Choosing the right solvent is critical for many industrial applications. A useful property for selection of solvents is their solubility parameters. This concept of solubility parameters is central to this thesis and has been used in two different case studies of material treatment applications. Silicone rubber (crosslinked poly(dimethyl siloxane), PDMS) has many favorable material properties making it useful in biomedical devices. However, a limiting aspect of its material properties is a hydrophobic surface. The aim of this work was to prepare a hydrophilic PDMS material while retaining the transparency of the material. To do this, PDMS was combined with a hydrophilic polymer, polyvinylpyrrolidone (PVP) in an interpenetrating polymer network (IPN). A two-step IPN synthesis method was developed and it was found that the solvent used for polymerization of PVP had a significant influence on the water-wettability and the transparency of the PVP/PDMS IPN. Several different analytical techniques were used for determining the degree of phase separation in the PVP/PDMS IPN. It was found, by using microscopy techniques, that the PVP phase domains varied between 200 nm up to a few micrometers, and the size of the phase domains was correlated to the solvent used for polymerization of the IPN. The second topic for which solvent effects were explored was for the use of mesoporous silica particles as potential drug delivery devices. In the present work a drug molecule, ibuprofen, was loaded into mesoporous silica particles using different solvents, and in addition adsorption isotherms were established in each solvent. The maximum loading of ibuprofen in the mesoporous material was achieved when using a nonpolar solvent, in particular liquid carbon dioxide was successfully used. One of the advantages of using liquid carbon dioxide is that no solvent residues are left in the final material, which is important for pharmaceutical applications. Furthermore, it was concluded that ibuprofen was stored in an X-ray amorphous form in the mesoporous particles. Release studies in water showed a rapid release of ibuprofen from the mesoporous silica particles, while the dissolution of samples with crystalline ibuprofen was slower. This was verified to be an effect of a larger exposed ibuprofen area in the ibuprofen-loaded mesoporous silica particles, and it was concluded that the intrinsic dissolution rate for the samples were identical.

The Onsager heat of transport for p-tert-butyltoluene was measured, as part of a series of preliminary experiments towards the determination of the importance of temperature gradients on the air-sea flux of carbon dioxide. The results presented in this thesis imply that the temperature gradient is a major contributor to the magnitude of the air-sea flux. The heat of transport has been measured for the p-tert-butyltoluene system by measuring stationary-state pressure changes for known temperature differences on the vapour side of the interface. At the pressure ranges used the number of mean free paths was always outside the Knudsen zone, but the values of Q* were approximately 100 % of the latent heat of vaporisation. Departures from linearity of plots of P against ΔT are attributed to temperature jumps at the surface of the dry upper plate. Both the results taken for p-tert-butyltoluene and the earlier results for water from this laboratory fit to a Type III BET isotherm, where the c parameter is not constant. They also reveal the importance of the temperature gradient in determining the value of the thermal accommodation coefficient, and provide a new method of measuring thermal accommodation coefficients for a variety of surfaces and vapours

Nas etapas de processamento do couro, de limpeza da pele, de recortes e ajuste da espessura do couro, diferentes tipos de resíduos sólidos são gerados. Dentre esses resíduos, os pelos provenientes da etapa de depilação são descartados. Além disso, nas etapas finais do acabamento molhado do couro, em especial no tingimento, são adicionados corantes e outros produtos químicos com o objetivo de dar ao couro características superficiais, como cor e textura, gerando, consequentemente, efluentes de difícil tratamento devido ao potencial recalcitrante dos produtos químicos. O objetivo deste trabalho é apresentar uma alternativa ao uso do pelo proveniente da etapa de depilação, possibilitando assim uma extensão no ciclo de vida deste resíduo como um adsorvente alternativo para remoção de corantes empregados na indústria do couro. O pelo (CHW) foi caracterizado através de microscopia eletrônica de varredura (MEV), espectroscopia de raios X dispersiva de energia (EDS), espectroscopia de infravermelho (FTIR), bem como sua área superficial específica e distribuição de tamanho de poro por análises de BET/BJH. A capacidade de remoção dos corantes Azul Ácido 161 (AB-161) e Preto Ácido 210 (AB-210) em soluções aquosas foi estudada emfaixas de pH de 1,0 a 10,0 e também a dosagem ótima de adsorvente. Nas isotermas de adsorção,o modelo de Liu foi o que melhor apresentou resultados para os dois corantes estudados em todas as temperaturas analisadas (30, 40 e 50ºC) No estudo cinético, o modelo de ordem-geral apresentou o melhor