This diploma thesis deals with microrheology measured via the fluorescence correlation spectroscopy. As microrheological probes, fluorescently marked nanoparticles of 5 sizes in the range of 10-100 nm, were used. The particles had been immersed in a variety of concentrated glycerol solutions and agarose gels of different concentrations, and the FCS measurement revealed a diffusion coefficient of individual particles in each environment. Based on the coefficient, the viscosity of the glycerol needed to stop the particles could be determined. Particles of 10 nm size were not stopped even by the 100 wt% glycerol. In the case of the agarose gels, a combination of higher agarose concentration and larger particles resulted in an increase in the diffusion coefficient to an unlikely high value. This was caused probably by an agarose autofluorescence and the value indicates stopping of the particles in the given agarose gel. Later, the data acquired by the FCS measurement were converted to MSD curves using MATLAB software. The thesis discusses the influence of the experimental parameters on the shape of the MSD curve. The results showed that the number of particles and autocorrelation function have the most significant effect.

In this dissertation electrochemical nickel oxide formation in alkaline solution and the electro-oxidation of glycerol on polycrystalline electrodes are studied as a function of temperature. This is done using electrochemical impedance spectroscopy (EIS), Tafel analysis, cyclic voltammetry, chronoamperometry, and chronopotentiometry among other techniques. Additionally, in order to facilitate the study of aqueous alkaline systems beyond the normal boiling point of water, an electrochemical cell was designed utilizing a self-pressurizing autoclave. This allowed for the study of aqueous alkaline systems up to 140 °C. Product analysis of glycerol electro-oxidation on nickel was performed at various temperatures using HPLC. A reaction pathway for the organic products was determined. At su ciently high temperatures a polymer was discovered. This polymer product was characterized by DLS, DSC, CP-MAS NMR, and ATR-IR and determined to likely be a pseudo-polysaccharide. DSC analysis suggests that the polymer exists as three distinct structures, and DLS analysis suggests that the polymer exists in three di erent size distributions. The lack of a glass transition temperature in the DSC spectrum indicates that it is likely thoroughly cross-linked. The aging process of alpha-Ni(OH)2 to beta-Ni(OH)2 was studied as a function of temperature using cyclic voltammetry and dynamic EIS. This lead to the observation that beta-Ni(OH)2 does not appear to form on the oxide surface at 100 °C and above. A methodology was developed for preferentially stabilizing either beta-NiOOH or gamma-NiOOH on the electrode surface. This methodology was used to determine that beta-NiOOH is the better oxygen evolution catalyst of the two oxide phases. The reversible potential of Ni(OH)2 oxidation was observed to have a shift of -1:14 mV K-1, and this data was used in a thermodynamic analysis to identify the nickel species involved in the reaction. Based on data from the literature the oxidation of NiO or Ni(OH)2 to NiO2 appears to best match the observed data. Mechanistic analysis was performed for glycerol on nickel in alkaline solution using a combination of Tafel analysis, cyclic voltammetry, AC voltammetry, and EIS. This study indicates that glycerol oxidation behaves differently on gamma-NiOOH and beta-NiOOH, perhaps explaining the discrepancy between various pieces of data found in the literature. Tafel analysis led to the observation that there appear to be two di erent glycerol oxidation regimes. Below 80 °C, alpha = 0.5, indicating that the rate determining step is an electron transfer step with no pre-equilibrium electron transfers. At 80 °C and above alpha = 1, indicating that the rate determining step has no electron transfer and one pre-equilibrium electron transfer. This was determined to be caused by the transition of the underlying nickel oxide phase from gamma-NiOOH to beta-NiOOH because the change is retained upon cooling. Additionally, EIS showed two semicircles which indicates the presence of one kinetically signifficant adsorbed intermediate. These observations were incorporated into a detailed proposed reaction mechanism. / Graduate

