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1
Grant, C. R. "Evaluation of the bio-oxidation of alkanes." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1367613/.
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This thesis documents the progress made in utilising the alkane hydroxylase complex of P.putida GPo1 expressed in E.coli as a whole-cell biocatalyst for the oxidation of n-dodecane to 1-dodecanol. The process is of considerable interest due to the difficulty in performing the reaction using conventional chemistry and the large global market for fatty alcohols. The first results chapter compares the fermentative bio-oxidations using E.coli pGEc47ΔJ on n-octane and n-dodecane in a stirred tank reactor. The first reported conversion of n-dodecane in-vivo using this enzyme system in a recombinant host is reported. A number of bottlenecks were identified in this chapter; in particular, (i) poor induction of the alkS expression system with ndodecane, which controls the expression of the alk enzymes (ii) a suspected mass transport limitation (iii) substantial over-oxidation of the desired 1- dodecanol product to dodecanoic acid. The second results chapter firstly describes the development of a microwell platform in order to characterise the system more efficiently. Phase mixing limitations and organic phase spillage/evaporation were overcome in order to develop the microwell platform for the fermentative bio-oxidation which is the first reported microwell scale-down which matches the volumetric and specific rates achieved in a bioreactor for a substrate of such low solubility. Secondly, the microwell platform was used with design of experiments (DoE) methodology to rapidly and systematically characterise the overoxidation issue and identify appropriate solutions. Using this approach, substrate solubility was identified as the most critical factor affecting the tendency for overoxidation; the use of cosolvents to improve n-dodecane solubility in the aqueous phase was found to improve the 1-dodecanol yields and reduce dodecanoic acid yields. Oxygen availability and carbon source availability also proved important factors in the extent of overoxidation. Despite the improvements made the problem was only partially overcome and it was decided, based on the results, that biological engineering of the strain was necessary to remove the downstream aldehyde dehydrogenase alkH which was likely to be exacerbating overoxidation. The process of designing and constructing 3 new plasmids is described in results chapters four and five. These plasmids were designed with the aim of identifying the role of various alk proteins and ultimately identifying ways of improving substrate access to the enzyme and reducing overoxidation. It was found as a result of this work that overoxidation was reduced by removal of alkH but that the alkane-1-monooxygenase alkB was still capable of direct overoxidation to the dodecanoic acid even in the absence of alkH. More significantly, the function of an outer membrane protein of unknown function was also confirmed by this work. It was found to be essential for conversion of n-dodecane in-vivo but was also found to be toxic to the host organism when overexpressed. Finally, it was found that the alkane-1-monooxygenase enzyme system was also capable of C14 and C16 alkane oxidation; this has not previously been reported in literature in-vivo.
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High, Jessica M. "Microcosm evaluation of vinyl chloride bio-oxidation under anaerobic conditions." Connect to this title online, 2008. http://etd.lib.clemson.edu/documents/1219865442/.
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Chaturvedula, Sumana. "Gold catalysis for selective oxidation for application to bio-derived substrates." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/14614.
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The depletion of fossil resources, the volatility of the oil price market and the urgency to mitigate the effects of climate change have pushed the development in chemical industry for sustainable, energy efficient and economic processes for fine chemical production. Selective oxidation of alcohols using noble metal catalysts is a key catalytic conversion for the production of carbonylic and carboxylic compounds for the chemical, pharmaceutical, automobile or consumer goods industry. Gold based catalysts, in particular, have demonstrated superior performance over commonly employed catalysts or stoichiometric oxidants. Challenges, however, remain to develop not only active and selective catalysts but with a long lifetime for industrial application. This thesis is based on the study and development of gold based catalyst systems for the selective oxidation of alcohols under mild conditions. The main model compound studied is the selective oxidation of salicyl alcohol to salicyl aldehyde and salicylic acid. Salicyl aldehyde is a very important chemical compound for the production of a range of fine chemicals and chelating compounds with an estimated market capacity of 4000-6000 tonnes/year. Reactions were carried out in a semi-batch stirred glass reactor under atmospheric pressure using air as oxidant and water as solvent. The setup successfully enabled the direct study of the kinetics and mechanism without influences of mass transport. Studies demonstrated the reaction followed sequential mechanism of first order with the consecutive oxidation of salicyl aldehyde to salicylic acid. The main catalyst system used was gold on powdered activated carbon, prepared by sol-immobilisation using Tetrakis(hydroxymethyl)phosphonium chloride (THPC) as stabiliser. 1wt% Au/C achieved maximum turnover frequency numbers (TOF) of 342 h-1 and selectivities of 79% towards salicyl aldehyde at 100% conversion. The increase in gold loading to 3wt% resulted in a decrease in activity caused by an increased gold particle size. The addition of Pd as second active metal showed the formation of an alloy and a decrease in activity with the increase in Pd amount. The application of the Au/C catalyst system for continuous processing was investigated using gold on granular carbon in a trickle bed reactor. Base-free selective oxidation of salicyl alcohol was studied via synthesis of MgO dispersed on oxides, in particular hydrotalcites. The basicity, measured by CO2 adsorption capacity, increased with increased loading of MgO. The catalysts showed potential activity, achieving 59% conversion with 90% selectivity towards salicyl aldehyde.
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Sopaci, Saziye Betul. "Microorganism Mediated Stereoselective Bio-oxidation And Bio-hydrogenation Reactions And Thiamine Pyrophosphate Dependent Enzyme Catalyzed Enantioselective Acyloin Reactions." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610516/index.pdf.
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In this study various microbial and enzymatic methods developed for enantioselective acyloin synthesis for preparation of some pharmaceutically important intermediates. By performing Aspergillus flavus (MAM 200120) mediated biotransformation, enantioselective bio-oxidation of meso-hydrobenzoin was achieved with a high ee value (76%). Racemic form of hydrobenzoin was also employed for the same bio-oxidation process and this bioconversion was resulted in accumulation of meso form (>90% yield) confirming the suggested mechanism of oxidation-reduction sequence of hydrobenzoin. Wieland-Miescher ketone (3,4,8,8a-tetrahydro-8a-methylnaphthalene-1,6(2H,7H)-dione) is an important starting material for bioactive compounds like steroids and terpenoids. Many synthetic approaches include enantioselective reduction of this compound. In this study Aspergillus niger (MAM 200909) mediated reduction of Wieland-Miescher ketone was achieved with a high yield (80%), de (79%) and ee (94%) value and these results were found much more superior than previously reported studies. Carboligating enzymes benzaldehyde lyase (BAL) (EC 4.1.2.38) and benzoiyl formate decarboxilase (BFD) (E.C. 4.1.1.7) are used for biocatalytic acyloin synthesis. These enzymes are immobilized to surface modified superparamagnetic silica coated nanoparticles by using metal ion affinity technique. With this system recombinant histidine tagged BAL and BFD purified and immobilized to magnetic particles by one-pot purification-immobilization procedure. SDS page analysis showed that our surface modified magnetic particles were eligible for specific binding of histidine tagged proteins. Conventional BAL and BFD catalyzed benzoin condenzation reactions and some representative acyloin reactions were performed with this system with a high enantioselectivity (99-92%) and yield. Results obtained with magnetic particle-enzyme system were also found comparable with that of free enzyme catalyzed reactions.
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Douthwaite, John. "The selective oxidation of bio-derived platform chemicals over supported gold catalysts." Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/93926/.
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A fundamental limitation effecting the exploitation of bio-fuels is that they are not currently economically competitive with conventional fossil fuels. The development of novel chemical processes to convert bi-products from these reactions into high value chemicals could be one method to reduce the economic deficit between these two industries. Glycerol and furfural are produced as bi-products in the production of 1st and 2nd generation bio-fuels. This thesis explores the potential of using supported Au catalysts for the oxidation of these bio-derived compounds for the synthesis of high value chemicals. The reaction conditions were found to significantly affect the product distribution and the reaction rate for the aerobic, liquid phase oxidation of glycerol over a AuPt/TiO2 catalyst. Mechanistic studies suggested that glycerol acid and tartronic acid are primary products in this reaction. This study also implied that C-C scission leading to the unfavourable formation of C1 and C2 products occurred from glyceraldehyde, dihydroxyacetone and glyceric acid. Au nanoparticles supported on hydrophobic supports were found reduce C-C scission, and the incorporation of Pd and Pt to a Au/BN catalyst was found to further increase desirable C3 selectivity. Additional work confirmed that the in-situ formation of H2O2 was primarily responsible for C-C cleavages, which led to the postulation that Dakin oxidation was the mechanistic process by which it proceeds. Supported trimetallic AuPdPt nanoparticles were found to be active for the oxidation of glycerol under base free conditions. The catalyst was found to significantly influence the activity of these particles. It was determined that a Au/TiO2 catalyst could selectively oxidise furfural to produce reasonable yields of furoic Acid. Polymerisation of the substrate was found to inhibit catalytic performance which was suggested to be a result of the polymers binding irreversibly to the catalyst. Optimisation of the catalyst and experimental procedure was found to reduce this unfavourable polymerisation, which led to the production of furoic acid yields in excess of 89% using a AuPd/Mg(OH)2 catalyst. Further tests indicated that the size of the metal nanoparticles and the Au:Pd ratio significantly affected catalytic performance for this reaction. Mechanistic studies identified the presence of three reactions; the direct oxidation of furfural, the oxidative dehydrogenation of furfuryl alcohol and the Cannizzaro reaction. A kinetic study allowed for the determination of the activation energies corresponding to each of these pathways, which ultimately highlighted the potential of using a catalyst for this reaction on an industrial scale.
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Yeh, Ruth Yu-Li. "Treatment of dye wastewaters by adsorption with and without the bio-oxidation process." Thesis, University of South Wales, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295273.
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Ardemani, Leandro. "Catalytic conversion of bio-derived platform molecules into useful chemicals via selective oxidation." Thesis, Aston University, 2016. http://publications.aston.ac.uk/31851/.
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Green Chemistry regards the design of products and processes that minimise the use and generation of hazardous substances. Heterogeneous catalysis facilitates such energy and atom efficient processes, affording simple and low cost product isolation methods, and catalytic materials that can be easily recovered and reused. This thesis reports on the selective aerobic oxidation of 5-hydroxymethyl-2-furufural (HMF), a potential platform chemical that may be derived from cellulose, into 2,5-furandicarboxylic acid (FDCA) over noble metal nanoparticles dispersed on a solid base support. FDCA has been touted as a potential replacement for polyethyleneterephtalate (PET) and is also an interesting synthetic building block. Au nanoparticles are extremely active and selective oxidation catalyst for a range of environmental and fine chemical transformations, however they require a homogeneous base, such as NaOH, to work. Au NPs dispersed on hydrotalcites (HT), anionic microporous clays, have shown promise in HMF oxidation to FDCA, hydrotalcite acting as both the support and the source of base. However, key questions remained regarding the nature of active site, potential role of homogeneous contributions and importance of reaction basicity upon activity and selectivity. Kinetic profiling of HMF and its intermediates HMFCA and FFCA over Na-free Au/MgAl HT catalysts highlight the role of base in achieving high FDCA yields. The order of reaction in Au, in oxygen and in HMF were found, determination of the Arrhenius Ea for the R-OH and the R-CHO functions allowed to find the rate-determining step. Ex situ and operando XAS were performed to detect Au oxidation state and Au chemical environment in the catalyst, enlighting the true active site during the selox. Eventual changes in Au oxidation state were investigated to find how the precursor HAuCl4 evolves during the calcination. As the reaction was found to be pH-sensitive and as the calcination of HTs convert them into stronger bases, the impact of calcination temperature was studied; also a comparison between calcination and calcination rehydration protocols was done. The incorporation of Pd into Au catalysts improved activity and lifetime for these AuPd bimetallic formulations. AuPd NPs were prepared via DP method on HT support, varying Au:Pd ratio, then kinetic studies for the selox of HMF to FDCA were carried out, followed by accurate characterisations.
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Chiari, Lucile. "Développement de nouveaux systèmes bio-hybrides pour la photocatalyse asymétrique." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAV029.
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Au cours des dernières décennies, le développement d'une chimie durable est devenu une priorité pour notre société Dans ce contexte, la biocatalyse, par l’utilisation d’enzymes naturelles, modifiées ou artificielles constituées d’un catalyseur de synthèse greffé au sein d’une protéine apparait comme une solution intéressante.Dans ce projet, nous cherchons à développer des photocatalyseurs bio-hybrides combinant un photosensibilisateurs (RuPhot) et un catalyseurs (RuCat) au sein d'un cristal protéique pour la photocatalyse hétérogène d’oxydation asymétrique de substrats organiques en utilisant l’eau comme seule source d’atome d’oxygène. La protéine sélectionnée est le domaine d'oligomérisation de la protéine Leafy du Ginkgo biloba. Cette protéine est capable de générer des structures poreuses par auto-assemblage. A l'intérieur des tubes, une chaîne peptidique d'environ 30 acides aminés par monomère est présente et servira de plateforme de greffage. Trois systèmes hybrides cristallins avec RuPhot et RuCat seuls ainsi qu’avec une combinaison des deux ont été obtenus. La mise au point des techniques de caractérisation a été faite sur l’hybride RuCat apportant des informations intéressantes sur la cinétique et la sélectivité du greffage ainsi que sur une modification du catalyseur intervenant au cours du greffage. Les études réalisées sur l’hybrides RuPhot ont quant à elles montrées qu’il était possible, comme cela était planifié de greffer plusieurs chromophores par protéine et de pouvoir bénéficier ainsi d’un effet d’antenne pour une efficacité maximisée. Les études catalytiques pour l'oxydation des sulfures et des alcènes sont en cours.Dans un tout autre domaine, 16% de cette thèse a été consacré à un contrat de doctorat conseil auprès de l'entreprise NMRBio. L'objectif était de développer de nouvelles voies de synthèses de composés marqués par des isotopes stables en vue d'études structurales et dynamiques de protéines par RMNFor the last decades the development of sustainable chemistry became a priority for our society. In this context, biocatalysis appears to be an interesting solution, through the use of natural, modified or artificial enzymes consisting of a synthetic catalyst grafted into a protein.In this project, we aim to develop bio-hybrid photocatalysts combining a photosensitizer (RuPhot) and a catalyst (RuCat) within a protein crystal for heterogeneous asymmetric oxidation photocatalysis of organic substrates using water as the only source of oxygen atoms. The selected protein is the oligomerization domain of the Leafy protein of Ginkgo biloba. This protein is able to generate porous structures by self-assembly. Inside the tubes, a peptide chain of about 30 amino acids per monomer is present and it will serve as grafting platform. Three crystalline hybrid systems were obtained with RuPhot and RuCat alone as well as a combination of the two. The characterization was carried out on the RuCat hybrid providing interesting information on the kinetics and selectivity of grafting as well as on a modification of the catalyst during grafting. The studies carried out on the RuPhot hybrids have shown that it was possible, as planned, to graft several chromophores per protein and thus benefit from an antenna effect for maximum efficiency. Catalytic studies for the oxidation of sulphides and alkenes are underway.In a completely different field, 16% of this thesis was devoted to a doctoral consulting contract with the company NMRBio. The objective was to develop new pathways for the synthesis of stable isotope-labelled compounds in order to perform structural and dynamic NMR studies in proteins
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Chukwuchendo, Emmanuel Chukwunonso. "Bio-oxidation of ferrous iron at low temperature conditions in a packed bed column bioreactors." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2545.
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Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2016.The oxidation of microbial ferrous iron is an important sub-process in the bioleaching process. Several studies focussing on microbial ferrous iron oxidation have been investigated and reported in various studies. These studies were carried out using stirred tank bioreactors and shake flasks at optimum conditions. However, these studies could not describe the context of heap bioleach system. Packed column system may describe heap bioleaching, and most studies on microbial ferrous iron oxidation were performed under flooded conditions, which do not represent solution flow dynamics in a heap situation. Biooxidation of ferrous iron oxidation kinetics of Acidiobacillus ferrooxidans was studied in a packed-bed bioreactor to investigate the kinetics in a system that mimics the solution flow dynamic of a heap bioleach operation at low-temperature conditions. This was done in a batch mode operation, with glass marble (15 mm) as reactor packing. The pH of the bioreactor was maintained at pH 1.35 ± 0.05 and aeration at 500 ml/min. Unstructured models known as Monod and Hansford were used to describe the experimental data in determining the kinetics of bio-oxidation.
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Chandraprabha, M. N. "Studies On Bio-Oxidation A Refractory Gold Containing Sulphidic Concentrate With Respect To Optimization And Modeling." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/188.
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Although bacterial leaching of sulphidic minerals is a well-known phenomenon, it is only in the last ten years that full-scale bacterial leaching plants have been commissioned for gold
processing. In order for bacterial leaching to compete successfully with other pretreatment processes for refractory ores, particularly with established technologies such as roasting and pressure leaching, it needs to be efficient. This requires the optimization of the parameters affecting the leaching reaction and the growth of bacteria.
