Solid Oxide Fuel Cells (SOFC) are electrochemical energy conversion devices which allow fuel gases, e.g. hydrogen or natural gas, to be converted to electricity and heat at much high efficiencies than combustion-based energy conversion technologies. SOFC are particularly suited to employment in stationary energy conversion applications, e.g. micro-combined heat and power (μ-CHP) and base load, which are certain to play a large role in worldwide decentralisation of power distribution and supply over the coming decades. Use of high-temperature SOFC technology within these systems is also a vital requirement in order to utilise fuel gases which are readily available in different areas of the world. Unfortunately, the limiting factor to the long-term commercialisation of SOFC systems is the redox instability, coking intolerance and sulphur poisoning of the state-of-the-art Ni-based cermet composite anode material. This research explores the ‘powder to power' development of alternative SOFC anode catalyst systems by impregnation of an A-site deficient La0.20Sr0.25Ca0.45TiO3 (LSCT[sub](A-)) anode ‘backbone' microstructure with coatings of ceria-based oxide ion conductors and metallic electrocatalyst particles, in order to create a SOFC anode which exhibits high redox stability, tolerance to sulphur poisoning and low voltage degradation rates under operating conditions. A 75 weight percent (wt. %) solids loading LSCT[sub](A-) ink, exhibiting ideal properties for screen printing of thick-film SOFC anode layers, was screen printed with 325 and 230 mesh counts (per inch) screens onto electrolyte supports. Sintering of anode layers between 1250 °C and 1350 °C for 1 to 2 hours indicated that microstructures printed with the 230 mesh screen provided a higher porosity and improved grain connectivity than those printed with the 325 mesh screen. Sintering anode layers at 1350 °C for 2 hours provided an anode microstructure with an advantageous combination of lateral grain connectivity and porosity, giving rise to an ‘effective' electrical conductivity of 17.5 S cm−1 at 850 °C. Impregnation of this optimised LSCT[sub](A-) anode scaffold with 13-16 wt. % (of the anode mass) Ce0.80Gd0.20O1.90 (CGO) and either Ni (5 wt. %), Pd, Pt, Rh or Ru (2-3 wt. %) and integration into SOFC resulted in achievement of Area Specific Resistances (ASR) of as low as 0.39 Ω cm−2, using thick (160 μm) 6ScSZ electrolytes. Durability testing of SOFC with Ni/CGO, Ni/CeO2, Pt/CGO and Rh/CGO impregnated LSCT[sub](A-) anodes was subsequently carried out in industrial button cell test rigs at HEXIS AG, Winterthur, Switzerland. Both Ni/CGO and Pt/CGO cells showed unacceptable levels of degradation (14.9% and 13.4%, respectively) during a ~960 hour period of operation, including redox/thermo/thermoredox cycling treatments. Significantly, by exchanging the CGO component for the CeO2 component in the SOFC containing Ni, the degradation over the same time period was almost halved. Most importantly, galvanostatic operation of the SOFC with a Rh/CGO impregnated anode for >3000 hours (without cycling treatments) resulted in an average voltage degradation rate of < 1.9% kh−1 which, to the author's knowledge, has not previously been reported for an alternative, SrTiO3-based anode material. Finally, transfer of the Rh/CGO impregnated LSCT[sub](A-) anode to industrial short stack (5 cells) scale at HEXIS AG revealed that operation in relevant conditions, with low gas flow rates, resulted in accelerated degradation of the Rh/CGO anode. During a 1451 hour period of galvanostatic operation, with redox cycles and overload treatments, a voltage degradation of 19.2% was observed. Redox cycling was noted to briefly recover performance of the stack before rapidly degrading back to the pre-redox cycling performance, though redox cycling does not affect this anode detrimentally. Instead, a more severe, underlying degradation mechanism, most likely caused by instability and agglomeration of Rh nanoparticles under operating conditions, is responsible for this observed degradation. Furthermore, exposure of the SOFC to fuel utilisations of >100% (overloading) had little effect on the Rh/CGO co-impregnated LSCT[sub](A-) anodes, giving a direct advantage over the standard HEXIS SOFC. Finally, elevated ohmic resistances caused by imperfect contacting with the Ni-based current collector materials highlighted that a new method of current collection must be developed for use with these anode materials.

