Dissertations / Theses on the topic 'Hydrogen recycling'

By 2002 the world market for polymer composites was 7.2 Million Tons. The automotive and industrial vehicle industry consumes 25% of the world's composite material output. Composite materials benefit the automotive industry in multiple ways. Regulatory pressure that encourages recyclablity and reduction of energy consumption pushes automotive manufacturers to consider new technologies to meet these environmental standards. The work being undertaken in this research is part of an ED integrated Project under the "Sixth Framework of Research and Development Funding". The project title is "Hydrogen Storage Systems for Automotive Application (StorHy)". Within this project, the Recycling Work Package (WP5) aims to develop recycling techniques for glass and carbon fibre reinforced polymer composite pressure vessels that were proposed for hydrogen storage. This thesis describes the development of a SIze reduction technique for the carbon/epoxy and glass/PP pressure vessels with respect to the particle size and investigates ways of preparing the granulated fractions for subsequent processing. An image analysis technique was successfully developed for the characterisation of the reground material from the carbon/epoxy pressure vessel. The same image analysis technique could not be used to analyse the reground material produced from the thermoplastic vessel. Alternatively, the reground material from the thermoplastic vessel were characterised through a sieve analysis technique. The reground material from the thermoset vessel produced in this work could be processed in a fluidized bed rig which is mentioned in a number of publications. In this work, the reground material from the thermoplastic vessel was successfully processed using an injection moulding machine, with mechanical properties as good as comparable to commercial composites. In this study micro mechanical models available in the short fibre composite literature such as Halpin-Tsai and the rule of mixtures were used to predict the stiffness of the injection moulded composites. The trend observed for the Halpin-Tsai model appeared not to be in a good agreement with the experimental data but the rule of mixtures model was found to predict the experimental data more accurately.

This thesis is based on the work carried out since January 2014 as a Ph.D. student in the Functional Materials department at Technische Universität Darmstadt. In the first part of my thesis, different waste streams of electrical and electronic equipment from an industrial recycling plant were analyzed in order to localize, identify and collect rare-earth permanent magnets of Nd-Fe-B type. This particular type of magnets were mainly found in hard disk drives from laptops and desktop computers, as well as in loudspeakers from compact products such as flat screen TVs, PC screens, and laptops. The study includes a systematic survey of the chemical composition of the Nd-Fe-B magnets found in the selected waste streams, which illustrates the evolution of the Nd-Fe-B alloys over the years. The study also provides an overview over the types of magnets that are integrated in different waste electric and electronic equipment. After localizing, identifying and recovering the rare-earth permanent magnets from waste electrical and electronic equipment, these magnets were processed together with other Nd-Fe-B scrap magnets from electric motors with a hydrogen based recycling process (hydrogen decrepitation (HD) and hydrogenation disproportionation desorption and recombination (HDDR) processes). The effects of the main HDDR processing parameters: hydrogen pressure, hydrogen desorption rate and temperatures on the magnetic properties of the recycled materials have been investigated systematically and are presented in the second section of the chapter 4. The optimum hydrogen pressures required for the complete disproportionation of the various magnet compositions were determined. It was found that a hydrogen heat treatment composed of two steps (780 °C and 840 °C) and a moderate desorption rate can be used for the magnets having a higher Dy and Co content to obtain high quality anisotropic HDDR powders. In addition to this section, it was performed a study where it was investigated the effects of increasing the Dy content on the processing parameters of the HDDR process. The variation of the magnetic properties for the magnets with different Dy contents processed at different hydrogen pressure, temperature and hydrogen desorption rate are presented in this study. The obtained recycled powders by HD and by HDDR were consolidated by either sintering, spark plasma sintering or bonding with epoxy resin. For the scrap magnets with a low content of Dy and Co, a better recovery of the magnetic properties (above 90%) was achieved compared with the magnets from electric motors (high Dy and Co) where the recovery rate is ~60%. For these magnets a “refreshing” of the recycled powders with 10% Nd90Al10 and Pr75Cu6.25Co18.75 was applied. Different post sintering treatments were applied for these recycled magnets in order to equally distribute the fresh added powder. All these treatments are presented in this study.

Detta examensarbete har utförts på Stena Aluminium (SA) i Älmhult. Undersökningen handlar om att mäta vätgashalten genom densitetsindexprover på smält aluminium, för att kartlägga hur vätgashalten påverkas av processtegen vid återvinning av aluminium i SAs produktions-anläggning. I arbetet ingick att undersöka vätgashalten för två olika legeringstyper (EN-AB 43400 och 46000), utvärdera avgasningseffektivitet för de utvalda legeringstyperna och att utvärdera den befintliga utgjutningssystemet. Mätningar för undersökningen är utförda i SAs smältverk, vid processtegen raffinering och utgjutning.

The work in this Thesis addresses the challenges associated with using redox enzymes for chemical synthesis. The use of enzymes as catalysts in the synthesis of fine chemicals is becoming more wide spread, in part due their ability to catalyse reactions with incredible selectivity under relatively mild conditions. In particular, enzymes are useful for selective reduction of ketones to enantiomerically pure alcohols or amines, and partial oxidations of alkanes to alcohols. However, a key limitation to exploiting redox enzymes in these reaction pathways is the requirement for a specialised electron source, usually the expensive nicotinamide cofactors NADH or NADPH. Existing cofactor regeneration methods use a second enzyme with a sacrificial substrate which is oxidised to generate a stoichiometric waste product; this complicates isolation of the desired product and prevents the environmental benefits of biocatalysis from being fully realised. In order to provide clean and efficient biocatalytic routes, improved recycling methods for these cofactors are crucial. This Thesis develops two novel methods for in situ cofactor recycling. The first is an electro-enzymatic system; an NAD⁺-reductase enzyme is shown to use electrons directly from an electrode for supply of NADH to a co-immobilised cofactor-dependent enzyme. The second uses a hydrogenase, NAD⁺ reductase and cofactor-dependent enzyme immobilised on conducting particles for H₂-driven NADH regeneration. This relies on the thermodynamically favourable reduction of NAD⁺ by H₂ when the hydrogenase and NAD⁺-reductase are in electronic contact, provided by the conducting particle. The electro-enzymatic approach to NAD⁺ reduction is then adapted for electrochemical devices; an enzyme catalysed fuel cell and a self-powered biosensor were considered.

