Hydrogen is considered one of the best alternatives to fossil-fuels for the transportation sector because hydrogen can be burnt cleanly and efficiently in a fuel cell to drive an electric motor. However, due to the low density of H2 at ambient conditions the conventional H2 storage technologies (cryogenic liquid and compressed gas) cannot achieve energy densities comparable to to gasoline and diesel. A second energy storage challenge onboard electric fuel cell vehicles is fuel cell power management at peak current loads, which requires an auxiliary power source like a battery or supercapacitor. The development of efficient onboard energy storage systems for H2 and auxiliary power is critical to realisation of a hydrogen economy. Mesoporous carbons were investigated as H2 storage materials in composites with magnesium hydride (MgH2),and as electrode materials for electrochemical double-later capacitors. The mesoporous carbons were prepared by two methods: (1) from porous silica and alumina templates, and (2) by chemical activation of a waste carbon source (waste coffee grounds). The experimental approach targeted reducing the cost of mesoporous carbon preparation by using a cheaper template, where the cost of alumina template was one-fifth the cost of the silica template (at the laboratory scale), or by using a waste material as a carbon source. The alumina template was found to be suitable to produce a mesoporous carbon with an average pore size of 4.8 nm. Chemical activation of coffee grounds with ZnCl2 produced activated carbons with BET surface areas up to 1280 m2/g. Mesopore volume increased with ZnCl2 impregnation ratio, with mesopore size distributions in the range 2 - 20 nm. The theoretical H2 capacity of MgH2 is 7.6 % but MgH2 application in fuel cell vehicles is limited by slow hydrogenation kinetics and high temperatures (> 573 K) for H2 release. Magnesium was impregnated on activated carbon fibres (ACF) and mesoporous carbon (prepared from silica and alumina templates) to improve H2 storage kinetics and thermodynamics by reducing the magnesium hydride particle size. Thermal gravimetric analysis (TGA) and temperature programmed desorption (TPD) studies showed that thermal decomposition of MgCl2 supported on ACF at 1173 K in N2 and H2 can produce a Mg-ACF composite. At 573 K and 2 MPa H2 pressure a Mg-ACF composite, containing 11.2 %wt Mg, showed improved H2 adsorption kinetics compared to bulk Mg powder, but the total capacity of the Mg-ACF composite was only 0.4 % wt H2. To achieve a target of 6 %wt for onboard H2 storage higher Mg loadings are required. Attempts to impregnate Mg in mesoporous carbon via the MgCl2 thermal decomposition process highlighted the difficulties of avoiding MgO formation, and show that MgH2 loaded carbon is unlikely to be a practical high density onboard H2 storage technology. Activated carbons from waste coffee grounds (CGCs) were used as electrode materials in electrochemical double-layer capacitors. The specific capacitance of CGCs was as high as 368 F/g in 1 mol/L H2SO4, with good capacitance retention at fast charge rates and stable cycling performance. The good electrochemical performance of CGCs is attributed to a porous structure featuring both micropores 0.5 - 1.0 nm wide, which are effective for double-layer formation, and small mesopores, which facilitate electrolyte transport at fast charge rates. The capacitance of CGCs is enhanced by pseudo-Faradaic reactions involving nitrogen and oxygen functional groups. At fast charge-discharge rates the CGCs had higher energy density and better stability than a commercial benchmark activated carbon (Maxsorb). The ZnCl2 activation process can be optimised to develop mesopores for improved capacitance at fast charge rates and capacitance in organic electrolytes. In 1 mol/L tetra ethyl ammonium tetrafluoroborate (TEABF4) / acetonitrile the CGC with the most mesopores, which was prepared with a ZnCl2 to coffee ratio of 5:1, has the highest capacitance at high power density. CGCs with greater mesopore content retained higher specific capacitance at fast charge-discharge rates as the mesopores acts as channels or reservoirs for electrolyte transport. An improved model for evaluation of contributions to capacitance from micropore surfaces and mesopore surfaces is proposed. From this model the double-layer capacitance of mesopores surface area was found to be about 14 μF/cm2 and did not change considerably with increasing current load. The contribution of micropores to capacitance is dependent on the accessibility of ions to the micropores, and this accessibility is proportional to the mesopore surface area. An exponential function was found to describe the contribution of mesopores and micropore surfaces to capacitance. The effective double-layer capacitance of the micropore surface area drops at fast charge-discharge rates as a result of restricted ion transport, and this result highlights the importance of mesopores to retain energy density for high power supercapacitor applications.