Cette thèse fait l’objet du développement d’un modèle numérique de la phase d’imprégnation d’une préforme lors du procédé de fabrication d’un matériau composite par infusion sous vide de type VARI (Vacuum Assisted Resin Infusion). La caractérisation in situ du comportement mécanique dans l’épaisseur d’une préforme (essais d’infusion réels) est confrontée à sa caractérisation ex situ par une machine de traction/compression. L’effet de différents paramètres est mis en valeur sur le comportement de la préforme (type de chargement appliqué, état de saturation, influence de la viscosité du fluide et de la vitesse de déformation). Les essais ont révélé le caractère viscoélastique d’un renfort de type tissé lors de sa décompression à l’état imprégné et ont permis la définition d’une loi de comportement viscoélastique non-linéaire du renfort lors de cette phase. En vue d’étendre l’usage de cette loi de comportement mécanique à une large gamme de renforts, la même démarche expérimentale est appliquée au cas d’un renfort de type mat, au comportement élastique non-linéaire. La forme générale de la loi de comportement proposée se veut être adaptée à la description des deux types de renforts testés, où les éventuels effets viscoélastiques sont pris en compte selon le renfort étudié. Suite à l’implantation de la nouvelle loi de comportement dans un code numérique dédié à la simulation de la phase de remplissage d’un moule, la comparaison entre les résultats numériques et ceux des essais d’infusion sous vide prouve la fiabilité de ce nouveau modèle pour ces deux renforts à l’architecture bien distincte. / This thesis focuses on the development of a numerical model for the preform impregnation during the VARI (Vacuum Assisted Resin Infusion) process for the manufacturing of a composite material. The in situ characterization of the mechanical behavior in the thickness direction of a preform (real infusion tests) was compared with an ex situ characterization by a universal testing machine. The preform behavior was characterized for different parameters such as loading type, saturation state, influence of fluid viscosity and strain rate. All the tests revealed the viscoelastic behavior of a woven fabric during its decompression in the impregnated state, leading to the definition of a non-linear viscoelastic constitutive law of the woven fabric during this phase. To extend the use of this mechanical constitutive law to a wide range of fabrics, the same experimental approach was applied to the case of a random mat fabric with non-linear elastic behavior. The generalized form of the constitutive law is adapted to the description of the two types of fabrics while the potential viscoelastic effects are taken into account according to the fabric type. After the implementation of the new constitutive law in a numerical code for the simulation of a mold filling process, the comparison between numerical and experimental results has proved the reliability of the new numerical model for these two reinforcements with distinct architectures.

Les phosphures de métaux de transition nanométriques trouvent de nombreuses applications, notamment en catalyse hétérogène. Les silices mésoporeuses organisées (SMO) de type SBA-15, grâce à leurs paramètres physico-chimiques ajustables (surface spécifique, taille de pores, épaisseur de parois, etc.) et la reproductibilité de leurs synthèses, sont des supports de nanoparticules (NPs) de choix. Dans ce contexte, l'objectif de cette thèse est de synthétiser des NPs de phosphure de cobalt dans les pores de matrices de type SBA-15 à partir de clusters organométalliques comme uniques précurseurs. Dans une première partie, nous étudions le comportement de trois clusters contenant un ou plusieurs ligands phosphorés à haute température. Ceux-ci présentent des rapports Co/P différents, ce qui a un impact direct sur la phase phosphure obtenue après activation. Nous suivons également l'influence de l'atmosphère et de la température sur les phases formées lors du traitement thermique. Pour contrôler la taille et la polydispersité des NPs étudiées, nous avons imprégné le cluster précurseur [Co4(CO)10(µ-NH(PPh2)2)] dans des SMO de type SBA-15. L'atmosphère et la température choisies pour le traitement thermique influent sur la phase obtenue, comme précédemment, mais les conditions ne sont pas identiques. De plus, des phases parasites ferromagnétiques sont formées et des lavages à l'acide chlorhydrique concentré sont nécessaires pour s'en affranchir. Enfin, la préparation de grandes quantités de produit (transfert d'échelle) requiert l'utilisation d'un volume contrôlé lors du traitement thermique, pour assurer une homogénéité dans l'échantillon. / Nanosized transition metal phosphides find applications in various fields, including heterogeneous catalysis. Ordered mesoporous silica (OMS) such as SBA-15 are supports of choice for nanoparticles (NPs), since they feature adjustable microstructural parameters (specific surface area, pore size, wall thickness, etc.) and reproducible synthesis conditions. In this context, the goal of this PhD work is to synthesize cobalt phosphide NPs within the pores of SBA-15-type OMS, starting from organometallic clusters as single-source precursors. First, we study the behavior of three organometallic clusters bearing one or more phosphine-based ligands at high temperatures. Depending on the initial Co/P ratio, those clusters afford different phosphide phases. We also monitored the influence of the atmosphere and the temperature during the thermal treatment on the phases obtained. To control size and polydispersity of the NPs, we impregnated the cluster precursor [Co4(CO)10(µ-NH(PPh2)2)] in SBA-15-type OMS. As in the previous case, atmosphere and temperature influence the obtained phase, but the conditions are different. Moreover, ferromagnetic impurities are formed and it is necessary to wash the samples with concentrated hydrochloric acid to remove them. Finally, larger quantities of product can be prepared (scale-up) but the volume of sample thermally treated at once needs to be controlled precisely to ensure homogeneity of the final product.

