This thesis deals with optimalization processes of adsorption of ferulic acid on different types of sorbents. Specifically, was used the activated carbon as a sorbent of heterogeneous character and Amberlyst A-21 and Amberlit XAD-16 as macroporous polymer sorbents. The ferulic acid is fully characterized in the theoretical part and are discussed the problems of adsorption processes. To determination of the phenolic acid were used UV-VIS and HPLC instrumental methods. The main aim of the experimental part is to optimize various parameters of adsorption, including the construction of adsorption isotherms, determination of maximum adsorption capacity of individual sorbents, study of kinetics and mechanisms of adsorption. Determination of the influence of salt was studied to assess the impact of the inorganic salts on the ferulic acid adsorption capacity. Based on these parameters, was carried out determination of an optimal pH value on 3, with an optimal adsorbent load (m/V ratio = 0,009 gml-1) and a contact time of 50 min for all three adsorbents. Equilibrium studies described by adsorption isotherms and the Langmiur model fitted the best, and the maximum adsorption capacities were determined for all three sorbents with 150,4 mgg-1 for activated carbon, 209,1 mgg-1 for Amberlyst A-21 and 82 mgg-1 for Amberlyte XAD-16. In the study of kinetic models was selected pseudo-second model for all three adsorbents, which correlated with the results obtained by the Langmuir isotherm. The decrease in adsorption capacity in the determination of NaCl influence was 4 % for activated carbon, for macroporous polymer sorbents was decreased by 52 % and 55 % for Amberlyst A-21 and Amberlyt XAD-16 respectively. In a selectivity test under optimized conditions, adsorption strength increased in the order of sinapic acid ferulic acid p-coumaric acid for polymeric sorbent XAD-16 and activated carbon. For the A-21 sorbent the adsorption strength increased in the order of p-coumaric acid ferulic acid sinapic acid. The results of the work indicate the suitability of all three sorbents for the phenolic acid adsorption.

The adsorption isotherm of two weak bases, Promethazine hydrochloride and Propranolol hydrochloride, were determined with isocratic reversed-phase liquid chromatography, with a 60 w% methanol in 20 mM sodium acetate buffer pH 4 as the mobile phase, and calculated by the elution by characteristic points method. The data obtained from the method were then fitted into the Langmuir isotherm and the electrostatically modified Langmuir. Propranolol fitted reasonably good into the models while Promethazine was not as good. When Promethazine and Propranolol were together in the same sample, there was indication of competition of the adsorption sites. For comparing retention and peak shape between a C18 column and a mixed mode column, Waters XBridge C18 and Thermo Scientific Acclaim WCX-1, were tested in gradient elution with 11.32 mM sodium acetate buffer and 10–70 % methanol. The mixed-mode column gave significantly better peak shapes, while the retention time were longer compared to the C18 column. / Adsorptions-isotermerna för två svaga baser, Prometazin hydroklorid och Propranolol hydroklorid, bestämdes med isokratisk omvänd-fas vätskekromatografi, med w% 60 metanol i en 20 mM natriumacetatbuffert pH 4 som mobil fas, och beräknad med metoden elution by characteristic points.  Från metoden erhållna data passades till Langmuir isotherm och den elektrostatiskt modifierade Langmuir. Propanolen passade ganska bra till de olika isotermerna, medan Prometazin var något sämre passad. När Prometazin och Propranolol var tillsammans i samma prov, fanns det indikationer på konkurrens om adsorptionsställen. För jämförelse av topparnas form och retentionstid mellan en C18-kolonn och en mixed-mode-kolonn, användes Waters XBridge C18 och Thermo Scientific Acclaim WCX-1, som testades i gradient eluering med 11, 32 mM natriumacetatbuffert och 10–70 % metanol. Mixed-mode-kolonnen gav åtskilligt bättre toppar, medan retentionstiden var längre jämfört med C18-kolonnen.

No description available.

