O crescimento excessivo da frota veicular mundial tem feito com que milhares de toneladas de poluentes sejam lançadas na atmosfera diariamente em todo o globo, no Brasil a frota de veículos atingiu aproximadamente 54 milhões de unidades, e tem aumentado significativamente em vários estados, segundo o DETRAN (Departamento Estadual de Transito de São Paulo) o estado conta hoje com aproximadamente 19,5 milhões de veículos, 6,5 milhões só na capital, onde são emplacados aproximadamente mil veículos por dia, este crescimento tem causado episódios críticos de poluição do ar nos centros urbanos. Dentre os poluentes lançados na atmosfera de origem veicular, encontram-se os aldeídos e os ácidos carboxílicos, (objetos de estudo deste trabalho), essas substâncias são de suma importância para saúde humana, e participam nas reações fotoquímicas de formação de ozônio na baixa troposfera. Desde a implantação do PROCONVE (Programa de Controle de Poluição do Ar por Veículos Automotores) em 1988, medidas como a redução dos limites de emissão, novas tecnologias na fabricação de veículos automotores, redução da porcentagem de enxofre no diesel, combustíveis renováveis, entre outras, e programas como a Inspeção veicular na cidade de São Paulo criada a partir de 2009, tem sido tomadas visando à constante melhoria na qualidade do ar. Dentre os combustíveis renováveis atualmente utilizados, o biodiesel tem se destacado, tendo em vista o grande consumo de diesel utilizado como fonte de energia no Brasil. Atualmente foram incorporados 2% de biodiesel ao diesel comercial, e antecipando a meta para 2013, possivelmente já no ano de 2010 a porcentagem será de 5%. O objetivo deste trabalho é a caracterização preliminar de aldeídos e ácidos carboxílicos na emissão de veículos do ciclo Otto e do ciclo diesel, utilizando combustíveis fósseis e renováveis. Para a realização deste trabalho foram utilizados três veículos, sendo dois do ciclo Otto e um do ciclo diesel. Os testes foram realizados em dinamômetro de chassis conforme norma ABNT NBR 6601 e ABNT NBR 12026, o método para amostragem dos ácidos carboxílicos foi validado e estabelecido conforme item 6.2 deste trabalho. Nos veículos do ciclo Otto, foram utilizados como combustíveis, a gasolina pura, gasolina com 22% de AEAC (Álcool etílico anidro combustível) e AEHC (álcool etílico hidratado combustível). No veículo do ciclo diesel foram utilizados como combustíveis o diesel comercial com 2% de biodiesel e biodiesel puro de soja. Os resultados obtidos indicaram uma emissão de ácidos carboxílicos 2,5 vezes maior para os testes realizados com os veículos do ciclo Otto, e 5,5 vezes superior para os aldeídos nos resultados dos testes realizados com o veículo do ciclo diesel. A média de todos os resultados obtidos na realização deste trabalho com os veículos do ciclo Otto e do ciclo diesel, utilizando combustíveis fósseis e renováveis, indicaram emissão 3,2 vezes superior dos poluentes pesquisados na utilização de combustíveis renováveis. Estudos com maior número de amostras, e diversificações nas categorias dos veículos devem ser realizados a fim de se detalhar o perfil destes poluentes na emissão veicular com o uso de combustíveis fósseis e renováveis. / The global automotive fleet is emitting thousands of tons of air pollutants daily all over the planet; in Brazil, the domestic fleet reached 54 million vehicles. According to DETRAN (São Paulo state traffic department), the state of São Paulo has 19,5 million vehicles and 6,5 million in São Paulo city, where a thousand new vehicles daily are registered. This fleet growing up is causing critical air pollution situations in metropolitan areas. Among the major automotive air pollutants are aldehydes and carboxylic acids, both are the subject of this study. These substances play an important role for human health and they take place at photochemical reactions generating ozone in low troposphere. Since the beginning of PROCONVE (National Automotive Pollution Control Regulation) in 1988, measures has been taken like emission regulation, development of new automotive technologies, reduction of sulfur content in diesel fuel, renewable fuels and inspection of in use vehicles. Among the fuels from renewable sources currently in use, the biodiesel plays an important role, because diesel is the most used energy source. Currently, with the enforcement of the law number 11097, from January 13rd of 2005, 2% of biodiesel must be added in the commercial diesel and until 2013 this addition will rise to 5%. The subject of this study is the determination of emission profile of aldehydes and carboxylic acids in vehicles powered by Otto and diesel engines using fossil and renewable fuels. In this study were used three vehicles, two of them powered by Otto engines and one sample with diesel engine. The tests were performed in vehicle chassis dynamometer in accordance of the standards ABNT NBR 6601 and ABNT NBR 12026. The method for sampling and evaluation of carboxylic acids was validated and established in article 6.2 of this study. Otto vehicles were tested with 100% gasoline, gasoline plus 22% of anhydrous ethanol and 100% Ethanol. Diesel vehicle were tested with commercial diesel plus 2% biodiesel and 100% soy biodiesel. The results indicates an average 3,2 times higher emission of aldehydes and carboxylic acids when the samples were tested with renewable fuels. Tests with a higher number of samples and variation in vehicle types should be performed in order to provide a more precise profile of these pollutants emission using fossil and renewable fuels.