The entire biotreatment process is agitation leaching, carried out in stirred reactors or Pachuca type reactors. The bacterial oxidation is a complex reaction involving gaseous, liquid and solid phases. The interactions are highly complex, and analysis is complicated by the presence of solids in the leaching medium. Inspite of the amount of research that has been performed, kinetic and process models are underdeveloped. Since kinetic data varies widely with the type and source of concentrate, experimental data should be generated before doing the full-scale reactor design. In sizing reactors for a commercial scale process, it would be useful to have a mathematical model that one could use to predict the amount and rate of release of metal, as a function of the various operating parameters of the system.
G.R.Halli arsenical gold sulphide concentrate obtained from Hutti Gold Mines Ltd., Karnataka, was chosen for our study, because of its high refractoriness. An indegenous strain of Thiobacillus ferrooxidans was used for biooxidation. The experiments were conducted in a well-agitated stirred tank reactor under controlled conditions. Sparged air was supplemented with carbon-dioxide for optimized growth. In this work, more than 90% gold and 95% silver could be recovered from the sulphidic gold concentrate when bioleaching was used ahead of cyanidation, compared to 40% and 50% by direct cyanidation.
A generalized model, which accounts for both direct bacterial attack and indirect chemical leaching, has been proposed for the biooxidation of refractory gold concentrates. The bacterial balance, therefore, accounts for its growth both on solid substrate and in solution, and for the attachment to and detachment from the surface. The overall process is considered to consist of several sub-processes, each of which can be described in terms of a mechanism and related rate expressions. These sub-processes were studied seperately under kinetically controlled conditions. The key parameters appearing in the rate equations were evaluated using the experimental data. Since the refractory concentrate contains pyrite and arsenopyrite as the major leachable entities, leaching studies have been done on pure pyrite and arsenopyrite as test minerals and the key parameters in the rate equations are evaluated using this data. The model so developed is tested with the leaching kinetics of the concentrate.
The growth of bacteria is dependent on the availability of the substrate, ferrous iron, and the dependence is modelled by the widely accepted Monod equation. The effect of carbon dioxide supplementation on the bacterial activity was studied and the optimal concentration for growth was found to be l%(v/v). Studies on indirect chemical leaching showed that the rate is sensitive to surface area of concentrate. Indirect rate constant of arsenopyrite was found to be greater than that of pyrite, since pyrite is more nobler than arsenopyrite. Conditions of direct leaching alone was obtained at high pulp density and using substrate adapted bacteria. The rate constant of arsenopyrite was found to be greater than that of pyrite. The parameters obtained were tested with the overall batch leaching data of the concentrate and favourable comparision was obtained.
Thus, it has been possible to isolate the various simultaneous sub-processes occurring during the leaching and propose useful models to describe these processes in some detail. The model has been extended successfully to predict the continuous leaching behaviour using the parameters obtained from the batch data. Studies on the effect of residence time and pulp density on steady state behaviour showed that there is a critical residence time and pulp density below which washout conditions occur. The critical residence time at 10% pulp density was found to be 11 hrs. Operation at pulp densities lower than 5% and residence times lower than 72 hrs is not favourable for efficient leaching. Studies on the effect of initial ferric iron concentration showed that there exists an optimum concentration of ferric iron at which the time required to reach steady state is minimum.
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Paradowska, Magdalena. "Tailored chemical oxidation techniques for the abatement of bio-toxic organic wastewater pollutants: an experimental study." Doctoral thesis, Universitat Rovira i Virgili, 2004. http://hdl.handle.net/10803/8524.
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La presencia de compuestos orgánicos cada vez más tóxicos en las aguas residuales, especialmente provenientes de la industria, ha desafiado los métodos convencionales de tratamiento de aguas residuales. Por esta razón existe una clara necesidad de buscar nuevas técnicas emergentes las cuales pueden tratar los contaminantes orgánicos muy concentrados en agua o no biodegradables. Como no es posible utilizar un único método universal para destruir todos los compuestos orgánicos, se ha probado Catalytic Wet Air Oxidation (CWAO), CWAO promovida por peróxido de hidrógeno, Wet Peroxide Oxidation and Oxidación de Fenton para eliminar compuestos aromáticos pertenecientes a diferentes grupos. Con este propósito un equipo de alta temperatura y alta presión ha sido diseñado y construido. Este equipo puede trabajar en un proceso tanto catalítico como no catalítico. El carbón activo, un material barato, ha sido utilizado como el catalizador heterogéneo (CWAO), mientras el sulfato de hierro ha sido empleado como un catalizador homogéneo (Oxidación de Fenton). Los compuestos estudiados fueron fenol, p-nitrofenol, anilina, nitrobenceno y sulfolano, porque son tóxicos y no biodegradable y al mismo tiempo son frecuentemente encontrados en los efluentes industriales. También se ha probado dos muestras de efluentes industriales reales provenientes de la producción de las resinas fenólicas. El peróxido de hidrógeno ha sido empleado como un oxidante, excepto en CWAO, donde se lo utilizó como un promotor, porque peróxido de hidrógeno es una excelente fuente de radicales hidroxilos muy oxidantes. En primer lugar, cada proceso ha sido probado con el fenol, como contaminante de referencia, para encontrar las variables de operación influyentes para la eficacia del proceso. El objetivo era no solo destruir el compuesto original, sino también convertirlo en dióxido de carbón y agua o al menos convertirlo en compuestos inocuos y fácilmente biodegradables. Posteriormente, el método ha sido también estudiado con otros compuestos. Se observó que es posible obtener la conversión completa para todos compuestos menos el nitrobenceno con el cual se obtiene la conversión máxima de 80% utilizando WPO. Sin embargo, para determinados compuestos se ha encontrado que algunos métodos presentaron desventajas, tales como problemas de corrosión en caso de sulfolano (WPO) o formación de un tapón en reactor en caso de CWAO con anilina sobre carbón activo. A pesar de esto, se puede proponer un método de tratamiento para cada compuesto. El peróxido de hidrógeno resultó ser un oxidante muy eficaz, así se encontró que el 100% de la cantidad estequiométrica de H2O2 era suficiente para mineralizar completamente todos los compuestos, excepto el nitrobenceno. El peróxido de hidrógeno también resultó ser un buen promotor de CWAO, aumentando considerablemente la eficacia del proceso. Cabe destacar que todos los métodos fueron estudiados siempre en el mismo equipo después de realizar pequeñas modificaciones. El método de la oxidación de Fenton en modo continuo, a 200ºC, empleando sulfato de hierro permite una eliminación similar (del 70%) de nitrobenceno al método WPO no catalítico a 550ºC (80%). Para los efluentes industriales reales las técnicas estudiadas han permitido obtener una conversión completa de fenol y la reducción de DQO por encima del 50%. Aunque esto no permite la completa mineralización, probablemente aumenta su biodegradabilidad.The identification of more and more toxic organic compounds in wastewater, especially from industry, has challenged the conventional wastewater treatment methods. That is why there is a need to look for a new emerging technologies that can treat highly concentrated or non-biodegradable organic water pollutants. As it is impossible to use one universal method to destroy all the organic compounds, we have tested Catalytic Wet Air Oxidation (CWAO), hydrogen peroxide promoted CWAO, Wet Peroxide Oxidation and Fenton's Oxidation to remove aromatic organics belonging to different groups. For this purpose high temperature and high pressure continuous reactor system was designed and constructed. This equipment can be used either for catalytic or noncatalytic process. An activated carbon, that is low cost material, was used as a heterogeneous catalyst (CWAO), while iron sulphate was employed as a homogeneous catalyst (Fenton's Oxidation). Phenol, p-nitrophenol, aniline, nitrobenzene and sulfolane were studied, because these compounds are toxic, mostly non-biodegradable and at the same time, they are commonly found in industrial effluents. Also two samples of real industrial effluents coming from phenolic resins production were tested. Hydrogen peroxide was used as an oxidant, except in CWAO, where it was used as a promoter. This is because hydrogen peroxide is an excellent source of highly oxidative hydroxyl radicals. Firstly, each process was tested for phenol in order to find the influence of operational variables on the process efficiency. The aim was not only to destroy the original compound, but also to convert it to gas carbon dioxide and water, or at least in much more innocuous compounds easily biodegradable. Than the method performance with other compounds was examined. Finally, there can be achieved the complete conversion for every compound except nitrobenzene with highest conversion of about 80% during WPO experiments. However, for some compounds certain methods exhibited drawbacks such as corrosion problems with sulfolane, and plugging in the reactor during CWAO of aniline over activated carbon. In spite of this for every compound a removal technique among the methods studied can be proposed. Hydrogen peroxide resulted to be efficient oxidant, as 100% of stoichiometric quantity of H2O2 was sufficient to mineralise completely all the compounds, except nitrobenzene. Also, hydrogen peroxide is efficient as promoter of CWAO, enhancing greatly process efficacy. It is also interesting that all the methods could be performed in the same equipment after slight modification of the system. And Fenton's oxidation in continuous system in temperature about 200ºC permits similar removal of nitrobenzene (70%) using iron sulphate (II), that during noncatalytic WPO when employing 550ºC (80%). Also for real effluents it was observed that the oxidation techniques studied permitted to obtain complete phenol conversion and COD reduction over 50%. Even if it does not allow a complete mineralisation of organic compounds more refractory that phenol present in the wastewater it can probably increase the biodegradability.
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Dias, Meriellen. "Estudo da degradação da enrofloxacina em solução aquosa por meio de processos foto-oxidativos." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-23052014-003818/.
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As tecnologias utilizadas em estações de tratamento de água e efluentes não são eficientes para a remoção total de resíduos farmacêuticos e os efeitos dessas substâncias sobre o meio ambiente e a saúde humana ainda não são bem conhecidos. No presente trabalho, estudou-se a degradação do antibiótico enrofloxacina (ENRO) por fotólise e pelo processo H2O2/UV na presença de compostos bio-orgânicos (BOS), que têm se apresentado como interessantes promotores da oxidação de poluentes. Os experimentos foram realizados em um reator fotoquímico tubular de imersão com fonte radiante (lâmpada de xenônio) concêntrica, operado em batelada com recirculação. Utilizaram-se concentrações iniciais de ENRO e de BOS iguais a 50 mg L-1 e 20 mg L-1, respectivamente. Para todos os pH mantidos constantes (3, 5, 7 ou 9), a solução foi irradiada por 240 minutos. Os resultados indicam que o antibiótico não sofreu hidrólise em qualquer dos pH estudados em um período de 24 horas. Por sua vez, a fotólise da enrofloxacina mostrou-se eficiente somente na presença do composto bioorgânico CVT 230 (BOS C), com remoção de ENRO de quase 90% em meio neutro (pH 7). Resultados da literatura, associados a experimento realizado em meio anóxico, sugerem a participação de oxigênio singlete como principal espécie oxidante da enrofloxacina. Por outro lado, a degradação da ENRO pelo processo H2O2/UV apresentou remoção máxima do fármaco de 48% em pH 7, o que sugere que a ação de oxigênio singlete e/ou radicais hidroxila não foi eficaz na presença de peróxido de hidrogênio. Portanto, o BOS C pode ser empregado como promotor no tratamento de águas e efluentes aquosos contaminados com enrofloxacina sob baixas potências radiantes ou em sistemas irradiados por luz solar.The technologies used in water and wastewater treatment plants are not efficient for the total removal of pharmaceutical compounds whose effect to the environment and to human health are still not well known. In this work, the degradation of the antibiotic enrofloxacin (ENRO) was studied by photolysis and by the H2O2/UV process in the presence of bio-organic substances (BOS), which have been identified as interesting promoters of pollutant oxidation. The experiments were carried out in a tubular immersion photochemical reactor equipped with a concentric radiant source (xenon lamp), and operated in batch mode with recirculation. Initial ENRO and BOS concentrations of 50 mg L-1 and 20 mg L-1 were used, respectively. The solution was irradiated for 240 minutes for all pH studied at constant values (3, 5, 7, and 9). The results show that the antibiotic did not undergo hydrolysis at any pH after 24 hours. The photolysis of enrofloxacin showed to be efficient only in the presence of the bio-organic substance CVT 230 (BOS C), with almost 90% ENRO removal in neutral solution (pH 7). Results from the literature, associated with an experiment carried out in anoxic conditions, suggest singlet oxygen as the main species responsible for enrofloxacin oxidation. On the other hand, ENRO degradation by the H2O2/UV process showed a maximum removal of 48% at pH 7, suggesting that the action of singlet oxygen and/or hydroxyl radicals was not effective in the presence of hydrogen peroxide. BOS C can therefore be used as an efficient promoter for the treatment of enrofloxacin-containing water and wastewater under low irradiant power or in solar-irradiated systems.
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Chhiti, Younes. "Gazéification non catalytique des huiles de pyrolyse de bois sous vapeur d'eau." Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0064/document.
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La production d'énergie à partir de biomasse ligno-cellulosique via la technologie de gazéification est une option intéressante dans le contexte énergétique actuel. La combinaison d‘une pyrolyse rapide décentralisée de la biomasse pour produire les bio-huiles, suivie par le transport et le vaporeformage dans des bio-raffineries, est apparue comme l'une des méthodes économiquement les plus viables pour la production de gaz de synthèse (H2+CO). L‘objectif de ce travail est de combler le manque de connaissances concernant les processus de transformation physicochimique de l‘huile de pyrolyse en gaz de synthèse utilisant la gazéification non catalytique dans des réacteurs à flux entrainé. Il s‘agit d‘un processus complexe, mettant en oeuvre la vaporisation, les réactions de craquage thermique avec formation de gaz, de tars et de deux résidus solides : le char et les suies, qui sont des produits indésirables. Ceci est suivi par le reformage des gaz et des tars, ainsi que la conversion du char et des suies. Pour mieux comprendre le processus, la première étape de la gazéification (la pyrolyse), et par la suite l'ensemble du processus (pyrolyse + gazéification) ont été étudiés. L‘étude de la pyrolyse est focalisée sur l‘influence de la vitesse de chauffe, de la température ainsi que de la teneur en cendres dans la bio-huile, sur les rendements en char, tars et gaz. A très grande vitesse de chauffe le rendement en char est inferieur à 1%. Les cendres semblent favoriser les réactions de polymérisation et provoquent la diminution du rendement en gaz. Concernant la gazéification, l'effet de la température sur le rendement et la composition du gaz de synthèse a été étudié. Une augmentation de la température de réaction implique une augmentation du rendement en hydrogène et une conversion très élevée du carbone solide. Un calcul d'équilibre thermodynamique a montré que l'équilibre a été atteint à 1400°C. Finalement les mécanismes de formation et d‘oxydation des suies ont été étudiés expérimentalement sous différentes atmosphères : inerte (pyrolyse), riche en vapeur d‘eau (gazéification) et en présence d‘oxygène (oxydation partielle). Un modèle semi empirique est proposé et validé. Il est fondé sur la chimie détaillée pour décrire les réactions en phase gaz, une seule réaction basée sur la concentration de C2H2 pour décrire la formation des suies et principalement une réaction hétérogène pour décrire l‘oxydation des suiesEnergy production from ligno-cellulosic biomass via gasification technology appears as an attractive option in the current energy context. The combination of decentralized fast pyrolysis of biomass to produce bio-oil, followed by transportation and gasification of bio-oil in bio-refinery has appeared as one of the most economically viable methods for syngas (H2+CO) production. The objective of this work is to bridge the lack of knowledge concerning the physicochemical transformation of bio-oil into syngas using non catalytic steam gasification in entrained flow reactors. This complex process involves vaporization, thermal cracking reactions with formation of gas, tars and two solid residues - char and soot - that are considered as undesirable products. This is followed by steam reforming of gas and tars, together with char and soot conversion. To better understand the process, the first step of gasification (pyrolysis) and thereafter the whole process (pyrolysis + gasification) were studied. The pyrolysis study focused on the influence of the heating rate, the final pyrolysis temperature and the ash content of bio-oil on char, tars and gas yields. At the higher heating rate char yield is smaller than 1%. In addition, ash seems to promote polymerization reactions and causes a decrease of gas yield. Concerning gasification, the effect of temperature on syngas yield and composition was studied. An increase in the reaction temperature implies higher hydrogen yield and higher solid carbon conversion. A thermodynamic equilibrium calculation showed that equilibrium was reached at 1400°C. Finally, the soot formation and oxidation mechanisms were investigated through experiments in three different atmospheres: inert (pyrolysis), rich in steam (gasification) and in the presence of oxygen (partial oxidation). A semi-empirical model was proposed and validated. It is based on detailed chemistry to describe gas phase reactions, a single reaction using C2H2 concentration to describe soot formation and one main heterogeneous reaction to describe soot oxidation
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Campolong, Cody James. "Bioaugmentation and Retention of Anammox Granules to a Mainstream Deammonification Bio-Oxidation Pilot with a Post Polishing Anoxic Partial Denitrification/Anammox Moving Bed Biofilm Reactor." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/99964.