The following dissertation is divided into two parts. Part I deals with the modeling of helium trapping at oxide-iron interfaces in nanostructured ferritic alloys (NFAs) using density functional theory (DFT). The modelling that has been performed serves to increase the knowledge and understanding of the theory underlying the prevention of helium embrittlement in materials. Although the focus is for nuclear reactor materials, the theory can be applied to any material that may be in an environment where helium embrittlement is of concern. In addition to an improved theoretical understanding of helium embrittlement, the following DFT models will provide valuable thermodynamic and kinetic information. This information can be utilized in the development of large-scale models (such as kinetic Monte Carlo simulations) of the microstructural evolution of reactor components. Accurate modelling is an essential tool for the development of new reactor materials, as experiments for components can span decades for the lifetime of the reactor. Part II of this dissertation deals with the development, and use of, kinetic Monte Carlo (KMC) simulations for improved efficiency in investigating catalytic chemical reactions on surfaces. An essential technique for the predictive development and discovery of catalysts relies on modelling of large-scale chemical reactions. This requires multi-scale modelling where a common sequence of techniques would require parameterization obtained from DFT, simulation of the chemical reactions for millions of conditions using KMC (requiring millions of separate simulations), and finally simulation of the large scale reactor environment using computational fluid dynamics. The tools that have been developed will aid in the predictive discovery, development and modelling of catalysts through the use of KMC simulations. The algorithms that have been developed are versatile and thus, they can be applied to nearly any KMC simulation that would seek to overcome similar challenges as those posed by investigating catalysis (such as the need for millions of simulations, long simulation time and large discrepancies in transition probabilities). / Ph. D.

A contaminação de aguas pela mistura Benzeno, Tolueno, Etilbenzeno e Xilenos (BTEX) vem gerando a necessidade do desenvolvimento de metodologias altamente eficientes na remoção de poluentes e de metodologias analíticas para monitoramento ambiental suficientemente sensíveis, seletivos, reprodutíveis e rápidos. Nesse contexto, adsorventes com propriedades magnéticas aparecem como alternativas eficientes, de baixo custo e de fácil automação, inclusive possibilitando o desenvolvimento de metodologia analítica baseada na extração em fase sólida magnética (m-SPE), que vem ganhando interesse crescente por permitir extração rápida e análise efetiva dos poluentes com alta sensibilidade. A busca por adsorventes adequados exige o estudo de materiais com grande área superficial, funcionalizáveis e estáveis como as sílicas, mais especificamente uma comparação entre os tipos de sílica e do tipo de agente funcionalizante nas propriedades de adsorção/dessorção. Sílicas mesoporosas oraganofuncionalizas magnéticas com diferentes morfologias foram preparadas: sílica mesoporosa ordenada MCM-48 e MCM-41, bem como nanoparticulas esféricas de sílica mesoporosa (NPSiO2). A formação da silica mesoporosa ordenada começa com a preparação de um template de CTAB sobre o qual são depositados/formados os materiais MCM-41 e MCM-48. A concentração de CTAB deve ser controlada com cuidado pois estruturas com diferentes morfologias podem ser geradas variando-se esse parâmetro. As análises de espectroscopia FTIR, DRX e sorção de N2 revelaram que os materiais preparados são sílicas mesoporosas ordenadas com arranjo tipo giroide 3D (MCM-48) ou do tipo hexagonal (MCM-41) com área superficial respectivamente de 1212 m2.g-1 e 1159 m2.g-1. Além disso, as imagens de MET do material MCM-48 mostraram tamanho médio de partícula igual a 116 nm ± 15 nm. Para facilitar a remoção do adsorvente, nanopartículas de magnetita (SPION) foram incorporadas na superfície dos materiais adsorventes. O tempo de remoção típico foi determinado como sendo de 1 minuto. A organofuncionalização da sílica com octadecilssilano (C18), octilssilano (C8) e difenilssilano (Ph2) foi confirmada por espectroscopia FTIR e análise