Die eingereichte Dissertation mit dem Thema „Heterogen katalysierte Hydrodehalogenierung von Borhalogeniden im Rahmen eines in sich geschlossenen BNHx-Recyclingkonzepts“ beinhaltet drei für das BNHx-Recycling zentrale Reaktionsschritte: Supersäureaufschluss, Hydrodehalogenierung und den Basenaustausch. Mit Hilfe dieser drei Schritte ist es möglich, die Zersetzungsrückstände von BH3NH3(Polyaminoboran, Borazin und Polyborazylen) wieder in BH3NH3 zu überführen, ohne teure Reduktionsmittel wie LiAlH4 oder Hydrazin verwenden zu müssen. Das Verfahren ermöglichte in einem Durchlauf die Gewinnung von 60 % der eingesetzten Menge an BH3NH3 ohne eine Erzeugung von Abfallprodukten. Mit Hilfe der Chloralkalielelektrolyse kann das Verfahren an Wind- bzw. Solarkraftwerke gekoppelt und über diese alle benötigten Ausgangsstoffe hergestellt werden. Die katalytische Erzeugung von B-H-Spezies auf der Grundlage der Aktivierung von molekularem Wasserstoff ist als Schwerpunkt dieser Arbeit zu sehen. Die mechanistischen Studien lieferten ein genaueres Verständnis über fundamentale Zusammenhänge zwischen dem Lösungsmittel Et3N und der Wasserstoffbereitstellung über die N-CH2-Gruppierung sowie der Wirkungsweise des Katalysators.

Les résidus miniers représentent les sous-produits minéraux finement broyés issus des procédés de traitement et d’enrichissement des minerais. Durant l’exploitation d’une mine, ces rejets sont habituellement transportés sous formes de pulpes et entreposés en surface dans des aires d’accumulation appelées parcs à résidus. Ces derniers sont des ouvrages, le plus souvent, difficiles à gérer et coûteux à restaurer. Ils sont à l’origine d’une multitude d’impacts environnementaux qui dépendent principalement de leur potentiel polluant, de leur mode de gestion, de la stabilité physique des infrastructures de confinement et des conditions climatiques spécifiques au site d’entreposage. Dans ce contexte, plusieurs études ont été entreprises afin de développer de nouvelles techniques qui permettraient une gestion effective et durable de ces sous-produits minéraux. Des voies de valorisation dans le domaine du BTP ont ainsi été explorées. Les résultats ont montré la possibilité de réutilisation de certains rejets miniers comme matériaux cimentaires et additifs pour mortiers ou béton. Toutefois, la majorité des formulations proposées n’ont pas dépassé le stade du laboratoire. De plus, l’utilisation des rejets miniers comme matériaux de construction est encore sujet à des difficultés en matière d’acceptabilité sociale et à d’innombrables préoccupations, notamment leur stabilité physico-chimique et leur éco-compatibilité. En parallèle, l’utilisation artisanale et non contrôlée des rejets miniers à faibles teneurs en sulfures comme matériaux de construction est en pleine croissance dans quelques pays tel que le Maroc. En effet, à proximité de quelques sites miniers abandonnés, ces rejets sont considérés comme des sables naturels et sont utilisés pour la confection de mortier de finition et de surfaçage des murs d’habitations. Ce recyclage artisanal peut constituer des risques mécaniques et environnementaux liés surtout à la non-conformité mécanique de ces matériaux et à la présence de concentrations non négligeables de métaux résiduels dans les rejets miniers. L’objectif de ce travail de recherche est donc d’évaluer l’impact de l’utilisation actuelle de deux rejets miniers marocains (Zeida et Mibladen), communément utilisés comme agrégats dans la région de la haute-Moulouya, sur les propriétés physico-chimiques des mortiers de finition et d’étudier, sur le long terme, le relargage des métaux lourds en scénario de lixiviation. Ce travail se donne aussi comme objectif spécifique, d’étudier la faisabilité technique d’utilisation des rejets miniers à faible teneur en sulfures comme substituant au sable conventionnel pour la confection de mortiers d’enduit et de maçonnerie<br>Mine tailings represent the finely ground industrial by products generated throw beneficiation of ore minerals. During mine exploitation, these tailings are generally transported in slurry form to large storage facilities, called tailings ponds or impoundments. These facilities are, in most cases, difficult to manage and expensive to rehabilitate. They are responsible for the generation of important environmental impacts and significant ecological disruptions, depending on their pollution potential, management technique, physical stability and the climate conditions. In this context, numerous studies have been conducted to develop new techniques for a sustainable management of mine tailings. The feasibility of reusing some tailings in the construction sector as cementing materials and additives for mortars or concretes were successfully achieved. However, the majority of the conducted studies are still at laboratory stages. Moreover the reuse of tailings as construction material is yet subject of numerous difficulties in term of social acceptance. Various parameters are also of concern, especially the physical and chemical stability of tailings as well as their eco-compatibility. In parallel, the uncontrolled reuse of low sulfide tailings as construction material is increasing in some developing countries (e.g. Morocco). In fact, nearby some abandoned mine sites, these tailings are considered as natural sands and are used for the manufacture of surface finishing mortars. This traditional recycling may constitute mechanical and environmental risks, principally related to tailings mechanical unconformity and to their non-negligible residual metal concentrations. Therefore, the aim of the current research is to evaluate the actual impact of two Moroccan mine tailings (named Zeida and Mibladen), commonly used as aggregates in the Upper-Moulouya region, on the mechanical properties of mortars and on their long term environmental behavior. This work has also as specific aim, to study the technical feasibility of using low sulfide tailings as sand substitute for the manufacture of rendering and masonry mortars. To attain this aim, a thorough characterization of the physical, chemical and mineralogical properties as well as the geochemical behavior of mine tailings was carried out. Mechanical properties of tailings-based mortars were then measured and compared to reference samples (sand-based mortars) using different tests such as setting time, entrained air volume and compressive strength. In parallel, mortars durability and hydration products were evaluated by mean of durability tests (wetting drying cycles, sulfate attack and acid rain simulation) and analytical methods (scanning electron microscopy, X-ray diffraction and thermo-gravimetric analysis). Finally, mortar samples were submitted to various leaching tests to evaluate the pollution potential of these matrices