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The Chesapeake Bay watershed has seen an increase in population, nutrient loading, and stringent effluent limits; therefore, cost-effective technologies must be explored and implemented to intensify the treatment of regional wastewater.
This work describes the bioaugmentation and retention of anammox (AMX) granules in a continuous adsorption/bio-oxidation (A/B) mainstream deammonification pilot-scale process treating domestic wastewater. The AMX granules were collected from the underflow of a sidestream DEMON® process. The bioaugmentation rate was based on several factors including full-scale sidestream DEMON® wasting rate and sidestream vs mainstream AMX activity. The retention of bioaugmented AMX granules required a novel settling column at the end of the deammonification step. The settling column was designed to provide a surface overflow rate (SOR) that allowed dense AMX granules to settle into the underflow and less dense floccular biomass to outselect into the overflow. B-Stage was operated to out-select nitrite oxidizing bacteria (NOB) by maintaining an ammonia residual (>2 mg NH4-N/L), a relatively high dissolved oxygen (DO) (>1.5 mg O2/L) concentration, an aggressive solids retention time (SRT) for NOB washout, and intermittent aeration for transient anoxia. AMX activity was not detected in the mainstream at any time. The settling column AMX retention quantification suggested but did not confirm AMX were maintained in the mainstream. NOB were not suppressed during this study and no nitrite accumulation was present in the mainstream process. It was theorized that AMX granules were successfully settled into the settling column underflow and accumulated in the intermittently mixed sidestream biological phosphorus reactor (SBPR) where they disintegrated.
This work also describes optimization of carbon addition to an anoxic partial denitrification anammox (PdN/A) moving bed biofilm reactor (MBBR) testing glycerol, acetate, and methanol as carbon sources to maximize total inorganic nitrogen (TIN) removal through the anammox pathway and to minimize effluent TIN. A carbon feeding strategy was developed and was evaluated by the extent of partial denitrification vs full denitrification (partial denitrification efficiency, PdN efficiency). All three carbon sources were capable of high TIN removal, low effluent TIN, and moderate to high PdN efficiency. Average TIN removal for glycerol was 10.0 ± 3.6 mg TIN/L, for acetate it was 8.7 ± 2.9 mg TIN/L, and for methanol it was 11.5 ± 5.6 mg TIN/L. Average effluent TIN for glycerol was 6.0 ± 4.0 mg TIN/L, for acetate it was 5.0 ± 1.1 mg TIN/L, and for methanol it was 4.3 ± 1.5 mg TIN/L. Average PdN efficiency for glycerol was 91.0 ± 9.0%, for acetate it was 88.0 ± 7.7%, and for methanol it was 74.0 ± 8.5%. When PdN efficiency was factored into the cost of each carbon source, methanol was 5.83% cheaper than glycerol per mass TIN removed and 59.0% cheaper than acetate per mass TIN-N removed.Master of Science
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Condassamy, Olivia. "Valorisation d'une lignine alcaline industrielle : vers le développement de nouveaux synthons et oligomères bio-sourcés issus de la lignine." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0265/document.
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La première partie de ce projet à consisté à isoler la lignine à partir de liqueurs industrielles et à la purifier pour s’affranchir des sucres, des minéraux et autres constituants. Pour cela, un protocole efficace en trois étapes a été proposé pour obtenir des échantillons de lignine avec une pureté satisfaisante (95%) et pour récupérer 68% de la lignine initialement présente dans la liqueur alcaline de départ. La lignine alcaline purifiée a ensuite été caractérisée d’un point de vue moléculaire et par analyses thermiques. L’élucidation de la structure de la lignine alcaline a permis d’appréhender sa fonctionnalisation par oxydation. Les analyses par chromatographie d’exclusion stérique de la lignine après oxydation ont montré une diminution de la masse molaire confirmant ainsi le clivage. Trois fractions différentes ont été isolées après l’oxydation de la lignine selon le solvant d’extraction ; d’une part des oligomères (plus ou moins fonctionnalisés) et d’autre part des molécules aromatiques (dont15% de vanilline). Ce travail de thèse aura abouti à la synthèse de composés aromatiques à haute valeur ajoutée (vanilline) et d’oligomères de lignine fonctionnalisés par des fonctions acide carboxylique. Les applications envisageables de ces « polyacides » issus de lignine sont nombreuses pour la formation de nouveaux polymères bio-sourcés tels que des polyesters, polyamides ou encore polyuréthanesA valorization of alkaline lignin from an industrial pulping liquor has been proposed for this project. Before considering any chemical modification or potential applications, the lignin structure has been elucidated. An efficient three-steps protocol for extraction and purification of lignin from industrial liquor has been established. This protocol leads to high purity sample of lignin (95%) and allows the recovery (68%) of the lignin initially present in the alkaline liquor. Alkaline lignin has been characterized utilizing analytical methods and thermogravimetric analysis. This precise structure elucidation was critical for proceeding to chemical modification of alkaline lignin. Chemical modification of alkaline lignin has been done by oxidation in alkaline media. Three major oxidized products have been isolated depending on the extraction solvent: oligomers bearing carboxylic groups and aromatic molecules. This thesis work led to the synthesis of value-added bio-sourced chemicals and functionalized oligomers. The polyacids from lignin obtained should be studied to form new biobased polymers such as polyesters, polyamids or polyurethanes
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Cameron, Rory. "Bioleaching of low-grade nickel sulphide ore at elevated pH." Thesis, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19784.
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This thesis examines the bioleaching of six different Canadian nickel sulphide ores at pH levels above what is generally considered optimum (~ 2). The majority of work discussed in this thesis was conducted with a low-grade metamorphosed ultramafic nickel sulphide ore from Manitoba, Canada (Ore 3), which is not currently exploitable with conventional technologies. The ore contains 21% magnesium and 0.3% nickel. Nickel is the only significant metal value, and is present primarily as pentlandite. A substantial fraction of the magnesium is present as the serpentine mineral lizardite, making processing difficult with conventional pyro- and biohydrometallurgical techniques. The work with this ore has two equally important objectives: to minimize magnesium mobilization and to obtain an acceptable level of nickel extraction. Batch stirred-tank bioleaching experiments were conducted with finely ground ore ( 147 µm) with temperature and pH control. The first phase of experimentation examined the effect of pH (2 to 6) at 30 °C, and the second phase examined all combinations of three pH levels (3, 4 and 5) and five temperatures (5, 15, 22.5, 30, and 45 °C).
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Sadowski, Michael Stuart. "Comparison of Aeration Strategies for Optimization of Nitrogen Removal in an Adsorption/Bio-oxidation (A/B) Process with an Emphasis on Ammonia vs. NOx (AvN) control." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/64385.
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Research was performed at a pilot-scale wastewater treatment plant operating an adsorption/bio-oxidation (A/B) process at 20C. The study compared B-Stage performance under DO Control, Ammonia Based Aeration Control (ABAC), and Ammonia vs. NOx (AvN) control. AvN in 1) fully-intermittent and 2) intermittently-aerated MLE configurations was compared to DO Control and ABAC, each with continuous aeration, in an MLE configuration. The study also examined operation of each aeration strategy with two different feed types: A-Stage effluent (ASE) and primary clarifier effluent (PCE). Operating modes were compared on the basis of nitrogen removal performance, COD utilization efficiency for denitrification, and alkalinity consumption.
AvN was found to provide comparable nitrogen removal performance to DO Control and ABAC. The highest nitrogen removal performance was seen when operating DO Control (81.4 ± 1.2%) and ABAC (81.1 ± 1.2%) with PCE. High nitrogen removal efficiency (77.5 ± 6.1%) was seen when fully-intermittent AvN operation was fed ASE containing a high particulate COD fraction. A high effluent nitrite accumulation ratio (NAR = NO2-/(NO2-+NO3-)) was seen during this period (46 ± 15%) accompanied by the out-selection of Nitrospira. Feeding effluent from AvN control to an Anammox MBBR improved removal efficiency.
Increased soluble COD loading resulted in greater nitrogen removal with strategies operating in an MLE configuration while particulate COD was found to be important for processes where removal was designed to occur in downstream reactors. Efficiency of COD for denitrification was found to vary based on the amount and type of influent COD; however AvN in an MLE configuration was found to use COD more efficiently than fully-intermittent AvN. In either configuration, AvN required less alkalinity addition than DO Control or ABAC. High sCOD concentrations in PCE led to increased nutrient removal as compared to ASE but increased heterotrophic growth and mixed liquor concentrations in the B-Stage making the A-Stage an attractive option for its ability to control the C/N ratio fed to BNR processes.Master of Science
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Ganzenko, Oleksandra. "Bio-electro-Fenton : optimization of electrochemical advanced oxidation process in the perspective of its combination to a biological process for the removal of pharmaceuticals from wastewater." Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1196/document.
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La pollution des ressources en eau est un des défis importants auquel les Hommes doivent faire face. En particulier, de nouvelles solutions doivent émerger, puisque les techniques conventionnelles de traitement utilisées actuellement ne permettent pas une élimination efficace des divers polluants. Parmi les polluants émergents, les composés pharmaceutiques ont récemment été détectés dans différentes sources d'eau à travers le monde. Leurs effets indésirables sur l'environnement naturel et sur l'Homme ont déjà été reconnus mais doivent encore être éclaircis. De nombreux nouveaux procédés de traitement de l'eau apparaissent. En particulier, le procédé électro-Fenton a démontré sa capacité à éliminer les pharmaceutiques et autres contaminants persistants. Ce procédé est basé sur la génération in-situ d'une espèce oxydante très puissante, les radicaux hydroxyles (OH), qui permettent la dégradation non-sélective des polluants. Cependant, cela nécessite l'utilisation d'une quantité d'énergie importante, relativement coûteuse. Une solution viable est de coupler le procédé électro-Fenton avec un procédé biologique. En effet, l'utilisation de ce dernier est beaucoup plus économique, mais il possède une efficacité limitée envers les polluants persistants tels que les pharmaceutiques. Ainsi, le procédé hybride bio-électro-Fenton apparaît comme un bon compromis entre le coût et l'efficacité. Le but de cette thèse de doctorat a donc été d'optimiser le procédé électro-Fenton dans l'optique de le coupler avec un procédé biologique, afin d'éliminer les pharmaceutiques. Les principaux objectifs de cette étude reposent sur l'étude de l'influence des paramètres opératoires utilisés au cours du procédé électro-Fenton sur (a) la dégradation des pharmaceutiques ; (b) la minéralisation de la matière organique ; (c) l'évolution de la biodégradabilité; (d) la consommation énergétique. Cette thèse est composée de trois parties, au cours desquelles la complexité des solutions traitées a progressivement augmentée. Premièrement, une étude a été menée sur des solutions de produits pharmaceutiques seuls afin de mieux comprendre les mécanismes impliqués au cours de leur dégradation. La seconde partie porte sur l'étude expérimentale d'une solution synthétique composée d'un mélange de 13 pharmaceutiques. La dernière étape a consisté à mettre en place un procédé bio-électro-Fenton pour le traitement d'un effluent pharmaceutique réel. Cette démarche progressive a permis de mieux comprendre l'influence des paramètres opératoires utilisés au cours du procédé électro-Fenton. Les principaux résultats obtenus sont notamment l'optimisation de deux paramètres opératoires important : la concentration du catalyseur (Fe2+) et l'intensité du courant. L'influence de ces paramètres s'est révélée similaires au cours du traitement de tous les types de solution testée. Il a donc été possible de conclure que les valeurs optimales sont une concentration en Fe2+ de 0,2 mM et une intensité entre 100 et 500 mA. L'efficacité d'élimination des pharmaceutiques a été plus importante en utilisant des intensités plus faibles (100-300 mA). Cependant, la biodégradabilité de l'effluent, un paramètre important dans l'optique du post-traitement biologique, a été d'avantage augmentée en utilisant des intensités élevées (500-1000 mA). Par ailleurs, l'utilisation d'intensités élevées a aussi mené à augmenter la consommation énergétique, en particulier dans le cas de temps de traitement longs. Il apparaît donc évident qu'un compromis entre efficacité et consommation énergétique doit être trouvé pour chaque cas particulier et effluent à traiter. Pour conclure, les avancées de cette recherche sont principalement attribuées à la nouveauté de la combinaison bio-électro-Fenton. L'étude de l'influence des paramètres opératoires du procédé électro-Fenton a aussi permis d'améliorer la compréhension de cette nouvelle technique et contribue à son développement vers une application industrielleWater pollution is one of the biggest challenges that humanity faces and combating it requires the development of treatment processes, as conventional methods used nowadays are no longer effective for the removal of various complex pollutants. Recently pharmaceuticals have been recognized to be contaminants of emerging environmental concern as their traces were detected in a spectrum of water bodies around the globe. The long term effects of their presence in a natural environment are not yet fully studied, but the potential outcomes can be detrimental to a sustainable future. Among the variety of currently rising treatment technologies, the electro-Fenton method, an electrochemical advanced oxidation process, has demonstrated an ability to eliminate pharmaceuticals as well as other types of persistent contaminants. This electrocatalytical process generates in situ strong oxidants species - hydroxyl radical (OH) - which non-selectively degrade organic pollutants. Due to the extensive cost in the application of electrical energy, its operation might be cost-prohibitive. A solution would be to combine it with biological processes which are more economically viable, but also less effective in the removal of pharmaceuticals. The combined process is expected to have a synergetic effect between cost and effectiveness. The goal of this PhD thesis is to optimize operating conditions of the electro-Fenton process for a feasible combination with a biological process as a means of treating pharmaceutical pollution. The main objectives addressed by this work are related to the influence of operating parameters of the electro-Fenton process on (a) removal of pharmaceuticals; (b) mineralization of organic matter; (c) enhancement of biodegradability; (d) energy consumption. The thesis has three distinct parts related to the type of treated aqueous solution. First, a mechanistic study was conducted on aqueous solutions of individual pharmaceuticals in order to understand general trends of their removal. Next, a series of experiments was carried out on a synthetic mixture of thirteen pharmaceuticals from different therapeutic classes. Lastly, laboratory bench-scale reactors of a combined bio-electro-Fenton process were operated for the treatment of real wastewater. The advance in the complexity of the treated solution allowed a comprehensive comparison and analysis of the influence of the operating parameters. The main results include the optimal values of two operating parameters: the catalyst (Fe2+) concentration and the applied current intensity for a given electro-Fenton setup. The effects of the operating parameters on the removal of pharmaceuticals and other organic matter were similar regardless of the treated solution. The optimal value for the Fe2+ concentration was concluded to be around 0.2 mM. The optimal current intensity was in the range 100-500 mA. The efficiency of the current in terms of the pharmaceuticals' removal was the highest with the lowest intensity (100-300 mA). At the same time the biodegradability, which was an important factor in the biological post-treatment process, improved with higher intensities of electric current (500-1000 mA). However, high current intensities resulted in an elevated energy consumption, particularly with a prolonged treatment time. A tradeoff would have to be consequently made between energy saving and the removal rates that should be found in any single case. The novelty of the research presented in this PhD thesis is firstly attributed to the novelty of the combination of electro-Fenton to a biological process. A detailed study of the influence of operating parameters of the electro-Fenton process on removal rates and biodegradability enhancement contributed not only to the general knowledge on the electro-Fenton process, but also to the advancement towards its upscaling and then further towards the industrial application of this technique
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Isci, Umit. "Novel N-bridged diiron phthalocyanine complexes : synthesis, characterization and application in oxidation." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00881309.
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The synthetic approach was developed for the preparation of N-bridged diiron phthalocyanines substituted by different electron-withdrawing alkylsulfonyl substituents. Six novel phthalocyanines bearing small (methylsulfonyl, ethylsulfonyl and hexylsulfonyl) and bulky (t-butylsulfonyl, adamantylsulfonyl and cyclohexylsulfonyl) substituents have been prepared and characterized by electrospray ionization mass spectrometry (ESI-MS), UV-Vis, FT-IR and EPR. Two complexes (with hexylsulfonyl and t-butylsulfonyl substituents) were characterized in addition by Mössbauer techniques, X-ray photoelectron spectroscopy (XPS) and Fe K-edge X-ray absorption spectroscopy (XANES, EXAFS, high resolution Kβ emission spectroscopy). It has been evidenced that the electronic state of iron in these complexes depends on the size of the substituents. While N-bridged diiron phthalocyanines having methylsulfonyl, ethylsulfonyl and hexylsulfonyl substituents are cationic (PcFeIVNFeIVPc)+N3- complexes, N-bridged diiron phthalocyanines with bulkier t-butylsulfonyl, adamantylsulfonyl and cyclohexylsulfonyl substituents are formally neutral PcFeIIINFeIVPc species. The catalytic properties of six N-bridged diiron phthalocyanines have been studied, using tert-butyl hydroperoxide (tBuOOH) as the oxidant in the oxidation of toluene, p-xylene as well as in the oxidation of various alcohols. This thesis demonstrates the efficiency of N-bridged diiron phthalocyanines substituted by electron-withdrawing alkylsulfonyl groups as oxidation catalysts, in conditions required by environmental and industrial preoccupations
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Musa, Corentin. "Élaboration et caractérisation de matériaux composites biosourcés à base de mucilage et de fibres de lin." Thesis, Littoral, 2019. http://www.theses.fr/2019DUNK0535.