abstract: With the aid of metabolic pathways engineering, microbes are finding increased use as biocatalysts to convert renewable biomass resources into fine chemicals, pharmaceuticals and other valuable compounds. These alternative, bio-based production routes offer distinct advantages over traditional synthesis methods, including lower energy requirements, rendering them as more "green" and "eco-friendly". <italic>Escherichia coli</italic> has recently been engineered to produce the aromatic chemicals (S)-styrene oxide and phenol directly from renewable glucose. Several factors, however, limit the viability of this approach, including low titers caused by product inhibition and/or low metabolic flux through the engineered pathways. This thesis focuses on addressing these concerns using magnetic mesoporous carbon powders as adsorbents for continuous, in-situ product removal as a means to alleviate such limitations. Using process engineering as a means to troubleshoot metabolic pathways by continuously removing products, increased yields are achieved from both pathways. By performing case studies in product toxicity and reaction equilibrium it was concluded that each step of a metabolic pathway can be optimized by the strategic use of in-situ adsorption as a process engineering tool. / Dissertation/Thesis / Masters Thesis Chemical Engineering 2014

abstract: According to sources of the Centers for Disease Control and Prevention, approximately 1.7 million traumatic brain injury (TBI) cases occur annually in the United States. TBI results in 50 thousand deaths, nearly 300 thousand hospitalizations and 2.2 million emergency room visits causing a $76 billion economic burden in direct and indirect costs. Furthermore, it is estimated that over 5 million TBI survivors in the US are struggling with long-term disabilities. And yet, a point-of-care TBI diagnostic has not replaced the non-quantitative cognitive and physiological methods used today. Presently, pupil dilation and the Glasgow Coma Scale (GCS) are clinically used to diagnose TBI. However, GSC presents difficulties in detecting subtle patient changes, oftentimes leaving mild TBI undiagnosed. Given the long-term deficits associated with TBIs, a quantitative method that enables capturing of subtle and changing TBI pathologies is of great interest to the field. The goal of this research is to work towards a test strip and meter point-of-care technology (similar to the glucose meter) that will quantify several TBI biomarkers in a drop of whole blood simultaneously. It is generally understood that measuring only one blood biomarker may not accurately diagnose TBI, thus this work lays the foundation to develop a multi-analyte approach to detect four promising TBI biomarkers: glial fibrillary acidic protein (GFAP), neuron specific enolase (NSE), S-100β protein, and tumor necrosis factor-α (TNF-α). To achieve this, each biomarker was individually assessed and modeled using sensitive and label-free electrochemical impedance techniques first in purified, then in blood solutions using standard electrochemical electrodes. Next, the biomarkers were individually characterized using novel mesoporous carbon electrode materials to facilitate detection in blood solutions and compared to the commercial standard Nafion coating. Finally, the feasibility of measuring these biomarkers in the same sample simultaneously was explored in purified and blood solutions. This work shows that a handheld TBI blood diagnostic is feasible if the electronics can be miniaturized and large quantity production of these sensors can be achieved. / Dissertation/Thesis / Doctoral Dissertation Biomedical Engineering 2017

abstract: The aims of this project are to demonstrate the design and implementation of separations modalities for 1) in situ product recovery and 2) upstream pretreatment of toxic feedstocks. Many value-added bioproducts such as alcohols (ethanol and butanol) developed for the transportation sector are known to be integral to a sustainable future. Likewise, bioproduced aromatic building blocks for sustainable manufacturing such as phenol will be equally important. The production of these compounds is often limited by product toxicity at 2- 20 g/L, whereas it may desirable to produce 20-200 g/L for economically feasible scale up. While low-cost feedstocks are desirable for economical production, they contain highly cytotoxic value-added byproducts such as furfural. It is therefore desirable to design facile detoxification methods for lignocellulose-derived feedstocks to isolate and recover furfural preceding ethanol fermentation by Escherichia coli. Correspondingly it is desirable to design efficient facile in situ recovery modalities for bioalcohols and phenolic bioproducts. Accordingly, in-situ removal modalities were designed for simultaneous acetone, butanol, and