termogravimétrica demostrando a presença e a percentagem em massa dos grupos orgânicos em cada tipo de sílica mesoporosa. Usando como referência sílica gel 60 comercial (Sílica), foram comparadas as propriedades de adsorção frente a BTEX em agua, quando o agente funcionalizante é C8, C18 ou Ph2. Os resultados indicaram que as capacidades de adsorção, segundo o modelo de Langmuir, seguem a seguinte ordem C8≥C18>>Ph2. A partir disso, as propriedades de adsorção das demais sílicas funcionalizadas com C8 foram comparadas determinando-se que as capacidades de adsorção, segundo o modelo de Langmuir, estão na seguinte ordem: MCM-48>Sílica>NPSiO2>MCM-41. O nanocompósito organofuncionalizado MCM48-C8/SPION, que mostrou as melhores propriedades de adsorção, foi usado para a extração em fase sólida magnética (m-SPE) de BTEX em agua de posto de gasolina. Verificou-se que apenas 30 mg de adsorvente, 5 min de contato com a solução de BTEX, 1 min para remoção do adsorvente e 1 min para a extração foram suficientes para concentração/recuperação de BTEX de agua pela técnica de m-SPE, viabilizando a análise quantitativa, no caso por CG-MS. / The contamination of water bodies by Benzene, Toluene, Ethylbenzene and Xylenes (BTEX) has prompted the development of more efficient methodologies for their removal and the development of sufficiently sensitive, selective, reproducible and fast analytical methods for environmental monitoring. In this context, adsorbent materials with magnetic properties appear as efficient, low cost and easy automation alternatives, including the development of analytical methods based on magnetic solid phase extraction (m-SPE), which has gaining increasing interest since allows rapid extraction and effective analysis of pollutants with high sensitivity. The search for suitable adsorbents requires the study of materials with large surface area, functionalizable and stable as the silica\'s family, more specifically a comparison between the types of silica and the type of functionalizing agent on their adsorption/desorption properties. Magnetic organofunctionalized mesoporous silicas with different morphologies were prepared: ordered mesoporous silica MCM-48 and MCM-41, as well as spherical nanoparticles of mesoporous silica (NPSiO2). The formation of ordered mesoporous silica begins with the preparation of a CTAB template on which silica is deposited/formed to produce MCM-41 and MCM-48 materials. The CTAB concentration must be carefully controlled since colloidal structures with different morphologies can be generated by varying this parameter. The FTIR, XRD and N2 sorption spectroscopy analyzes confirmed the preparation of ordered mesoporous silica materials with a gyroid 3D (MCM-48), or hexagonal type (MCM-41) arrangement respectively with a surface area of 1212 m2.g-1 and 1159 m2.g-1. In addition, the MET images of the MCM-48 material showed mean particle size equal to 116 nm ± 15 nm. To facilitate removal from water, magnetite nanoparticles (SPIONs) were incorporated into the surface of adsorbent materials. The typical removal time was determined to be 1 minute. The organofunctionalization of the silica with octadecylsilane (C18), octylsilane (C8) and diphenylsilane (Ph2) was confirmed by FTIR spectroscopy and thermogravimetric analysis demonstrating the presence and allowing the determination of the mass percentage of the organic fraction in each type of mesoporous silica. Using commercial silica gel (Silica) as reference, the adsorption properties toward BTEX in water were compared when the functionalizing agent is C8, C18 or Ph2. The results indicated that the adsorption capacities, according to the Langmuir model, decrease in the following order C8 ≥ C18 >> Ph2. From this, the adsorption properties of the C8 functionalized silicas were compared showing that the adsorption capacities according to the Langmuir model decrease in the following order: MCM-48 > Silica > NPSiO2 > MCM-41. The organofunctionalized nanocomposite MCM48-C8/SPION, exhibiting the best adsorption properties, was used in magnetic solid phase extraction (m-SPE) of BTEX from gas station water. Only 30 mg of adsorbent, 5 min of contact with the BTEX solution, 1 min to remove the adsorbent and 1 min for extraction were enough for concentration/recovery of BTEX in water by m-SPE technique suitable for quantitative analysis, in this case by CG-MS.

