This thesis pertains to the processing of ultra-fine mineral particles and low rank coal using the hydrophobic--hydrophilic separation (HHS) method. Several explorative experimental tests have been carried out to study the effect of the various physical and chemical parameters on the HHS process. In this study, the HHS process has been employed to upgrade a chalcopyrite ore. A systematic experimental study on the effects of various physical and chemical parameters such as particle size, reagent dosage and reaction time on the separation efficiencies have been performed. For this, a copper rougher concentrate (assaying 15.9 %Cu) was wet ground and treated with a reagent to selectively hydrophobize the copper-bearing mineral (chalcopyrite), leaving the siliceous gangue minerals hydrophilic. The slurry was subjected to a high-shear agitation to selectively agglomerate the chalcopyrite and to leave the siliceous gangue dispersed in aqueous phase. The agglomerates were then separated from dispersed gangue minerals by screening and the agglomerates dispersed in a hydrophobic liquid (n-pentane) to liberate the water trapped in the agglomerates. The chalcopyrite dispersed in the hydrophobic liquid was separated from the medium to obtain a concentrate substantially free of gangue minerals and moisture. The copper recoveries were substantially higher than those obtained by flotation. The HHS process was also tested on ultrafine mono-sized silica beads. The results were superior to those obtained by flotation, particularly with ultrafine particles. The HHS process has also been tested successfully for upgrading subbituminous coals. Low-rank coals are not as hydrophobic as high-rank coals such as bituminous and anthracite coals. In the present work, a low-rank coal from Wyoming was hydrophobized with appropriate reagents and subjected to the HHS in a similar manner as described for processing copper. The results showed that the HHS process reduced the moisture substantially and increased the heating value up to 50% without heating the coal. Laboratory-scale tests conducted under different conditions, e.g., particle size, reagent type, reaction time, and pretreatments, showed promising results. Implementation for the HHS process for upgrading low-rank coals should help reduce CO2 emissions by improving combustion efficiencies. / Master of Science

Matéria orgânica natural (MON) é uma complexa matriz de compostos orgânicos originados de fontes naturais que estão presentes nas bacias hidrográficas e dentro dos corpos hídricos. MON é comprovado precursor de subprodutos da desinfecção (SPD), além de afetar processos de tratamento de água tais como coagulação, desinfecção, oxidação, adsorção em carvão ativado e filtração em membranas. Por estas razões, a redução da MON no tratamento de água para consumo humano é importante. Muitos métodos têm sido utilizados para caracterizar e quantificar a MON. Entre os métodos usados se encontram a adsorção em resinas e parâmetros de massa. Carbono orgânico total (COT), carbono orgânico dissolvido (COD), absorção à luz ultravioleta (UV254) e absorbância específica de luz ultravioleta (AEUV) são usualmente utilizados como parâmetros de massa. O fracionamento rápido é uma técnica que usa diferentes resinas para separar frações da MON. Nesse contexto, este trabalho teve como objetivo geral caracterizar a matéria orgânica dissolvida usando o método do fracionamento rápido e os parâmetros COD, UV254 e AEUV em processos de tratamento de água para consumo humano. Também foram analisados turbidez, cor, pH e alcalinidade. Foram avaliados os efeitos dos processos de coagulação, sedimentação, filtração em filtro de areia e adsorção em carvão ativado granular (CAG) nas frações que formam a MON. As amostras de água foram coletadas em estação de tratamento de água da cidade de Porto Alegre, RS. Os valores de turbidez, cor, pH, alcalinidade, UV254 e COD reduziram-se ao longo dos processos de tratamento, enquanto que a AEUV aumentou na sequência dos processos. Os valores de absorção de UV254 decresceram à medida que as amostras passavam através das distintas resinas do fracionamento rápido (DAX-8, XAD-4 e IRA-958). Estas frações tiveram reduções importantes em todas as amostras. Os AMH decresceram de 2,29 mg/L COD na água bruta para 0,25 mg/L COD no efluente da coluna de carvão ativado, enquanto que os ALH reduziram de 1,29 mg/L na água bruta para 0,22 mg/L no efluente do filtro de CAG. As concentrações observadas de matérias hidrofílicas carregadas (MHC) (ex., proteínas) e hidrofílicas neutras (MHN) (ex., carboidratos) foram próximas a zero em todas as amostras. Foi possível concluir que os