Dans les réacteurs à fusion nucléaire, un échange constant de particules se développe entre le plasma et la paroi. Ce phénomène, appelé recyclage, présente un intérêt crucial pour ces réacteurs car, une fois le plasma établi, le recyclage représente la principale source de particules pour le plasma. Une connaissance complète du recyclage est donc essentielle pour assurer un contrôle fiable de la densité plasma ainsi qu'une performance optimale du réacteur. Cependant, les études in-situ du recyclage demeurent complexes. La modélisation numérique peut assister dans la compréhension de ce phénomène. Les codes de transport de plasma de bord présentent la description la plus avancée de l’interaction plasma-paroi. La description du recyclage reste néanmoins partielle : la réflexion atomique est déjà traitée tandis que la désorption moléculaire est fixée ad-hoc par l’utilisateur. Cette thèse de doctorat se concentre sur le développement d’une extension au code de transport SolEdge2D-EIRENE, dénommée D-WEE, dont l’objectif est de modéliser la dynamique de la désorption. Afin d’initialiser D-WEE, une séquence de décharges plasma est simulée pour modéliser l’opération d’un tokamak. La dynamique simulée pendant ces décharges est étudiée, révélant des comportements intéressants qui pourraient impacter l’opération du réacteur. Pour évaluer la pertinence de la simulation, une confrontation avec l'expérience est effectuée et révèle un accord qualitatif entre la chute de pression post-décharge simulée (avec une tendance en t^{-0.8}) et celle observée expérimentalement. Le taux de rétention simulé pendant la décharge est étudié et présente un accord qualitatif avec l'expérience<br>In all plasma devices, a constant exchange of particle develops between the plasma and the wall. This phenomenon, referred to as recycling, is of critical interest for those reactors as, once the plasma is established, particle recycling represents the main particle source for the plasma. A complete understanding of the recycling phenomenon is therefore essential to ensure a reliable plasma density control and optimum performance. However, the in-situ experimental study of recycling remains challenging. Modelling can assist in the understanding of this phenomenon.The edge-plasma transport codes present the most-advanced description of the plasma-wall interaction. However, the description of recycling remains partial: atomic reflection is already handled while molecular desorption is set ad-hoc by the code user. This PhD focuses on the development of an extension of the SolEdge2D-EIRENE transport code, named D-WEE, whose goal is to model the dynamics of desorption.To initialise D-WEE, a sequence of plasma discharges is simulated with D-WEE to model a tokamak operation. The simulated wall dynamics during those discharges is studied, reveling some interesting behaviours that could impact the reactor operation. To assess the relevance of the simulated wall dynamics, a confrontation to post-pulse experimental pressure measurement is performed which reveals a qualitative agreement between the temporal pressure drop obtained in the simulation (with a t^{-0.8} trend) and the one observed experimentally under ILW configuration. The retention rate during the discharge is also studied and reproduces qualitatively the experimental trends

La thèse porte sur la conception et la simulation d'un réservoir de stockage solide de l'hydrogène sous forme d'hydrure de magnésium (MgH2). La particularité du réservoir conçu réside dans sa capacité à stocker l'énergie d'absorption grâce à un matériau de changement de phase (MCP). Afin de pouvoir prouver la viabilité du système, une étude portant sur le comportement de l'hydrure de magnésium compacté lors du cyclage à été effectuée. Celle-ci montre qu'après 100 cycles, les cinétiques de réaction et les taux massiques de stockage d'hydrogène ne sont pas affectés. En revanche, un changement de morphologie important a été observé puisqu'une dilatation ainsi qu'une augmentation importante de la conductivité des matériaux composites ont été relevées. L'étude du MCP révéla l'importance de certains paramètres, en particulier la conductivité thermique et l'enthalpie de fusion. Le MCP sélectionné est un alliage métallique en composition eutectique. Celui ci est bon conducteur de chaleur, présente une enthalpie de fusion élevée et une stabilité de comportement thermique au cyclage. Le réservoir construit contient 10 kg d'hydrure de magnésium co-broyé + 5 % de Graphite Naturel Expansé. Il est capable de stocker 7000 NL d'hydrogène (625 g) en 3h. L'avantage principal du réservoir est son efficacité énergétique, puisque la chaleur stockée par le MCP à l'absorption est refournie lors de la désorption. Afin de pouvoir prédire les comportements thermiques et cinétiques des prochains réservoirs basés sur cette technologie, 2 modèles numériques utilisant Matlab et Fluent ont été développés et validés.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>Levando em consideração medidas para diminuir os efeitos das mudanças climáticas e tecnologias que auxiliam na segurança energética, esta dissertação tem como tema central o estudo da geração de gás hidrogênio como energia alternativa. O gás hidrogênio é um vetor energético com reduzidas emissões de poluentes na atmosfera se comparados com as fontes tradicionais existentes de energia. No entanto, estudos e pesquisas sobre suas potencialidades e viabilidades, tanto técnicas quanto socioeconômicas e ambientais, precisam ser desenvolvidas para amadurecimento tecnológico. O objetivo desta dissertação é analisar a produção de hidrogênio por hidrólise alcalina, com a reutilização de alumínio, correlacionando-a aos aspectos da sustentabilidade. Parte-se de um processo já conhecido e bem difundido no meio científico o qual será analisado e discutido suas possibilidades como tecnologia alternativa para produção de energia. O método empregado para a análise foi bibliográfico junto com o levantamento de dados primários em laboratório de um processo com requerimento de patente, dando caráter de pesquisa exploratória e descritiva. Os principais resultados técnicos foram: vazão média 77,53 ml.(min.g) -1 de H2, com pureza de 84,20%. Em seguida, realizou-se uma análise econômica, em moeda nacional, real R$/(m³.H2) e dólar norte-americano US$/kWh, comparando com outros estudos que determinaram o custo de produção em processos de geração deste tipo do gás. Estruturou-se uma matriz de aspectos e impactos que ilustram os potenciais efeitos na geração de energia. Concluiu-se que à geração de gás hidrogênio por hidrólise alcalina com a reutilização de alumínio secundário contribui para a visão direcionada para a sustentabilidade do planeta, podendo ser uma alternativa energética descentralizada.<br>Taking into account measures to reduce the effects of climate change and technologies that help energy security, this dissertation focuses on the study of generation of hydrogen gas as alternative energy. Hydrogen gas is an energy vector with reduced emissions of pollutants into the atmosphere compared to existing traditional sources of energy. However, studies and research on their potentialities and viabilities, both technical and socioeconomic and environmental, need to be developed for technological maturation. The objective of this dissertation is to analyze the production of hydrogen by alkaline hydrolysis, with the reuse of aluminum, correlating it to the aspects of sustainability. It starts from a process already known and well diffused in the scientific environment which will be analyzed and discussed its possibilities as alternative technology for energy production. The method used for the analysis was bibliographic along with the collection of primary data in the laboratory of a process with patent application, giving character of exploratory and descriptive research. The main technical results were: average flow 77.53 ml (min.g) -1 .H2, with a purity of 84.20%. Then, an economic analysis was performed in national currency, real R $ / (m³.H2) and US$ / kWh, comparing with other studies that determined the cost of production in this type of generation processes. gas. A matrix of aspects and impacts was drawn up illustrating the potential effects on energy generation. It was concluded that the generation of hydrogen gas by alkaline hydrolysis with the reuse of secondary aluminum contributes to the vision aimed at the sustainability of the planet, and can be a decentralized energy alternative.