ajuste dos dados, com menor tempo de contato para remoção do corante AB-161 de 600 min com o pelo (CHW) e 90 min com o carvão ativado comercial (CAC), nos valores de pH 3,0 e pH 4,0, respectivamente. Para o corante AB-210 o menor tempo de contato para atingir o equilíbrio foi de 120 min e 90 min para CHW e o CAC, nos valores ótimos de pH de 2,0 e 4,0, respectivamente. O carvão produzido (AC-CHW) a partir do pelo residual foi ativado com H3PO4, caracterizado e testado em efluentes reais para remoção dos corantes Laranja Ácido 142 (AO-142) e Marrom Ácido 414 (AB-414). O carvão produzido apresentou um elevado diâmetro de poro (140,70 A), o que favoreceu a adsorção de moléculas maiores e mais complexas, como as presentes nos efluentes reais. Através do MEV e do FTIR observou-se a presença dos compostos estudados no AC-CHW após aadsorção, onde os resultados indicaram que os grupos funcionais de -CH=CH- participaram ativamente do processo de remoção. O pHzero obtido do AC-CHWfoi de 3,65, o que favoreceu a remoção desses compostos já que o efluente real apresenta um pH inferior a 4,0. Os percentuais de remoção obtidos de área sob as curvas de adsorção indicam uma remoção de 51,94% e 49,73% dos efluentes contendo AB-414 e AO-142, respectivamente. / In the stages of leather processing, skin cleansing, trimming and leather thickness adjustment, different types of solid waste are generated. Among these residues, hairs from the depilation stage are discarded. In addition, in the final stages of the wet finishing of leather, in particular in dyeing, dyes and other chemical products are added with the aim of giving the leather surface characteristics, such as color and texture, thus generating effluents that are difficult to treat due to the potential recalcitrant of chemicals. The objective of this work is to present an alternative to the use of hair from the depilation stage, thus allowing an extension in the life cycle of this residue as an alternative adsorbent for the removal of dyes used in the leather industry. The hair (CHW) was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), infrared spectroscopy (FTIR), as well as its specific surface area and pore size distribution by analysis of BET/BJH. The ability to remove Acid Blue 161 (AB-161) and Acid Black 210 (AB-210) dyes in aqueous solutions was studied in pH ranges from 1 to 10 and also the optimum dosage of adsorbent. In the adsorption isotherms, Liu model presented the best results for the two dyes studied at all temperatures (30, 40 and 50ºC). In the kinetic study, the general-order model presented the best fit of the data, with a lowest contact time to remove the AB-161 dye of 600 min with the hair (CHW) and 90 min with the commercial activated charcoal (CAC) at pH 3.0 and pH 4.0, respectively For the dye AB-210, the lowest contact time to reach equilibrium was 120 min and 90 min for CHW and CAC, at the optimum pH values of 2.0 and 4.0, respectively. The charcoal produced (AC-CHW) from the residual was activated with H3PO4, characterized and tested in actual effluents to remove the Acid Orange 142 (AO-142) and Acid Brown 414 (AB-414) dyes. The carbon produced had a high pore diameter (140,70 A), which favored the adsorption of larger and more complex molecules, such as those present in the actual effluents. The presence of the compounds studied in the AC-CHW after adsorption was observed through the SEM and the FTIR, where the results indicated that the functional groups of -CH = CH- actively participated in the removal process. The obtained pHzero of AC-CHW was 3.65, which favored the removal of these compounds since the actual effluent had a pH lower than 4.0. The percentages of removal obtained from area under the adsorption curves indicate a 51.94% and 49.73% removal of the effluents containing AB-414 and AO-142, respectively.

Made available in DSpace on 2014-06-11T19:25:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-02-24Bitstream added on 2014-06-13T18:29:01Z : No. of bitstreams: 1 britto_pf_me_ilha.pdf: 560643 bytes, checksum: 54cea600ab279deb0d7e2d6533cdb694 (MD5) / A combinação de diferentes tipos de materiais para obtenção de novas propriedades tem despertado grande interesse em vários campos da ciência de materiais. Em processos de separação, é de considerável interesse o uso de materiais com propriedades básicas extremamente diferentes. Entre os suportes mais usados está a sílica gel, um material com tamanho de partículas e porosidade bem definidas, elevada área superficial, e estabilidades mecânica, química e térmica elevadas. Neste contexto, a sílica gel modificada com grupos organofuncionais pode ser utilizada para a adsorção de íons metálicos em soluções aquosas e não aquosas, pré-concentração e separação de íons metálicos. Neste trabalho, a sílica gel 60 (Merck), com tamanho de partículas entre 0,2 e 0,05 mm e área superficial específica de 486 m2.g-1, foi quimicamente modificada em duas etapas. Primeiro, a sílica gel foi quimicamente modificada com 3-cloropropiltrimetoxisilano, resultando o 3-cloropropil sílica gel (CPSG). Na segunda etapa, o produto resultante, CPSG, reagiu com 2-mercaptopirimidina e 4-amino-2-mercaptopirimidina, resultando os materiais sólidos 2-mercaptopirimidina-propil