A contaminação de aguas pela mistura Benzeno, Tolueno, Etilbenzeno e Xilenos (BTEX) vem gerando a necessidade do desenvolvimento de metodologias altamente eficientes na remoção de poluentes e de metodologias analíticas para monitoramento ambiental suficientemente sensíveis, seletivos, reprodutíveis e rápidos. Nesse contexto, adsorventes com propriedades magnéticas aparecem como alternativas eficientes, de baixo custo e de fácil automação, inclusive possibilitando o desenvolvimento de metodologia analítica baseada na extração em fase sólida magnética (m-SPE), que vem ganhando interesse crescente por permitir extração rápida e análise efetiva dos poluentes com alta sensibilidade. A busca por adsorventes adequados exige o estudo de materiais com grande área superficial, funcionalizáveis e estáveis como as sílicas, mais especificamente uma comparação entre os tipos de sílica e do tipo de agente funcionalizante nas propriedades de adsorção/dessorção. Sílicas mesoporosas oraganofuncionalizas magnéticas com diferentes morfologias foram preparadas: sílica mesoporosa ordenada MCM-48 e MCM-41, bem como nanoparticulas esféricas de sílica mesoporosa (NPSiO2). A formação da silica mesoporosa ordenada começa com a preparação de um template de CTAB sobre o qual são depositados/formados os materiais MCM-41 e MCM-48. A concentração de CTAB deve ser controlada com cuidado pois estruturas com diferentes morfologias podem ser geradas variando-se esse parâmetro. As análises de espectroscopia FTIR, DRX e sorção de N2 revelaram que os materiais preparados são sílicas mesoporosas ordenadas com arranjo tipo giroide 3D (MCM-48) ou do tipo hexagonal (MCM-41) com área superficial respectivamente de 1212 m2.g-1 e 1159 m2.g-1. Além disso, as imagens de MET do material MCM-48 mostraram tamanho médio de partícula igual a 116 nm ± 15 nm. Para facilitar a remoção do adsorvente, nanopartículas de magnetita (SPION) foram incorporadas na superfície dos materiais adsorventes. O tempo de remoção típico foi determinado como sendo de 1 minuto. A organofuncionalização da sílica com octadecilssilano (C18), octilssilano (C8) e difenilssilano (Ph2) foi confirmada por espectroscopia FTIR e análise termogravimétrica demostrando a presença e a percentagem em massa dos grupos orgânicos em cada tipo de sílica mesoporosa. Usando como referência sílica gel 60 comercial (Sílica), foram comparadas as propriedades de adsorção frente a BTEX em agua, quando o agente funcionalizante é C8, C18 ou Ph2. Os resultados indicaram que as capacidades de adsorção, segundo o modelo de Langmuir, seguem a seguinte ordem C8≥C18>>Ph2. A partir disso, as propriedades de adsorção das demais sílicas funcionalizadas com C8 foram comparadas determinando-se que as capacidades de adsorção, segundo o modelo de Langmuir, estão na seguinte ordem: MCM-48>Sílica>NPSiO2>MCM-41. O nanocompósito organofuncionalizado MCM48-C8/SPION, que mostrou as melhores propriedades de adsorção, foi usado para a extração em fase sólida magnética (m-SPE) de BTEX em agua de posto de gasolina. Verificou-se que apenas 30 mg de adsorvente, 5 min de contato com a solução de BTEX, 1 min para remoção do adsorvente e 1 min para a extração foram suficientes para concentração/recuperação de BTEX de agua pela técnica de m-SPE, viabilizando a análise quantitativa, no caso por CG-MS. / The contamination of water bodies by Benzene, Toluene, Ethylbenzene and Xylenes (BTEX) has prompted the development of more efficient methodologies for their removal and the development of sufficiently sensitive, selective, reproducible and fast analytical methods for environmental monitoring. In this context, adsorbent materials with magnetic properties appear as efficient, low cost and easy automation alternatives, including the development of analytical methods based on magnetic solid phase extraction (m-SPE), which has gaining increasing interest since allows rapid extraction and effective analysis of pollutants with high sensitivity. The search for suitable adsorbents requires the study of materials with large surface area, functionalizable and stable as the silica\'s family, more specifically a comparison between the types of silica and the type of functionalizing agent on their adsorption/desorption properties. Magnetic organofunctionalized mesoporous silicas with different morphologies were prepared: ordered mesoporous silica MCM-48 and MCM-41, as well as spherical nanoparticles of mesoporous silica (NPSiO2). The