In dieser Arbeit wurde die Möglichkeit untersucht, Bortrihalogenide mit Wasserstoff unter milden Bedingungen (T < 100 °C, p(H2) < 50 bar) zu hydrieren. Um eine Triebkraft für die thermodynamisch ungünstige Reaktion zu erhalten, wurden Amine als Hilfsbasen zugesetzt, welche den bei der Reaktion entstehenden Halogenwasserstoff als Ammoniumsalz binden und damit das Reaktionsgleichgewicht in Richtung der Produkte verschieben. Es wurden dafür verschiedene Amin-Boran bzw. Amin-HCl Addukte synthetisiert und mittels IR, NMR und DSC charakterisiert. Bei den anschließenden Hydrierungsversuchen wurden verschiedene Katalysatoren auf ihre Eignung getestet und weiterentwickelt. Unterstützt wurden die experimentellen Arbeiten durch Berechnungen mit Gaussian 03. IR- und NMR-Spektren vieler Addukte wurden berechnet und freie Reaktionsenthalpien der Hydrierung in Abhängigkeit des verwendeten Amins und Borhalogenids bestimmt. Mögliche Übergangszustände wurden diskutiert und ihre Aktivierungsenergien ermittelt.

Yes<br>Antibacterial hydrogels have been intensively studied due to their wide practical potential in wound healing. However, developing an antibacterial hydrogel that is able to integrate with exceptional mechanical properties, cell affinity, and adhesiveness will remain a major challenge. Herein, a novel hydrogel with antibacterial and superior biocompatibility properties was developed using aluminum ions (Al3+) and alginate− dopamine (Alg-DA) chains to cross-link with the copolymer chains of acrylamide and acrylic acid (PAM) via triple dynamic noncovalent interactions, including coordination, electrostatic interaction, and hydrogen bonding. The cationized nanofibrillated cellulose (CATNFC), which was synthesized by the grafting of long-chain quaternary ammonium salts onto nanofibrillated cellulose (NFC), was utilized innovatively in the preparation of antibacterial hydrogels. Meanwhile, alginate-modified dopamine (Alg-DA) was prepared from dopamine (DA) and alginate. Within the hydrogel, the catechol groups of Alg-DA provided a decent fibroblast cell adhesion to the hydrogel. Additionally, the multitype cross-linking structure within the hydrogel rendered the outstanding mechanical properties, self-healing ability, and recycling in pollution-free ways. The antibacterial test in vitro, cell affinity, and wound healing proved that the as-prepared hydrogel was a potential material with all-around performances in both preventing bacterial infection and promoting tissue regeneration during wound healing processes.<br>This work was supported by the National Natural Science Foundation of China (32070826 and 51861165203), the Chinese Postdoctoral Science Foundation (2019M650239, 2020T130762), the Sichuan Science and Technology Program (2019YJ0125), the State Key Laboratory of Polymer Materials Engineering (sklpme2019-2-19), the Chongqing Research Program of Basic Research and Frontier Technology (cstc2018jcyjAX0807), Chongqing Medical Joint Research Project of Chongqing Science and Technology Committee & Health Agency (2020GDRC017), and the RCUK China-UK Science Bridges Program through the Medical Research Council, and the Fundamental Research Funds for the Central Universities.<br>The full-text of this article will be released for public view at the end of the publisher embargo on 12 Feb 2022..