sílica gel (MPSG) e 4-amino-2-mercaptopirimidinapropil sílica gel (AMSG). As quantidades de grupos funcionais conectados na superfície da sílica gel, N0, foram 7,007 x 10-4 mols e 7,416 x 10-4 mols de moléculas por grama de sílica, para MPSG e AMSG, respectivamente. Conhecendo a área superficial específica e assumindo que as moléculas cobrem uniformemente a superfície, a densidade média, d, das moléculas ancoradas e a distância intermolecular média, l, podem ser calculadas aplicando as equações d = N0 N/SBET e l = (l/d) 1/2 , onde N é o número de Avogadro. Os valores calculados são d = 1,42 moléculas.nm2 e l = 0,979 nm, e d = 1,166 moléculas.nm2 e l = 0,926 nm, para MPSG e... . / The combination of different type of materials for achieving novel properties has always been of high interest in many fields of the materials sciences. The use of materials with extremely different basic properties, like organic and inorganic compounds, is of considerable interest in separation processes. Among the supports the most used is silica gel, a material of well-established particle sizes and well-define porosity, high surface area, and high mechanical, chemical, and thermal stability. In this context, silica gel modified with organofunctional groups has been used for adsorption of metal ions from aqueous and non-aqueous solutions, pre-concentration and separation of metallic ions. In this work, silica gel 60 (Merck) having secondary particles sized between 0,2 and 0,05 mm and specific surface area of 486 m2.g-1 was modified using a two step approach. First, the silica gel was chemically modified with 3- chloropropyltrimetoxysilane, resulting the 3-chloropropyl-silica gel (CPSG). Second, the resultant product, CPSG, reacted with 2-mercaptopyrimidine and 4-amino-2- mercaptopyrimidine, resulting the solid materials 2-mercaptopyrimidine-propyl-silica gel (MPSG) and 4-amino-2-mercaptopyrimidine-propyl-silica gel (AMSG). The quantities of functional groups attached on the silica gel surface, No, were 7,007 x 10-4 mols e 7,416 x 10-4 mols .g-1 of molecules per gram of silica, for MPSG and AMSG, respectively. It being known the specific surface area and assuming that the molecules uniformly cover the surface, the average density, d, of the attached molecules and the average intermolecular distance, l, can be calculated by applying the equations: d = N0 N /SBET and l = (l/d)1/2, where N is Avogadro's number. The calculated values were d = 1,042 molecules.nm-2 and l = 0,979 nm and d = 1,166 molecules.nm-2 and... (Complete abstract click electronic address below).

Nas etapas de processamento do couro, de limpeza da pele, de recortes e ajuste da espessura do couro, diferentes tipos de resíduos sólidos são gerados. Dentre esses resíduos, os pelos provenientes da etapa de depilação são descartados. Além disso, nas etapas finais do acabamento molhado do couro, em especial no tingimento, são adicionados corantes e outros produtos químicos com o objetivo de dar ao couro características superficiais, como cor e textura, gerando, consequentemente, efluentes de difícil tratamento devido ao potencial recalcitrante dos produtos químicos. O objetivo deste trabalho é apresentar uma alternativa ao uso do pelo proveniente da etapa de depilação, possibilitando assim uma extensão no ciclo de vida deste resíduo como um adsorvente alternativo para remoção de corantes empregados na indústria do couro. O pelo (CHW) foi caracterizado através de microscopia eletrônica de varredura (MEV), espectroscopia de raios X dispersiva de energia (EDS), espectroscopia de infravermelho (FTIR), bem como sua área superficial específica e distribuição de tamanho de poro por análises de BET/BJH. A capacidade de remoção dos corantes Azul Ácido 161 (AB-161) e Preto Ácido 210 (AB-210) em soluções aquosas foi estudada emfaixas de pH de 1,0 a 10,0 e também a dosagem ótima de adsorvente. Nas isotermas de adsorção,o modelo de Liu foi o que melhor apresentou resultados para os dois corantes estudados em todas as temperaturas analisadas (30, 40 e 50ºC) No estudo cinético, o modelo de ordem-geral apresentou o melhor ajuste dos dados, com menor tempo de contato para remoção do corante AB-161 de 600 min com o pelo (CHW) e 90 min com o carvão ativado comercial (CAC), nos valores de pH 3,0 e pH 4,0, respectivamente. Para o corante AB-210 o menor tempo de contato para atingir o equilíbrio foi de 120 min e 90 min para CHW e o CAC, nos valores ótimos de pH de 2,0 e 4,0, respectivamente. O carvão produzido (AC-CHW) a partir do pelo residual foi ativado com H3PO4, caracterizado e testado em efluentes reais para remoção dos corantes Laranja Ácido 142 (AO-142) e Marrom Ácido 414 (AB-414). O carvão produzido apresentou um elevado diâmetro de poro (140,70 A), o que favoreceu a adsorção de moléculas maiores e mais complexas, como as presentes nos efluentes reais. Através do MEV e do FTIR observou-se a presença dos compostos estudados no AC-CHW após aadsorção, onde os resultados indicaram que os grupos funcionais de -CH=CH- participaram ativamente do processo de remoção. O pHzero obtido do AC-CHWfoi de 3,65, o que favoreceu a remoção desses compostos já que o efluente real apresenta um pH inferior a 4,0. Os percentuais de remoção