processos de tratamento afetam a distribuição de frações da MON presente na água. / Natural organic matter (NOM) is a complex matrix of organic compounds originated from natural sources that are present in the watershed and in within water bodies. NOM is a known precursor of disinfection byproducts (DBP) and affects drinking water treatment processes such as coagulation, disinfection, oxidation, carbon adsorption and membrane filtration. For these reasons, the reduction of NOM in water treatment is important. Many methods have been used to characterize and quantify NOM, among them, the resin adsorption and the mass parameters methods. The latter include total organic carbon (TOC), dissolved organic carbon (DOC), ultraviolet absorption at 254 nm (UV254), and specific UV absorption (SUVA). Rapid fractionation is one of the resin adsorption methods. This study has as objective the characterization of dissolved organic matter using rapid fractionation and the parameters DOC, UV254 and SUVA in drinking water treatment processes. Turbidity, color, pH and alkalinity were also analyzed. It was evaluated the effect of coagulation, sedimentation, filtration in sand filter and granular activated carbon (GAC) adsorption in the fractions that form NOM. Samples were collected in a drinking water treatment plant in the city of Porto Alegre, RS. Values of turbidity, color, pH, alkalinity, UV254 and DOC decreased along treatment, while values of SUVA increased. UV254 reduced as the samples passed through the distinct resins used for rapid fractionation (DAX-8, XAD-4 e IRA-958). The main fraction of DOC in samples was very hydrophobic acids (VHA) (as humic acids) followed by slightly hydrophobic acids (SHA) (as fulvic acids). These fractions had major reductions as the samples run through the resins. VHA decreased from 2,29 mg/L COD in raw water to 0,25 mg/L COD in activated carbon column effluent, while SHA decreased from 1,29 mg/L in raw water to 0,22 mg/L in GAC filter effluent. Charged hydrophilic matters (CHA) (as proteins) and hydrophilic neutral (NEU) (as carbohydrates) were observed at concentrations next to zero in most samples. It was possible to conclude that drinking water treatment processes affect the fraction distribution of NOM in water.

Matéria orgânica natural (MON) é uma complexa matriz de compostos orgânicos originados de fontes naturais que estão presentes nas bacias hidrográficas e dentro dos corpos hídricos. MON é comprovado precursor de subprodutos da desinfecção (SPD), além de afetar processos de tratamento de água tais como coagulação, desinfecção, oxidação, adsorção em carvão ativado e filtração em membranas. Por estas razões, a redução da MON no tratamento de água para consumo humano é importante. Muitos métodos têm sido utilizados para caracterizar e quantificar a MON. Entre os métodos usados se encontram a adsorção em resinas e parâmetros de massa. Carbono orgânico total (COT), carbono orgânico dissolvido (COD), absorção à luz ultravioleta (UV254) e absorbância específica de luz ultravioleta (AEUV) são usualmente utilizados como parâmetros de massa. O fracionamento rápido é uma técnica que usa diferentes resinas para separar frações da MON. Nesse contexto, este trabalho teve como objetivo geral caracterizar a matéria orgânica dissolvida usando o método do fracionamento rápido e os parâmetros COD, UV254 e AEUV em processos de tratamento de água para consumo humano. Também foram analisados turbidez, cor, pH e alcalinidade. Foram avaliados os efeitos dos processos de coagulação, sedimentação, filtração em filtro de areia e adsorção em carvão ativado granular (CAG) nas frações que formam a MON. As amostras de água foram coletadas em estação de tratamento de água da cidade de Porto Alegre, RS. Os valores de turbidez, cor, pH, alcalinidade, UV254 e COD reduziram-se ao longo dos processos de tratamento, enquanto que a AEUV aumentou na sequência dos processos. Os valores de absorção de UV254 decresceram à medida que as amostras passavam através das distintas resinas do fracionamento rápido (DAX-8, XAD-4 e IRA-958). Estas frações tiveram reduções importantes em todas as amostras. Os AMH decresceram de 2,29 mg/L COD na água bruta para 0,25 mg/L COD no efluente da coluna de carvão ativado, enquanto que os ALH reduziram de 1,29 mg/L na água bruta para 0,22 mg/L no efluente do filtro de CAG. As concentrações observadas de matérias hidrofílicas carregadas (MHC) (ex., proteínas) e hidrofílicas neutras (MHN) (ex., carboidratos) foram próximas a zero em todas as amostras. Foi possível concluir que os processos de tratamento afetam a distribuição de frações da MON presente na água. / Natural organic matter (NOM) is a complex matrix of organic compounds originated from natural sources that are present in the watershed and in within water bodies. NOM is a known precursor of disinfection byproducts (DBP) and affects drinking water treatment processes such as coagulation, disinfection, oxidation, carbon adsorption and membrane filtration. For these reasons, the reduction of NOM in water treatment is important. Many methods have been used to characterize and quantify NOM, among them, the resin adsorption and the mass parameters methods. The latter include total organic carbon (TOC), dissolved organic carbon (DOC), ultraviolet absorption at 254 nm (UV254), and specific UV absorption (SUVA). Rapid fractionation is one of the resin adsorption methods. This study has as objective the characterization of dissolved organic matter using rapid fractionation and the parameters DOC, UV254 and SUVA in drinking water treatment processes. Turbidity, color, pH and alkalinity were also analyzed. It was evaluated the effect of coagulation, sedimentation, filtration in sand filter and granular activated carbon (GAC) adsorption in the fractions that form NOM. Samples were collected in a drinking water treatment plant in the city of Porto Alegre, RS. Values of turbidity, color, pH, alkalinity, UV254 and DOC decreased along treatment, while values of SUVA increased. UV254 reduced as the samples passed through the distinct resins used for rapid fractionation (DAX-8, XAD-4 e IRA-958). The main fraction of DOC in samples was very hydrophobic acids (VHA) (as humic acids) followed by slightly hydrophobic acids (SHA) (as fulvic acids). These fractions had major reductions as the samples run through the resins. VHA decreased from 2,29 mg/L COD in raw water to 0,25 mg/L COD in activated carbon column effluent, while SHA decreased from 1,29 mg/L in raw water to 0,22 mg/L in GAC filter effluent. Charged hydrophilic matters (CHA) (as proteins) and hydrophilic neutral (NEU) (as carbohydrates) were observed at concentrations next to zero in most samples. It was possible to conclude that drinking water treatment processes affect the fraction distribution of NOM in water.

Matéria orgânica natural (MON) é uma complexa matriz de compostos orgânicos originados de fontes naturais que estão presentes nas bacias hidrográficas e dentro dos corpos hídricos. MON é comprovado precursor de subprodutos da desinfecção (SPD), além de afetar processos de tratamento de água tais como coagulação, desinfecção, oxidação, adsorção em carvão ativado e filtração em membranas. Por estas razões, a redução da MON no tratamento de água para consumo humano é importante. Muitos métodos têm sido utilizados para caracterizar e quantificar a MON. Entre os métodos usados se encontram a adsorção em resinas e parâmetros de massa. Carbono orgânico total (COT), carbono orgânico dissolvido (COD), absorção à luz ultravioleta (UV254) e absorbância específica de luz ultravioleta (AEUV) são usualmente utilizados como parâmetros de massa. O fracionamento rápido é uma técnica que usa diferentes resinas para separar frações da MON. Nesse contexto, este trabalho teve como objetivo geral caracterizar a matéria orgânica dissolvida usando o método do fracionamento rápido e os parâmetros COD, UV254 e AEUV em processos de tratamento de água para consumo humano. Também foram analisados turbidez, cor, pH e alcalinidade. Foram avaliados os efeitos dos processos de coagulação, sedimentação, filtração em filtro de areia e adsorção em carvão ativado granular (CAG) nas frações que formam a MON. As amostras de água foram coletadas em estação de tratamento de água da cidade de Porto Alegre, RS. Os valores de turbidez, cor, pH, alcalinidade, UV254 e COD reduziram-se ao longo dos processos de tratamento, enquanto que a AEUV aumentou na sequência dos processos. Os valores de absorção de UV254 decresceram à medida que as amostras passavam através das distintas resinas do fracionamento rápido (DAX-8, XAD-4 e IRA-958). Estas frações tiveram reduções importantes em todas as amostras. Os AMH decresceram de 2,29 mg/L COD na água bruta para 0,25 mg/L COD no efluente da coluna de carvão ativado, enquanto que os ALH reduziram de 1,29 mg/L na água bruta para 0,22 mg/L no efluente do filtro de CAG. As concentrações observadas de matérias hidrofílicas carregadas (MHC) (ex., proteínas) e hidrofílicas neutras (MHN) (ex., carboidratos) foram próximas a zero em todas as amostras. Foi possível concluir que os processos de tratamento afetam a distribuição de frações da MON presente na água. / Natural organic matter (NOM) is a complex matrix of organic compounds originated from natural sources that are present in the