Hydrophobic impregnations often referred to as water repellent agents, today mainly consisting of alkylalkoxysilanes, are often used on concrete to prolong the service life of the structure. This is accomplished by protecting the reinforcement bars from chlorides or by changing the moisture content inside. When the concrete is treated with a water repellent agent the properties of the surface layer becomes hydrophobic and thereby water droplets are stopped from entering, still allowing water vapour to pass through. This change can reduce chloride ingress and stop heavy rain from penetrating through the surface layer. This thesis presents results concerning how the properties of concrete are affected by a hydrophobic impregnation. Moisture transport and fixation in the surface layer of the concrete are studied as well as the secondary effects of more practical use such as the effect on chloride ingress, water absorption and humidity level. It also presents results on how the penetration depth and concentration of the water repellent agent (i) depend on a number of parameters, and (ii) affect the outcome of the treatment. Water repellent treatments on a number of different concrete structures in Stockholm, ranging from tunnel to high-rice building, are evaluated as well. The three most important factors for the penetration of any water repellent agent into concrete are time, porosity and degree of saturation. A semi-empirical equation is derived that gives an idea on how much these factors affect the efficient penetration depth of the water repellent agent. The depth and concentration have a major effect on the performance of the treatment. The moisture diffusion coefficient for a water repellent treated concrete is close to constant and not nearly as dependent on the relative humidity (RH) as for untreated concrete. Unlike untreated concrete, where capillary suction plays an important role for the moisture transport at high RH, the vapour transport is the dominant transport mechanism even at high RH for water repellent treated concrete. The moisture fixation is affected by a water repellent treatment and the effect is clearest at high moisture levels. The main reason for this is that the capillary porosity is affected by the treatment to a relatively high degree while the gel porosity to a large extent remains unaffected. A hypothesis is presented which suggests that the RH inside the concrete at the time of the treatment affects not only the depth and concentration but also in which range of pore radii the water repellent agent is present and active. The durability of hydrophobic impregnations can be divided into surface effects and in depth effects. The first is sensitive to the environmental and mechanical loadings and normally disappears within a year while the later can be long lasting if a sufficient depth is reached. Hydrophobic impregnations are not the answer to all problems in concrete related to moisture, but if correctly used it can prolong the service life of the structure which will lead to savings of natural resources and thus both economical and environmental savings for the community. / Vattenavvisande impregneringsmedel, som i dagsläget till största del består av alkylalkoxysilaner, används ofta på betong för att förlänga livslängden på konstruktionen. Detta syfte uppnås genom att armeringen skyddas mot klorider eller att fukthalten inuti betongen sänks. När betongen impregneras ändras ytskiktets fuktmekaniska egenskaper från hydrofila till hydrofoba vilket gör att vattendroppar kan stoppas medan vattenånga tillåts passera. Dessa förändrade egenskaper kan medföra att kloridinträngningen minskar och att kraftiga regn inte tränger genom det impregnerade skiktet. Denna avhandling presenterar resultat om hur betongen påverkas av en vattenavvisande impregnering. Fukttransport och fuktfixering i betongens ytskikt har undersökts men även sekundära effekter som kloridinträngning, vattenabsorption och förändring i fuktinnehåll vilka alla är av större praktisk nytta. Avhandlingen presenterar också resultat om vilka faktorer som påverkar impregneringens inträngningsdjup och koncentration samt vilken betydelse dessa har för funktionen. För att utvärdera impregneringars effekt i olika miljöer har ett stort antal objekt i Stockholm