obtidos de área sob as curvas de adsorção indicam uma remoção de 51,94% e 49,73% dos efluentes contendo AB-414 e AO-142, respectivamente. / In the stages of leather processing, skin cleansing, trimming and leather thickness adjustment, different types of solid waste are generated. Among these residues, hairs from the depilation stage are discarded. In addition, in the final stages of the wet finishing of leather, in particular in dyeing, dyes and other chemical products are added with the aim of giving the leather surface characteristics, such as color and texture, thus generating effluents that are difficult to treat due to the potential recalcitrant of chemicals. The objective of this work is to present an alternative to the use of hair from the depilation stage, thus allowing an extension in the life cycle of this residue as an alternative adsorbent for the removal of dyes used in the leather industry. The hair (CHW) was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), infrared spectroscopy (FTIR), as well as its specific surface area and pore size distribution by analysis of BET/BJH. The ability to remove Acid Blue 161 (AB-161) and Acid Black 210 (AB-210) dyes in aqueous solutions was studied in pH ranges from 1 to 10 and also the optimum dosage of adsorbent. In the adsorption isotherms, Liu model presented the best results for the two dyes studied at all temperatures (30, 40 and 50ºC). In the kinetic study, the general-order model presented the best fit of the data, with a lowest contact time to remove the AB-161 dye of 600 min with the hair (CHW) and 90 min with the commercial activated charcoal (CAC) at pH 3.0 and pH 4.0, respectively For the dye AB-210, the lowest contact time to reach equilibrium was 120 min and 90 min for CHW and CAC, at the optimum pH values of 2.0 and 4.0, respectively. The charcoal produced (AC-CHW) from the residual was activated with H3PO4, characterized and tested in actual effluents to remove the Acid Orange 142 (AO-142) and Acid Brown 414 (AB-414) dyes. The carbon produced had a high pore diameter (140,70 A), which favored the adsorption of larger and more complex molecules, such as those present in the actual effluents. The presence of the compounds studied in the AC-CHW after adsorption was observed through the SEM and the FTIR, where the results indicated that the functional groups of -CH = CH- actively participated in the removal process. The obtained pHzero of AC-CHW was 3.65, which favored the removal of these compounds since the actual effluent had a pH lower than 4.0. The percentages of removal obtained from area under the adsorption curves indicate a 51.94% and 49.73% removal of the effluents containing AB-414 and AO-142, respectively.

Orientador: Yoshitaka Gushikem / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-09T15:34:14Z (GMT). No. of bitstreams: 1 Pissetti_FabioLuiz_D.pdf: 855103 bytes, checksum: e55ee07323e46240da5c3f9bf26b3491 (MD5) Previous issue date: 2007 / Resumo: Neste trabalho foram preparadas redes poliméricas com propriedades elastoméricas a partir do poli(dimetilsiloxano) (PDMS), modificadas com íon piridínio ou etilenodiamina. Os materiais preparados foram caracterizados por espectroscopia no infravermelho, análise termogravimétrica, calorimetria diferencial de varredura e ressonância magnética nuclear de C e Si. Os resultados destas análises mostraram que ambos os materiais apresentam boa estabilidade térmica e uma temperatura de transição vítrea de ~ 160 K. Os dados de RMN indicaram que rede foi formada pela reticulação das cadeias lineares de PDMS por ¿clusters¿ de siloxanos do tipo T, provenientes da hidrólise/condensação de 3-cloropropiltrimetoxissilano e do 2-aminoetil-3- aminopropiltrimetoxissilano. Além disso, por ensaios de intumescimento foi calculada a massa molecular média entre os nós da rede polimérica e também a densidade de reticulação dos materiais. Os valores encontrados sugerem um alto grau de reticulação para ambos os materiais estudados. A rede modificada com etilenodiamina apresentou a maior densidade de reticulação. Com intuito de avaliar a potencialidade dos materiais como adsorventes de íons metálicos de uma solução etanólica, foram obtidas isotermas de adsorção. Para o material modificado com o íon piridínio os metais estudados foram o Co, Cu e Fe, que foram retirados da solução com boa eficiência, 0,25, 0,29 e 0,45 mmol g, respectivamente. Os haletos metálicos foram adsorvidos pela rede polimérica modificada na forma de complexos aniônicos FeCl4¨, CuCl4 e CoCl4. Os resultados de UV-Vis sugeriram que os complexos formados na interface têm uma simetria tetraédrica ou tetraédrica distorcida. Para a rede modificada com etilenodiamina foram estudados os metais Cu, Ni e Fe. Neste caso o material apresentou uma elevada capacidade de adsorção para os cloretos de Fe (1,35 mmol g) e Cu (1,25 mmol g), enquanto que, para o Ni a capacidade de adsorção foi consideravelmente menor, 0,36 mmol g. Os resultados de espectro eletrônico para este material sugeriram que o cobre é adsorvido pela rede polimérica modificada na forma do complexo, [Cu(en)], com uma estrutura tetraédrica distorcida, enquanto que para o níquel os resultados sugeriram formação de um complexo octaédrico. Os