watershed and in within water bodies. NOM is a known precursor of disinfection byproducts (DBP) and affects drinking water treatment processes such as coagulation, disinfection, oxidation, carbon adsorption and membrane filtration. For these reasons, the reduction of NOM in water treatment is important. Many methods have been used to characterize and quantify NOM, among them, the resin adsorption and the mass parameters methods. The latter include total organic carbon (TOC), dissolved organic carbon (DOC), ultraviolet absorption at 254 nm (UV254), and specific UV absorption (SUVA). Rapid fractionation is one of the resin adsorption methods. This study has as objective the characterization of dissolved organic matter using rapid fractionation and the parameters DOC, UV254 and SUVA in drinking water treatment processes. Turbidity, color, pH and alkalinity were also analyzed. It was evaluated the effect of coagulation, sedimentation, filtration in sand filter and granular activated carbon (GAC) adsorption in the fractions that form NOM. Samples were collected in a drinking water treatment plant in the city of Porto Alegre, RS. Values of turbidity, color, pH, alkalinity, UV254 and DOC decreased along treatment, while values of SUVA increased. UV254 reduced as the samples passed through the distinct resins used for rapid fractionation (DAX-8, XAD-4 e IRA-958). The main fraction of DOC in samples was very hydrophobic acids (VHA) (as humic acids) followed by slightly hydrophobic acids (SHA) (as fulvic acids). These fractions had major reductions as the samples run through the resins. VHA decreased from 2,29 mg/L COD in raw water to 0,25 mg/L COD in activated carbon column effluent, while SHA decreased from 1,29 mg/L in raw water to 0,22 mg/L in GAC filter effluent. Charged hydrophilic matters (CHA) (as proteins) and hydrophilic neutral (NEU) (as carbohydrates) were observed at concentrations next to zero in most samples. It was possible to conclude that drinking water treatment processes affect the fraction distribution of NOM in water.

No description available.

Esta tese apresenta pela primeira vez a obtenção, a partir de alcoóis, de nanotubos de carbono do tipo cup-stacked nitrogenados sendo esses nanotubos hidrofílicos e semicondutores. Os compósitos híbridos de fibra de carbono/nanotubos de carbono possuem geometria tridimensional nanoestruturada e foram preparados em reator de deposição química de vapor de leito fixo. Neste processo nanotubos de carbono do tipo cup-stacked nitrogenados, de paredes múltiplas organizadas ou helicoidais são crescidos diretamente sobre as fibras de carbono com diferentes graus de grafitização. Os compósitos obtidos foram analisados principalmente por microscopia eletrônica de varredura e de transmissão de alta resolução que mostrou que o grau de grafitização do substrato de carbono tem influência sobre o crescimento. A densidade de NTC diminui com a redução da grafitização das fibras de carbono, o que produz um material com porosidade não observada quando as fibras são bem grafitizadas. O material compósito foi estudado como elemento filtrante, eletrodos de baterias de íons de lítio, emissor de elétrons e como reforço em compósitos de silicone. A constatação da eficiência na filtragem seletiva de uma série de compostos orgânicos voláteis presentes na fumaça do cigarro bem como a preparação de eletrodos de baterias de íons de lítio sem o uso de folhas metálicas de alumínio ou cobre resultaram no deposito de dois pedidos de patente. / This thesis presents for the first time nitrogen-cup-stacked carbon nanotubes with hydrophilic and semiconducting properties synthesized by alcohol precursor. The hybrid carbon fiber/carbon nanotubes composite have three-dimensional geometry and nanostructure. The material was prepared via fixed-bed chemical vapor deposition reactor. In this process nitrogen-cup-stacked, multi-walled or helical carbon nanotubes were synthesized directly onto carbon fibers with different graphitization grade. The composites were analyzed by high resolution scanning and transmission electron microscopy. This characterization showed that the fiber graphitization has influence on the growth. Carbon nanotube density decreases producing a porous composite that was not observed in well-graphitized fibers. The hybrid composite material was studied as a filter, lithium ion battery electrode, electron field emission and as silicone reinforcement. The efficiency to filter several volatile organic compounds present in the mainstream smoke and the development of lithium-ion battery electrodes, aluminum and copper foils free resulted in two patent applications deposit.