ethanol recovery. Additionally, a furfural removal modality from lignocellulosic hydrolysates was designed for upstream pretreatment. Solid-liquid adsorption was found to serve well each of the recovery modalities characterized here. More hydrophobic compounds such as butanol and furfural are readily recovered from aqueous solutions via adsorption. The primary operational drawback to adsorption is adsorbent recovery and subsequent desorption of the product. Novel magnetically separable mesoporous carbon powders (MMCPs) were characterized and found to be rapidly separable from solutions at 91% recovery by mass. Thermal desorption of value added products was found efficient for recovery of butanol and furfural. Fufural was desorbed from the MMCPs up to 57% by mass with repeated adsorption/thermal desorption cycles. Butanol was recovered from MMCPs up to an average 93% by mass via thermal desorption. As another valuable renewable fermentation product, phenol was also collected via in-situ adsorption onto Dowex Optipore L-493 resin. Phenol recovery from the resins was efficiently accomplished with tert-butyl methyl ether up to 77% after 3 washes. / Dissertation/Thesis / Doctoral Dissertation Chemical Engineering 2017

Orientadores: Heloise de Oliveira Pastore, Leonardo Marchese / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-16T12:57:15Z (GMT). No. of bitstreams: 1 Gallo_JeanMarcelRibeiro_D.pdf: 4780624 bytes, checksum: 5426a4e169601ec9fd875fbe271a36c9 (MD5) Previous issue date: 2010 / Resumo: Esse trabalho teve como objetivo a aplicação de peneiras moleculares mesoporosas de sílica como suporte para metal em aplicações em eletrodos na Célula a combustível a metanol direto (DMFC). As peneiras moleculares mais importantes, MCM-41, MCM-48 e SBA-15, foram escolhidas. Em um primeiro momento a reprodutibilidade das sínteses foi verificada. Como pesquisa lateral foi estudada a acidez de superfície da SBA-15 contendo alumínio obtida por síntese direta. Além disso, foi desenvolvida a primeira síntese direta para a [Al]-SBA-15 Sílica é um isolante elétrico e, portanto, não pode ser utilizada como um eletrodo, deste modo, uma nova família de compósitos chamada Carbonos Cerâmicos Mesoporosos (MCC) foi preparada pela adição de grafite comercial na síntese das sílicas mesoporosas (MCM-41, MCM-48 ou SBA-15). A grafite não influenciou na formação da mesofase de sílica, de qualquer maneira, a MCC-MCM-41 e a MCC-MCM-48 cresceram na superfície da grafite. As MCCs preparadas com razão em massa sílica/carbono de 1/1 e 1/1.25 apresentaram condutividades elétricas similares enquanto MCCs com menos quantidade de carbono se mostraram isolantes elétricos. As MCCs(1/1) modificadas com 20 % em massa de paládio foram usadas na DMFC chegando no máximo a desempenhos 10 vezes menores que o do sistema usando o suporte comercia Vulcan XC-72R. Esse comportamento foi atribuida a menos condutividade elétrica dos MCCs. Para aumentar a condutividade elétrica dos MCCs(1/1), o agente direcionador orgânico usado na síntese da fase silícica foi carbononizado ( ao invez de calcinado, como feito anteriormente) Alternativamente, os MCCs foram sintetizados com uma razão em massa sílica/carbono de 1/3. Os testes dos MCCs contendo 20 % em massa de platina no cátodo da DMFC mostraram melhores resultados para a MCC-SBA-15(1/3) e a MCC-MCM-48(1/1) pirolisada. Por outro lado, o despenho do sistema usando o suporte Vulcan-XC-72R foi o dobro. Modificados com 60 % em massa da liga PtRu, o MCC-SBA-15(1/3) e o MCC-MCM-48(1/1) pirolisado foram aplicados no ânodo da DMFC, alcançando desempenhos 20 e 40 % maiores que a Vulcan XC-72R. / Abstract: The present work aimed at using mesoporous silica as metal support for Direct Methanol Fuel Cell (DMFC) electrodes. The most important mesoporous silica, MCM-41, MCM-48 and SBA-15, were chosen. In a first moment their synthesis were verified with respect to the reproductibility. As side results, the surface acidity of aluminum containing SBA-15 obtained by direct synthesis was also studied and it is also reported the first [Al]-SBA-16 obtained by direct synthesis was reported. Silica is electrically insulating and thus cannot be used directly in a cell electrode, thus it was reported here the preparation of the novel composite named Mesoporous Carbon Ceramics (MCC) obtained by the addition of commercial graphite into the mesoporous silica synthesis (MCM-41, MCM-48 or SBA-15). The graphite did not influence in the formation of the silica mesophase, however, MCC-MCM-41 and MCC-MCM-48 grow on the graphite surface. The MCCs prepared with silica/carbon weight ratio of 1/1 and 1/1.25 presented similar electrical conductivities while lower carbon loading MCCs were found insulating. The MCCs(1/1) modified with 20 wt % of platinum were used on Direct Methanol Fuel Cell electrodes (DMFC) reaching performances