Yau, Chung Wah. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 55-57). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abstract --- p.ii / Table of Contents --- p.iv / Index of Compounds --- p.v / Chapter 1. --- Introduction / Chapter 1.1 --- Fundamentals of inclusion chemistry --- p.1 / Chapter 1.2 --- Hydrogen bonding in supramolecular chemistry and crystal engineering --- p.3 / Chapter 1.3 --- Hydrogen-bonded rosette system --- p.4 / Chapter 1.4 --- Research plan --- p.7 / Chapter 2. --- Descriptions of crystal structures / Chapter 2.1 --- Supramolecular rosette layer and rosette ribbon constructed from guanidinium cations and hydrogen carbonate dimers /carbonate anions / Chapter 2.1.1 --- (Et4N+)[C(NH2)3+]7(C032-)3[C3N2H2(C00-)2] (1) --- p.11 / Chapter 2.1.2 --- [(n-Bu)4N+]3[C(NH2)3+]4(HC03-)4[H+{C3N2H-(C00-)(C00H)}2] (2) --- p.14 / Chapter 2.1.3 --- [(n-Bu)4N+]2[C(NH2)3+]2(HC03-)2[NCC6H4(C00-)]2 ´Ø 2H20 (3)…… --- p.16 / Chapter 2.1.4 --- "[(n-Bu)4+]8[C(NH2)3+]8(HCO3-)8[4,4'-C12H8(C00-)2]4 ´Ø 8H20 ´″…" --- p.17 / Chapter 2.2 --- Channel- and layer-type anionic host structures constructed from benzene hexacarboxylic acid and guanidinium cation / Chapter 2.2.1 --- [C6(COO-)6][C(NH2)3]6 ´Ø H20 (5) --- p.20 / Chapter 2.2.2 --- [C6(COOH)3(COO´ؤ)3][C(NH2)3+]3 ´Ø 2H20 (6) --- p.23 / Chapter 2.2.3 --- [(n-Pr)4N+][C6(COOH)5(COO-)] ´Ø 3H20 (7) --- p.27 / Chapter 2.2.4 --- [(n-Bu)4N+]4[C6(COOH)5(COO-)]2[C6(COOH)4(COO-)2]2 [C(NH2)3+]2.8H2O(8) --- p.30 / Chapter 2.2.5 --- (Et4N+)2[C6(COOH)4(COO-)2]2[C(NH2)3+]2 ´Ø 2H20 (9) --- p.35 / Chapter 2.2.6 --- (Me4N+)[C6(COOH)3(COO-)3][C(NH2)3+]2 ´Ø H20 (10) --- p.37 / Chapter 3. --- Summary and discussion / Chapter 3.1 --- Robustness of hydrogen-bonded supramolecular rosette networks --- p.40 / Chapter 3.2 --- Versatile hydrogen bonding modes of guanidinium with mellitate anions --- p.43 / Chapter 4. --- Experimental / Chapter 4.1 --- Preparation methods --- p.48 / Chapter 4.2 --- X-ray crystallography --- p.52 / Chapter 5. --- References --- p.55 / "Appendix A: Tables of atomic coordinates, thermal parameters, bond lengths and angles and hydrogen bonds" --- p.58

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Switchable surfaces, also called smart surfaces or controllable surfaces, respond to changes in their local environment resulting in altered surface properties. There are various environmental perturbations that can cause changes to the surface properties but the focus of this thesis is on the affect of electrostatic potential. Significant evidence is provided from previous reports on electrochemical and infrared spectroscopic experiments suggesting that self-assembled monolayers (SAMs) of 4-mercaptobenzoic acid (4-MBA) undergo protonation-deprotonation by the application of an electric field. However, there are plenty of aspects of this electric field driven protonation-deprotonation mechanisms using carboxylic acid terminated SAMs that are not well understood. Most importantly, there is a lack of model independent measurements to validate this process. As such, experimental techniques utilizing infrared spectroscopy were employed to correlate electrochemical measurements and models.