Afin de développer une chimie plus respectueuse de l'environnement, l'accès à de nouveaux procédés est nécessaire. Plus spécifiquement, dans le domaine de l'oxydation, l'utilisation d'oxydants toxiques doit être bannie, l'utilisation de solvants limitée et l'utilisation de catalyseurs recyclables développée. Dans ce contexte, deux approches " vertes " ont été explorées. La première d'entre elle consiste à éliminer ou remplacer l'acide acétique, additif qui, en présence de H2O2 et de complexes de Mn ou de Fe, favorise la formation exclusive d'époxydes lors d'oxydation d'alcènes. Pour cela, deux stratégies ont été testées. La première consiste à introduire dans la seconde sphère de coordination de complexes de Fe(III) et de Mn(II) des fonctions fluoroalcools devant faciliter l'activation d'H2O2. Comparés aux complexes analogues non modifiés, aucune amélioration de l'activité catalytique pour l'oxydation de cyclooctène n'est observée. Cependant, des complexes de Ni(II) et de Co(II) à ligands non modifiés ont démontré une activité catalytique élevée pour la photoproduction d'hydrogène. La seconde stratégie est basée sur le remplacement de l'acide acétique. Pour cela, en utilisant des billes de silice fonctionnalisées par des fonctions COOH (SiO2@COOH) comme co-réactif, une sélectivité significative en faveur de l'époxyde est observée lors de l'oxydation d'alcènes en présence de complexes de Mn(II) et de Fe(III) à ligand BPMEN. La seconde approche concerne des réactions d'(ép)oxydation sans solvant et utilisant des catalyseurs recyclables à base de polyoxométallates (POMs). Les catalyseurs SiO2@PMo et SiO2@PW, respectivement obtenus par greffage ionique de H3PMo12O40 ou H3PW12O40 sur des billes de silices fonctionnalisées par des fonctions pendantes NH2 (SiO2@NH2). Avec une faible charge catalytique, les deux catalyseurs sont efficaces lors de réactions d'oxydation avec une meilleure sélectivité que les POM libres. De plus, les deux catalyseurs réutilisés ont donné des conversions et des sélectivités similaires après deux recyclages<br>In order to develop a chemistry more respectful of the environment, access to sustainable processes is mandatory. More specifically, in the field of oxidation chemistry, use of toxic oxidants has to be banished, use of solvents limited and reusable catalysts developed. In this context, two types of greener approaches have been explored. The first approach concerns removal or replacement of acetic acid, an additive - in association with H2O2, favoring exclusive formation of epoxides with Mn and Fe metal complexes as catalysts. For this objective, two strategies have been explored. The first one consists in introducing fluoroalcohol functions in the second coordination sphere of metal complexes with pyridinophane-based ligand to easily activate H2O2. Those complexes did not enhance the catalytic activity for cyclooctene oxidation reactions in comparison to analogous Mn(II) and Fe(III) complexes with unmodified ligands. However, Ni(II) and Co(II) metal complexes with unmodified ligands display interesting catalytic activity for H2 photoproduction. The second strategy aimed to replace acetic acid. Using silica beads functionalized with COOH pendant arms (SiO2@COOH) as additive and H2O2 as oxidant, catalytic epoxidation reactions catalyzed by Mn(II) and Fe(III) metal complexes with BPMEN ligand displayed significant selectivity towards epoxide. The second approach concerns organic-solvent free (ep)oxidation processes with catalysts based on polyoxometalates (POMs). Catalysts SiO2@PMo and SiO2@PW, respectively obtained by ionic grafting of H3PMo12O40 or H3PW12O40 on silica beads functionalized with NH2 pending functions (SiO2@NH2), have been fully characterized. With low catalyst loading, both catalysts displayed efficient oxidation activity and better selectivity than the free POMs. Moreover, recovered beads gave similar conversion and selectivity after two recycling processes

The large-scale adoption of a "hydrogen economy" is hindered by the lack of a practical storage method and concerns associated with its safe handling. Chemical hydndes have the potential to address these concerns. Sodium borohydride (sodium tetrahydroborate, NaBH₄), is the most attractive chemical hydride for H₂ generation and storage in automotive fuel cell applications but recycling from sodium metaborate (NaB0₂) is difficult and costly. An electrochemical regeneration process could represent an economically feasible and environmentally friendly solution. In this thesis, the properties of diluted NaB0₂ aqueous solutions and concentrated NaB0₂ alkaline aqueous solutions that are necessary for the development of electrochemical recycling methods have been studied. The conductivity and viscosity of dilute aqueous solutions of NaB0₂ were measured as a function of concentration at 25°C. Also, the solubility, pH, density, conductivity and viscosity of the filtrate of saturated aqueous NaB0₂ solutions containing varying weight percentages (1, 2, 3, 5, 7.5 and 10 wt%) of alkali hydroxides (NaOH, KOH and LiOH) were evaluated at 25°C. Selected experiments were repeated at 50 and 75°C to investigate the effect of temperature on the NaB0₂ alkaline aqueous solution solubility and physicochemical properties. Preliminary experiments to investigate the effect of glycine (C₂H₅N0₂), the smallest amino acid, on the solubility and physicochemical properties of NaB0₂ alkaline aqueous solutions were conducted at 25°C. Furthermore, the precipitates formed in the supersaturated 10 wt% alkaline aqueous NaB0₂ solutions at 25°C were characterized by X-Ray Diffraction and Scanning Electron Microscopy. The use of KOH as the electrolyte was found to be more advantageous for the H₂ storage and generation system based on NaBO₂ solubility and NaBH₄ half-life due to the pH effect. However, the addition of NaOH led to the highest ionic conductivity, and its use seems more suitable for the electroreduction of NaB0₂. Further investigations on the impact of KOH and NaOH on the electroreduction of NaB0₂ in aqueous media have the potential to enhance the commercial viability of this H₂ generation and storage system.<br>Applied Science, Faculty of<br>Materials Engineering, Department of<br>Graduate