undersökts, innefattande olika konstruktioner från en tunnel till höghus. Impregneringens inträngningsdjup och koncentration har en avgörande betydelse för dess funktion. De tre viktigaste faktorerna för alla impregneringsmedels inträngning i betong är tid, porositet och fuktnivå. En semiempirisk ekvation har tagits fram där det framgår hur dessa tre faktorer påverkar det slutliga inträngningsdjupet för impregneringen. Till skillnad från obehandlad betong är transportkoefficienten för en impregnerad betong nästan oberoende av den relativa fuktigheten (RF) i omgivningen. Vid höga RF, där största delen av fukttransporten i obehandlad betong sker på grund av kapillärkrafter, är ångtransporten fortfarande den dominerande transportmekanismen i impregnerad betong. Fuktfixeringen i betong påverkas av en impregnering och effekten är störst vid höga RF. Det är dock tydligt att en viss mängd fukt finns inuti den impregnerade betongen. Detta kan förklaras med att största delen av kapillärporerna påverkas av impregneringen medan gelporerna förblir obehandlade. Resultaten indikerar också att fuktnivån vid impregneringstillfället avgör vilken del av porsystemet som kan behandlas och inte bara koncentrationen och inträngningsdjupet. Långtidsegenskaperna hos impregneringen kan delas upp i yt- och djupeffekt. Effekten på ytan avtar normalt sett inom ett år på grund av damm och partiklar, UV-ljus, slitage mm. Djupeffekten påverkas däremot inte av dessa faktorer och kan finnas kvar i decennier. Vattenavvisande impregneringar är inte lösningen på alla fuktrelaterade problem i betong, men om de används på rätt sätt så kan det förlänga livslängden på många konstruktioner. Detta leder till ett bättre hushållande med naturresurser och därmed både ekonomiska och miljömässiga besparingar för samhället. / QC20100715

Supercapacitors are important electrochemical energy storage devices for microelectronic and telecommunication systems, electric cars, and smart grids. However, the energy densities of existing supercapacitors are still inadequate for many applications. Vanadium oxides have been studied as viable supercapacitor alternatives, with varying results. Methods are often complicated or time-consuming, and electrode fabrication often includes carbon powder and binder. The objective of this work was to study the effect of processing conditions on specific capacitance of supercapacitors based on vanadium oxides coated on carbon fiber papers. This study was conducted to form easily-fabricated compounds of vanadium oxides which could offer promise as pseudocapacitor material, and to nucleate these compounds directly onto inexpensive carbon fiber without binder. The incipient wetness impregnation technique was used to fabricate the electrodes. Electrochemical performance of the resulting electrodes was tested in a Swagelok-type electrochemical two-electrode cell, and the electrodes were characterized by XRD and SEM. Interesting nanofeatures were formed and the vanadium oxides exhibited pseudocapacitance at a respectable level.

The three main components of wood, namely, cellulose, hemicellulose, and lignin, can be used in various areas. However, since lignin covalently crosslinks with wood polysaccharides creating networks that is an obstacle for extraction, direct extraction of different wood components in high yield is not an easy matter. One potential approach to overcome such obstacles is to treat the wood with specific enzymes that degrade the networks by specific catalysis. However, the structure of wood is so compact that the penetration of the wood fibers by large enzyme molecules is hindered. Thus, the pretreatment of wood prior to the application of enzymes is necessary, for “opening” the structure. One pretreatment method that was performed in this thesis is based on kraft pulping, which is a well-established and industrialized technique. For untreated wood, the wood fibers cannot be attacked by the enzymes. A relatively mild pretreatment was sufficient for wood polysaccharides hydrolyzed by a culture filtrate. A methanol-alkali mixture extraction was subsequently applied to the samples that were pretreated with two types of hemicellulases, Gamanase and Pulpzyme HC, respectively. The extraction yield increased after enzymatic treatment, and the polymers