formation of ordered mesoporous silica begins with the preparation of a CTAB template on which silica is deposited/formed to produce MCM-41 and MCM-48 materials. The CTAB concentration must be carefully controlled since colloidal structures with different morphologies can be generated by varying this parameter. The FTIR, XRD and N2 sorption spectroscopy analyzes confirmed the preparation of ordered mesoporous silica materials with a gyroid 3D (MCM-48), or hexagonal type (MCM-41) arrangement respectively with a surface area of 1212 m2.g-1 and 1159 m2.g-1. In addition, the MET images of the MCM-48 material showed mean particle size equal to 116 nm ± 15 nm. To facilitate removal from water, magnetite nanoparticles (SPIONs) were incorporated into the surface of adsorbent materials. The typical removal time was determined to be 1 minute. The organofunctionalization of the silica with octadecylsilane (C18), octylsilane (C8) and diphenylsilane (Ph2) was confirmed by FTIR spectroscopy and thermogravimetric analysis demonstrating the presence and allowing the determination of the mass percentage of the organic fraction in each type of mesoporous silica. Using commercial silica gel (Silica) as reference, the adsorption properties toward BTEX in water were compared when the functionalizing agent is C8, C18 or Ph2. The results indicated that the adsorption capacities, according to the Langmuir model, decrease in the following order C8 ≥ C18 >> Ph2. From this, the adsorption properties of the C8 functionalized silicas were compared showing that the adsorption capacities according to the Langmuir model decrease in the following order: MCM-48 > Silica > NPSiO2 > MCM-41. The organofunctionalized nanocomposite MCM48-C8/SPION, exhibiting the best adsorption properties, was used in magnetic solid phase extraction (m-SPE) of BTEX from gas station water. Only 30 mg of adsorbent, 5 min of contact with the BTEX solution, 1 min to remove the adsorbent and 1 min for extraction were enough for concentration/recovery of BTEX in water by m-SPE technique suitable for quantitative analysis, in this case by CG-MS.

Made available in DSpace on 2014-12-17T15:41:49Z (GMT). No. of bitstreams: 1 DanyelleMA_DISSERT.pdf: 886887 bytes, checksum: bdfc465050e9656b4d629363ccd362a0 (MD5) Previous issue date: 2010-07-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Corrosion inhibitors in solution are utilized to minimize processes from corrosion in steel. Of the present dissertation was evaluated the efficiency by inhibition from the surfactant saponified coconut oil (OCS) in the carbon steel 1020 through in linear polarization electrochemistry technique, well as, studied the process from adsorption through from the isotherms from Langmuir, Frumkin and Temkin. The corrosion current was determined through in Tafel extrapolation from the curves in the polarization, and then, was calculated the efficiency in the inhibitor to each concentration and temperature. Were studied four concentrations (12,5 ppm, 25 ppm, 50 ppm, and 75 ppm) in the inhibitor OCS and one in the NaCl salt (10.000 ppm) in six temperatures (301 K, 308 K, 313 K, 318 K, 323 K, and 328 K) in triplicate. By the results obtained observed that the technique applied can evaluated with rapidity and efficiency corrosion inhibitors. In relation to the isotherms, the than best appropriated was the in Langmuir and in the concentrations studied, the that obtained the best efficiency was the concentration of 75 ppm / Inibidores de corros?o em solu??o s?o utilizados para minimizar processos de corros?o em a?o. Na presente disserta??o foi avaliada a efici?ncia de inibi??o do tensoativo ?leo de coco saponificado (OCS) no a?o carbono 1020, atrav?s da t?cnica eletroqu?mica polariza??o linear, bem como, estudado o processo de adsor??o atrav?s das isotermas de Langmuir, Frumkin e Temkin. A corrente de corros?o foi determinada atrav?s da extrapola??o de Tafel nas curvas de polariza??o e, ent?o, foi calculada a efici?ncia do inibidor para cada concentra??o e temperatura. Foram estudadas quatro concentra??es (12,5, 25,0, 50,0 e 75,0 ppm) do inibidor OCS e uma do sal NaCl (10.000 ppm) em seis temperaturas (301, 308, 313, 318, 323 e 328 K) em triplicata. Pelos resultados obtidos, observou-se que a t?cnica utilizada pode avaliar com rapidez e efici?ncia inibidores de corros?o. Em rela??o ?s isotermas, a que melhor se adequou foi a de Langmuir e dentre as concentra??es estudadas a que obteve a melhor efici?ncia foi ? concentra??o de 75 ppm