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Crude glycerol is the major byproduct of the biodiesel industry. In general, for every 100 pounds of biodiesel produced, approximately 10 pounds of crude glycerol are created. Because this glycerol is expensive to purify for use in food, pharmaceutical, or cosmetics industries, biodiesel producers must seek alternative methods for its disposal. Using crude glycerol as a carbon source for fermentation is a promising alternative use for this waste material. In this project, we propose to use crude glycerol in the fermentation of the microalga Schizochytrium limacinum, which is a prolific producer of docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid with proven beneficial effects on treating human diseases such as cardiovascular diseases, cancers, and Alzheimer's. The first part of this study provided "proof-of-concept" that Schizochytrium limacinum was capable of utilizing crude glycerol while producing DHA. The results show that pretreated crude glycerol was a viable carbon source for algal growth and DHA production, with 75 g/L to 100 g/L of glycerol being the optimum concentration range. In addition to glycerol concentration, temperature, trace metal levels, ammonium acetate concentration, and NH4Cl concentration also had significant effects (P < 0.1) on algal DHA production. Optimizing these factors using response surface methodology led to a DHA yield of 4.91 g/L and a DHA productivity of 0.82 g/L-day. The second part of this study investigated the effects of impurities within the glycerol on DHA production and algal biomass composition, with a goal of ensuring that the algal biomass produced from crude glycerol can be safely utilized as an ingredient in omega-3 fortified foods or animal feed additives. Crude glycerol samples obtained from different biodiesel producers were tested. All the samples contained methanol, soaps, and various elements including calcium, phosphorus, potassium, silicon, sodium, and zinc. Both methanol and soaps in the glycerol negatively influence algal DHA production. The two impurities can be removed from the culture medium by evaporation through autoclaving (for methanol) or by precipitation through pH adjustment (for soap). The results showed that the crude glycerol-derived algal biomass contained 45-50% lipid, 14-20% protein, and 25% carbohydrate, with 8-13% ash content. Palmitic acid (C16:0) and DHA (C22:6) were the two major fatty acids in the algal lipid. ICP analysis showed that that boron, calcium, copper, iron, magnesium, phosphorus, potassium, silicon, sodium, and sulfur were present in the algal biomass, but no heavy metals (such as mercury) were detected. The crude glycerol-derived algal biomass had a high level of DHA and a nutritional profile similar to glucose-derived commercial algal biomass, suggesting a great potential for using crude-glycerol derived algae in omega-3 fortified food or feed. Overall, this study shows that crude glycerol can be used as a safe and effective substrate for algal culture to produce high levels of omega-3 fatty acids. With the rapid expansion of the biodiesel industry, there is an urgent need to develop new markets for large quantities of crude glycerol. This research provides an exciting opportunity to utilize a large quantity of this low grade glycerol. / Master of Science

Omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA, C20:5, n-3) and docosahexaenoic acid (DHA, C22:6, n-3), have many medically established benefits against cardiovascular diseases, cancers, schizophrenia, and Alzheimer's. Currently, fish oil is the main source of omega-3 fatty acids, but there are many problems associated with it such as undesirable taste and odor, and heavy metal contamination. As a result, it is necessary to seek alternative production sources based on various microorganisms. In this thesis we have developed a novel microfungal culture process to produce EPA from the crude glycerol byproduct generated in biodiesel industry. This process provides both an alternative source of omega-3 fatty acids and a benefit to the biodiesel industry. Indeed, as oil prices reach historical highs, biodiesel has attracted increasing interest throughout the United States. The disposal of the crude glycerol byproduct has been a challenge faced by the biodiesel producers. Crude glycerol presents a cheap carbon source for growth of many microorganisms. In this thesis, we tested the feasibility of using crude glycerol for producing eicosapentaenoic acid (EPA, 20:5, n-3) by one algal species, Phaeodactylum tricornutum and two fungal species, Mortierella alpina and Pythium irregulare. We observed that the algal growth is inhibited in the crude glycerol while the fungi can grow very well in crude glycerol-containing medium. The fungus M. alpina produced significant amount of ARA but negligible amount of EPA. P. irregulare produced significant amount of biomass as well as a relatively high level of EPA. The maximum dry biomass for the P. irregulare culture was 2.9 g/L with an EPA productivity of 7.99 mg/L-day. Based on these