Considerações ambientais têm aumentado a pesquisa e o desenvolvimento de sistemas poliméricos aquosos para diversos tipos de aplicações, principalmente como revestimentos. Nesta dissertação, foram sintetizadas formulações não-poluentes à base de poliuretanos dispersos em água (PUDs), com 40% de teor de sólidos, na ausência de solventes orgânicos. Os monômeros empregados foram copolímeros em bloco à base de poli(glicol etilênico) e poli(glicol propilênico) (EG-b-PG), com teor de 25% de segmento hidrofílico EG, poli (glicol propilênico) (PPG), ácido dimetilolpropiônico (DMPA), diisocianato de isoforona (IPDI) e hidrazina (HYD), como extensor de cadeia. Foram variadas as razões entre o número de equivalente-grama de grupamentos isocianato e hidroxila (NCO/OH) e a proporção em equivalente-grama de PPG e dos copolímeros em bloco (EG-b-PG). Foi observado que a incorporação de altas quantidades de copolímero dificultou a síntese dos poliuretanos dispersos em água, levando à formação de géis. O tamanho médio de partícula e a viscosidade das dispersões foram determinados. Os filmes vazados a partir dessas dispersões foram avaliados quanto à capacidade de absorção de água, resistência mecânica, termogravimetria (TG), e caracterizados por espectroscopia na região do infravermelho (FTIR). As dispersões poliuretânicas produzidas se mostraram satisfatórias quando aplicadas como revestimento para madeira, metais e vidro / Environmental considerations are increasing the research and development of waterborne polymeric systems for many different applications, particularly as coatings. In this dissertation, non-polluting formulations based on waterborne polyurethanes (WPU), with 40% solids content, were synthesized in the absence of organic solvents. The monomers (polyols) employed were block copolymers of ethylene glycol and propylene glycol (EG-b-PG), with 25% of EG hydrophilic segments, poly(propylene glycol) (PPG), dimethylolpropionic acid (DMPA), isophorone diisocyanate (IPDI) and hydrazine (HYD), as chain extender. The ratio between the number of equivalent-grams of isocyanate and hydroxyl groups (NCO/OH) and the ratio between the equivalent-grams of PPG and (EG-b-PG) were varied. It was observed that the incorporation of high quantities of the copolymer resulted in gels instead of dispersions. The average particle size and the viscosity of the resins were determined. Thermal and mechanical resistances and water absorption of cast films produced from the dispersions were evaluated. The chemical structure of the chains was characterized by infrared spectroscopy (FTIR). The waterborne polyurethanes showed to be suitable as coatings for wood, metals and glass

This thesis focuses on the development of new stationary phases for use in hydrophilic interaction liquid chromatography using TRIS-based and phosphorylcholine typed monomers and porous silica particles as starting substrates. In this thesis, several ways of polymerizing highly hydrophilic mono­mers onto pore surfaces of silica supports are described, based on several “grafting from” schemes. “Controlled/living” radical polymerizations including atom transfer radical polymerization (ATRP) and iniferter-mediated polymerization in conjunction with conventional free radical polymerization are demonstrated to be successful tools for grafting different hydrophilic monomers (polyhydroxyl and phosphorylcholine [meth]acrylamide/acrylates) onto the silica surfaces. Reaction solvents are proven to play an essential role to achieve efficient graft polymerization of activated silica surfaces with these amphiphilic vinylic monomers, which is difficult because of their restricted access to the activated surface in solvents that can be used because of solubility constraints. Two tentacle TRIS-based polymer grafted silica, namely TRIS-WAX – TRIS functionality bonded to silica via a C–N–C imine bond and TRIS-Amide – TRIS bonded to silica via an amide bond, prove to be useful as stationary phases for hydrophilic interaction chromatography (HILIC).The TRIS-WAX exhibits a mixed mode hydrophilic partitioning and weak anion exchange (HILIC/WAX) retention mechanism while retention by hydrophilic partitioning is the dominant mechanism on the neutral TRIS-Amide phase which lacks weak anion exchange (WAX) properties. Interestingly, both these phases have selectivities that are radically different from most commercial HILIC stationary phases. Finally, a method is demonstrated for synthesizing a stratified (graft-copolymerized) silica material based on N,N′-methylenebisacrylamide and 2-methacryloyloxyethyl phosphorylcholine (MPC) using a “controlled/living” photoiniferter-mediated polymerization from the N,N-diethyldithiocarbamate iniferter moiety immobilized silica surfaces. This polymerization method proves to be successful for graft-blockcopolymerization of different highly hydrophilic monomers onto the activated surfaces of porous silica. In this way, silica surfaces are grafted with a cross-linked amide-based hydrogel, on top of which a tentacle zwitterionic phosphorylcholine-typed layer is synthesized. The resulted material proves to be useful for HILIC separations and possesses different selectivity for the tested organic acids compared to that of commercial ZIC-cHILIC stationary phase.