that were extracted from monocomponent enzyme-treated wood had a higher degree of polymerization. Experiments with in vitro prepared lignin polysaccharide networks suggested that the increased extraction was due to the enzymatic untying. However, the relatively large loss of hemicellulose, particularly including (galacto)glucomannan (GGM), represents a problem with this technique. To improve the carbohydrate yield, sodium borohydride (NaBH4), polysulfide and anthraquinone were used, which increased the yields from 76.6% to 89.6%, 81.3% and 80.0%, respectively, after extended impregnation (EI). The additives also increased the extraction yield from approximately 9 to 12% w/w wood. Gamanase treatment prior to the extraction increased the extraction yield to 14% w/w wood. Sodium dithionite (Na2S2O4) is an alternative reducing agent for the preservation of hemicelluloses because it is less expensive than metal hydrides and only contains sodium and sulfur, which will not introduce new elements to the recovery system. Moreover, Na2S2O4has the potential to be generated from black liquor. Na2S2O4 has some preservation effect on hemicelluloses, and the presence of Na2S2O4 also contributed to delignification. The extraction yield increased to approximately 15% w/w wood. Furthermore, Na2S2O4 has been applied in the kraft pulping process of spruce. The yield and viscosity increased, while the Klason lignin content and kappa number decreased, which represents a beneficial characteristic for kraft pulp. The brightness and tensile strength of the resulting sheets also improved. However, the direct addition of Na2S2O4 to white liquor led to greater reject content. This problem was solved by pre-impregnation with Na2S2O4 and/or mild steam explosion (STEX) prior to the kraft pulping process. Following Na2S2O4 pre-impregnation and mild STEX, the obtained kraft pulp had substantially better properties compared with the properties exhibited after direct addition of Na2S2O4 to the white liquor. The wood structure opening efficiency of mild STEX alone was also tested. The accessibility of the wood structure to enzymes was obtained even at very modest STEX conditions, according to a reducing sugar analysis, and was not observed in untreated wood chips, which were used as a reference. The mechanical effect of STEX appears to be of great importance at lower temperatures, and both chemical and mechanical effects occur at higher STEX temperatures. / <p>QC 20140903</p>

Cette thèse discute différentes situations dans lesquelles les interfaces jouent un rôle prépondérant dans la dynamique de gouttes et de fronts liquides. Dans une première partie, nous nous intéressons à des gouttes très mobiles, dans trois situations de mouillage nul. (i) Lorsqu'on dépose un liquide sur une surface portée à une température très supérieure à sa température d'ébullition, un film de vapeur s'intercale entre le liquide et le substrat, empêchant tout contact. (ii) Sur un substrat superhydrophobe, c'est-à-dire un substrat rugueux et hydrophobe, la surface inférieure d'une goutte n'est en contact qu'avec une fraction réduite de solide. (iii) Enfin, lorsqu'on met en contact une goutte avec des grains hydrophobes, elle les capture à sa surface, ce qui l'isole de son substrat. Dans chacun de ces trois cas, nous étudions la friction résiduelle qui se manifeste lorsque ces gouttes dévalent. Nous montrons que le frottement est bien plus faible que celui observé habituellement en mouillage partiel et qu'il a une origine physique différente. Dans une seconde partie, nous étudions des fronts mobiles variés. Lorsqu'un liquide est mis en contact avec des grains, il peut soit l'imprégner si son angle de contact est inférieur à un angle de contact critique, soit rester en surface dans le cas contraire. Dans ce dernier cas, le dévalement d'une goutte entraîne l'érosion du tas de grains : nous nous intéressons à la quantité de grains emportée par la goutte. Par ailleurs, un goutte-à-goutte tombant sur une surface refroidie sous la température de solidification provoque la croissance d'une stalagmite de glace. Enfin, lorsqu'on confine une goutte en caléfaction entre deux plaques parallèles, une série d'instabilités se développe : un anneau se forme, qui grandit ensuite avant de se briser en gouttelettes.