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Les travux de thèse ont été menés dans un contexte de développement et de valorisation de la filière lin au travers de l'élaboration de nouveaux matériaux composites biosourcés à base de mucilage et de fibres de lin. Ces travaux ont conduit dans un premier temps à la synthèse de précurseurs d'isosorbide époxy et polyuréthanes comme alternative aux précurseurs toxiques conventionnels. Pour cela nous avons proposé une voie originale d'optimisation de la synthèse de diglycidyle éther d'isosorbide (DGEI) en utilisant un procédé ultrasonique. Par la suite, la comparaison des méthodes de transformation des époxys en carbonates cycliques par l'inclusion de CO₂ nous a servi de base dans l'élaboration d'un protocole efficace de conversion des DGEI en cyclocarbonates d'isosorbide (CCI) dans des conditions douces de pression et de température. Dans une seconde partie, l'extraction de composés hydrosolubles de la graine de lin a permis d'identifier la structure complexe du mucilage et les effets des paramètres d'extraction sur les propriétés physico-chimiques et thermiques du mucilage. Ensuite, pour la première fois, l'oxydation du mucilage au 2,2,6,6-tétraméthylpipéridine-1-oxyle (TEMPO) a été réalisée avec succès. Puis, nous avons pu mettre en évidence l'efficience de l'oxydation assistée par ultrasons comparée à la méthode classique lors de la montée en échelle du procédé. En vue d'améliorer la compatibilité fibre/matrice des composites à fibres végétales, des traitements appliqués sur des fibres courtes de lin ont été effectués amenant à l'individualisation des fibres et à l'amélioration de l'oxydation appliquée sur des fibres sonifiées. Ces différents matériaux ont permis de formuler un panel de nouveaux biocomposites. Les DGEI ont été valorisés par la confection d'une résine réticulée par une amine renforcée par des fibres longues de lin dont les performances sont identiques aux composites pétro-sourcés. Par la suite, la sonicationdes fibres courtes de lin a mené à l'amélioration des propriétés mécaniques de composite PLA/Lin. L'utilisation de mucilage oxydé a démontré les aspects positifs de l'incorporation du mucilage de lin dans les composites légers et résistants en compressionThe thesis was carried out in a context of development and valorisation of the flax through the conception of new bio-based composite materials made of mucilage and flax fibres. This work initially led to the synthesis of isosorbide epoxy and polyurethane precursors as an alternative to the conventional toxic precursors. For this, we proposed an original route for optimizing the synthesis of isosorbide diglycidyl ether (DGEI) using an ultrasonic process. Subsequently, the comparison of the conversion methods of epoxies into cyclic carbonates by the inclusion of CO₂ served as a basis for the development of an efficient protocol for converting DGEI into isosorbide cyclic carbonates (CCI) under moderate conditions of temperature and pressure. In the second part, the extraction of water-soluble compounds from the flaxseed allowed us to identify the complex structure of the mucilage and the effects of the extraction parameters on its physicochemical and thermal properties. Then, for the first time, oxidation of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) mucilage was successfully performed. After that, we have highlighted the enhanced efficiency of ultrasonic assisted oxidation over the conventional method when scaling up the process. In order to improve the fibre/matrix compatibility of natural fibre-based composites, different treatments of short flax fibres led to the individualizationof the fibres and to the improvement of the oxidation of sonicated fibres.These new materials allowed to formulate a series of novel biocomposites. The DGEI have been enhanced by making an amine-crosslinked resin reinforced with long flax fibres which have a comparable performance to oil-based composites. Additionally, the sonication of short flax fibres led to the improvement of the mechanical properties of PLA/Flax composite. The use of oxidized mucilage has demonstrated the beneficial aspects of flax mucilage incorporation into lightweight, compression-resistant composites
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Cerniak, Samuel Nogueira. "Estudo e desenvolvimento de um capacitor eletrol?tico de ni?bio." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12713.
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It seeks to find an alternative to the current tantalum electrolytic capacitors in the market due to its high cost. Niobium is a potential substitute, since both belong to the same group of the periodic table and because of this have many similar physical and chemical properties. Niobium has several technologically important applications, and Brazil has the largest reserves, around 96%. There are including niobium in reserves of tantalite and columbite in Rio Grande do Norte. These electrolytic capacitors have high capacitance specifies, ie they can store high energy in small volumes compared to other types of capacitors. This is the main attraction of this type of capacitor because is growing demand in the production of capacitors with capacitance specifies increasingly high, this because of the miniaturization of various devices such as GPS devices, televisions, computers, phones and many others. The production route of the capacitor was made by powder metallurgy. The initial niobium powder supplied by EEL-USP was first characterized by XRD, SEM, XRF and laser particle size, to then be sieved into three particle size, 200, 400 e 635mesh. The powders were then compacted and sintered at 1350, 1450 and 1550?C using two sintering time 30 and 60min. Sintering is one of the most important parts of the process as it affects properties as porosity and surface cleaning of the samples, which greatly affected the quality of the capacitor. The sintered samples then underwent a process of anodic oxidation, which created a thin film of niobium pent?xido over the whole porous surface of the sample, this film is the dielectric capacitor. The oxidation process variables influence the performance of the film and therefore the capacitor. The samples were characterized by electrical measurements of capacitance, loss factor, ESR, relative density, porosity and surface area. After the characterizations was made an annealing in air ate 260?C for 60min. After this treatment were made again the electrical measurements. The particle size of powders and sintering affected the porosity and in turn the specific area of the samples. The larger de area of the capacitor, greater is the capacitance. The powder showed the highest capacitance was with the smallest particle size. Higher temperatures and times of sintering caused samples with smaller surface area, but on the other hand the cleaning surface impurities was higher for this cases. So a balance must be made between the gain that is achieved with the cleaning of impurities and the loss with the decreased in specific area. The best results were obtained for the temperature of 1450?C/60min. The influence of annealing on the loss factor and ESR did not follow a well-defined pattern, because their values increased in some cases and decreased in others. The most interesting results due to heat treatment were with respect to capacitance, which showed an increase for all samples after treatment
Procura-se encontrar uma alternativa para os atuais capacitores eletrol?ticos de t?ntalo existentes no mercado, devido ao seu alto custo. O ni?bio ? um substituto em potencial, pois ambos pertencem ao mesmo grupo da tabela peri?dica e devido a isso t?m v?rias propriedades f?sicas e qu?micas semelhantes. O ni?bio apresenta diversas aplica??es tecnologicamente importantes e o Brasil possui as maiores reservas mundiais, em torno de 96%. Existe inclusive ni?bio contido em reservas de tantalita e columbita no Rio Grande do Norte. Esses capacitores eletrol?ticos possuem alta capacit?ncia especifica, ou seja, podem armazenar altas energias em volumes pequenos comparados a outros tipos de capacitores. Esse ? o principal atrativo desse tipo de capacitores, pois existe uma crescente demanda na produ??o de capacitores com capacit?ncia especifica cada vez mais alta, isso devido ? miniaturiza??o de diversos aparelhos como GPSs, televisores, computadores, celulares e muitos outros. A rota de produ??o do capacitor foi feita atrav?s da metalurgia do p?. O p? de ni?bio inicial fornecido pela EEL-USP foi primeiramente caracterizado atrav?s de DRX, MEV, granulometria a laser e FRX, para ent?o ser peneirado em tr?s granulometrias, 200, 400 e 635mesh. Os p?s foram ent?o compactados e sinterizados em 1350, 1450 e 1550?C usando dois patamares, 30 e 60min. A sinteriza??o ? uma das partes mais importantes do processo, pois afeta propriedades como porosidade e limpeza superficial das amostras, que afetaram grandemente a qualidade do capacitor. As amostras sinterizadas sofreram ent?o um processo de oxida??o an?dica, que criou um filme fino de pent?xido de ni?bio sobre toda a superf?cie porosa da amostra, este filme ? o diel?trico do capacitor. As vari?veis do processo de oxida??o influenciaram no desempenho do filme e conseq?entemente do capacitor. As amostras foram caracterizadas atrav?s de medidas el?tricas de capacit?ncia, fator de perdas, ESR, densidade relativa, porosidade e ?rea superficial. Ap?s as caracteriza??es foi feito um tratamento t?rmico de recozimento em atmosfera de ar a 260?C por 60min. Ap?s esse tratamento foram feitas novamente as medidas el?tricas. A granulometria do p? e a sinteriza??o afetaram a porosidade e por sua vez a ?rea especifica das amostras. Quanto maior a ?rea do capacitor, maior sua capacit?ncia. O p? que apresentou capacit?ncia mais alta foi o com menor granulometria. Temperaturas e tempos de sinteriza??o maiores causaram amostras com ?rea superficial menores, por?m, por outro lado a limpeza superficial de impurezas foi maior para esses casos, de maneira que deve ser feito um balanceamento entre o ganho que se obt?m com a limpeza das impurezas e a perda com a diminui??o da ?rea especifica. Os melhores resultados foram obtidos para a temperatura de 1450?C/60min. A influ?ncia do tratamento t?rmico de recozimento no fator de perdas e na ESR n?o seguiu um padr?o bem definido, pois seus valores aumentaram em alguns casos e diminu?ram em outros. Os resultados mais interessantes devido ao tratamento t?rmico foram com rela??o ? capacit?ncia, que apresentou um aumento para todas as amostras ap?s o tratamento
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Esmilaire, Roseline. "Matériaux membranaires en TiO₂ sous-stœchiométrique pour le traitement de l'eau par procédé électrochimique d'oxydation avancée." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT182.
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Ce projet vise à contribuer à la gestion durable d'une ressource naturelle essentielle, l'eau, à travers le développement d'une technologie innovante basée sur le couplage d’un procédé de filtration baromembranaire et de procédés d'oxydation avancée électrochimiques (POAE) afin de minéraliser des molécules organiques très stables.Comme ces polluants dits bio-réfractaires ne peuvent pas être dégradés par les procédés d’oxydation classiques (biologiques, O3, Cl2, H2O2…), les procédés d'oxydation avancée (POA) sont alors envisagés. En électrochimie, les radicaux hydroxyles peuvent être générés sur des cathodes en carbone par le procédé électro-Fenton ou encore à l’anode sur des matériaux à forte surtension de dégagement d'oxygène tels que l'oxyde de titane sous-stœchiométrique ou le diamant dopé au bore (DDB) par une réaction d'oxydation de l'eau.Ce travail porte sur l'élaboration et la caractérisation de membranes tubulaires de filtration composées des phases Magnéli les plus conductrices électroniques : Ti4O7 et Ti5O9. Ce matériau peut être utilisé dans le procédé d’oxydation anodique avec un coût de fabrication plus faible que le diamant dopé au bore. Des membranes tubulaires de microfiltration composées de ces phases ont été préparées en collaboration avec le Centre de Recherches et d’Études Européen du groupe Saint-Gobain. Celles-ci ont été élaborées par réduction carbothermique de TiO2, ce qui est très novateur par rapport à la réduction sous dihydrogène. Des poudres de TinO2n-1 (avec 3 ≤ n ≤ 5) ont été préparées par électrofusion de poudres de TiO2 et de carbone suivie de broyages. Ces poudres de granulométrie contrôlée ont ensuite été utilisées à l’IEM pour préparer des suspensions stables de particules en vue de réaliser des couches minces de basse microfiltration, par trempage ou engobage, composées de TinO2n-1 (avec 4 ≤ n ≤ 6). Nous proposons également une première méthode d’élaboration de couches minces en TinO2n-1 (n à définir) par voie sol-gel suivie d’un traitement thermique dans le but d’obtenir des couches réactives d’ultra et de nanofiltration. Après optimisation, ces matériaux ont pu montrer leur efficacité vis-à-vis de la dégradation de polluants bio-réfractaires de type pharmaceutique (Paracétamol) lorsqu’ils sont utilisés en tant que « membranes réactives électrochimiques » que ce soit en mode statique (bécher) ou en mode dynamique (pilote de filtration). La prochaine étape portera sur le couplage des procédés d’oxydation anodique et de filtration baromembranaire utilisant les membranes réactives développées. Au vu des premiers tests, cette technologie s’avère d’ores et déjà prometteuse pour le traitement de polluants bio-réfractaires dans l’eau. Cette thèse a été financée par l'Agence Nationale de la Recherche (ANR) dans le cadre du programme ECO-TS (Projet CElectrON)This project aims to contribute to the sustainable management of water as an essential natural resource, through the development of an innovative technology based on the coupling of a baromembranar filtration process and electrochemical advanced oxidation processes (EAOP) in order to mineralize very stable organic molecules.Since these bio-refractory pollutants cannot be totally degraded by common oxidants (biological, O3, Cl2, H2O2), advanced oxidation processes (AOP) are thus considered. In electrochemistry, these hydroxyl radicals can be generated by water oxidation on carbon cathodes by the electro-Fenton process or on anode showing high oxygen evolution overvoltage like sub-stoichiometric titanium oxide and Boron Doped Diamond (BDD).This work deals with the development and characterization of tubular filtration membranes composed of the most conductive Magnéli phases: Ti4O7 and Ti5O9. These materials can be used in anodic oxidation process with lower manufacturing cost compared to BDD. Microfiltration tubular membranes composed of these phases were prepared with the support of CREE (Research Group of Saint-Gobain). They were elaborated by carbothermal reduction of TiO2, which is very innovative compared to dihydrogen reduction. TinO2n-1 powders (with 3 ≤ n ≤ 5) of controlled grain size were elaborated by electrofusion of TiO2 powder and coke followed by grinding. These powders were further used at the European Institute of Membranes to formulate stable suspensions of particles to prepare thin solid films of low microfiltration, by dip-coating or slip-casting. We also propose an original method for the production of thin layers of TinO2n-1 (n to be defined) by sol-gel route followed by a thermal treatment to obtain ultra or nanofiltration active layers. After optimization, those materials have shown their efficiency towards the degradation of bio-refractory compounds such as pharmaceutics (Paracetamol) when used as electrochemical reactive membranes either in static (beaker) or in dynamic mode (filtration pilot). The next step will focus on the coupling of the anodic oxidation and the baromembranar filtration processes using the reactive developed membranes. From first results, this technology appears really promising for the treatment of bio-refractory pollutants in water. This thesis was financially supported by the National Research Agency (NRA) within the framework of the ECO-TS program, the CElectrON project
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Bailey, Andrew Douglas. "An assessment of oxygen availability, iron build-up and the relative significance of free and attached bacteria, as factors affecting bio-oxidation of refractory gold-bearing sulphides at high solids concentrations." Doctoral thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/21417.
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Bibliography: pages 121-132.Bacterial oxidation is currently finding significant application for the oxidative pretreatment of refractory gold-bearing sulphides. Plants processing sulphide concentrates have commonly been operated at solids concentrations of between 18 and 20 per cent (m/v) (Le 180 and 200 kg.m-3). At higher concentrations, a decline in the bio-oxidation rate has been observed. Other metallurgical processes, such as chemical leaching and cyanidation, are performed at higher solids concentrations of between 40 and 50 per cent (400 and 500 kg.m-3), providing an incentive to increase the solids concentration at which bio-oxidation plants are operated. A review of literature indicated the following factors to be potential causes of reduced bio-oxidation rates at high solids concentrations: oxygen and carbon dioxide mass transfer; a low bacteria-to-solids ratio; mechanical damage of the bacte.ria; and the build-up of inhibitory oxidation products. Interaction of these factors in the completely-mixed reactors that are commonly used for biooxidation, has confounded the interpretation of the effects of individual factors. Analysis of literature data revealed a link between the sulphide grade of a particular material and the highest solids concentration at which the bacterial oxidation rate was maximal. The oxygen demand is directly proportional to the sulphide concentration in the reactor. Correlations were used to predict the oxygen transfer potential in the experimental reactors and it was found that as long as the oxygen transfer potential exceeded the oxygen demand, the biooxidation rate was proportional to the solids concentration for a specific material. Wh~n the oxygen demand equalled or exceeded the oxygen transfer potential, then the bacterial oxidation rate was limited by oxygen availability. The sulphide grade is characteristic of a particular ore or concentrate and from the data analysis oxygen availabiiity appeared to be the underlying reason why low grade materials could be oxidised at the maximum specific bio-oxidation rate at far higher solids concentrations than high-grade f!laterials. Abstract ii The experiments performed in this study were designed to further investigate the apparent relationship, identified by analysis of literature data, between sulphide grade and the solids concentration at which the bacterial oxidation rate was maximal. The effect of both solids concentration and sulphide grade on the biooxidation rate was investigated and related to the oxygen availability in the reactor.