This thesis explored how asphaltene and naphthenic amphiphile species influence the formation (morphology and size) and stability of heavy crude oil (bitumen) emulsions. It was experimentally shown that asphaltenes produce water-in-oil emulsions. Naphthenic amphiphiles on the other hand flip the emulsion morphology to oil-in-water. It was further demonstrated that the size and stability of these emulsions is influenced by physicochemical effects such as the pH, solvent-bitumen-water ratios, solvent aromaticity, and temperature. In view of these findings, the hydrophilic-lipophilic deviation (HLD) and net-average curvature (NAC) models were looked at as potential means for predicting the formation and stability of emulsions. Owing to the complexity of bitumen emulsions, however, the HLD and NAC models were instead tested against well-defined sodium dihexyl sulfosuccinate-toluene-water emulsions. The morphologies of these emulsions were predicted as a function of the formulation salinity whereas corresponding droplet sizes were predicted as a function of the continuous phase density and interfacial tension (γow). Emulsion stability trends were in turn predicted using a collision-coalescence-separation assumption. From this assumption, emulsion stability was expressed as a function of the emulsion droplet collision frequency and activation energy. The key parameters of the highly scrutinized activation energy term included the γow, interfacial rigidity, and critical film thickness. In applying the same modeling approach to the stability of other emulsions already published in the literature, it was found that the rigidity of adsorbed multilayer/liquid crystal films cannot yet be fully accounted for. This shortcoming was the reason for which only minimum stability times were reported for bitumen emulsions.

This thesis explored how asphaltene and naphthenic amphiphile species influence the formation (morphology and size) and stability of heavy crude oil (bitumen) emulsions. It was experimentally shown that asphaltenes produce water-in-oil emulsions. Naphthenic amphiphiles on the other hand flip the emulsion morphology to oil-in-water. It was further demonstrated that the size and stability of these emulsions is influenced by physicochemical effects such as the pH, solvent-bitumen-water ratios, solvent aromaticity, and temperature. In view of these findings, the hydrophilic-lipophilic deviation (HLD) and net-average curvature (NAC) models were looked at as potential means for predicting the formation and stability of emulsions. Owing to the complexity of bitumen emulsions, however, the HLD and NAC models were instead tested against well-defined sodium dihexyl sulfosuccinate-toluene-water emulsions. The morphologies of these emulsions were predicted as a function of the formulation salinity whereas corresponding droplet sizes were predicted as a function of the continuous phase density and interfacial tension (γow). Emulsion stability trends were in turn predicted using a collision-coalescence-separation assumption. From this assumption, emulsion stability was expressed as a function of the emulsion droplet collision frequency and activation energy. The key parameters of the highly scrutinized activation energy term included the γow, interfacial rigidity, and critical film thickness. In applying the same modeling approach to the stability of other emulsions already published in the literature, it was found that the rigidity of adsorbed multilayer/liquid crystal films cannot yet be fully accounted for. This shortcoming was the reason for which only minimum stability times were reported for bitumen emulsions.