<p> This body of work demonstrates the importance of the intermolecular hydrogen bonding network on the measured voltammetric peak associated with the protonation-deprotonation of these SAMs. The voltammetric peak height diminishes with increasing exposure to an electrolyte solution. This behaviour is attributed to the replacement of the carboxylic acid protons with electrolyte cations and ultimately the disruption of the hydrogen bonded network.<p> We attempted to further our ex-situ infrared measurements by using an in-situ spectroelectrochemical technique. We had some initial successes, presented within, but more work is needed to complete this picture and is beyond the scope of this thesis. To summarize, the protonated state of SAMs of 4-MBA can be driven by the application of an electric field providing a potential platform to build a controllable smart surface.

This thesis presents the study of biodegradation factors of a candidate naphthenic acid compound, the trans isomer of 4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA). Low molecular weight components of naphthenic acids such as trans-4MCHCA are known to be toxic in aquatic environments and there is a need to better understand the factors controlling the kinetics of their biodegradation. In this study, a relatively low molecular weight naphthenic acid compound and a microbial culture developed in our laboratory (primarily Alcaligenes paradoxus and Pseudomonas aeruginosa) were used to study the biodegradation of this candidate naphthenic acid. The purpose of the research was to evaluate the kinetic parameters and model the biodegradation of this compound in three bioreactor systems: batch reactors, a continuously stirred tank reactor and immobilized cell reactors. <p>In batch reactors, the maximum specific growth rate (0.52±0.04 d-1) of the consortium at 23oC and neutral pH was not highly variable over various initial substrate concentrations (50 to 750 mg/L). Batch experiments indicated that biodegradation can be achieved at low temperatures; however, the biodegradation rate at 4oC was only 22% of that at room temperature (23oC). Biodegradation at various pH values indicated a maximum specific growth rate of 1.69±0.40 d-1 and yield (0.41±0.06 mg/mg) at a pH of 10. <p>Study of the candidate substrate using a continuously stirred tank reactor and the microbial culture developed in the batch experimentations revealed that the kinetics of the candidate naphthenic acid are best described by the Monod expression with a maximum specific growth rate of 1.74±0.004 d-1 and a half saturation constant of 363±17 mg/L. The continuously stirred tank reactor achieved a maximum reaction rate of 230 mg/(L∙d) at a residence time of 1.6 d-1 (39 h).<p>Two high porosity immobilized cell reactors operating continuously over three months were found to consume trans-4MCHCA at a rate almost two orders of magnitude higher than a continuously stirred tank reactor. The immobilized cell systems attained a maximum reaction rate of 22,000 mg/(L∙d) at a residence time of 16 minutes. High porosity immobilized cell reactors were shown to effectively remove a single naphthenic acid substrate in continuously fed operation to dilution rates of 90 d-1. A plug flow model best represented the degradation in the immobilized cell systems and was demonstrated to be a useful tool for studying the effects of parameter variation and prediction of reactor performance. This work highlights the potential of augmented bioremediation systems for the degradation of naphthenic acids.