Οι ζεόλιθοι είναι κρυσταλλικά αργιλοπυριτικά υλικά με πόρους μοριακών διαστάσεων και για το λόγο αυτό συχνά καλούνται και ως μοριακά κόσκινα. Χαρακτηρίζονται από την ικανότητα ρόφησης αερίων και ατμών, ανταλλαγής των κατιόντων της δομής τους, καθώς και κατάλυσης σημαντικού αριθμού χημικών αντιδράσεων. Λόγω των ιδιαίτερων φυσικοχημικών ιδιοτήτων τους, οι ζεόλιθοι αποτελούν ιδανικά υλικά για το διαχωρισμό μορίων με διαφορετικό σχήμα, μέγεθος ή πολικότητα γι’αυτό την τελευταία δεκαετία μέρος του ερευνητικού ενδιαφέροντος έχει επικεντρωθεί στην ανάπτυξη πολυκρυσταλλικών μεμβρανών από ζεόλιθους με σκοπό το διαχωρισμό αερίων και υγρών μιγμάτων. Στην παρούσα Διατριβή μελετήθηκε η κρυστάλλωση μεμβρανών φωγιασίτη πάνω σε πορώδη υποστρώματα από α-Al2O3 με επίπεδη και κυλινδρική γεωμετρία συναρτήσει διαφόρων παραμέτρων σύνθεσης όπως ήταν η σύσταση, η θερμοκρασία, ο χρόνος και η γήρανση των αιωρημάτων σύνθεσης των μεμβρανών Συνολικά εξετάστηκαν πέντε διαφορετικές συστάσεις. Η σύσταση 4.17Na2O : 1.0Al2O3 : 10TEA (τριαιθανολαμίνη) : 1.87SiO2 : 460H2O οδήγησε στην ανάπτυξη μεμβρανών φωγιασίτη με λιγότερες ατέλειες και για αυτό μελετήθηκε περισσότερο. Η ικανότητα των μεμβρανών να διαχωρίζουν μίγματα CO2 / H2, CO2 / N2, CO2 / CH4, CO2 / H2 / N2 / CH4, C3H6 / C3H8, C3H6 / N2, C3H8 / N2 και C3H6 / C3H8 / N2 εξετάστηκε συναρτήσει της θερμοκρασίας, της σύστασης και της πίεσης της τροφοδοσίας καθώς και της παρουσίας ή μη υγρασίας στο ρεύμα της τροφοδοσίας. Τα πειράματα διαπερατότητας απέδειξαν, ότι ευνοείται η εκλεκτική μεταφορά κυρίως του CO2 και του C3H6 μέσα από τις μεμβράνες. Η εκλεκτικότητα μπορεί να αποδοθεί στην ισχυρή αλληλεπίδραση των μορίων αυτών με τα κατιόντα Na+ που περιέχονται στη δομή του φωγιασίτη. Τέλος, μελετήθηκαν οι μηχανισμοί μεταφοράς μάζας των μιγμάτων CO2 / H2 και CO2 / H2 / N2 / CH4 με τη χρήση της θεωρίας Stefan-Maxwell. Επιπρόσθετα εξετάστηκαν διάφορες περιπτώσεις αργού σταδίου (διάχυση και εκρόφηση) καθώς και συνδυασμοί διαφορετικών μηχανισμών διάχυσης (επιφανειακή διάχυση και ενεργοποιημένη διάχυση αερίων). Οι συντελεστές διάχυσης υπολογίστηκαν από το συνδυασμό των πειραματικών δεδομένων ρόφησης και διαπερατότητας των καθαρών συστατικών. Η ανάλυση που πραγματοποιήθηκε οδήγησε στο συμπέρασμα ότι η μεταφορά των μιγμάτων μέσα από τις μεμβράνες μπορεί να προβλεφθεί κυρίως από το μηχανισμό της επιφανειακής διάχυσης. / Zeolites are crystalline aluminosilicate materials. They are frequently called molecular sieves because they have pores of molecular dimensions. They are able to adsorb gases or vapors, to exchange framework cations and to catalyze a large number of chemical reactions. Due to their physicochemical properties they are ideal materials for the discrimination of molecules based on their shape, size or polarity. The last decade part of the research attention has been focused on the synthesis of polycrystalline zeolite membranes for the separation of gas and vapor mixtures. In the present thesis the crystallization of faujasite membranes on porous flat or tubular α-Al2O3 substrates was studied as a function of several synthesis parameters such as composition, temperature, time and aging of sol mixtures. Five different compositions were examined. Membranes synthesized using sols with composition 4.17Na2O : 1.0Al2O3 : 10TEA (triethanolamine) : 1.87SiO2 : 460H2O, had the best separation performance. The ability of the membranes to separate CO2 / H2, CO2 / N2, CO2 / CH4, CO2 / H2 / N2 / CH4, C3H6 / C3H8, C3H6 / N2, C3H8 / N2 and C3H6 / C3H8 / N2 mixtures was examined as a function of temperature, feed mixture composition, total feed pressure and the presence or not of humidity in the feed side. In all cases the membranes were either CO2 or C3H6 selective. The separation ability can be attributed to the strong interaction between those molecules with the Na+ cations of the faujasite framework. The transport of CO2, H2, N2 and CH4 through the membranes was modeled using the Maxwell-Stefan theory. Two different cases of rate limiting step (diffusion and desorption) as well as several combinations of different diffusion mechanisms (surface diffusion and activated gaseous diffusion) were considered. The diffusion coefficients were calculated using the single-component permeation and adsorption data. It has been possible to predict the multicomponent permeation fluxes when surface diffusion was assumed the transport mechanism of all species.