dados obtidos nas isotermas de adsorção foram usados para calcular as constantes de equilíbrio para a adsorção dos íons metálicos. Estes resultados permitiram verificar que no material modificado com o íon piridínio a adsorção de CoCl2 e CuCl2 segue o modelo descrito por Langmuir. Para a adsorção do FeCl3 outro modelo, em que centro adsorvedor é composto por dois grupos ligantes, foi necessário para descrever o processo de adsorção. Neste caso, há um efeito cooperativo entre as espécies formadas na superfície. Para o material modificado com etilenodiamina, os cálculos mostraram que a adsorção dos três íons metálicos pode ser descrito adequadamente pelo modelo de Langmuir / Abstract: In this work elastomeric polymeric networks based on poly(dimethilsiloxane) PDMS, modified with pyridine ion or ethylenediamine, were prepared. These materials were characterized by infrared spectrometry, thermogravimetric analysis, differential scanning calorimetry and nuclear magnetic resonance (NMR) of Si and C. The results showed that both materials presented a good thermal stability and a glass transition temperature at ~ 160 K. The NMR data indicated that the polymeric network was formed by PDMS linear chain crosslinked with siloxane clusters of T Si units formed from hydrolyses/condensation of 3-chloropropyltrimethoxysilane or 2-aminoethyl-3- aminopropyltrimethoxysilane. Using the swelling measurements, the average molecular weight between crosslinking points and the polymeric network crosslinking density were calculated. The results obtained suggested a high degree of crosslinking for the prepared materials, which was higher for the ethylenediamine. To evaluate the potential use of the prepared materials as adsorbents, adsorption isotherms were obtained from an ethanolic solution. For the polymeric network modified with pyridine ion the metallic ions studied were Cu, Co and Fe, which were adsorbed with high efficiency of 0.25, 0.29 e 0.45 mmol g, respectively. Metal halides were adsorbed by the modified polymeric network as an anionic complex, FeCl4¨, CuCl4 and CoCl4. The UV-Vis data suggested that the formed complexes at surface presented a tetrahedral symmetry or distorted tetrahedral symmetry. For The polymeric network modified with ethylenediamine, the metallic ions studied were Cu, Ni and Fe. In this case, the material showed a higher capacity of adsorption for Fe (1.35 mmol g) and Cu (1.25 mmol g), while, to Ni that capacity was significantly lower, 0.36 mmol g. The electronic spectra data suggested that the copper was adsorbed by the modified polymeric network as [Cu(en)], with a distorted tetrahedral symmetry, while the nickel was adsorbed with a octahedral symmetry. From the isotherm data, the equilibrium constants of the metallic ion adsorption were calculated. These results allowed verifying that the adsorptions of CoCl2 e CuCl2 are appropriate described by Langmuir equation. For the FeCl3 another model, which two adsorptions centers are envolved was necessary to describe the adsorption process. In this case, there was a cooperative effect among the adsorbed species. The results for polymeric network modified with ethylenediamine showed an adsorption described by the Langmuir equation for all metallic ions studied / Doutorado / Quimica Inorganica / Doutor em Ciências

Ce doctorat porte sur la fonctionnalisation de silices colloïdales en vue de la rétention de micropolluants métalliques dans des effluents. Les nanoparticules et microparticules ouvrent des potentialités d’application dans de nombreux secteurs industriels (chimie, environnement, pharmacie...). Ainsi, ces travaux de recherche portent sur la synthèse et la caractérisation de matériaux composites submicroniques : il s’agit de silices colloïdales sur lesquelles sont greffés des silanes ou supportés des polysaccharides. Une des applications de ces travaux de recherche porte sur l’adsorption de métaux de transition sur ces composites en solution aqueuse. Dans le cadre de ce doctorat, les caractéristiques des composites sont définies par leur morphologie de surface, par l’étude des groupements fonctionnels présents, par détermination de leurs surfaces spécifiques ainsi qu’en solution aqueuse par détermination de leurs diamètres hydrodynamiques et de leurs potentiels zéta. Dans un premier temps, la fonctionnalisation de la silice a permis le greffage de groupements carboxyliques et amines dont tes taux de greffage obtenus ont été respectivement de 0,47 µmol/m² et 3,86 µmol/m². En présence de groupements amines, le potentiel  des composites est positif jusqu’ à pH 9 alors qu’il est négatif dès pH 3 pour des silices non fonctionnalisées. Dans un second temps, la silice est supportée par du chitosane dont le degré de désacétylation est de 77%. Conjointement, l’encapsulation de la silice est réalisées par du chitosane sur lequel des fonctions carboxyliques ont été greffées. La morphologie des particules est alors modifiée, leurs diamètres hydrodynamiques sont plus élevés et leurs potentiels  sont positifs jusqu’ à pH basique. La rétention d’ions métalliques (Cu(II) et Ni(II)) par ces composites à différents pH est ensuite étudiée. Pour chacun des cations métalliques, les capacités d’adsorption sont