碩士<br>崑山科技大學<br>機械工程研究所<br>97<br>This study was to develop a small reformer for hydrogen production from bio-fuel, i.e. ethanol. The reformer will be installed in the motorcycle exhaust pipe for recycling the exhaust heat for reforming. Hydrogen-rich gas was produced and will be used as the supplementary fuel of the engine for the improvement of thermal efficiency and exhaust emissions. Autothermal reforming was performed on the short and long models of A and B catalysts under the parameters of ethanol flow rate, H2O/EtOH ratio and O2/EtOH ratio with various temperatures to simulate the exhaust stream for hydrogen production. The experimental results of the short models of catalysts were shown as follows. No matter what the A-Short catalyst or B-Short catalyst is, the best thermal efficiency could be obtained under the ethanol flow rate of 6 mL/min. They were 56.6~60.4% and 45.4~48.5% respectively. With higher O2/EtOH ratio and suitable H2O/EtOH ratio, better hydrogen and carbon monoxide of yield were achieved. As reforming temperature reached 680℃ for A-Short catalyst, the best hydrogen yield of 61.4% and carbon monoxide yield of 41.9% were obtained; and as reforming temperature reached 720℃ for the B-Short catalyst, the best hydrogen yield of 59.4% and carbon monoxide yield of 26.7% were obtained. For the long models of A-Long and B-Long catalysts, the experimental results were shown as follows. It could be found that better ethanol conversion efficiency, hydrogen yield and thermal efficiency were obtained. The improvement of ethanol conversion efficiency was about 3~5%, hydrogen yield 1~4% and thermal efficiency 3~4% for A-Long catalyst. Higher H2/(CO+CO2) mole ratio was obtained by the long models of A-Long and B-Long catalysts due to the longer residence time. The hydrogen-rich gas was produced and would be used as the supplementary fuel of the engine. The suitable A/I ratio is needed. For the A catalyst of short and long models, the A/I ratios were between 0.4~1and between 0.37~1.1, respectively. For B catalyst, the A/I ratio were in the range of 0.15~0.68 and 0.32~0.8 respectively. Wider range of A/I ratio can meet the requirement of engine operation for the improvement of thermal efficiency and exhaust emissions. However, the reaction temperature should be monitored, because high temperature would cause the sintering and damage of the catalyst.

碩士<br>國立雲林科技大學<br>環境與安全衛生工程系<br>104<br>The film technology (Membrane technology) has been used in waste water treatment over past few years, although plants can significantly reduce the area of processing unit, the high maintenance costs and pores on films can easily be clog by impurities, In today, there is a lot of demand from electronics and industry, and many industrial have a higher costs problem on its chemical consumption, and therefore the idea of re-use of chemical film technology getting attention by the government and manufacturers. For example from cutting fluid by solar energy, there are a number of treatment and recycling plants used in the film technology at end of process treatment. Reused on high-purity of chemical liquid, based on the protection of the original manufacturers of chemical liquid formulations as well as higher cost of high purity chemical solution is now an important and necessary topic. Therefore, compared to the traditional chemical treatment method, there is widespread exist a safety risk on physical treatment method. Physical treatment of film technology for reusing have its advantages, the main purpose of this study is addressing on the waste cleaning fluid from wet process of wafer (Such as HCl / H2O2 / H2O, H2SO4 / H2O2 / H2O, NH4OH / H2O2 / H2O) . The material which cleaning fluid to be removed, used in this study was hydrogen peroxide after treatment for reusing the cleaning fluid. This study choose the cleaning solution after removal of hydrogen peroxide and used film return the original high purity component (HCl / H2SO4 / NH4OH) to reuse, recycling or other ways. Finally observe the removal efficiency of film. Keywords : Membrane,Wastewater engineering,Recycling, Piranha clean, Hydrogen peroxide.

碩士<br>崑山科技大學<br>機械工程研究所<br>100<br>This study was to investigate the hydrogen-rich gas produced from methanol reforming by exhaust heat recovery on the exhaust emissions and performance of engine. Hydrogen-rich gas was introduced into the engine to improve the fuel consumption and exhaust emissions. The experiments can be divided into four stages. The first phase of experiments is to derive the basic data of the original engine. The parameters studied included engine speed of 2000-6500rpm and the throttle openings. From the results, the original engine operating air-fuel ratio, fuel injection duration and exhaust emissions could be obtained. In the second stage, the simulation gas of premixed hydrogen-carbon dioxide was introduced into the engine, and a series of experiments were carried out. The feeding flow rate included 5, 10, and 15L/min with the molar fraction of 75%-hydrogen and 25%-carbon dioxide. The tested engine speeds were 4000rpm, 5000rpm and 6000rpm; and the throttle openings were 1/3, 2/3 and 3/3. In the third stage, the reformer was installed in the exhaust pipe to utilize the waste heat of the engine to supply the energy required for methanol reforming, and partial oxidation was used to produce hydrogen-rich gas. The parameters, including O2/C (Oxygen/methanol molar) ratio, are experimented, and the best reforming parameters will be obtained. The best parameters obtained in the last stage would be applied to the fourth stage. That is, the best O2/C ratio of 0.3 with the flow rate of 3, 6, 9c.c/min for reforming was employed. The tested engine speeds were 4000rpm, 5000rpm and 6000rpm; and the throttle openings were 1/3, 2/3 and 3/3. The hydrogen-rich gas introduced into the engine was to improve the lean limit and fuel economy. Among the series of experiments, many results were obtained. In the simulation gas experiments, it was found that CO, HC emissions, fuel consumption and thermal efficiency were improved as compared to the original engine. However, NOx emission increased, and the brake power decreased due to the reduction of volumetric efficiency. The trends by introducing the hydrogen-rich gas produced from the pipe reformer into the engine were similar to those of simulation gas experiments. However, there were differences between these two conditions because the compositions of the gases were not the same.