This thesis focused on the modelling of a pulping process. The purpose was to see if an accurate model can be crated based on relatively simple premises and if the errors can be identified or analysed. To realise this, the authors conducted a literature study to identify the current state of the art regarding the chemical pulping process. In addition, flow charts and sample data from a case study were examined. Based on the literature review and case study, model assumptions were derived. The model is divided into sixteen components. Where mixing occurs, lumped conditions are assumed. The model has five validation points, four of which are temperatures and a mass flowrate. These are shown as deviations from the measured values. In conclusions, it was the model could produce stable results over a narrow time frame. More so if the transition period at the start of the simulation is overlooked. Several new model assumptions are presented with the purpose to increase accuracy e.g. account for the components ability to store mass.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho, dois copolímeros à base de 2-vinilpiridina (2Vpy), estireno (Sty) e divinilbenzeno (DVB) foram sintetizados empregando a técnica de polimerização em suspensão aquosa via radical livre. Os copolímeros com diferentes características morfológicas foram preparados variando a composição da mistura diluente, constituída por tolueno e n-heptano, solventes solvatantes e não solvatantes para as cadeias poliméricas. A caracterização estrutural desses materiais foi feita através de medidas de área específica, volume de poros, diâmetro médio de poros e densidade aparente. Além disso, esses materiais foram avaliados por microscopia ótica e eletrônica de varredura, por espectroscopia na região do infravermelho (FTIR), análise termogravimétrica (TGA) e análise elementar. Os copolímeros Sty-DVB-2Vpy foram modificados quimicamente através de reação de quaternização das unidades de 2Vpy usando dois reagentes: iodeto de metila e acrilonitrila. A quaternização dos copolímeros Sty-DVB-2Vpy foi confirmada através de espectroscopia de infravermelho, pelo aparecimento das bandas de absorção características do íon peridíneo e do grupo nitrila e também pela análise do comportamento térmico. Os produtos dessas reações foram submetidos à avaliação da capacidade bactericida através do método de contagem em placas contra suspensão de Escherichia coli. O copolímero do tipo gel quaternizado com iodeto de metila apresentou a maior ação bactericida registrada, com eficiência até a concentração de 104 células/mL. Contudo, a maioria dos materiais quaternizados não apresentou ação biocida significativa. Com o objetivo de maximizar a atividade bactericida dos materiais preparados, os copolímeros quaternizados e não quaternizados foram impregnados com iodo por meio de duas metodologias: em solução e em fase vapor. O teor de iodo incorporado foi quantificado por análise gravimétrica. Foi possível observar que os copolímeros quaternizados e impregnados com iodo se mostraram mais eficientes como agentes bactericidas que os copolímeros não funcionalizados impregnados com iodo. De uma forma geral, foi possível perceber que a ação bactericida dos polímeros é fruto da associação entre as suas características de porosidade, o grau de quaternização alcançado e o teor de iodo incorporado. Para efeito de comparação foram feitos também ensaios bactericidas com uma resina comercial à base de Sty-DVB com grupo amônio quaternário, VP OC 1950. Os testes mostraram que a resina comercial não possui atividade bactericida. A impregnação de iodo a essa resina comercial forneceu um material com ação biocida semelhante à do copolímero do tipo gel, quaternizado com iodeto de metila e impregnado com iodo / In this work two 2-Vinylpyridine-Styrene-Divinylbenzene copolymers with different porosity degrees were synthesized by aqueous suspension polymerization in the presence of diluent mixtures formed by toluene (solvating solvent) and n-heptane (nonsolvating solvent) in different proportions. Their structural characteristics were characterized by determination of surface area, average pore diameter and pore volume by BET/BJH, bulk density, optical and electron microscopies. In addition the chemical morphology those materials were characterized by FT-IR, elemental analysis and thermogravimetry. The pyridine units were quaternized using two reagents: methyl iodide and acrylonitrile. Those reactions were confirmed by FT-IR, the presence of characteristics bands of piridinium ion and nitrile group was used as a qualitative indication of the quaternizations reactions. The extension of those modifications was also evaluated by thermogravimetry. The antibacterial activities of the quaternized materials were determined towards 103 to 107 cells/mL dilutions of the auxotrophic (OHd5 k-12) Escherichia coli strain. The gel type copolymer quaternized with methyl iodide presented the better bactericidal action, with significant efficiency until 104 cells/mL, however most quaternized copolymers did not present significant bactericidal action. In order to maximize the bactericidal performance, the modified and unmodified copolymers were impregnated with iodine using two different methods: solution and vapor. The iodine incorporation was quantified by gravimetry. It was observed that the copolymers quaternized and impregnated with iodine presented higher biocidal action than the unmodified copolymers impregnated with iodine. It was verified that the biocidal action the polymers is a result of three contributions: porous characteristics of the supports, quaternization degree and iodine incorporation degree. The bactericidal performance of a commercial resin with quaternary ammonium groups, VP OC 1950, was also evaluated. The tests showed that the commercial resin did not present bactericidal efficiency. That resin impregnated with iodine presented bactericidal action similar to gel type copolymer quaternized with methyl iodide and impregnated with iodine.