more ten 10 times lower than that of a system using the commercial metal support Vulcan XC-72R, probably due to their lower electrical conductivity. To increase the electrical conductivity of the MCCs(1/1), the surfactant used to synthesize the silica phase was carbonized (instead of calcined as done for the previous materials). Alternatively, MCCs was synthesized with silica/carbon weight ratio of 1/3. The test of 20 wt. % platinum-containing MCCs on the cathode of the DMFC showed that the best results were obtained for the MCC-SBA-15(1/3) and for the template-pyrolysed MCC-MCM-48(1/1), however, the performance was approximately half of that of the system using Vulcan-XC-72R. When modified with 60 wt % of PtRu alloy, MCC-SBA-15(1/3) and to the template-pyrolysed MCC-MCM-48(1/1) and applied on the DMFC anode, the performances at 343 K was ca. 20 and 40 % higher that that obtained for the system using Vulcan XC-72R. / Doutorado / Quimica Inorganica / Doutor em Ciências

Water pollution is a profound ecological concern, exerting detrimental effects on human well-being, ecological systems, and animal life. Among the emerging contaminants that critically influence water quality and have garnered substantial scientific interest in recent times are per- and polyfluoroalkyl substances (PFAS). It is crucial to investigate the de- velopment of an easy technique for PFAS detection and measurement that can be used for quick analysis. This thesis explores the possibility to use amine-functionalized mesoporous carbon as an adsorbent to develop a detection method based on sequential adsorption of per- and polyfluoroalkyl substances (PFAS) and a dye, Rose Bengal, onto the adsorbent. The hypothesis is that the concentration of non-adsorbed dye is dependent on the amount of PFAS present, making the color intensity of the remaining solution proportional to the PFAS concentration. Mesoporous carbon was chosen as the adsorbent due to their high specific surface area, providing a high adsorption capacity, and the potential to functionalize the surface with amine groups which will attract the PFAS. Rose Bengal was selected as a concentration indicator as it has been shown that it can be used as a proxy for PFAS. In this study, the most prevalent PFAS compounds, namely PFOA and PFOS, were investigated. Prior to testing, the adsorbent underwent characterization using diverse techniques to show the porosity and particle morphology. The adsorption experiments encompassed varying PFAS concentrations and a range of dye solutions to determine the detection range, the powder-to-solution ratio necessary for discernible differentiation, and the adsorption or saturation time for both PFAS and dye. This thesis concludes that it was not possible to detect neither PFOA nor PFOS in the range of 0.1 pg/mL to 1 μg/mL with the setup, even though Rose Bengal adsorption could be detected down to 0.6 μg/mL. It was further observed that amine-functionalized hard templated mesoporous carbon has a higher adsorption capacity compared to the soft templated material.

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No description available.

New catalyst development for the hydrotreating process, employing functionalized mesoporous carbon (mC) support is studied. mC support was prepared by the volume templating of alkali modified SBA-15 using sucrose as the carbon source and then functionalized using nitric acid of various concentrations (upto 8M HNO3). A series of NiMo catalysts (12% Mo and 2.4% Ni) were prepared using these functionalized mC supports. The supports and catalysts were characterized by N2 physisorption, SAXS, XRD, FTIR, TGA, SEM, TEM, H2-TPR and HRTEM. SAXS results indicated mild reduction in ordered structure of mesoporous carbons after functionalization. N2 physisorption analysis indicated progressive reduction in surface area and pore volume with the increase in nitric acid concentration. Enhancement of surface functional groups and acidity after functionalization were observed through FTIR spectroscopy and Boehm titration. SEM images showed the retention of needle like morphology in all functionalized carbon supports. TEM images showed that the increase in nitric acid concentration causes excessive etching, resulting in the reduction of ordered structure of functionalized mesoporous carbons. Hydrotreating study of these NiMo/mC catalysts were carried out under industrial operating conditions in a laboratory scale trickle bed reactor using coker light gas oil derived from Athabasca bitumen as feedstock. NiMo catalyst supported on 6M acid treated mC (i.e. NiMo/mC-6M) showed the highest activity due to higher surface functional groups, higher acidity and better textural properties. The HDS and HDN activities of NiMo/mC-6M catalyst were higher than that of NiMo/ã-Al2O3 catalyst owing to lower support metal