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Monteil, Hélène. "Development and implementation of the Bio-electro-Fenton process : application to the removal of pharmaceuticals from water A review on efficiency and cost effectiveness of electro- and bio-electro-Fenton processes: application to the treatment of pharmaceutical pollutants in water. Efficient removal of diuretic hydrochlorothiazide from water by electro-Fenton process using BDD anode: a kinetic and degradation pathway study Electro-Fenton treatment of the widely used analgesic tramadol using BDD anode: a kinetic, energetic and degradation pathway study Efficiency of a new pilot scale continuous reactor for wastewater treatment by electrochemical advanced oxidation processes: influence of operating conditions and focus on hydrodynamics Electrochemical advanced oxidation processes combined with a biological treatment for wastewater treatment: a deep understanding on the influence of operating conditions and global efficiency." Thesis, Paris Est, 2019. http://www.theses.fr/2019PESC2045.
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Les procédés électrochimiques d'oxydation avancée constituent une technologie efficace pour traiter les produits pharmaceutiques car ils permettent la formation d'oxydants puissants tels que les radicaux hydroxyles capables d'éliminer presque tout type de contaminants organiques grâce à leur très haut pouvoir oxydant. Parmi eux, l’électro-Fenton et l’oxydation anodique sont des méthodes respectueuses de l'environnement car ils n'utilisent aucun réactif chimique (oxydation anodique) ou uniquement l'oxygène de l'air et des ions fer en tant que catalyseur (électro-Fenton).Dans cette thèse, quatre produits pharmaceutiques appartenant à des familles différentes ont été sélectionnés en fonction de leur toxicité et de leur présence dans les eaux de l'environnement. Leur élimination de l'eau a été effectuée par électro-Fenton. Les objectifs de ce travail étaient de déterminer (i) les meilleures conditions opératoires à l’échelle du laboratoire (courant et concentration du catalyseur), (ii) la cinétique de dégradation et de minéralisation et enfin (iii) de proposer une voie de minéralisation basée sur des intermédiaires aromatiques, des acides carboxyliques et des ions libérés dans la solution.Comme ces traitements ont été appliqués avec succès, un réacteur pilote composé alternativement d'anodes en BDD et de cathodes en feutre de carbone, doté d’un système d'aération et fonctionnant en mode continu a été construit pour évaluer la faisabilité d’un changement d’échelle et se diriger vers une pré-industrialisation du procédé. Différentes configurations d'électrodes ont été testées. Le débit et le courant se sont avérés être plus influents sur le taux de minéralisation et sur la consommation d'énergie, respectivement. Pour mieux comprendre le rôle du débit et des configurations, une étude hydrodynamique a été réalisée. Le modèle hydrodynamique a été associé à un modèle cinétique de minéralisation afin d'obtenir un modèle permettant de prédire le pourcentage de minéralisation à différentes positions à l'intérieur du réacteur en régime permanent. Ainsi, ce modèle peut aider à optimiser les conditions opératoires et à dimensionner les futurs réacteurs en fonction de l’objectif de minéralisation du traitement (taux de minéralisation élevé, traitement combiné, flux élevé,…).Afin de réduire les coûts opératoires, la combinaison d’un procédé électrochimique et d’un traitement biologique a ensuite été étudiée. Afin d’obtenir un traitement combiné efficace, il a été constaté que le traitement électrochimique devait (i) dégrader l'hydrochlorothiazide (ii) réduire de manière significative la concentration de ses intermédiaires aromatiques car ils inhibent de manière significative l'activité bactérienne, (iii) favoriser la formation de molécules biodégradables telles que les acides carboxyliques. La biodégradation de quatre acides carboxyliques formés lors du traitement par électro-Fenton de l'hydrochlorothiazide a également été étudiée. Il a été démontré qu'ils étaient dégradés de manière séquentielle avec différentes phases de latence et cinétiques de dégradation. Ainsi, pour les minéraliser, un réacteur de type «piston» est recommandé. La combinaison de traitement a ensuite été appliquée à un traitement électrochimique effectué à faible courant avec une anode en BDD et une anode en Platine. Un degré de minéralisation de 38 et 50% a été obtenu par le traitement biologique permettant d'atteindre un taux de minéralisation global de 66 et 85% avec les anodes en BDD et Platine respectivement. Ainsi, cette combinaison de traitement a été un succès, un changement d’échelle du procédé peut alors être envisagéElectrochemical advanced oxidation processes (EAOPs) constitute an efficient technology to treat the pharmaceuticals as they allow the formation of strong oxidants such as hydroxyl radicals able to remove nearly any type of organic contaminants thanks to their very high oxidation power. Among them the electro-Fenton and anodic oxidation processes are environmentally friendly methods as they use no chemical reagent (anodic oxidation) or only oxygen of air and iron ions as a catalyst (electro-Fenton).In this thesis, four pharmaceuticals from different families and structures were selected based on their toxicity and their occurrence in environmental waters and their removal from water was performed by EAOPs. The objectives of this work were to determine the best operating conditions at lab scale (current and catalyst concentration), investigate the kinetic of degradation and mineralization and finally propose a mineralization pathway based on aromatic intermediates, carboxylic acids and ions released to the solution.As these treatments were successfully applied, a lab scale pilot reactor composed alternately of BDD anodes and carbon felt cathodes with a bottom aeration system and working in the continuous mode was built to scale-up these processes in order to pre-industrialize them. Different configurations of electrodes were tested. The flow rate and the current were found to be more influent on the mineralization rate and on the energy consumption, respectively. To deeper understand the role of the flow rate and the configurations a hydrodynamic study was performed. The hydrodynamic results were gathered with a kinetic model for the mineralization to obtain a model predicting the percentage of mineralization at different position inside the reactor during the steady state. Thus, this model can help to optimize the operating conditions and to size future reactors depending on the mineralization objective of the treatment (high mineralization rate, combined treatment, high flow, …).To reduce operating cost, the combination of an electrochemical process and a biological treatment was then investigated. In this frame, it was found that electrochemical treatment can (i) degrade the hydrochlorothiazide (ii) reduce significantly the concentration of its aromatic intermediates as they were shown to significantly inhibit the bacterial activity, (iii) promote the formation of biodegradable molecules such as carboxylic acids. The biodegradation of four carboxylic acids formed during the electro-Fenton treatment of the hydrochlorothiazide at lab scale was also studied. It was demonstrated that they were sequentially degraded with different lag phases and kinetics of degradation. Thus to mineralize them, a “plug flow” type reactor is recommended. The combination of treatment was then applied with an electrochemical treatment performed at low current with a BDD anode and a Platine anode. A mineralization degree of 38% and 50% were obtained by the biological treatment enabling to globally reach a mineralization rate of 66% and 85% with the BDD and the Platine anodes respectively. Thus this combined treatment was successful and open the way for the scale-up of these processes
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Choo-Kun, Marlène. "Intégration de la méthanisation des boues dans une filière alternative de traitement des eaux usées basée sur le procédé A/B : Vers la station d’épuration à énergie positive." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0142/document.
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Depuis le début des années 2000, la station d’épuration n’est plus seulement perçue comme une installation industrielle traitant les eaux résiduaires urbaines afin d’en minimiser leurs impacts sur le milieu naturel, mais aussi comme un moyen de récupérer des ressources : eau, nutriments, énergie. Ce travail de thèse traite de cette dernière ressource, l’énergie. Comment tendre vers la station d’épuration auto-suffisante en énergie, voire encore productrice d’énergie sans en affecter l’efficacité de traitement? A l’aide d’une filière de traitement ancienne revisitée : le procédé A/B (Adsorption/Bio-oxydation), le bilan énergétique de la station peut tendre vers la neutralité en réduisant les demandes liées à l’aération et en optimisant la production de biogaz. Ce travail de doctorat se concentre principalement sur la méthanisation des boues issues de ce procédé A/B afin d’en connaître leurs caractéristiques et leur digestibilité, de les comparer avec la digestion anaérobie de boues davantage connues et enfin d’utiliser ces résultats pour dresser le bilan énergétique du procédé A/B, ceci à partir des données récoltées sur un pilote de 50 m3/j installé sur la station d’épuration de Kranji à Singapour. Les boues A et B présentent respectivement les productions spécifiques de méthane respectives de 290 et 135 LCH4/kgMVentrante en conditions mésophiles. Le procédé A/B avec ses deux étages de boues activées permet de capter un maximum de carbone en première étape de traitement pour le transférer directement en digestion. En effet, la production totale de boues provient à 90% des boues A et seulement à 10% des boues B ce qui porte à 95% la production de méthane attribuée aux boues A. Ces résultats induisent une production d’énergie supérieure par rapport à une filière de traitement conventionnelle avec un seul étage de boues activées. Par ailleurs, ce procédé permet de diminuer les besoins en aération pour le traitement des pollutions carbonée et azotée, tout en gardant les mêmes efficacités de traitement. Il est ainsi possible de conclure que la filière de traitement des eaux usées en procédé A/B présente un degré d’efficacité énergétique proche de 300% (ratio entre l’énergie électrique produite à partir du biogaz et la consommation énergétique liée à l’aération), ce qui représente 73% d’auto-suffisance énergétique globale en considérant le cas de la station de Kranji en boues activées conventionnelles traitant les pollutions en carbone et en azoteSince the early 2000’s, wastewater treatment plants (WWTP) have not been only seen as a mean to reduce the impact of the harmful emissions towards water bodies but also as a way to recover the resources contained in the raw wastewater: water, nutrients and energy. This doctorate seeks to study the latter one. How to tend to the energy self-sufficient or even energy positive WWTP without altering its treatment efficiencies? Using an old wastewater treatment process: the A/B process (Adsorption/Bio-oxidation) and state-of-the-art technologies, the energy autarky of a WWTP can become a reality by reducing its electricity consumption related to the aeration and by optimizing its energy production through anaerobic digestion. This work mainly focuses on the anaerobic digestion of the sludge produced by the A/B process. It aims at evaluating their characteristics and digestibility and thus at comparing these to the ones of better-known sludge such as primary, secondary and mixed sludge from a conventional wastewater treatment system. Eventually, these results with the addition of data collected on a 50 m3/d A/B process pilot plant on the Water Reclamation Plant of Kranji, Singapore, are used to draw the energy balance of the A/B process and to try to make a comparison to conventional systems. The A/B process produces the A and B sludge which respectively show specific methane productions of 290 and 135 LCH4/kgVSintroduced in mesophilic anaerobic digestion and can be considered quite similar to primary and secondary sludge respectively from conventional WWTPs. With its two stages of activated sludge, this process enables the early entrapment of carbon to be directly transferred to the digesters. Indeed, 90% of the sludge production comes from the A sludge in matter of Volatile Solids, which brings to 95% the biogas production to be ascribed to this sludge. Hence, the A/B process does produce more energy than a conventional single-stage activated sludge. It also reduces the aeration demand for the biological treatment of the carbon and nitrogen pollutions whilst complying with the same treatment performances. Drawing the energy balance of the A/B process leads to the conclusions that this process presents an energy efficiency of 300% by comparing only the electrical needs for the aeration (40-70% of the whole plant demand) and the electricity production from biogas generation, which, at the end, represents an energy self-sufficiency of 73% considering the Kranji conventional water reclamation plant
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Malibo, Petrus Molaoa. "Development of heterostructured tin oxide nanocatalysts for the synthesis of bio-based maleic acid." University of Western Cape, 2021. http://hdl.handle.net/11394/8438.
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Philosophiae Doctor - PhDMaleic acid (MA) is a key intermediate for the synthesis of polyester resins, surface coatings, lubricant additives, plasticizers, copolymers, pharmaceuticals and agricultural chemicals. The current industrial production of MA is an energy-intensive gas-phase oxidation process of n-butane. The dwindling fossil resources and environmental issues have brought about a worldwide paradigm shift from fossil feedstocks to biomass resources for the sustainable production of fuel and chemicals. Furfural (FFR) and 5-hydroxymethylfurfural (HMF) are excellent biomass-derived platform chemicals, which present an alternative route for the production of renewable bio-based MA. There has been considerable success achieved in the oxidation of furfural and HMF to maleic acid and maleic anhydride with different catalysts in recent years.
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Asous, Nadia K. "Hydrogen Atom Transfer Reactivity of Bio-inspired Unsymmetrical Dicopper– oxo/peroxo Complexes." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1533245264093817.
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Sampson, Mark Ian. "Influence of the cell properties of acidophilic bacteria during attachment to mineral sulfides and consumption during the oxidation of ferrous iron." Thesis, University of Exeter, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297789.
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Hernandez-Gonzalez, Sergio Manuel. "Non-Catalytic Production of Hydrogen via Reforming of Diesel, Hexadecane and Bio-Diesel for Nitrogen Oxides Remediation." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1228317376.
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Soykal, Ibrahim Ilgaz I. "Characterization of cobalt and cerium coordination environments for catalytic steam reforming of bio-derived liquids." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1378898730.
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Acosta, Arlen Mabel Lastre. "Processos de tratamento não convencionais para degradação do antibiótico sulfadiazina em meio aquoso." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-22082016-102752/.
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A presença de antibióticos no meio ambiente aquático tem causado crescente preocupação mundial. Além dos relatos de resistência de bactérias a antibióticos, essa classe de fármacos também pode causar efeitos tóxicos e atuar como perturbadores endócrinos em diversos organismos vivos e, possivelmente, em humanos. Dentre os antibióticos comumente usados destacam-se as sulfonamidas, detectadas em águas subterrâneas e superficiais. Os processos avançados de oxidação (POA) têm sido apontados como tecnologias eficientes para tratamento de poluentes recalcitrantes em diferentes matrizes aquosas. Dentre os POA, o processo foto-Fenton é uma alternativa para a degradação de compostos não biodegradáveis, incluindo fármacos. Uma vez que a principal limitação do processo é o intervalo de pH (2,5- 4,0), a reação pode ser vantajosamente conduzida empregando-se substâncias bio-orgânicas solúveis (BOS) como agentes complexantes de Fe3+ em condições ligeiramente ácidas (pH 5). Por sua vez, o emprego da energia ultrassônica tem sido menos estudado. Nesse contexto, o objetivo deste trabalho é estudar a degradação do antibiótico sulfadiazina (SDZ) por meio do processo foto-Fenton na presença de substâncias bio-orgânicas solúveis (UVvis/ Fe3+/H2O2/BOS) e do processo de cavitação por meio de ultrassom (US). Os resultados obtidos mostram que a sulfadiazina é eficientemente degradada por ultrassom de alta frequência. As maiores porcentagens e taxas de remoção são obtidas usando menor frequência de operação (580 kHz), maior potência dissipada e em pH ligeiramente ácido (melhor condição: pH 5,5). Além disso, a reação de Fenton, combinada com o tratamento US, melhorou notavelmente a degradação da SDZ, particularmente quando quantidades extras de H2O2 foram adicionadas ao sistema. Por sua vez, o uso de BOS como aditivos no processo foto-Fenton apresenta influência marcante na fotodegradação da SDZ em condições ligeiramente ácidas (pH 5). Os BOS podem estabilizar espécies de ferro em solução aquosa em pH próximos ao neutro, o que constitui uma propriedade de grande interesse. Sob as condições estudadas, o BOS CVT230 foi mais eficiente do que FORSUD, provavelmente devido às diferenças nos grupos funcionais presentes na composição destas substâncias. Finalmente, foram calculados os indicadores de consumo de energia elétrica por ordem de grandeza (EEO) para o processo de ultrassom (1572 kW h m-3 ordem-1) e área do coletor por ordem de grandeza (ACO) para o processo foto-Fenton (8,07 m2 m-3 ordem-1).The potential impacts of antibiotic residues in the environment have become an emerging concern during recent years due to their relation with the development of resistant bacteria, and in some cases to their ability to cause toxic and endocrine disrupting effects in humans and other living organisms. Highlighted among the commonly used antibiotics are the sulfonamides, detected in groundwater and surface water. Advanced oxidation processes (AOP) might constitute an important alternative to deal with pharmaceuticals degradation. Among them, the photo-Fenton process has been widely used. One of its major drawbacks is the highly acidic pH needed (2,5-4,0) to avoid the formation of photochemically inactive iron oxides and hydroxides. The ability of soluble bio-organic substances (SBO) to complex metal cations such as iron is useful for the development of photo-Fenton at mild acidic conditions (pH 5). In turn, the use of ultrasonic energy has been less studied. In this context, the aim of this work is to study the degradation of the antibiotic sulfadiazine (SDZ) by the photo-Fenton process in the presence of soluble bio-organic substances (UV-vis/Fe3+/H2O2/SBO) and by ultrasonic cavitation (US). The results confirm that SDZ is effectively degraded by highfrequency ultrasound. Higher SDZ percent removals and removal rates were observed for the lowest operating frequency (580 kHz), higher dissipated power, and in slightly acidic solution (pH 5.5). On the other hand, SDZ degradation is highly improved in the case of the US/ Fe(II)/H2O2 system. The use of the SBO as Fenton additives in turn has a remarkable influence in SDZ photodegradation at slightly acid conditions (pH 5). This could be ascertained to the complexation of iron by the SBO, hence maintained in the reaction medium as a photoactive species. Under the studied conditions, the BOS CVT230 was more efficient than FORSUD, probably due to differences in the functional groups present in the composition of these substances. Finally, the figures-of merit electrical energy per order (EEO) and collector area per order (ACO) were calculated for the ultrasound (1572 kW h m-3 ordem-1) and photo-Fenton (8,07 m2 m-3 ordem-1) processes respectively.