Made available in DSpace on 2016-06-02T19:56:59Z (GMT). No. of bitstreams: 1 6783.pdf: 3853594 bytes, checksum: 5c76462cb2ede47f0f6638372f3f2364 (MD5) Previous issue date: 2015-02-18 / Financiadora de Estudos e Projetos / The fluid catalytic cracking (FCC) is one of the most important process in the petroleum refining industry, being responsible for the increase of the yield of the most valuable light hydrocarbons. On the other hand, the FCC process generates big amounts of CO, NOx and SOx emissions. The CO emissions from the most of pollution sources are abatement using noble metal based catalysts. However, the growing demand and scarcity of those metals have caused an increase in the process cost and consequently promoting studies to find alternative catalysts with comparable efficiency and lower in cost. In this respect, the literature had presented interesting results with transitions metal catalysts. Thus, the objective of this work was to prepare exchanged or impregnated Fe or Mn on H-mordenite or Ce-mordenite, which were evaluated between 150 and 550 oC in the CO oxidation with O2, in the presence or absence of interfering compounds (water steam or SO2). The catalysts were characterized by ICP-OES, DRX, DRS-UV-VIS and Mössbauer spectroscopy. The results showed that the preparation procedures of the interchanged or impregnated Fe or Mn catalysts were adequate, and no mordenite crystallinity loss was observed. Contrary to the exchanged Fe or Mn based catalysts, those based on impregnated Fe or Mn oxides showed a important potential as catalysts in the CO oxidation with O2. Then, in the applied operational conditions the Ce-MOR/Fe10, Ce-MOR/Mn5, Ce-MOR/Mn10 e H-MOR/Mn5 catalysts were able to produce an effluent with CO content lower than 500 ppm, which is the allowed limit by the environmental regulations related with FCC units. In the presence of water steam the evaluated Fe or Mn catalysts presented activity loss that was recovered after the elimination of that interfering from the feed. Nevertheless, in the presence of SO2, the tested catalysts showed an irreversible and significantly activity loss. / O craqueamento catalítico fluido (FCC) é uma das etapas mais importantes no refino de petróleo, sendo responsável pelo aumento do rendimento em frações leves, de maior valor agregado. Por outro lado, o FCC é responsável na refinaria por uma grande parcela das emissões de monóxido de carbono (CO), óxidos de nitrogênio (NOx) e óxidos de enxofre (SOx). O CO, em particular, na maioria das fontes poluidoras é eliminado via oxidação sobre catalisadores à base de metais nobres. Porém, o aumento na demanda desses metais e sua baixa disponibilidade criam um forte impacto no custo do processo, surgindo a necessidade de buscar catalisadores alternativos, com eficiência comparável e de menor custo. Assim, o objetivo deste trabalho foi preparar catalisadores à base de ferro ou manganês impregnados ou trocados em H-mordenita ou Ce-mordenita e avaliá-los entre 150 e 550 oC na oxidação de CO com oxigênio (O2), na ausência ou presença de compostos interferentes à reação como vapor de água e dióxido de enxofre (SO2). Os catalisadores foram caracterizados por espectroscopia de emissão atômica (ICP-OES), difração de raios X (DRX), espectroscopia de reflectância difusa (DRS-UV-VIS), redução com H2 à temperatura programada (RTP-H2) e espectroscopia Mössbauer (MOSS). Os resultados mostraram que os procedimentos de preparação dos catalisadores, trocados ou suportados, foram eficientes, não se observando perda de cristalinidade da mordenita. Os catalisadores com óxidos de Fe ou Mn suportados na mordenita apresentaram um importante potencial para serem utilizados como catalisadores na oxidação de CO com O2, contrário ao que ocorreu com cátions de Fe ou Mn em sítios de troca. Assim, nas condições operacionais utilizadas, os catalisadores Ce-MOR/Fe10, Ce-MOR/Mn5, Ce-MOR/Mn10 e H-MOR/Mn5 foram capazes de converter CO suficiente para produzir um efluente gasoso com teor menor que 500 ppm de CO, sendo essa a concentração limite permitida pela legislação que rege as emissões de unidades FCC. Os catalisadores impregnados com Fe e Mn, quando avaliados na presença de vapor de água e de SO2, ocorreu perda da atividade, a que foi recuperada somente no caso do vapor de água.