interaction (SMI), higher surface area and effective functionalization. Using the mC-6M support, NiMo catalysts with different metal loading (12 27% Mo, 2.4 to 5.4% Ni) were prepared and characterized. Hydrotreating activity study of these catalysts indicated that the catalyst with 22% Mo and 2.9% Ni loading was the optimum catalyst on 6M functionalized mC support. Higher metal loading (>22%Mo) led to excessive pore blockage and improper metal dispersion resulting in decreased activity. Kinetic study of the optimum catalyst was carried out by varying temperature (330°C to 370°C), gas-to-oil ratio (400 1000 Nm3/m3), LHSV (1.0 to 2.5 hr-1) and pressure (7.8 to 9.8 MPa) and the data was fitted by non-linear regression method using power law model. The calculated reaction orders and activation energies were 2.8, 1.5 and 189 KJ/mol, 98.9 KJ/mol for HDS and HDN, respectively. The results of HRTEM and H2-TPR indicated lower SMI in mC supported catalyst resulting in the generation of qualitatively Type-II like NiMoS phase on functionalized mC supports, which is considered to be very active for hydrotreating. The hydrotreating activity of the optimum catalyst was higher than that of commercial catalyst (supported on ã-Al2O3). Long term deactivation experiment carried out over a total period of 10 weeks confirmed the durability of NiMo/mC catalyst for the duration of operation. This study reveals the immense capability of functionalized mC supports to become the potential alternative catalyst support to conventional ã-Al2O3 for the hydrotreating of gas oil feedstocks.

New catalyst development for the hydrotreating process, employing functionalized mesoporous carbon (mC) support is studied. mC support was prepared by the volume templating of alkali modified SBA-15 using sucrose as the carbon source and then functionalized using nitric acid of various concentrations (upto 8M HNO3). A series of NiMo catalysts (12% Mo and 2.4% Ni) were prepared using these functionalized mC supports. The supports and catalysts were characterized by N2 physisorption, SAXS, XRD, FTIR, TGA, SEM, TEM, H2-TPR and HRTEM. SAXS results indicated mild reduction in ordered structure of mesoporous carbons after functionalization. N2 physisorption analysis indicated progressive reduction in surface area and pore volume with the increase in nitric acid concentration. Enhancement of surface functional groups and acidity after functionalization were observed through FTIR spectroscopy and Boehm titration. SEM images showed the retention of needle like morphology in all functionalized carbon supports. TEM images showed that the increase in nitric acid concentration causes excessive etching, resulting in the reduction of ordered structure of functionalized mesoporous carbons. Hydrotreating study of these NiMo/mC catalysts were carried out under industrial operating conditions in a laboratory scale trickle bed reactor using coker light gas oil derived from Athabasca bitumen as feedstock. NiMo catalyst supported on 6M acid treated mC (i.e. NiMo/mC-6M) showed the highest activity due to higher surface functional groups, higher acidity and better textural properties. The HDS and HDN activities of NiMo/mC-6M catalyst were higher than that of NiMo/ã-Al2O3 catalyst owing to lower support metal interaction (SMI), higher surface area and effective functionalization. Using the mC-6M support, NiMo catalysts with different metal loading (12 27% Mo, 2.4 to 5.4% Ni) were prepared and characterized. Hydrotreating activity study of these catalysts indicated that the catalyst with 22% Mo and 2.9% Ni loading was the optimum catalyst on 6M functionalized mC support. Higher metal loading (>22%Mo) led to excessive pore blockage and improper metal dispersion resulting in decreased activity. Kinetic study of the optimum catalyst was carried out by varying temperature (330°C to 370°C), gas-to-oil ratio (400 1000 Nm3/m3), LHSV (1.0 to 2.5 hr-1) and pressure (7.8 to 9.8 MPa) and the data was fitted by non-linear regression method using power law model. The calculated reaction orders and activation energies were 2.8, 1.5 and 189 KJ/mol, 98.9 KJ/mol for HDS and HDN, respectively. The results of HRTEM and H2-TPR indicated lower SMI in mC supported catalyst resulting in the generation of qualitatively Type-II like NiMoS phase on functionalized mC supports, which is considered to be very active for hydrotreating. The hydrotreating activity of the optimum catalyst was higher than that of commercial catalyst (supported on ã-Al2O3). Long term deactivation experiment carried out over a total period of 10 weeks confirmed the durability of NiMo/mC catalyst for the duration of operation. This study reveals the immense capability of functionalized mC supports to become the potential alternative catalyst support to conventional ã-Al2O3 for the hydrotreating of gas oil feedstocks.