This thesis presents the study of biodegradation factors of a candidate naphthenic acid compound, the trans isomer of 4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA). Low molecular weight components of naphthenic acids such as trans-4MCHCA are known to be toxic in aquatic environments and there is a need to better understand the factors controlling the kinetics of their biodegradation. In this study, a relatively low molecular weight naphthenic acid compound and a microbial culture developed in our laboratory (primarily Alcaligenes paradoxus and Pseudomonas aeruginosa) were used to study the biodegradation of this candidate naphthenic acid. The purpose of the research was to evaluate the kinetic parameters and model the biodegradation of this compound in three bioreactor systems: batch reactors, a continuously stirred tank reactor and immobilized cell reactors. <p>In batch reactors, the maximum specific growth rate (0.52±0.04 d-1) of the consortium at 23oC and neutral pH was not highly variable over various initial substrate concentrations (50 to 750 mg/L). Batch experiments indicated that biodegradation can be achieved at low temperatures; however, the biodegradation rate at 4oC was only 22% of that at room temperature (23oC). Biodegradation at various pH values indicated a maximum specific growth rate of 1.69±0.40 d-1 and yield (0.41±0.06 mg/mg) at a pH of 10. <p>Study of the candidate substrate using a continuously stirred tank reactor and the microbial culture developed in the batch experimentations revealed that the kinetics of the candidate naphthenic acid are best described by the Monod expression with a maximum specific growth rate of 1.74±0.004 d-1 and a half saturation constant of 363±17 mg/L. The continuously stirred tank reactor achieved a maximum reaction rate of 230 mg/(L∙d) at a residence time of 1.6 d-1 (39 h).<p>Two high porosity immobilized cell reactors operating continuously over three months were found to consume trans-4MCHCA at a rate almost two orders of magnitude higher than a continuously stirred tank reactor. The immobilized cell systems attained a maximum reaction rate of 22,000 mg/(L∙d) at a residence time of 16 minutes. High porosity immobilized cell reactors were shown to effectively remove a single naphthenic acid substrate in continuously fed operation to dilution rates of 90 d-1. A plug flow model best represented the degradation in the immobilized cell systems and was demonstrated to be a useful tool for studying the effects of parameter variation and prediction of reactor performance. This work highlights the potential of augmented bioremediation systems for the degradation of naphthenic acids.

Switchable surfaces, also called smart surfaces or controllable surfaces, respond to changes in their local environment resulting in altered surface properties. There are various environmental perturbations that can cause changes to the surface properties but the focus of this thesis is on the affect of electrostatic potential. Significant evidence is provided from previous reports on electrochemical and infrared spectroscopic experiments suggesting that self-assembled monolayers (SAMs) of 4-mercaptobenzoic acid (4-MBA) undergo protonation-deprotonation by the application of an electric field. However, there are plenty of aspects of this electric field driven protonation-deprotonation mechanisms using carboxylic acid terminated SAMs that are not well understood. Most importantly, there is a lack of model independent measurements to validate this process. As such, experimental techniques utilizing infrared spectroscopy were employed to correlate electrochemical measurements and models.<p> This body of work demonstrates the importance of the intermolecular hydrogen bonding network on the measured voltammetric peak associated with the protonation-deprotonation of these SAMs. The voltammetric peak height diminishes with increasing exposure to an electrolyte solution. This behaviour is attributed to the replacement of the carboxylic acid protons with electrolyte cations and ultimately the disruption of the hydrogen bonded network.<p> We attempted to further our ex-situ infrared measurements by using an in-situ spectroelectrochemical technique. We had some initial successes, presented within, but more work is needed to complete this picture and is beyond the scope of this thesis. To summarize, the protonated state of SAMs of 4-MBA can be driven by the application of an electric field providing a potential platform to build a controllable smart surface.