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Trehoux, Alexandre. "Synthèse de complexes binucléaires de fer pour activation réductrice du dioxygène : vers de nouveaux catalyseurs d'oxydation bio-inspirés." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS052/document.
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Ces travaux décrivent la synthèse et l'étude de la réactivité de complexes binucléaires à fer, développés dans le but de mimer l'activité catalytique d'enzymes binucléaires à fer telles que la méthane monooxygénase soluble. Nous avons synthétisé et caractérisé plusieurs complexes binucléaires à fer(III), possédant différents types de groupements (électro-donneurs, électro-attracteurs, donneurs de liaison hydrogène) dans leur seconde sphère de coordination, de façon symétrique ou dissymétrique. Nous avons étudié l'influence de la seconde sphère de coordination de ces différents complexes sur les différents intermédiaires formés (notamment l'intermédiaire µ-peroxo-FeIIIFeIII) lorsque que ces complexes sont exposés au peroxyde d'hydrogène. Nous avons également étudié la capacité de ces différents complexes à catalyser les réactions d'oxydation de différents substrats (sulfures, alcènes et alcanes) par le peroxyde d'hydrogène, en absence et en présence d'eau dans le milieu réactionnel. Une modification intéressante de la chimiosélectivité de la réaction d'oxydation du cyclooctène par le peroxyde d'hydrogène, en présence d'un complexe binucléaire à fer dissymétrique et d'eau dans le milieu réactionnel a été observée. Différentes études d'aspect mécanistique ont été réalisées afin de déterminer l'origine des différents phénomènes observés en catalyse d'oxydationThis work describes the synthesis and the study of the reactivity of diiron complexes, developed in order to mimic the catalytic activity of diiron enzymes such as the soluble methane monooxygenase. We synthesized and characterized several diiron(III) complexes, bearing different types of groups (electron-donating, electron-withdrawing, hydrogen bond donating) in their second coordination sphere, in a symmetrical or non-symmetrical way. We studied the influence of the second coordination sphere of these different complexes over the different intermediates (particularly the µ-peroxo-FeIIIFeIII intermediate) formed by exposing them to hydrogen peroxide. We also studied the ability of these complexes to catalyze the oxidation of various substrates (sulfurs, alkenes, alkanes) by hydrogen peroxide, in absence or in presence of water in the reaction mixture. An interesting modification of chemoselectivity was observed in the case of oxidation of cyclooctene by hydrogen peroxyde, catalyzed by a non-symmetrical diiron complex, in presence of water in the reaction mixture. Several mechanistic studies were performed in order to investigate on the origin of the phenomenons we observed during oxidation catalysis studies
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Garcia, Luane Ferreira. "Remediação bio-eletroquímica do hormônio sexual sintético 17-α-etinilestradiol." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/5661.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Hormones are released constantly in sewage, originated by of human/animal excreta, or waste of pharmaceutical industries, not treated satisfactorily. The eviction of these pollutants in water resources produces great environmental impact, as disruption in animals’ endocrine system. The 17α-ethinylestradiol (EE2) is the most popular synthetic estrogen, which is found in water and in considerable concentrations. Several strategies are being studied to remedy this pollutant. Enzymes as laccases, which have low specificity, are able to oxidize various pollutants, thus suggesting their potential in the treatment of effluents. Another alternative are the electrochemical processes as electro-oxidation and electrocoagulation. The aim of this study was to evaluate the removal efficiency of the EE2 for biological or/and electrochemical process. The crude extract containing the laccase from Pycnoporus sanguineus was immobilized in Ca/Cu-alginate-chitosan beads. For partial characterization were determined optimum pH and optimum temperature of enzyme activity, for free and immobilized enzyme. Biological remediation was performed in these conditions: shaking (100 rpm); temperature at 28°C (± 2); times of 4, 8 and 24 hours; EE2 solution buffered at pH 4 and 5, and EE2 solution without addition of buffer. For the electrochemical remediation: magnetic stirring; voltage of 2.5, 5 and 7.5 V; times of 10, 20 and 40 minutes; pHs 5 and 7. For bio-electrochemical remediation the best conditions were used. In the remediation assays of the EE2 with immobilized enzyme, the best result was obtained for the support Ca-alginate-chitosan with 89.81% (± 2.71) removal, in sodium acetate buffer pH 5.0 and 24 hours of treatment. Under the same conditions to the free enzyme, 91.81% (± 0.86) of removal was obtained. For electrochemical remediation with titanium electrode, 86.21% (± 9.30) was removed in pH 7 phosphate buffer and 40 minutes. For sequential bio-electrochemical remediation, EE2 concentrations were below the limit of detection of the chromatograph, with the removal by immobilized enzyme acting in unbuffered solution. It can be concluded that the two technologies are very effective for the removal of the EE2.
Hormônios são lançados constantemente em esgotos, sejam oriundos de excretas humanas ou animais, sejam de resíduos provenientes das indústrias farmacêuticas, não tratados de forma eficaz. O despejo destes micropoluentes nos recursos hídricos produz grande impacto ambiental, como desregulação do sistema endócrino em animais. O 17α-etinilestradiol (EE2) é o mais popular estrogênio sintético, sendo encontrado nos recursos hídricos em concentrações consideráveis. Diversas estratégias estão sendo estudadas para remediação deste poluente. Enzimas como as lacases, que possuem baixa especificidade, são capazes de oxidar diversos poluentes, sugerindo assim seu potencial no tratamento de efluentes. Outra alternativa são os processos eletroquímicos, como a eletro-oxidação e eletrocoagulação. Sendo assim, o objetivo deste trabalho foi avaliar a eficiência de remoção do EE2 por processo biológico ou/e eletroquímico. O extrato bruto contendo a lacase de Pycnoporus sanguineus foi imobilizado em beads de quitosana-alginato-Ca/Cu. Para caracterização parcial da enzima livre e imobilizada foram determinados pH e temperatura ótima de atividade enzimática. A remediação biológica foi realizada nas condições: agitação (100 rpm); temperatura em 28°C (± 2); tempos de 4, 8 e 24 horas; solução de EE2 tamponada em pHs 4 e 5, e solução do hormônio sem adição de tampão. A remediação eletroquímica: agitação magnética; tensão de 2,5, 5 e 7,5 V; tempos de 10, 20 e 40 minutos; solução de EE2 tamponada em pHs 5 e 7. Para remediação bio-eletroquímica, de modo sequencial, foram utilizadas as condições mais adequadas para ambas as tecnologias. Nos ensaios de remediação do hormônio EE2 com a enzima imobilizada, o melhor resultado foi obtido para beads de quitosana-alginato-Ca com remoção de 89,81% (± 2,71) em tampão acetato de sódio pH 5 e 24 horas de tratamento. Nas mesmas condições, para a enzima livre foi obtido 91,81% (± 0,86) de remoção. Para remediação eletroquímica, com eletrodo de titânio foi removido 86,21% (± 9,30) do EE2, em tampão fosfato pH 7 e 40 minutos. Para a remediação bio-eletroquímica em modo sequencial, obteve-se remoção do EE2 em concentrações abaixo do limite de detecção do cromatógrafo, com a enzima imobilizada atuando em solução não tamponada. Conclui-se que as duas tecnologias são bastante eficientes para a remoção do EE2, podendo ser utilizadas separadamente ou em conjunto.
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Mohamed, Bouh Salma. "Contribution à l'étude complexes bio-inspirés du site actif des hydrogénases [FeFe]." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0128.
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Les hydrogénases [FeFe] sont des métalloenzymes capables de catalyser de façon réversible la production et l’oxydation du dihydrogène. Depuis que la structure du site actif des hydrogénases [FeFe] a été déterminée, de nombreux modèles bio-inspirés ont été élaborés et étudiés en vue de comprendre et de reproduire le fonctionnement de cette classe d’enzyme. Le site actif des hydrogénases [FeFe], le cluster-H, présente un état entatique caractérisé par une conformation particulière permettant d’activer efficacement la conversion H+/H2. Dans la littérature, très peu de modèles reproduisant une telle conformation dans l’état réduit Hred (FeIFeI) du site actif ont été décrits. Notre équipe a obtenu récemment un complexe FeIFeI de formule [Fe2(CO)4(ҡ 2-dmpe)(μ-adtBn)] (adtBn= {SCH2}2NCH2C6H5, dmpe = (CH3)2PCH2-CH2P(CH3)2), présentant une conformation ‘inversée’, à l’état solide, permettant de mimer la géométrie particulière du cluster-H. Cette conformation est stabilisée dans ce dérivé par la présence d’un pont dithiolate encombré, d’une liaison agostique et par la coordination dissymétrique d'un ligand bidentate bon σ-donneur. Les travaux de cette thèse ont été consacrés à l’étude du comportement électrochimique en oxydation de ce composé, [Fe2(CO)4(ҡ2-dmpe)(μ-adtBn)], dans différents solvants et en présence de substrats, comme CO, RNC et P(OMe)3, en vue de comprendre les mécanismes impliqués dans ces processus redox. Les oxydations chimiques du complexe [Fe2(CO)4(ҡ2-dmpe)(μ-adtBn)] ont permis de compléter l’identification des espèces formées qui ont été caractérisées par différentes méthodes spectroscopiques (IR, RMN) et par diffraction des rayons X[FeFe]-Hydrogenases are metalloenzymes having the capacity to catalyze efficiently both the production of H2 and its oxidation. Since the structure of the active site of [FeFe]-Hydrogenases has been determined, many bio-inspired models have been synthesized and studied to understand and to mimick the functioning of this class of enzyme. The active site of the [FeFe]-hydrogenases, the Hcluster, presents an entatic state characterized by a particular conformation that allows an efficient H+/H2 conversion. Very few models mimicking such a conformation in the reduced state, Hred (FeIFeI), of the active site have been described in the literature. Our group recently obtained a FeIFeI complex [Fe2(CO)4(k2-dmpe)(μ-adtBn)] (adtBn = {SCH2}2NCH2C6H5, dmpe = (CH3)2PCH2-CH2P(CH3)2), having an 'inverted' conformation, in the solid state, that mimicks the particular geometry of the H-cluster. This conformation is stabilized in this derivative by the presence of a crowded dithiolate bridge, an agostic interaction and the dissymmetrical coordination of a chelating good σ-donor ligand. The works in this thesis have been devoted to the study of the electrochemical properties in oxidation of the complex [Fe2(CO)4(k2-dmpe)(μ-adtBn)] in various solvents and in the presence of substrates, such as CO, RNC, P(OMe)3, in order to understand the mechanisms involved in these redox processes. The chemical oxidations of the complex [Fe2(CO)4(k2-dmpe)(μ-adtBn)] have been also performed in order to identify the species formed by oxidation. They were characterized using various spectroscopic methods (IR, NMR) and X-ray diffraction
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Kouame, Bitty Roméo Serge. "Étude de la valorisation de molécules bio-sourcées par conversion électrocatalytique." Thesis, Poitiers, 2020. http://www.theses.fr/2020POIT2269.
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Le glycérol est formé comme produit secondaire à hauteur de 10 wt% lors du processus de trans-estérification d’huiles végétales pour la production d’ester méthyliques et est donc considéré comme un déchet. Ses stocks à travers le monde augmentent significativement. Or, la conversion du glycérol peut permettre d’obtenir des composés à haute valeur ajoutée pour le domaine de la chimie fine, la cosmétique, les détergents l’alimentaire etc., avec la co-production d’énergie électrique ou d’hydrogène lorsqu’elle est réalisée dans des réacteurs électrochimiques. De catalyseurs mono-et bimétallique à base de platine d’une part (Pt/C, PtxAg10-x/C, PtxBi10-x/C, PtxCu10-x/C, PtxCo10-x/C, PtxIn10-x/C, PtxNi10-x/C, avec x=1, 2 et 3) et de palladium d’autre part (Pd/C, Pd9Bi1/C, Pd7Cu3/C, Pd7In3/C et Pd7Ag3/C) ont été synthétisés avec pour objectif d’électro-oxyder le glycérol en aldéhyde et/ou cétone. Ces matériaux ont été caractérisés par des méthodes physico-chimiques et électrochimiques afin d’établir une corrélation structure de surface/réponse électrochimique. Les réactivités du glycérol et du diglycérol ont été évaluées en milieu alcalin pour déterminer le catalyseur offrant la meilleure conversion. La sélectivité des catalyseurs a été étudiée par spectroscopie infrarouge in-situ. Les meilleurs catalyseurs en termes d’activité et de sélectivité ont été utilisés dans une cellule d’électrolyse de 100 cm² pour accumuler les produits de réactions et les analyser. Enfin, l’amination réductrice par l’ammoniac d’une part et la n-butylamine d’autre part sur les produits d’intérêt (glycéraldéhyde/dihydroxyacétone) a été réalisée avec succèsGlycerol is a by-product of the transesterification reaction of vegetable oils by methanol leading to the formation of methyl ester (methanolysis), with the weight ratio of 10 wt.%. Stocks are increasing significantly worldwide. Glycerol can be converted into high added value compounds of interest for industries of fine chemistry, cosmetic, detergent, food, etc., together with the co-production of electrical energy or hydrogen when its conversion is performed in electrochemical reactors. On the one hand, Pt-based mono and bimetallic catalysts (Pt/C, PtxAg10-x/C, PtxBi10-x/C, PtxCu10-x/C, PtxCo10-x/C, PtxIn10-x/C, PtxNi10-x/C, with x = 1, 2 or 3) catalysts and, on the other hand, palladium-based (Pd/C, Pd9Bi1/C, Pd7Cu3/C, Pd7In3/C and Pd7Ag3/C) catalysts have been synthesized by a wet chemistry method and characterized, with the objective of favor the electrooxidation reaction of glycerol and diglycerol towards aldehydes and ketones. The reactivity of glycerol and diglycerol was evaluated in an alkaline medium to determine the catalyst offering the best conversion. The selectivity of catalysts was studied by in-situ infrared spectroscopy. The best catalysts in terms of activity and selectivity were used at the anode of a 100 cm² electrolysis cell and electrolyses of alkaline solutions of glycerol or diglycerol were carried out at different voltages in order to evaluate the distribution of the reaction products. The reductive amination with ammonia on the one hand and n-butylamine on the other hand on products of interest (glyceraldehyde / dihydroxyacetone) has been successively carried out
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Bour, Aurélien. "Influence de la composition lipidique sur la résistance de membranes bio-mimétiques au stress oxydant." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS394.