déterminées ainsi que les cinétiques d’adsorption. L’application de plusieurs modèles d’isotherme d’équilibre a été réalisée. Dans le cas de Cu(II), à pH 5, les meilleures capacités d’adsorption sont obtenues pour des silices supportées par du chitosane greffé : la capacité de rétention des ions Cu(II) est de 270 mg/g à pH 5. De même, c’est ce composite qui permet la meilleurs rétention des ions Ni(II) à pH 7 avec une capacité d’adsorption de 263 m/g. Concernant la cinétique, le modèle de réaction de surface du pseudo-second ordre s’applique bien aux résultats expérimentaux. / This study is focused on the preparation of three types of silica-based composites for the capture of Cu(II) and Ni(II) ions. The first strategy consists in coating chitosan on colloidal fumed silica after acidic treatment yielding the composite SiO2+CS. The second strategy can be separated into two routes: the first one involves surface grafting of silica with aminopropyltriethoxysilane to obtaining silica particles covered by amino groups (SiO2(NH2)). The second one involves in surface condensation of triethoxysilylbutyronitrile, followed by acidic hydrolysis of the surface-bound nitrile groups affording silica particles covered by carboxyl groups (SiO2(CO2H)). In the last step, chitosan has been grafted on the surface bound NH2 or -CO2H groups yielding the composites SiO2(NH2)+CS or SiO2(CO2H)+CS. The third strategy involves in the modified CS surface with -CO2H groups, followed by coating onto the non-modified silica nanoparticles to obtain the composite SiO2+CS(CO2H). The novel hybrid materials were characterized by IR spectroscopy, scanning electron microscopy, atomic force microscopy, and zeta potential measurements. Batch experiments were conducted to study the sorption performance of these composites for Cu(II) and Ni(II) removal from aqueous solution at optimum pH at 298 K. The kinetics were evaluated utilizing pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The adsorption kinetics followed the mechanism of the pseudo-second-order equation for all types of adsorbents. The adsorption isotherms were evaluated utilizing Langmuir, Freundlich, and Temkin models. The best interpretation for equilibrium data was given by Langmuir isotherm model. This study demonstrates that the adsorption capacities for Cu(II) ion is more efficient for the SiO2+CS (256 mg g-1) compared to SiO2(NH2) (75 mg g-1). However, the carboxyl grafted CS-coated silica (SiO2+CS(CO2H) exhibited an excellent adsorption capacity (333 mg g-1). In case of Ni(II), based on Langmuir isotherm the maximum adsorption capacity found to be 182 mg g-1for SiO2+CS, and 210 mg g-1 for SiO2(CO2H) + CS. Using single-metal solutions, these adsorbents were found to have an affinity for metal ions in order as Cu(II) > Ni(II). The adsorption of Cu(II) ion by SiO2+CS was affected by the nature of the respective anion. Application of these composite materials to remove Cu(II) and Ni(II) from aqueous solution was shown to be more efficient than the adsorption capacities of many sorbents probed by other research groups.

This thesis aims at a deeper understanding of Supercritical Fluid Chromatography (SFC). Although preparative SFC has started to replace Liquid Chromatography (LC) in the pharmaceutical industry - because of its advantages in speed and its less environmental impact - fundamental understanding is still lacking. Therefore there is no rigid framework to characterize adsorption or to understand the impact of changes in operational conditions.   In Paper I we demonstrated, after careful system verification, that most methods applied to determine adsorption isotherms in LC could not be applied directly in SFC. This was mainly due to operational differences and to the fact that the fluid is compressible which means that everything considered constant in LC varies in SFC.   In Paper II we showed that the most accurate methods for adsorption isotherm determination in LC, the so called plateau methods, do not work properly for SFC. Instead, methods based on overloaded profiles should be preferred.   In Paper III a Design of Experiments approach was successfully used to quantitatively describe the retention behavior of several solutes and the productivity of a two component separation system. This approach can be used to optimize SFC separations or to provide information about the separation system.   In Paper IV severe peak distortion effects, suspected to arise from injection solvent and mobile phase fluid mismatches, were carefully investigated using experiments and simulations. By this approach it was possible to examine the underlying reasons for the distortions, which is vital for method development.   Finally, in Paper V, the acquired knowledge from Paper I-IV was used to perform reliable scale-up in an industrial setting for the first time. This was done by carefully matching the conditions inside the analytical and preparative column with each other. The results could therefore provide the industry with key knowledge for further implementation of SFC. / This thesis aims at a deeper understanding of Supercritical Fluid Chromatography (SFC). Although preparative SFC has started to replace Liquid Chromatography (LC) in the pharmaceutical industry - because of its advantages in speed and its less environmental impact - fundamental understanding is still lacking. Therefore there is no rigid framework to characterize adsorption or to understand the impact of changes in operational conditions.   