results, we concluded that P. irregulare was a promising candidate for EPA production from biodiesel derived crude glycerol. Further optimization work showed that P. irregulare grown 30 g/L crude glycerol and 10g/L yeast extract results in the highest level of EPA production. A temperature of 20o C is optimal for high fungal biomass and EPA levels. Addition of vegetable oil (at 1%) enhanced the EPA production and almost doubled the amount of biomass reached. Soap inhibits growth as well as EPA production severely even in small amounts. Methanol completely inhibits growth. The final optimized growth conditions for the fungus P.irregulare were a medium with 30g/L of crude glycerol, 10 g/L of yeast extract at a pH of 6 with 1% supplementation of oil, at a temperature of 20o C for a period of 7 days.Thus we have established that the fungus P.irregulare can be used successfully to produce high mounts of EPA from crude glycerol. / Master of Science

Aspectos fundamentais das reações de eletrooxidação do glicerol e álcoois similares em ouro foram estudados por meio da comparação com a eletrooxidação de álcoois similares: 1-propanol, 2-propanol, propano-1,2-diol e propano-1,3-diol, além de sorbitol e glicose. Testes eletroquímicos foram feitos em soluções ácida, neutra e alcalina. Também foram realizados testes em meio alcalino com os possíveis subprodutos de oxidação do glicerol: dihidroxiacetona, gliceraldeído, glicerato, hidroxipiruvato, mesoxalato, tartronato, oxalato e formato. Por fim, os produtos de reação foram analisados por FTIR in situ e HPLC. Conforme esperado, o ouro foi praticamente inativo para todos os álcoois nos meios neutro e ácido, e muito ativo no meio alcalino. Entretanto, os dados de RDE mostraram que a formação de alcóxido não é a responsável pela atividade, como era proposto até então. Comparando a eletrooxidação do glicerol com álcoois similares, foi possível notar que a presença de hidroxilas vizinhas na molécula é a propriedade mais importante para render altas densidades de corrente (para a eletrooxidação de álcoois em geral) sobre ouro. Ela facilita a quebra das ligações C-C favorecendo a formação de produtos mais oxidados, conforme observado por FTIR e HPLC. As medidas de FTIR in situ também mostraram que pode haver neutralização e até acidificação nas proximidades do eletrodo em meio alcalino (se a concentração de base não for suficientemente alta), devido à formação de subprodutos ácidos, o que pode levar a uma mudança no mecanismo da reação. Medidas de RDE indicam que é possível controlar a seletividade dos produtos de eletrooxidação de glicerol e outros álcoois sobre ouro pela convecção artificial, entretanto, o controle pelo potencial ou concentração são limitados, conforme constatado pela análise de produtos. Os testes realizados com os subprodutos e análise de produtos permitiram refinar a rota reacional de eletrooxidação do glicerol. / Fundamental aspects of glycerol and similar alcohols electrooxidation reactions on gold were studied by comparing with similar alcohols: 1-propanol, 2-propanol, propane-1,2-diol and propane-1,3-diol, and also sorbitol and glucose. Electrochemical measurements were performed in acidic, neutral and alkaline solutions. Moreover, CV tests were performed in alkaline environment with the main possible glycerol oxidation byproducts: dihydroxyacetone, gyceraldehyde, glycerate, hydroxypyruvate, mesoxalate, tartronate, oxalate and formate. Finally, the reaction products were analyzed by in situ FTIR and HPLC. As expected, gold was practically inactive for all alcohols in acidic and neutral conditions, but highly active in alkaline medium. However, RDE data showed that the alkoxide formation is not the responsible for the high activity, as proposed until now. By comparing the glycerol electrooxidation with the other alcohols, it was possible note that the vicinal hydroxyl groups is the key property to yield the high current densities (for alcohols electrooxidation in a general way) seen on gold. It favors the C-C bonding break, that leads to more oxidized products, as seen by FTIR and HPLC data. In addition, FTIR measurements showed that neutralization and even acidification can occur near to the electrode in alkaline medium (if the base concentration is not high enough), due to the formation of acidic byproducts that can also lead to different reaction mechanism. RDE experiments indicated that it is possible to control the selectivity of glycerol and other alcohols electrooxidation products on gold by artificial convection, but control by the potential or concentration are limited, as shown by products analysis. The CV tests with byproducts and products analysis allowed to refine the glycerol electrooxidation reaction pathways.

Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-05-19T17:29:27Z No. of bitstreams: 1 JonnyFerreira.pdf: 3245371 bytes, checksum: 31437c781c5f38b977832295aa4ecd66 (MD5) / Made available in DSpace on 2017-05-19T17:29:27Z (GMT). No. of bitstreams: 1 JonnyFerreira.pdf: 3245371 bytes, checksum: 31437c781c5f38b977832295aa4ecd66 (MD5) Previous issue date: 2017-03-16 / Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão (FAPEMA) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Therefore, this research proposes the glycerol transformation in a product with a larger value aggregated the glycerol carbonate. For this, catalysts were synthesized under the influence of modified alumina with calcium and magnesium, produced by methods of polymeric precursors and impregnating in a wet system. The X-ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning electron microscopy and dispersive energy spectrometry (SEM-EDS) and X-ray fluorescence spectroscopy (FRX). The glycerol reaction with the dimethyl carbonate was processed in 95º C, with 3.5 dimethyl carbonate/glycerol and 20% of the mass of the catalyst relative to glycerol. The sprectroscopic analysis in the infared region of the reactional product suggested the formation of the carbonyl group (C = O), vibrational mode in the region 1770cm-1 , what is characteristic of a glycerol carbonate Chromatograms confirmed the formation of glycerol carbonate. The conversion values of carbonation of the glycerol with the Al-Ca01 and Al-Ca02 catalysts were 96.5 and 68.6%, respectively, whereas for Al-Mg01 and Al-Mg02, 50.9 and 39.6%, respectively, noting that the conversion potential of glycerol to glycerol carbonate followed the sequence Al-Ca01 <AlCa02 <Al-Mg01 <Al-Mg02. It was observed the formation of glycidol as a minor product. It was fullfilled a 24 factorial planning to evaluate the efects of the variables, composition of the catalyst, molar ration between glycerol and dimethyl carbonate, time and temperature on the reaction of the formation of the glycerol carbonate and determine if the ideal conditions of the process for better results of conversion and selectivity. / Este trabalho propõe a transformação do glicerol em um produto de maior valor agregado, o carbonato de glicerol. Para tanto, foram sintetizados catalisadores a base de alumina modificada com cálcio e magnésio, produzidos pelos métodos de precussor polimérico e impregnação via úmida. A caracterização dos catalisadores ocorreu por meio das análises de difração de raios X (DRX), Infravermelho com transformada de Fourier (FTIR), Microscopia eletrônica de varredura e espectrometria de energia dispersiva (MEV-EDS) e Espectroscopia de fluorescência de raios X (FRX). A reação do glicerol com o carbonato de dimetila se processou a 95 °C com uma razão carbonato de dimetila / glicerol de 3,5 e 20% em massa do catalisador relativo ao glicerol. A análise espectroscópica na região do infravermelho do produto reacional indicou a formação do grupo carbonila (C=O), modo vibracional na região de 1770 cm-1 , aspecto característico do carbonato de glicerol. Os cromatogramas confirmaram a formação do carbonato de glicerol. Os valores de conversão de carbonatação do glicerol com a utilização dos catalisadores Al-Ca01 e Al-Ca02 foram 96,5 e 68,6%, respectivamente enquanto que para os sistemas Al-Mg01 e Al-Mg02, 50,9 e 39,6%, respectivamente, notando que o potencial de conversão de glicerol à carbonato de glicerol seguiu a sequência Al-Ca01 < Al-Ca02 < Al-Mg01 < AlMg02. A formação do glicidol foi observado no emprego do catalisador de AlCa01 como um produto minoritário. Foi realizado um planejamento fatorial 24 para avaliar os efeitos das variáveis, composição do catalisador, razão molar entre glicerol e carbonato dimetila, tempo e temperatura na reação de formação do carbonato de glicerol e determinar se as condições ideais do processo para melhores resultados de conversão e seletividade.

With the increasing demand for biodiesel, the accumulation of byproduct, crude glycerol has become a problem which needs to be solved. Lactic acid is one of the value-added chemical which can be produced from glycerol that has wide uses in food and chemical industry. Although glycerol can be converted to lactic acid with an alkali as the catalyst at high glycerol conversion (100 mol%) and lactic acid yield (around 90 mol%), the high alkalinity would cause severe corrosiveness to a stainless steel reactor. In this study two tasks were performed to convert glycerol to lactic acid with satisfactory conversion and selectivity, and to reduce the corrosiveness of reaction medium. First, CaO was used as solid base catalyst. The highest lactic acid yield achieved was 40.8 mol% with a 97.8 mol% glycerol conversion, when operating at 290°C after 150 min reaction with molar ratio of CaO: glycerol=0.3. Also CaO has advantages such as high lactic acid productivity (3.35 g/(min·L)) and reusability. Meanwhile, CaO can be used as the catalyst for both biodiesel production and the following crude glycerol conversion to lactic acid. Second, for glycerol conversion with NaOH as catalyst, a fed-batch reactor was applied to continuously supply NaOH during reaction process, compensating the OH- neutralized by newly formed lactic acid. The optimal lactic acid yield of 80.5 mol%, with 92.8% glycerol conversion was obtained at 300 °C for 220min, with 1.1 M glycerol initial concentration. A first-order kinetic model for glycerol concentration versus time was developed and verified experimentally under conditions with different initial glycerol concentration and reaction temperature. Although crude glycerol samples contained large amount of impurities, both methods, conversion with solid base catalyst and with fed-batch reactor, were applied successfully to three crude glycerol samples provided by biodiesel manufacturers, and the lactic acid yield reached 52.3 mol% and 72.7 mol% respectively. Finally, the corrosion issue of different methods was compared based on the Fe3+ concentration (analyzed with atomic-absorption spectroscopy) in the products. Both methods of glycerol conversions, with solid base catalyst and fed-batch reactor, can reduce the corrosiveness of glycerol conversion with an alkali as the catalyst.