brio foi inferior a 60 minutos para os tr?s adsorventes. Os valores negativos da varia??o da energia livre de Gibbs (?G) mostraram que a adsor??o dos contaminantes ? um processo espont?neo. Os valores negativos para varia??o de entalpia (?H) e os valores positivos de entropia (?S) para argila e carv?o ativado, indicam uma natureza exot?rmica e que as mol?culas dos contaminantes encontram-se mais desordenadas no estado adsorvido do que em solu??o. O valor positivo de ?H para a terra diatom?cea indica que o processo de adsor??o para esse adsorvente ? endot?rmico. As an?lises dos resultados de adsor??o obtidos nas temperaturas de 298,15, 305,65 e 313,15 K, mostraram que os dados experimentais foram bem correlacionados ?s isotermas de Langmuir, Freundlich e Redlich Peterson. Utilizando as mesmas vari?veis para o processo de adsor??o usando o glicerol bruto, os resultados mostraram que os adsorventes n?o foram capazes de adsorver as impurezas, mas sim glicerol. A adsor??o realizada para purifica??o n?o clarificou a glicerina, indicando que n?o houve remo??o das impurezas, concluindo que somente o processo de adsor??o n?o ? apropriado para purifica??o do glicerol bruto, sendo necess?rio uma pr?-purifica??o para pr?via remo??o de alguns contaminantes.

Arsenic is a toxic element that is widely distributed throughout the earth??s crust as a result of both natural geologic processes and anthropogenic activities. In virtually all environments, methylated forms of arsenic can be found. Because of the widespread distribution and toxicity of arsenic and methyl-arsenic, their adsorption behavior on soil minerals is of great interest. Although considerable attention has been given to the behavior of inorganic arsenic on mineral surfaces, little research has been conducted regarding interactions of the methyl-arsenic forms. The objective of this study was to compare the adsorption and desorption behavior of methylarsonate (MMAsV), methylarsonous acid (MMAsIII), dimethylarsinate (DMAsV), dimethylarsinous acid (DMAsIII), arsenate (iAsV), and arsenite (iAsIII) on iron oxide minerals (goethite and ferrihydrite) by means of adsorption isotherms and adsorption envelopes. Additionally, desorption envelopes were obtained using sulfate and phosphate as competitive ligands. Arsenic was measured by FI-HG-AAS. MMAsV and iAsV were adsorbed in higher amounts than DMAsV on goethite and ferrihydrite at all pH values studied. Although MMAsV and iAsV were adsorbed quantitatively at lower concentrations on goethite and ferrihydrite, as arsenic concentration was increased MMAsV was adsorbed in slightly lower quantities than iAsV. DMAsV was not quantitatively adsorbed at any concentration on goethite or ferrihydrite. MMAsV and iAsV exhibited high adsorption affinities on both goethite and ferrihydrite at pH values below 9 and showed decreasing adsorption above this point (more rapidly for MMAsV). DMAsV was adsorbed only at pH values below 8 on ferrihydrite and below 7 on goethite. MMAsV, iAsV, and DMAsV each exhibited adsorption characteristics suggesting specific adsorption on both goethite and ferrihydrite. Increased methyl substitution resulted in increased ease of arsenic release from the iron oxide surface. MMAsIII and DMAsIII exhibited no evidence for any type of specific adsorption under the conditions studied. Phosphate was a more effective desorbing ion than sulfate, but neither desorbed all arsenic species quantitatively.

The aim of this research is to understand the solid state physical properties of inulin in regards to the spray-drying treatments. In this context, inulin powders were produced by pilot spray-drying a commercial inulin dispersion under various feed (Tfeed) and inlet air (Tin) temperatures. More particularly, the amorphous and crystalline properties of the powders were studied by developing different fine characterization tools, such as modulated differential scanning calorimetry or powder X-ray diffraction. When the temperature of the inulin water systems increased, the crystallinity of the powder decreased. To a smaller extent, this tendency is also observed with the increase of the inlet air temperature of the spray drier. For example, an amorphous powder is obtained with a Tfeed of 90°C whatever the Tin (comprised between 120 and 230°C); whereas for a Tfeed of 80°C, a Tin of 230°C is necessary to obtain the same result. Adsorption isotherms were established on four powders covering a large range of crystallinity (crystallinity index from 0 to 92). The Guggenheim Anderson de Boer model was fitted to the experimental data. As the water content of the powders increased, the glass transition of inulin decreased. When the Tg droped below the storage temperature (20°C for example), the powders crystallized and underwent clumping phenomenon. Under these conditions, a continuous hard mass was observed for the amorphous powders; while their semi-crystalline counterparts were agglomerated but friable. To understand these changes, a kinetic study of the physical properties evolution and stability of an amorphous powder as a function of its water content was realized. These results allowed to correlate the Tg water content relationship to the evolution of the powders behaviour, such as stickiness or hardening during storage.

Hydrophilic interaction chromatography is well known as a powerful technique separation of polar and ionizable compound nowadays. However the retention mechanism of the technique is still under debate. Understanding retention mechanism would facilitate the method development using the technique and its future improvement. This was inspiring and became the goal of this thesis. This work involves the characterization of the water enriched layer regarding to water and buffer salt accumulation. Twelve HILIC stationary phase with a diverse surface chemistry regarding to function groups and modification type were studied. Effect of water and salt on regarding to the retention mechanism was investigated by correlating the adsorption data to the retention of selected solutes This also involved the characterization of interactions involve in the separation of 21 HILIC columns. Interactions was probe by retention ratio of pair solutes which are characteristic for each specific interaction. The data was evaluate using principle component analysis – a multivariable data analysis method. The model was comprehensive and its outcomes were confirmed by the studies on adsorptions of water and salts.