In Paper I-II it was demonstrated why most methods applied to determine adsorption isotherms in LC could not be applied directly for SFC. Methods based on extracting data from overloaded profiles should be preferred.   In Paper III a Design of Experiments approach was successfully used to quantitatively describe the behavior of several solutes in a separation system. This approach can be used to optimize SFC separations or to provide information about the separation system.   In Paper IV severe peak distortion effects often observed in SFC were carefully investigated and explained using experiments and simulations.   Finally, in Paper V, the prerequisites for performing reliable and predictable scale-up of SFC were investigated by small and large scale experiments. / <p>Paper 4 ("Evaluation of scale-up from analytical to preparative...") ingick som manuskript med samma titel i avhandlingen. Nu publicerad. </p>

Este trabalho consistiu em uma investigação sobre a utilização da sílica mesoporosa ordenada tipo SBA-15 como veículo para a incorporação, proteção, transporte e liberação de substâncias biológicas de interesse imunológico e/ou terapêutico. Estudos preliminares incluíram experimentos para estudar o recobrimento da sílica SBA -15 com o polímero Eudragit® e a estabilidade dessa sílica tanto em meios experimentais (água e solução PBS) quanto em meios corporais rnimetizados. Ambos esses estudos demonstraram que as propriedades da SBA-15 e do Eudragit possibilitariam o prosseguimento do trabalho. Os experimentos iniciais de liberação foram feitos principalmente com albumina bovina (BSA), e demonstraram a capacidade da sílica de incorporar, em sua estrutura, as diversas moléculas utilizadas, bem como a influência do Eudragit sobre a dinâmica de liberação, sobretudo em meio ácido. Também foi explorada a incorporação de compostos à SBA-15 sob pressão, tanto in-situ quanto ex-situ. As intensidades relativas dos picos de difração mostraram ser sensíveis à exerção de pressão sobre a amostra, especialmente no que se referiu à incorporação de insulina. Os experimentos in-si tu durante a incorporação e liberação de insulina ajudaram a elucidar a dinâmica desses fenômenos, através da adaptação do modelo teórico, originalmente utilizado em estudos sobre a síntese da SBA-15. Nesse modelo, parâmetros de ajuste foram monitorados durante o experimento e a partir da sua evolução conclusões puderam ser traçadas. A instrumentação necessária para os experimentos in-situ foi desenvolvida, e fica aqui documentada para referências futuras em experimentos envolvendo soluções expostas ao feixe de raios X, especialmente no equipamento Nanostar, onde o arranjo foi originalmente implementado. Os procedimentos de análise, incluindo o modelo teórico, também ficam à disposição para que estudos futuros possam ser executados. A introdução teórica (Cap. 2), complementada pelos apêndices C e B, fica como resumo da teoria e da técnica para os interessados, que podem ainda consultar a literatura para maiores detalhes. / This work consisted of an investigation on the use of SBA-15-type ordered mesoporous sílica as a vehicle for incorporation, protection, transport and release of biological substances for ímmunologic and/or terapeutic processes. Preliminary studies included experiments regarding the coating ofthe SBA-15 sílica with the Eudragit® polymer and the stability of SBA-15 in experimental media (water and PBS solution) and in simulated body fluids. Both studies demonstrated that the properties o f SBA -15 and Eudragit allowed for continuation o f the work. The initial experiments were performed mainly with bovine serum a1bumin (BSA), and showed the silica\'s capacity of incorporating, in its structure, the various molecules, as well as the influence of Eudragit on the release dynamics. Also, the íncorporation of molecules into SBA-15 under pressure, both in-situ and ex-situ, was explored. The relative intensities of the diffraction peaks were found to be susceptible to the pressure exerted on the sample, especially regarding insulin. In-situ experiments made during the incorporation and release o f insulin helped elucidate the dynamics of those phenomena, through the adaptation of the theoretical model, which was or~ginally desinged to study the synthesis process of the sílica. In this model, fit parameters were monitored during the experiment and from their behavior some conclusions were drawn. The necessary instrumentation for the in-situ experiments was developed, and is documented for future referene in experiments involving the exposure of solutions ro X-rays, especially in the Nanostar, where it was originally designed. The analysis procedures, including the theoretical model, are also available for future studies. The theoretical introduction (Chap. 2), together with appendices B and Ç, is left for those interested in the theory and technique, who are also referred to the literature for further details.

Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2019-02-27T21:17:17Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Ariane Caroline.pdf: 6051822 bytes, checksum: c1a56154adb0e6b52f2cba5bb3654d0b (MD5) / Made available in DSpace on 2019-02-27T21:17:17Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Ariane Caroline.pdf: 6051822 bytes, checksum: c1a56154adb0e6b52f2cba5bb3654d0b (MD5) Previous issue date: 2018-12-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho reporta a preparação, caracterização e aplicação de novos materiais híbridos silsesquioxanos, obtidos a partir do método sol-gel de síntese, que consistiu em reações de hidrólise e policondensação dos precursores a base de sílica e por meio da reação SN2 dos precursores com os ligantes orgânicos 4-(aminometil)piridina e imidazol, obtendo assim o Si4ampy+Cl- e o SiImi+Cl-, respectivamente. Os silsesquioxanos nitrogenados foram submetidos a técnicas de caracterização como RMN, DRX, MEV, UV-VIS, FTIR e BET para confirmação das estruturas apresentadas nesta tese, bem como a organofuncionalização dos materiais. No caso do Si4ampy+Cl-, verificou-se dois sítios de reação com ligação do carbono –α do grupo npropil ao nitrogênio do grupamento amino e do nitrogênio do anel piridínio, com proposta de dois arranjos da cadeia carbônica. O Si4ampy+Cl- foi aplicado na construção de eletrodos modificados com a NiTsPc, utilizando a técnica LbL para a fabricação de filmes finos. O eletrodo na configuração (Si4ampy+Cl-/NiTsPc)11 foi aplicado como sensor eletroquímico sensível ao nitrito, com r = 0,999 na faixa de 0,113 mmol L-1 a 0,860 mmol L-1, LD e LQ de 0,026 mmol L-1 e 0,127 mmol L-1, respectivamente e os valores de desvio-padrão foram de aproximadamente 3%, estando de acordo com recomendações da ANVISA e Inmetro. Outro emprego do Si4ampy+Cl- foi na estabilização de nanopartículas de prata para fabricação de filmes finos. A presença das Ag-NPs/Si4ampy+Cl- foi confirmada por UV-VIS, pela banda plasmon em 426 nm, as quais apresentaram distribuição com tamanho aproximado entre 12 e 131 nm, constatado por DLS e corroborado por MEV, apresentando boa estabilidade (= +43,4 mV). As Ag-NPs/Si4ampy+Cl- mostraram-se promissoras na modificação do eletrodo ITO com a NiTsPc, apresentando um crescimento linear do filme LbL e processos redox referentes à oxirredução do centro metálico e à oxidação do anel da ftalocianina vistos por voltametria cíclica, exibindo a capacidade do eletrodo modificado (Ag-NPs/Si4ampy+Cl-/NiTsPc)7 em eletrocatalisar espécies químicas. No geral, os eletrodos modificados (Si4ampy+Cl-/NiTsPc)11 e (Ag-NPs/Si4ampy+Cl-/NiTsPc)7 proporcionaram aprimoramento na resposta de corrente anódica e redução do potencial de oxidação comparado com o eletrodo não-modificado (ITO) em presença de nitrito. O SiImi+Cl- que foi destinado a adsorção dos íons Cu2+, Cd2+ e Ni2+, apresentou capacidade de troca iônica de 2,944 mmol g-1, resultado considerado excelente de acordo com a literatura para a aplicação proposta. Os resultados de adsorção mostraram a viabilidade do uso do SiImi+Cl- como eficiente material adsorvente, exibindo maior afinidade para os íons Cu2+ em pH 4. Ao aplicar os modelos de Langmuir e Freundlich nas isotermas de adsorção, verificou-se que tanto o pH como a natureza do íon são fatores que influenciaram o ajuste das isotermas aos modelos propostos. / This work reports the preparation, characterization and application of new silsesquioxanes hybrid materials obtained from the sol-gel synthesis method, which consisted of hydrolysis and polycondensation reactions of the silica-based precursors and SN2 reaction of the precursors with 4-(aminomethyl)pyridine and imidazole groups, obtaining Si4ampy+Cl- and SiImi+Cl-, respectively. Silsesquioxanes with nitrogen groups were characterized by techniques such as NMR, XRD, MEV, UV-VIS, FTIR and BET to confirm the structures presented in this thesis, as well as the materials functionalization. In the case of Si4ampy+Cl- two reaction sites were observed with carbon-α of the n-propyl group bonding with the amino group and the pyridinium ring, having as proposal two arrangements of the carbonic chain. The Si4ampy+Cl- was applied in the construction of electrodes modified with NiTsPc using the LbL technique for the thin films manufacture. The electrode in the configuration (Si4ampy+Cl-/NiTsPc)11 was applied for nitrite electrochemical sensor, with r = 0.999 in the range of 0.113 mmol L-1 to 0.860 mmol L-1, LD and LQ of 0.026 mmol L-1 and 0.127 mmol L-1, respectively and standard deviation values of approximately 3%, according to recommendations of ANVISA and Inmetro. Another use of Si4ampy+Cl- was the stabilization of silver nanoparticles for the thin films production. The presence of Ag-NPs/Si4ampy+Cl- was confirmed by UV-VIS technique by the plasmon band at 426 nm which presented a distribution with approximate size between 12 and 131 nm, verified by DLS and MEV, presenting good stability (= +43.4 mV). The Ag-NPs/Si4ampy+Cl- showed promising in the modification of the ITO electrode with NiTsPc, showing linear growth of the LbL film and redox processes related to the oxidation of the metal center and to the oxidation of the phthalocyanine ring observed by cyclic voltammetry, exhibiting the performance of the modified electrode (Ag-NPs/Si4ampy+Cl-/NiTsPc)7 to electrocatalyse chemical species. In general, the modified electrodes (Si4ampy+Cl-/NiTsPc)11 and (Ag-NPs/Si4ampy+Cl-/NiTsPc)7 obtained an improvement in the anodic current response and reduction of the oxidation potential compared to the unmodified electrode (ITO) in the presence of nitrite. The SiImi+Cl- was used to adsorb Cu2+, Cd2+ and Ni2+ ions and presented ion exchange capacity of 2.944 mmol g-1, which was considered excellent according to the literature for the proposed application. The adsorption results showed the viability of using SiImi+Cl- as an efficient adsorbent material, exhibiting a higher affinity for the Cu2+ ions at pH 4. Applying the Langmuir and Freundlich models to the adsorption isotherms, it was verified that both the pH as the nature of the ion are factors that influenced the adjustment of the isotherms to the proposed models.