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La mitochondrie est à la fois le lieu de la production d’énergie de la cellule et le centre régulateur de la mort cellulaire. L’efficacité de ces 2 fonctions est liée au niveau d’oxydation de la membrane mitochondriales interne (MMI). Le but de ce travail est de comprendre l’influence des lipides de la membrane sur sa résistance au stress oxydant. Les expériences sont menées sur des liposomes mimant la MMI. Leur oxydation est déclenchée par l’irradiation de la Ce6, une molécule photo-sensibilisatrice ayant une forte affinité pour les bicouches lipidiques. D’abord, l’association entre membranes et Ce6 est quantifiée par fluorimétrie. Ces mesures permettent de garder constant le ratio Ce6/lipides d’une composition membranaire à l’autre. Nous étudions ensuite, par microscopie à contraste de phase, l’influence de la nature des têtes des lipides et de la position, du nombre et de la conformation des insaturations des chaines lipidiques sur la perméabilisation du liposome déclenchée par son oxydation. Cette perméabilisation est due à deux phénomènes : la formation de défauts dans la bicouche et l’ouverture de pores micrométriques dans la membrane. Les seconds ne permettent une fuite significative que pour des membranes de composition proche des MMI. La présence du cardiolipide, spécifique aux mitochondries, retarde et réduit la perméabilité induite. La perméabilisation est d’autant plus efficace que les lipides comportent des insaturations et qu’elles sont proches de la tête polaire. La spectrométrie Raman donne en outre accès à la chimie du phénomène. Notamment, l’oxydation de la membrane n’est possible que si les électrons engagés dans la double liaison peuvent être délocalisésMitochondrion is both the place of cell energy production and the regulatory center of apoptosis. The efficiency of these functions depends on the oxidation level of inner mitochondrial membranes (IMM). The aim of this work is to decipher the influence of lipids on the membrane resistance to oxidative stress. Experiments are done on IMM-mimicking liposomes. Membrane oxidation is controlled by irradiation of the Ce6, a photosensitizer with high affinity for lipid bilayers. First we quantifiy the binding of Ce6 to membrane by fluorimetry. This measures are used to have a ratio Ce6/lipids equal between membrane compositions. Then we study, by phase contrast microscopy, the influence of the nature of lipid polar head and of the number, position and conformation of aliphatic chains insaturations on the oxidation-induced liposome permeabilization. This permeabilization is due to 2 phenomena : the formation of membrane defects and micrometric pore openings. These latter allow, for IMM-like membranes, a significant leak of liposome inner medium. The presence of cardiolipin, a mitochondrion-specific lipid, delays and decreases the induced permeability. The more insaturations lipids have and the closer to the polar head they have, the more efficient is the permeabilization. Raman spectroscopy allows us to follow chemical scenario of this phenomenon. In particular, membrane oxidation is possible only if the double bonds electron can be delocalized
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Jollet, Véronique. "Complexes de fer bio inspirés pour la catalyse d'oxydation : systèmes homogènes et supportés." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00915279.
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Certaines métalloenzymes catalysent l'oxydation de petites molécules organiques, dans des conditions douces (par activation du dioxygène à température et pression ambiante). Ce travail a pour but d'améliorer l'utilisation et l'efficacité catalytique des complexes de fer mimant cette activité.D'abord, par fonctionnalisation du ligand, un des complexes les plus efficaces pour catalyser l'oxydation de substrats aromatiques par H2O2, a pu être greffé dans des mésopores de silice. Ce matériau est utilisé comme support de catalyseur, en raison de sa grande surface spécifique et de sa chimie de surface versatile. Par ailleurs, la méthode de synthèse permet de structurer la taille des cavités formées, à l'aide d'un surfactant utilisé comme modèle. Le contrôle du nombre de sites catalytiques sur la surface est rendu possible par la procédure qui exploite le concept du pochoir moléculaire. Le confinement du catalyseur dans les pores pourrait être mis à profit pour former des produits à haute valeur ajoutée. En parallèle, ce complexe a aussi été greffé sur des billes de silices, un matériau moins élaboré pouvant être utilisé pour la dégradation de polluants. L'élaboration de ce type de catalyseurs supportés a nécessité de nombreuses caractérisations : analyses élémentaires, spectroscopies RMN, IR, XPS, UV-vis, RPE, isotherme d'adsorption d'azote, ATG, DRX sur poudre. Différentes méthodes de greffage ont été ainsi développées, et leur efficacité a été comparée. L'activité en catalyse d'oxydation de ces différents systèmes a aussi été évaluée.Concernant le développement des catalyseurs homogènes, le renforcement des positions des pyridines du ligand a permis l'obtention de nouveaux complexes de fer, possédant une meilleure stabilité pour réaliser des réactions catalytiques en milieu homogène et des propriétés structurales, spectroscopiques, chimiques et catalytiques analogues aux complexes de la même famille.Enfin, un autre complexe de fer a été mis en jeu dans un procédé électrochimique utilisant le dioxygène en présence de protons pour catalyser l'hydroxylation de substrats aromatiques.
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Kariuki, Peter, A. Yasothai, G. C. Jayakumar, and S. V. Kanth. "A Pragmatic Approach Towards the Manufacture of Wet-White Leathers Using a Bio-Polymeric Tanning System - 240." Verein für Gerberei-Chemie und -Technik e. V, 2019. https://slub.qucosa.de/id/qucosa%3A34262.
Full textAbstract:
Content:
Different tanning materials endow leather with varying colors observable in undyed leathers. Periodateoxidized starch tanned leathers have a yellow tinge or light brown color and get darker with age. The color change in situ is ascribable to iodate ions that are byproducts of periodate oxidation. Iodate ions undergo reduction to form iodine molecules that are yellow or brown in low or at higher concentrations. This study focuses on the removal of iodate ions from Dialdehyde Tapioca Starch (DTS) using a simple precipitation method. Preparation of DTS is by periodate oxidation and precipitation of iodate ions using an inorganic precipitant. The experiments for manufacturing wet-white leathers used pickled goatskins and DTS (unmodified and modified) tanning agents at various percentages based on pelt weight. Glutaraldehyde (GTA) tanning was the control. The percentage removal of iodate ions in modified DTS was 98%. Both unmodified and modified DTS had an aldehyde content of 70%. FT-IR and 1H-NMR confirmed the aldehyde groups. GTA, unmodified, and modified DTS tanned leathers had shrinkage temperatures of 80, 87, and 89°C, respectively. The physico-mechanical properties of the control and experimental leathers are comparable. GTA tanned leather had the typical brown color associated with GTA tannages. The ‘b’ color value of unmodified DTS tanned leather was high confirming yellowing of leathers upon ageing. Wet-white leather tanned with modified DTS had no discernible color change. Analysis of the spent tan liquor shows a reduction in the BOD, COD, TS, and TDS load when compared to GTA tanning system evincing the biodegradability of DTS. This study has overcome the drawback associated with periodate-oxidized starch tanning agents, viz. leather darkening over time, considering the chemical and physico-mechanical properties of the resultant leathers. The novel iodate free DTS can be scaled-up for commercial availability.
Take-Away:
Removal of iodate ions from periodate-oxidized starch before its use as a tanning agent is imperative to avoid leather color change over time.
This study reports the successful removal of iodate ions from Dialdehyde Tapioca Starch (DTS).
Wet-white leather tanned with the modified DTS had no observable color change upon ageing.
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Mogashoa, M. E. "Seasonal variation in haematological parameters and oxidative stress bio-markers for selected fish species collected from the Flag Boshielo Dam, Olifants River System, Limpopo Province, South Africa." Thesis, University of Limpopo, 2015. http://hdl.handle.net/10386/1188.
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Thesis (M.Sc. (Physiology)) --University of Limpopo, 2015Water is an essential and yet scarce resource, which has a vital role for human use and also serve as a habitat for numerous organisms in aquatic environments. Despite its scarcity there have been many reports indicating that it is continually polluted by domestic, agricultural, mining and other anthropogenic activities; subsequently affecting the health of organisms residing in such water bodies. Fish have been selected as the bio-monitoring species due to its direct interaction with the environment; thereby making it an appropriate model to monitor and evaluate the health status of the environment. The feral population of the alien species, Hypopthalmichtys molitrix (Valenciennes, 1844) commonly known as the silver carp in Flag Boshielo Dam has been considered a healthy population. However, this perception changed considerably after reports of lethargic, dying fish were first noted in 2011. Currently the sporadic deaths amongst mature specimens (>0.7m) persist; and the reason(s) for their demise remains unclear. Therefore, the aim was to employ a seasonal study design to investigate the health status of selected fish species such as H. molitrix in Flag Boshielo Dam by evaluating haematological parameters, oxidative stress biomarkers and bio-accumulation levels of particular transition metals. Seasonal surveys were carried out from February 2012 to January 2013 at Flag Boshielo Dam, Olifants River System, Limpopo Province. The locality surrounding the dam is known to be in an agriculture and mining catchment. Hypopthalmichtys molitrix and Labeo rosae (Steindachner, 1894) commonly known as the rednose labeo were collected with the use of scoop nets, conventional angling gear and gill nets. Following collection, morphometric measurements were taken and blood was collected. The blood samples required for further analysis at the Medical Science Department, University of Limpopo were kept on ice (4˚C). After the collection of all blood samples the specific fish was sacrificed and muscle samples were collected for bio-accumulation analysis and gills and liver samples were collected for the measurement of oxidative stress biomarkers. These tissue samples were rapidly frozen and kept frozen (-85˚C) until further analysis. Haematological parameters from the study reflected a variation amongst comparison of the inter- and intra-species. It was observed that mature H. molitrix suffered from anaemia. The response of glutathione-S-transferase (GST) and thiobarbituric acid reactive substances (TBARS) was relatively constant throughout all seasons when the young (<0.5m) and mature H. molitrix (0.6 – 0.90m) specimens were compared. However, the catalase (CAT) response of mature H. molitrix was dramatically impaired. This would increase their vulnerability to oxidative stress. Bioaccumulation levels of the eleven selected transition elements exhibited various trends. Metals such as Molybdenum (Mo), Vanadium (V), (Chromium) Cr, Cobalt (Co), Zinc (Zn), Cadmium (Cd) and Mercury (Hg) exhibited seasonal bio-accumulation levels that were in support of the various feeding behaviours of the fish species in this study. On the other hand, metals such as Manganese (Mn), Iron (Fe), Copper (Cu), Zinc (Zn), Cadmium (Cd) and Mercury (Hg) also illustrated the potential to be contributing factors in the death of the mature specimens. In conclusion, the findings from this study illustrate the complex nature of metabolic disturbances resulting in the death of mature H. molitrix specimens. It is clear that no single aspect investigated in this study could be solely implicated as the major cause of death. This multifactorial presentation necessitates further haematological assessment focussing on blood cell morphology and pathology, as well as investigations into other oxidative stress biomarkers in liver and gill tissue. In addition, identifying the most appropriate tissue type for future bio-accumulation measurements of transition metals in this feral population is necessitated. It is further suggested that neuro-muscular assessments, focussing on neurotransmitters such as γ-aminobutyric acid (GABA) and acetylcholine (Ach), form part of the investigation into the lethargic behaviour of the mature fish.
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Ramirez, Lancheros Helena. "Etude expérimentale et modélisation cinétique de l'oxydation, l'auto-inflammation et la combustion de carburants Diesel et bio-Diesel." Phd thesis, Université d'Orléans, 2012. http://tel.archives-ouvertes.fr/tel-00717701.
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L'oxydation d'un gazole commercial et d'un gazole modèle (70% n-décane/30% 1-méthylnaphtalène en mol), ainsi que l'oxydation d'un carburant B30 " réel " (30% EMHV en vol.) et d'un B30 modèle (49% de n-décane, 21% de 1-méthylnaphtalène et 30% d'octanoate de méthyle en mole), a été étudiée dans un réacteur auto-agité par jets gazeux, un tube à choc et une bombe sphérique. Les études ont été effectuées dans un réacteur auto-agité en silice fondue, dans les mêmes conditions expérimentales initiales (560-1030 K, à 6 et 10 bar, à des richesses allant de 0,25 à 1,5). Les résultats de cette série d'expériences sont constitués de profils de concentration des espèces intermédiaires stables et des produits de combustion mesurés en fonction de la température, après prélèvement à basse pression par une sonde sonique, par infrarouge et par chromatographie en phase gazeuse. Les résultats obtenus avec les " carburants réels " ainsi qu'avec les carburants modèles (gazole et B30) ont été comparés, montrant que les carburants modèles sont d'excellents substituts simplifiés pour les " carburants réels " gazole et B30. Nous avons mesuré des délais d'auto-inflammation du carburant modèle B30 dans un tube à choc à haute pression dans une large gamme de conditions expérimentales (20 et 40 bar, intervalle de richesse de 0.5 à 1.5, et températures allant de 700 à 1200 K). Les vitesses fondamentales de flammes de 1-méthylnaphtalène, de l'octanoate de méthyle, et des carburants modèles gazole et B30 ont été mesurées dans une bombe sphérique, sous différentes conditions expérimentales (une pression initiale de 1 et 4 bar, une température initiale de 423K et une large gamme de richesses). Un mécanisme détaillé a été développé, validé, puis été réduit. Il prédit raisonnablement les données expérimentales obtenues en bombe sphérique dans cette étude.
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Gentil, Solène. "Enzymes et catalyseurs bio-inspirés immobilisés sur électrodes nanostructurées pour l'élaboration de piles H2/air sans métaux nobles." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAV058/document.
Full textAbstract:
Le développement de technologies de l’énergie alternatives à la combustion des ressources fossiles est un enjeu majeur pour réduire l’émission des gaz à effet de serre et développer une économie durable. Dans cette optique, les piles à combustible à membrane échangeuses de protons (PEMFC) utilisent le platine en tant que catalyseur pour transformer l’énergie chimique en énergie électrique, en réduisant l’oxygène de l’air en eau et en oxydant l’hydrogène en protons. Dans la nature, les enzymes à cuivre et les hydrogénases catalysent respectivement ces réactions. Ces dernières, ainsi que des complexes bio-inspirés de leur site actif, ont été envisagés en tant qu’alternatives au platine, métal noble et coûteux. Ainsi, un complexe mononucléaire bisdiphosphine de nickel renfermant des acides aminés arginines en troisième sphère de coordination a été immobilisé sur une matrice de nanotubes de carbone (NTCs). Cette anode a démontré d’excellentes performances pour oxyder l’hydrogène avec des densités de courant élevées et sur une large gamme de pH. Son utilisation dans une PEMFC a permis d’obtenir une densité de puissance de 15 mW.cm-2, seulement cinq fois inférieure à celle d’une pile classique à base de platine préparée dans les mêmes conditions. Concernant la catalyse de réduction de l’oxygène, des méthodes covalentes ont été développéespour réaliser la connexion électronique directe de laccase de Trametes sp C30, ainsi qu’un mutant de cetten enzymesur matrice de NTCs L’’association du catalyseur de nickel avec une cathode à base de bilirubine oxydase immobilisée sur NTCs a permis de proposer un nouveau concept de pile hybride enzymatique/bio-inspirée. Une densité de puissance de l’ordre de 1,8 mW.cm-2 et une force électromotrice proche de 1V ont ainsi été mesurées pour cette pile sans métaux nobles. Le greffage de complexes de cuivre mono- et dinucléaires, bio-inspirés du site actif d’enzymes à cuivre et actifs vis-à-vis de la réduction de l’oxygène a enfin permis d’élaborer la première pile H2/air ne renfermant que des catalyseurs moléculaires et sans métaux nobles. Cette dernière délivre une densité de puissance de 160 µW.cm-2New energy technologies alternative to fossil fuels utilization is a key issue to mitigate greenhouse gases emission and develop a sustainable economy. In this context, platinum-based proton exchange membrane fuel cells use oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) to convert chemical energy into electrical energy. In nature multicopper oxidases and hydrogenases catalyze these two reactions, respectively. These enzymes and corresponding bioinspired catalysts have been used as alternatives to the rare and expensive platinum metal. First, a mononuclear bis-diphosphine nickel complex surrounded by arginine residues was immobilized onto carbon nanotubes (CNTs) and demonstrated excellent performances for HOR developing high current densities over a wide range of pH. This anode was integrated in a PEMFC, which achieved high power densities (15 mW cm-2), only five times lower as compared to classical PEMFC prepared under similar conditions. Regarding ORR catalysis, we covalently grafted LLaccases from Trametes sp C30 multicopper oxidases onto NTCs electrodes and achieved direct electron transfer. Using, bilirubin oxidase deposited on CNTs at the cathode side, we proposed a new concept of hybrid enzymatic/bio-inspired H2/air fuel cell. This hydrogen fuel cell delivered 1.8 mW.cm-2 and a high open circuit voltage of 1V. Finally, various copper complexes inspired from the active sites of copper enzymes were assessed for ORR and the first H2/air fuel cell containing noble metal-free molecular catalysts at both electrodes is reported, achieving 160 µW.cm-2 power density
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Soufi, Jihène. "Traitement des gaz d’échappement des groupes électrogènes alimentés par des gasoils, fuels marines ou bio-huiles : élimination des HAP en présence ou non de SOx." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1120.
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Nguyen, Khac Minh Huy. "Activation de liaisons C-H au moyen d’un système catalytique bio-inspiré pour la synthèse d’hétérocycles d’intérêt pharmacologique." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCB023.