Analytical chemistry is a field with a vast variety of applications. A robust companion in the field is liquid chromatography, the method used in this thesis, which is an established workhorse and a versatile tool in many different disciplines. It can be used for identification and quantification of interesting compounds generally present in low concentrations, called analytical scale chromatography. It can also be used for isolation and purification of high value compounds, called preparative chromatography. The latter is usually conducted in large scale with high concentrations. With high concentrations it is also possible to determine something called adsorption isotherms. Determination of adsorption isotherms is a useful tool for quite a wide variety of reasons. It can be used for characterisation of chromatographic separation systems, and then gives information on the retention mechanism as well as provides the possibility to study column-column and batch-batch reproducibility. If a protein is immobilised on a solid support, adsorption isotherms can be used for pharmacological characterisation of drug-protein interactions. Moreover, they can be used for the study of unexpected chromatographic phenomena. If the adsorption isotherm is known it is also possible to simulate chromatograms, and subsequently optimise the separation process numerically. The gain of a numerically optimised separation process is higher purity or yield of valuable compounds such as pharmaceuticals or antioxidants, as well as reducing the solvent usage. Taken all together, it saves time, money and the environment. However, the process of the adsorption isotherm determination requires a number of careful experimental considerations and preparations, and these are the main focus of the thesis. Important steps along the way include the choice of separation system and of suitable analytes, preparation of mobile phases and sample solutions, calibration, determination of injection profiles and column void, and of course the adsorption isotherm determination method itself. It is also important to keep track of parameters such as temperature and pH. These issues are discussed in this thesis. At the end, a description of useful methods for processing of the raw adsorption isotherm data is presented, as well as a brief passage on methods for numerical optimisation.

This thesis concerns the development and validation of methods for the industrially important area of adsorption isotherm parameter estimation in preparative, nonlinear high performance liquid chromatography (HPLC). Preparative chromatography is a powerful separation method to get pure compounds from more or less complex liquid mixtures, e.g., mixtures of mirror-image molecules. Computer simulations can be used to optimize preparative chromatography, but then competitive adsorption isotherm parameters are usually required. Here two methods to estimate adsorption isotherm parameters are treated: (i) the perturbation peak (PP) method and (ii) the inverse method (IM). A new theory for the PP method was derived and led to a new injection technique which was validated experimentally. This injection technique solved the severe problem with vanishing peaks and enabled us to use the PP method to estimate binary competitive adsorption isotherms valid over a broad concentration range. Also, the injection technique made it possible to estimate competitive adsorption isotherms for a quaternary mixture for the first time. Finally, an interesting perturbation peak phenomenon, known as the “Helfferich Paradox”, was experimentally verified for the first time. The IM is a relatively new method to determine adsorption isotherm parameters. It has the advantage of requiring very small samples, but also requires an advanced computer algorithm. An improved implementation of this computer algorithm was developed and tested experimentally. Also, a variant of the IM called “the inverse method on plateaus” was tested experimentally and the estimated adsorption isotherm parameters were shown to be valid over a broader concentration range than those estimated with the standard IM.