Die eingereichte Dissertation mit dem Thema „Heterogen katalysierte Hydrodehalogenierung von Borhalogeniden im Rahmen eines in sich geschlossenen BNHx-Recyclingkonzepts“ beinhaltet drei für das BNHx-Recycling zentrale Reaktionsschritte: Supersäureaufschluss, Hydrodehalogenierung und den Basenaustausch. Mit Hilfe dieser drei Schritte ist es möglich, die Zersetzungsrückstände von BH3NH3(Polyaminoboran, Borazin und Polyborazylen) wieder in BH3NH3 zu überführen, ohne teure Reduktionsmittel wie LiAlH4 oder Hydrazin verwenden zu müssen. Das Verfahren ermöglichte in einem Durchlauf die Gewinnung von 60 % der eingesetzten Menge an BH3NH3 ohne eine Erzeugung von Abfallprodukten. Mit Hilfe der Chloralkalielelektrolyse kann das Verfahren an Wind- bzw. Solarkraftwerke gekoppelt und über diese alle benötigten Ausgangsstoffe hergestellt werden. Die katalytische Erzeugung von B-H-Spezies auf der Grundlage der Aktivierung von molekularem Wasserstoff ist als Schwerpunkt dieser Arbeit zu sehen. Die mechanistischen Studien lieferten ein genaueres Verständnis über fundamentale Zusammenhänge zwischen dem Lösungsmittel Et3N und der Wasserstoffbereitstellung über die N-CH2-Gruppierung sowie der Wirkungsweise des Katalysators.:1 Einleitung und Motivation 8 2 Literaturteil 15 2.1 Borazan (AB) Zersetzung 15 2.2 Regenerierung der Zersetzungsprodukte 17 2.3 Gemeinsamkeiten und Unterschiede der Recyclingverfahren 20 2.3.1 Supersäure-Aufschluss zur Herstellung von BCl3 und BBr3 aus BNHx-Abfall 22 2.3.2 Bekannte Verfahren zur Herstellung von BCl3 23 2.3.3 Bekannte Verfahren zur Herstellung von BBr3 24 2.3.4 Basenaustausch zwischen Trialkylamin-Boranen und NH3 24 2.4 Hydrodehalogenierung 26 2.4.1 Gasphasen-Verfahren ohne Verwendung von Aminen als Hilfsbase 28 2.4.2 Flüssigphasen-Verfahren mit Aminen als Hilfsbase 31 2.4.3 Mechanistische Betrachtung 34 2.4.4 Hydrodehalogenierung von Borhalogeniden mit homogenen Katalysatoren 37 2.5 Amorphe Nickelboride als heterogene Katalysatoren 38 2.5.1 Synthese des amorphen Nickelborids 40 2.5.2 Angewandte Synthese- und Charakterisierungsmöglichkeiten zur Darstellung und Charakterisierung von amorphen Nickelboriden 41 2.5.3 Bekannte Hydrodehalogenierungen mit Nickelborid-Katalysatoren 47 2.5.4 Bekannte Nickelboride als Wasserstoffspeichermaterial 47 2.5.5 Nickelboranat (Ni(BH4)2) – Das wasserstoffreichste Nickelborid? 48 2.6 Heterogene Katalyse am Beispiel der Hydrodehalogenierung von Amin-BX3-Addukten (X=Cl, Br, I) in flüssiger Phase (Et3N) 51 2.6.1 Stofftransport innerhalb eines Drei-Phasen-Slurry-Reaktors 51 2.7 Methoden zur Bestimmung einer Katalysatorvergiftung (TPR) und zur Bestimmung der katalytischen Aktivität (TDS) des amorphen Nickelborids 55 2.7.1 Temperaturprogrammierte Reduktion (TPR) 55 2.7.2 Temperaturprogrammierte Desorption (TDS) 58 3 Ergebnisteil und Diskussion 59 3.1 Charakterisierung von amorphen Nickelboriden der allgemeinen Zusammensetzung NixByHz 59 3.1.1 Bestimmung der katalytischen Produktivität und der Aktivität am Beispiel der Hydrodehalogenierung von Et3NBCl3 59 3.1.2 Bestimmung des Ni/B-Verhältnisses mittels ICP-OES 61 3.1.3 Photoelektronenspektroskopie (XPS) -Bestimmung der Elementzusammensetzung an der Katalysatoroberfläche 62 3.1.4 TPR-Nachweis für das Vorhandensein oxidierter Metall-Spezies im Material 70 3.1.5 DSC-Untersuchung der Phasenumwandlung 73 3.1.6 TPD-Untersuchung der Wasserstoffabgabe 75 3.1.7 Wiederbeladung des Materials mit Wasserstoff (Zyklenstabilität) 81 3.1.8 PXRD-Röntgenpulverdiffraktometrie 84 3.1.9 IR-Spektroskopische Untersuchung zur Aufklärung der Bindungssituation des Wasserstoffs in amorphen Nickelboriden 90 3.1.10 TEM- und REM-Aufnahmen zur Bestimmung der Morphologie von amorphem Nickelborid 94 3.1.11 Bestimmung der BET-Oberfläche durch N2-Physisorption (T=-196 °C) 97 3.1.12 Zusammenfassung der Ergebnisse der Katalysatoraufklärung 100 3.2 BNHx-Abfall Recycling und die Wiedergewinnung von BH3NH3 102 3.3 Die Herstellung von BX3 (X= Cl, Br) aus BNHx –Abfall 102 3.3.1 Supersäure-Aufschluss von Polyaminoboran (BH2NH2)x mit AlCl3/HCl/CS2 und AlBr3/HBr/CS2 103 3.3.2 Supersäure- Aufschluss von Borazin AlCl3/HCl/CS2 106 3.3.3 Supersäure-Aufschluss von stark vernetztem Polyborazylen (PB) mit den Systemen AlCl3/HCl/CS2 und AlBr3/HBr/CS2 108 3.3.4 Zusammenfassung der Ergebnisse der vorgestellten Aufschlussverfahren 112 3.3.5 Mechanistische Betrachtungen zum Supersäure-Aufschluss des BNHx-Abfalls 113 3.4 Reaktionstechnische Untersuchungen zur Hydrode-halogenierung von Borhaliden des Typs BX3 (Cl, Br, I) 116 3.4.1 Stofftransportphänomene innerhalb der heterogen katalysierten Hydrodehalogenierung 117 3.4.2 Diffusion der Reaktanten in der flüssigen Phase zum Katalysator 119 3.4.3 Wechselwirkungseinflüsse der Addukte Et3NBCl3, Et3NBHCl2, Et3NBH2Cl und Et3NBH3 auf den Katalysator 122 3.4.4 Zusammenfassung der Ergebnisse aus den Stofftransport-Untersuchungen 123 3.5 Katalytische Hydrodehalogenierung von Et3NBCl3 123 3.5.1 Verfolgung der Reaktion über die Probenentnahme der Flüssigphase und Konzentrationsbestimmung mittels 11B NMR-Spektroskopie 124 3.5.2 Bestimmung der Geschwindigkeitskonstanten durch die Verwendung der Methode der Anfangsgeschwindigkeit 133 3.5.3 Katalytische Hydrodehalogenierung anderer Et3NBX3 (X=Br,I) Addukte 134 3.5.4 Nebenreaktionen – Eine Frage von Temperatur und Druck 138 3.6 Reaktionsmechanismus-Aufklärung am Beispiel der Hydrodehalogenierung von Et3NBCl3 145 3.6.1 Die Rolle des tertiären Amins 146 3.6.2 Die Rolle des Katalysators 154 3.6.3 Markierungsexperimente mit schwerem Wasserstoff (D2) 158 3.6.4 Einfluss von Radikalstartern auf die Reaktionsgeschwindigkeit der HDC 162 3.7 Disproportionierung von Et3NBH2Cl durch BCl3-Überschuss 165 3.8 Basenaustausch- Synthese von BH3NH3 aus Et3NBH3 und NH3 167 4 Thermodynamische Bewertung beider Recycling-Verfahren (Cl und Br) auf der Basis der Standard-Reaktionsenthalpien 170 5 Zusammenfassung der Ergebnisse 176 5.1 Amorphe Nickelboride 176 5.2 Supersäureaufschluss 178 5.3 Hydrodehalogenierung 178 5.4 Basenaustausch 180 5.5 Durchführung eines vollständigen Zyklus: Von der Dehydrierung bis zur Synthese von BH3NH3 180 5.6 Bewertung des Recyclingprozesses- Kopplung des Verfahrens mit einer Chloralkalielektrolyse 181 6 Ausblick 184 7 Anhang 185 7.1 Experimenteller Teil 186 7.1.1 Herstellung des BNHx-Abfalls (spent fuel) 186 7.1.2 Supersäure-Aufschluss des BNHx-Abfalls mit dem System AlCl3/HCl/CS2 187 7.1.3 Supersäure-Aufschluss des BNHx-Abfalls mit dem System AlBr3/HBr/CS2 189 7.1.4 Bestimmung der Donor-Akzeptor-WW in Bortrihalid- Trialkylaminkomplexen 190 7.2 Synthese des amorphen Nickelboridkatalysators 198 7.2.1 Probenvorbereitung und Analyseparameter für die einzelnen Analysemethoden 200 7.3 Synthese von wasserstoffreichem Nickelborid unter wasserfreien Bedingungen 203 7.4 Hydrodehalogenierung 204 7.4.1 Experimente für den Katalysatorvergleich in Kapitel 3.1.1 205 7.4.2 Hydrodehalogenierungsexperimente aus Kapitel 3.5 205 7.4.3 Experimente mit Probenentnahme aus Kapitel 3.4 206 7.4.4 Hydrodehalogenierung mit anderen Borhalogenid-Addukten (Et3NBBr3, Et3NBI3) aus Kapitel 3.5.3 206 7.4.5 Hydrodechlorierungsexperimente mit Me2EtN und Me3N 206 7.4.6 Markierungsexperimente mit schwerem Wasserstoff siehe Kapitel 3.6.3 207 7.4.7 Testexperiment Imminiumsalzbildung 207 7.4.8 Nebenreaktionen der Hydrodehalgenierung durch thermische Zersetzung der Addukte 208 7.5 Disproportionierung 209 7.6 Basenaustausch zwischen Et3NBH3 und NH3 210 7.7 Durchführung eines vollständigen Recycling-Zyklus 211 7.7.1 Die Dehydrierung von BH3NH3 (Herstellung von Polyborazylen) 211 7.7.2 Supersäureaufschluss des Polyborazylens 211 7.7.3 Hydrodechlorierung von BCl3 213 7.7.4 Basenaustausch-Experiment 214 8 Kalorimetrie –Bestimmung thermodynamischer Stoffdaten 215 9 NMR-Daten ausgewählter Zersetzungsprodukte von Et3NBX3-Addukten 216 10 Verzeichnisse 217 10.1 Abkürzungsverzeichnis 217 10.2 Tabellenverzeichnis 219 10.3 Abbildungsverzeichnis 221 11 Liste verwendeter Chemikalien 227 12 Versicherung 228 13 Literaturverzeichnis 229