Full textAbstract:
Les métalloenzymes d’origine naturelle constituent une riche source d’inspiration pour la conception de catalyseurs synthétiques en raison de leur capacité à réaliser des réactions d’oxydation sélective dans des conditions douces. Parmi ces métalloenzymes, les amine-oxydases à cuivre (CuAOs) permettent l’oxydation sélective des amines primaires grâce à la coopération d’un catalyseur organique quinonique (topaquinone) et d’un ion cuivrique. Récemment, un regain d’intérêt s’est manifesté pour le développement de catalyseurs biomimétiques permettant l’oxydation des amines en imines à l’air ambiant, en raison de l’importance des imines comme intermédiaires de synthèse en chimie fine et en pharmacologie. Au laboratoire, un système co-catalytique mimant l’activité des CuAOs a été décrit pour l’oxydation, à l’air ambiant, des amines primaires en imines, permettant une forte économie d’atomes. Le procédé catalytique comprend deux couples redox comparables à ceux des CuAOs : le catalyseur organique o-iminoquinonique 1ox, généré in situ à partir de l’o-aminophénol correspondant 1red, est le véritable catalyseur de l’oxydation de l’amine substrat, tandis que le sel de cuivre (II) sert de médiateur redox. Il est intéressant de noter que de faibles quantités de sel de cuivre (II) biocompatible et de catalyseur organique 1ox suffisent à activer la liaison C-H située en α de la fonction NH2 des amines primaires aliphatiques, qui sont converties, à l’air ambiant, en imines issues du couplage hétérolytique, à l’issue d’un processus de transamination qui conduit à l’imine résultant du couplage homolytique, suivi d’une réaction de transimination. Les conditions douces utilisées sont particulièrement intéressantes d’un point de vue synthétique, notamment pour engager les alkylimines instables in situ dans des réactions subséquentes. Aussi, avons-nous envisagé d’utiliser ce système co-catalytique bioinspiré dans la synthèse one-pot d’hétérocycles d’intérêt pharmacologique. Dans la première partie de la thèse, nous avions l’intention d’utiliser le système co-catalytique Cu(II)/1ox dans la synthèse de nouveaux dérivés de la 1,4-benzoxazine. Dans le cas particulier des amines primaires de type R1R2CHCH2NH2, le processus catalytique se trouvait bloqué après un certain nombre de cycles catalytiques en raison de l’engagement du catalyseur 1ox dans une réaction de Diels-Alder à demande électronique inverse avec la forme énamine tautomère de l’imine éliminée au cours du processus catalytique, conduisant ainsi aux dérivés de la 1,4-benzoxazine. Toutefois, l’utilisation de ce procédé s’avéra un échec, les énamines générées étant trop instables à l’air ambiant pour permettre l’isolement des dérivés de la 1,4-benzoxazine avec des rendements acceptables. Nous avons ainsi été amenés à développer une réaction alternative en tandem : les dérivés o-aminophénols sont oxydés dans le méthanol sous atmosphère d’azote, à l’aide d’une quantité stoechiométrique de dioxyde de manganèse activé, en o-iminoquinones. Ces hétérodiènes sont ensuite piégés in situ par différentes énamines diénophiles pour conduire aux dérivés de la 1,4-benzoxazine attendus, dans des conditions douces. La possibilité d’introduire des éléments de diversité dans chacun des partenaires de la cycloaddition permet de préparer des dérivés de la 1,4-benzoxazine hautement substitués. Parmi ces composés, un dérivé présentant deux groupements phényle en position 3 s’est avéré présenter une activité neuroprotectrice notable chez la souris nouveau-né, faisant de lui un candidat potentiel pour le traitement et la prévention de la paralysie cérébrale du nouveau-né. Dans la seconde partie de la thèse, le système co-catalytique Cu(II)/1ox est utilisé dans une réaction de couplage oxydatif d’amines primaires, activées ou non, avec des o-aminoanilines conduisant ainsi à des dérivés du benzimidazole d’intérêt biologique au travers d’un procédé multi-étapes. (...)Naturally occurring metalloenzymes constitute a rich source of inspiration for the design of synthetic catalysts because of their ability to perform controlled aerobic oxidations under very mild conditions. Among metalloenzymes, copper amine oxidases (CuAOs) promote selective aerobic oxidation of primary amines through the cooperation of a quinone-based cofactor (topaquinone) and a copper ion. Recently, there has been a boost in the development of biomimetic catalysts for the aerobic oxidation of amines to imines owing to the importance of imines as pivotal intermediates in the synthesis of fine chemicals and pharmaceuticals. In our laboratory, a CuAOs-like homogeneous co-catalytic system has been described for the atom-economical oxidation of primary amines to imines, under ambient air. The catalytic process combines two redox couples in a way reminiscent of CuAOs: the o-iminoquinone organocatalyst 1ox, generated in situ from the corresponding o-aminophenol 1red, is the substrate-selective catalyst, whereas the copper (II) salt serves as an electron transfer mediator. Interestingly, low loadings of biocompatible CuII and organocatalyst 1ox are sufficient to activate the α-C-H bond of primary aliphatic amines, which are converted, under ambient air, into cross-coupled imines through a transamination process that leads to the homocoupled imine intermediate, followed by dynamic transimination. The mild reaction conditions are highly favorable from a synthetic viewpoint, in particular for trapping the unstable alkylimines in situ for further reactions. So, we have envisioned the use of this bioinspired co-catalytic system in the one-pot synthesis of heterocycles of pharmacological interest. In the first part of the thesis, we envisioned that the Cu(II)/1ox cooperative system might be utilized to synthesize novel 1,4-benzoxazine derivatives. In the specific case of R1R2CHCH2NH2 amines, the catalytic process should stop after a few turnovers, because the catalyst 1ox should be trapped through inverse-electron-demand Diels-Alder (IEDDA) reaction with the simultaneously in situ generated tautomeric enamine form of the alkylimine extruded during the catalytic process, leading to 1,4-benzoxazine derivatives. Unfortunately, this protocol failed to produce the expected cycloadducts in acceptable yields as enamines rapidly decomposed under ambient air. For this reason, we have developed a tandem oxidation-inverse electron demand Diels-Alder reaction as an alternative: a stoichiometric amount of activated MnO2, in deaerated methanol, was then sufficient to convert various o-aminophenol derivatives into o-iminoquinone heterodienes which were trapped in situ by different enamine dienophiles leading to the expected 1,4-benzoxazine derivatives under mild conditions. The possibility of introducing variations in both cycloaddition partners led to highly substituted 1,4-benzoxazine cycloadducts with up to five elements of diversity. Among these compounds, a 3,3-diphenyl-substituted-1,4-benzoxazine derivative was identified as an effective neuroprotective agent in newborn mice, suggesting that it could be a potential candidate for the treatment and prevention of cerebral palsy. In the second part of the thesis, the Cu(II)/1ox cooperative system has been successfully used for the catalytic oxidative coupling of a diverse range of activated and non-activated primary amines with o-amino-anilines under ambient air leading to benzimidazoles of biological interest through multistep oxidation and nucleophilic addition reactions. Through the variation of both solvent and coupling partners, MeOH proved to be the best solvent for this transformation because it provided the ideal balance of 1ox solvation and reaction rate, except when reactive N-alkyl o-aminoanilines were used as in situ imine traps, due to the concomitant formation of a benzimidazole byproduct originated from MeOH itself. (...)
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Hatat, Fraile Mélisa Marie. "Etude des méthodes d'élaboration et de la mise en oeuvre de photocatalyseurs pour le traitement de la micro pollution bio-réfractaire dans l'eau." Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20043/document.
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Ce travail de thèse est consacré à l'élaboration de membrane photocatalytique à partir de nanoparticules de TiO2 obtenues par voie sol-gel (système TTIP-eau). Les sols sont préparés dans un réacteur à micro-mélange rapide (turbulent). L'effet de l'hydrodynamique au sein de différents mélangeurs (T simple, T chicanes, T rétrécissement) sur la morphologie et l'activité photocatalytique de nanoparticules déposées sur des plaques d'α-alumine a été étudié. Les dépôts de TiO2 ont été réalisés durant la période d'induction de la réaction sol-gel. Le mélange des réactifs a été simulé en utilisant un logiciel de modélisation numérique (modèle k-ε), Les différences hydrodynamiques au sein du micro-mélange a seulement un impact significatif sur le temps de stabilité des nanoparticules (période d'induction). Des couches minces et des membranes photo-actives ont été réalisées en vue du couplage membrane et réaction photocatalytique. Ces membranes ont été caractérisées et testées en photocatalyse. Elles ont montrées de bonnes photo-activités. Des tests de couplage direct séparation/photodégradation ont été réalisés sur des solutions aqueuses d'acide orange 7. Ce dispositif expérimental a permis de mettre en évidence une augmentation de flux de perméation significative avec de l'eau et en présence de colorant en solution. L'effet de la concentration et du pH de la solution a été évalué sur les flux de perméat et sur la photodégradationThis PhD work is devoted to the elaboration of photocatalytic membranes using TiO2 nanoparticles synthetized by sol-gel process (titanium tetra-isopropoxyde precursor – water). Sols are prepared in sol-gel reactor with rapid turbulent micro-mixing. The effect of hydrodynamic using 3 T mixers (T simple, T with 3 baffles and T with narrow) during the mixing was studied with k-ε modeling Computational fluid Dynamics (CFD), as well as the morphology and the photo-activity of thin layers deposited on alumina support during induction period. Differences on hydrodynamic during micro-mixing have only impact on the time of nanoparticles stability (induction period). Photo-active thin layers and membranes are synthesized for coupling membrane separation and photocatalytic reaction. Photocatalytic activities of thin layers and membranes are performed with an aqueous solution of acid orange 7. Significant increases of permeate flux are observed during the filtration of water and solution containing dye. Effects of concentration and pH are evaluated on permeation flux and photodegradation
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Syed, Sajid Ahmed. "Oxidation studies of surrogate bio-diesel fuels in opposed flow diffusion flames." 2005. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=370380&T=F.
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Chao, Wen-Chuan, and 趙文全. "The Enhancement of the Sensitivity for SiGe Nanowire Bio-sensor by Oxidation." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/325pg2.
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碩士國立交通大學
電機學院微電子奈米科技產業專班
96
Si nanowires (SiNWs) have been studied for Bio-sensor in recent years. However, as far as sensitivity is concerned, SiGe nanowires are more promising than Si nanowires because of SiGe nanowires have higher change in drive current when the same chemical species bonding to surface of nanowire. In addition, we have reported the sensitivity increase with Ge concentration (7%~30%). But it is difficult to fabricate higher Ge concentration nanowire. Therefore, we utilize oxidation process to enhance Ge concentration in SiGe nanowire because Ge is rejected from the oxide during oxidation process. We found that the sensitivity of lower Ge concentration (7%~20%) nanowires were enhanced by oxidation process after the oxidation of 2min at 900°C. After the oxidation of 2min at 950°C, we observed that the sensitivity of Si0.93Ge0.07 nanowires were improved but the sensitivity of Si0.89Ge0.11 nanowires not increased. The reason maybe higher defect was formed during this oxidation process.
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Huyen, Khuat Thi Thanh, and 屈氏青玄. "Bio-augmentation of anaerobic ammonium oxidation activity supported on graphene oxide and titanium nanotubes." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/p9jkf4.
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碩士國立交通大學
環境工程系所
105
Nitrogen removal from wastewater is gaining worldwide attention because of the potential threat of nitrogen species to the environment. Anaerobic ammonium oxidation (Anammox) is a promising method which can convert ammonium ion directly to nitrogen gas. However, Anammox still faces the difficulty in the enhancement of slow growth rate of Anammox microorganisms. Herein, we have systematically investigated the effect of graphene oxide (GO) and titanium nanotube (TNTs) on the Anammox biomass for nitrogen removal. TNTs, the 1- dimensional negatively charged nanomaterials show little effect on the enhancement of Anammox growth, presumably attributed to the strong repulsive force between TNTs and Annamox bacteria. GO makes a remarkable impact on the bacterial growth. After the batch incubation of 5h, the Anammox activity in the presence of 0.1 g/L GO is enhanced 14.2 % when compares with that in the absence of nanomaterial. The continuous experiment also proves the applicability of using GO as an effective support to improve nitrogen removal. GO utilization can enhance Anammox activity by 30% compares with that of the normal reactor after 113d of incubation. In the GO induced reactor, the effluent concentrations of ammonium and nitrite decrease steadily and reach the steady state after 80d of incubation, while it takes 127 d in the reactor without GO to achieve the steady state. These results clearly demonstrate the feasibility of utilizing GO as the support for Anammox bacteria to shorten the start-up incubation time by rapid acclimation as well as to enhance the activity of Anammox bacteria.
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Huang, Wei-Chih, and 黃偉智. "Hydrogen-rich syngas production from bio-butanol by partial oxidation and oxidative steam reforming." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/04427276116786614238.
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碩士崑山科技大學
機械工程研究所
103
This study used the bio-butanol as the main fuel for reforming to produce hydrogen-rich synthesis gas. Two different reforming methods were adopted, including Partial Oxidation Reforming (POX) and Oxidation Steam Reforming (OSR). The theoretical equilibrium calculations were performed and compared with the experimantal results. Research is divided into two major parts, first one was to discuss the partial oxidation of butanol for hydrogen production and to identify the operation range of reforming; the second part is to investigate the synthesis of butanol oxidative steam reforming, and the parameters including hydrogen yield, conversion efficiency, reforming efficiency, and space velocity were investigated and analyzed. The results show that, firstly, the coke formation is almost close to zero by partial oxidation method under O2/C4H9OH molar ratio of 1.5, and the reaction temperature is above 700oC. Under different parameters in experiments, the maximum reforming range fell at the input fuel heating value of 1.5kW; and the best hydrogen concentration and yield of hydrogen was 30.6%, 81.98%, respectively; and the conversion efficiency of fuel and reforming efficiency was 94.57% and 76.85%, respectively. Then, from the theretical calculation on the oxidative steam reforming, the carbon deposition was depressed by the conditions of reaction temperature 600oC, O2/C4H9OH = 1.5 and S/C molar ratio over 3. With the parameters O2/C4H9OH = 1.5 and 2.0, S/C = 3 ~ 7, all experiments can reach the reaction temperature and have the widest reforming range. Under the operating conditions, hydrogen yield was 75.88%, the best conversion efficiency is 70.41% and reforming efficiency is 60.75%.
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Chien-YunLin and 林謙妘. "Sunlight-responsive Bio-based Alginate Aerogel: Reduction of Hexavalent Chromium and Hydroxyl Radical Induced Oxidation." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/y8h4h6.
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Yang, Hung-wen, and 楊宏文. "Research on the pollutants of catalytic oxidation for gasoline and emission reduction of bio-diesel fuel." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/22360473767816647393.
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博士國立中山大學
環境工程研究所
98
How effective would the implementation of biodiesel fuel in reducing emissions caused by automobiles and motorcycles in the densely populated regions? The goal of this research is targeted at determining the most proficient methods in depleting the harmful substances emitted from refueling stations and the efficiency of biodiesel fuel in emissions reduction. The initial stages in the research involved the use of aluminum oxide and molecular sieve, which would act as active metals for copper and manganese. Impregnation and solgel method of catalytic production were utilized with 12 sets of oxidized copper, and molecular sieve catalysts, totaling at 24 sets. With results from the primary testing, initial selection of impregnation production methods based on its conversion rate had a carrying capacity of 20% CuMn/ oxidized copper catalyst (Cu: Mn ratio at 1:1), and a 20% CuMn/molecular sieve catalyst (Cu: Mn ratio of 1:1) with the solgel method. The two exogenous tests were not only found to be the most efficient rate of conversion as base standards, but were also found to be the most competent method to date. Approximate calculations from the two catalytic testing showed that CuMn/oxidized copper catalyst conversion are less affected by variation in concentration density. Furthermore, the CuMn/oxidized copper and CuMn/molecular sieve catalysts faced a positive conversion rate when reacted with a decreased space velocity, but leveled off once it reached a specific level. Moreover, the two catalysts also faced an increased conversion rate when conducted with an increase in oxygen concentration, and reached maximized efficiency at 30% concentration. Secondary stage of the research focuses on operational efficiency of the biodiesel fuel, with emphasis on its pollutant emissions and economical standpoint. The initial testing concluded that not only did the fuel has a lower cost in reducing greenhouse gas emission than alternative energy sources, but it can also reduce SOx emissions by 7,200kg, 23 metric tons of PM10, and 262,400 metric tons of CO2 annually when applied with B2 fuel. Pollution reduction assessment indicated that if all diesel powered automobiles utilized the B10 biodiesel fuel, then it’s estimated that it would have an annual THC reduction rate of 2.83x102 metric tons, 1.98x103 tons in COs, 4.56x103 in NOx, and 5.66x101 metric tons in PM gases. Furthermore, if the B20 fuel cells were incorporated, then it’s estimated to have an annual reduction rate of 2.83x102 metric tons in THC, 2.83x103 metric tons of CO, 1.14x103 metric tons of NOx, and 1.16x102 metric tons of PM. Results from the beta stage testing indicated that if B10 fuel were incorporated into all diesel powered automobiles, with a budget of NT$1million would result in an annual reduction rate of 0.57 metric tons of THC, 9.12 metric tons of NOx, 0.11 metric tons of PM and a totaled 9.8 metric tons of reduction. Furthermore, if B20 were implemented, again with NT$1 million budget, we would expect to see annual reductions of 0.06 metric tons of THC, 0.25 metric tons of NOx, 2.51 tons of PM gases, totaling at 2.81 metric tons of reductions.