With the inevitable depletion of the petroleum supply and increasing energy demands in the world, interest has been growing in bioconversion of lignocellulosic biomass (e.g., sugarcane bagasse). Lignocellulosic biomass is an abundant, inexpensive, and renewable resource. Most of current conversion technologies require expensive enzymes and sterility. In contrast, the patented MixAlco process requires no enzymes or sterility, making it attractive to convert lignocellulosic biomass to transportation fuels and valuable chemicals. This study focuses on pretreatment and thermophilic fermentation in the MixAlco process. Ammonium bicarbonate (NH4HCO3) was discovered to be a better pH buffer than previously widely used calcium carbonate (CaCO3) in anaerobic fermentations under thermophilic conditions (55°C). The desired pH should be controlled within 6.5 to 7.5. Over 85% acetate content in the product was found in paper fermentations and bagasse fermentations. Hot-lime-water-treated bagasse countercurrent fermentations buffered by ammonium bicarbonate achieved 50–60% higher total product concentrations than those using calcium carbonate. It was nearly double in paper batch fermentations if the pH was controlled around 7.0. Ammonium bicarbonate is a “weak” methane inhibitor, so a strong methane inhibitor (e.g., iodoform) is still required in ammonium bicarbonate buffered fermentations. Residual calcium salts did not show significant effects on ammonium bicarbonate buffered fermentations. Lake inocula from the Great Salt Lake, Utah, proved to be feasible in ammonium bicarbonate buffered fermentations. Under mesophilic conditions (40°C), the inoculum from the Great Salt Lake increased the total product concentration about 30%, compared to the marine inoculum. No significant fermentation performance difference, however, was found under thermophilic conditions. The Continuum Particle Distribution Model (CPDM) is a powerful tool to predict product concentrations and conversions for long-term countercurrent fermentations, based on batch fermentation data. The experimental acid concentrations and conversions agree well with the CPDM predictions (average absolute error < 15%). Aqueous ammonia treatment proved feasible for bagasse. Air-lime-treated bagasse had the highest acid concentration among the three treated bagasse. Air-lime treatment coupled with ammonium bicarbonate buffered fermentations is preferred for a “crop-tofuel” process. Aqueous ammonia treatment combined with ammonium bicarbonate buffered fermentations is a viable modification of the MixAlco process, if “ammonia recycle” is deployed.

In this work, 80% lime-treated rice straw and 20% lime-treated chicken manure were used as substrates in rotary fermentors. Countercurrent fermentation was performed at various volatile solid loading rates (VSLR) and liquid residence times (LRT). The highest acid productivity of 1.69 g/(L·d) was at a total acid concentration of 32.4 g/L. The highest conversion and yield were 0.692 g VS digested/g VS fed and 0.29 g total acids/g VS fed, respectively. The continuum particle distribution model (CPDM) was used to predict product concentrations at various VSLR and LRT. CPDM predicted the experimental total acid concentration and conversion at an average error of 6.41% and 6.55%, respectively. A fixed-bed fermentation system was designed to perform pretreatment and fermentation in the same unit. High product concentrations (~48 g/L) as well as high conversions (0.741 g VS digested/g VS fed, F4, Train B) were obtained from the same fermentor. CPDM was extended to predict product concentrations in the fixed-bed fermentation system. The model gave a good estimate of the product concentrations and retention time. After biomass fermentation, the residue can be combusted to generate heat. For pretreatment purposes, the use of ash can replace lime. A study was performed using ash as a potential pretreatment agent. Ash from raw poplar wood was effective in pretreating poplar wood; however, ash from bagasse fermentation residues was not useful in pretreating bagasse. Previous modeling studies indicate that a conversion of 95% could be achieved with bagasse using countercurrent fermentation. Because lignin constitutes 13% of the dry weight of bagasse, this means lignin would have to be digested to obtain a conversion of 95%. Experiments on the fermentation of enzymatically liberated lignin from both poplar wood and bagasse do not show that solubilized lignin was fermented to organic acids by using a mixed culture of marine microorganisms. Two buffer systems (ammonium bicarbonate and calcium carbonate) were used to compare product concentrations of carboxylic acid fermentations using office paper and chicken manure. It has been demonstrated that the total product concentration using ammonium bicarbonate is almost double the product concentration using calcium carbonate.

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