Urban water systems in many developed cities are mostly stressed due to increased demand from population growth and an extended period of drought. The pressure on these systems has led to a number of adaptations such as the adoption of Water Demand Management and Alternative Water Sources. These adaptations are called Water Management Practices (WMP), which include Water Demand Management, Rainwater Harvesting, Greywater Recycling, Sewer Mining, and so on. These WMP lead to an increased uptake of residential rainwater, greywater or mixed wastewater for indoor and outdoor use and thus lead to water savings due to reduced imported water to study area. Besides the well-known benefits of water saving from adoption of WMP, many studies have found that the implementation of WMP reduces wastewater flow, hence causing sewer problems such as blockages, odour and corrosion. While the impact of WMP on sewer blockages has been investigated, the effects on sewer odour and corrosion are still largely unknown. Therefore, using WMP scenario analysis, this study will investigate the impact of WMP on odour and corrosion problems in sewer networks. Some scenarios developed in this study are 1) Base case, 2) Water Demand Management, 3) Greywater reuse/recycling, 4) Rainwater Harvesting, 5) Sewer Mining and 6) Combined Water Demand Management and Alternative Water Sources called as Sustainable Practice. A residential area was selected since the adoption of WMP is mostly conducted in households. A model was developed to simulate urban wastewater systems associated with sewerage pipe networks. The results show that Rainwater Harvesting scenario of RH-B is a comparatively more effective scenario than other WMP in reducing potable water demand and causing less impact on sewer odour and corrosion. RH-B reduced the total imported water to study area by 38% and increased the hydrogen sulphide concentration in sewer pipe by 6%. For the worst impact, there were two scenarios that were classified as worst scenarios, they are scenario of Greywater Recycling of GR-BL and Sustainable Practice of WDM-GR. GR-BL only reduced the imported water by 15% while increased hydrogen sulphide concentration by 40%. On the other hand WDM-GR reduced the total imported water by 46%, while increased hydrogen sulphide concentration by 62%. Scaling up the number of households adopted WMP also increased the risk of sewer odour and corrosion.