For the purpose of sulphide removal in aquaculture ponds, three strains (name: TH21, QN71, QN51) were isolated and selected with the highest sulphide removal activity from Thanh Hoa and Quang Ninh coastal zones. These strains have identified and tested in a number of aquaculture ponds in different areas with good water quality results. With the objective of purple non sulfur bacteria biomass production containing 3 selected strains for wide application and suitable price for farmers, in this study, we study on optimum conditions of mixed purple non sulfur bacteria biomass production at pilot scale. The results showed that the sources of substrates were soybean meal (1g/l) and acetate (0.5g/l). These substrates are low cost, easy to find, convenient in large culture. The mixture of photosynthetic bacteria can be cultured in glass tanks, under micro aerobic and natural lighting conditions that produce highly concentrated photosynthetic bacteria and lowest rest media. / Nhằm mục tiêu xử lý sulphide trong môi trường nuôi trồng thủy sản, chúng tôi đã phân lập và lựa chọn được ba chủng vi khuẩn tía quang hợp có khả năng loại bỏ sulphide cao nhất ký hiệu TH21, QN71, QN52 từ các vùng ven biển Thanh Hóa và Quảng Ninh. Các chủng này đã được định loại và thử nghiệm tại một số ao nuôi thủy sản ở các vùng khác nhau thu được kết quả tốt về chất lượng nước. Để tạo chế phẩm vi khuẩn tía quang hợp từ 3 chủng lựa chọn được ứng dụng rộng rãi và có giá thành phù hợp cho nông hộ, trong nghiên cứu này, chúng tôi nghiên cứu tối ưu hóa các điều kiện sản xuất sinh khối hỗn hợp 3 chủng vi khuẩn tía quang hợp ở quy mô pilot. Kết quả cho thấy đã tìm kiếm được nguồn cơ chất là bột đậu tương (1g/l) và acetate (0.5g/l) là những chất có giá thành thấp, dễ tìm kiếm, thuận tiện trong nhân nuôi ở quy mô lớn. Hỗn hợp vi khuẩn tía quang hợp có thể nuôi trong các bể kính, ở điều kiện vi hiếu khí, có ánh sáng chiếu tự nhiên có thể sản xuất được chế phẩm vi khuẩn tía quang hợp có mật độ cao, cơ chất còn lại sau sản xuất là ít nhất.

The raw water in some of Umeå's abstraction wells has shown high nickel levels for more than a decade. The cause has not been determined but there is an investigation from 2010 where the results indicate sulphide clay found adjacent to two basins used for artificial infiltration. The previous investigation further declares that the leaching occurs due to oxidation in an unsaturated state when the groundwater is lowered. However, the data points used for the investigation are limited and the source references are few. Today, over 10 years of data have been collected and the number of published scientific articles dealing with sulphide soils has increased, which motivates a follow-up on the subject. This degree project aims to contribute with further knowledge to the issue of high nickel concentrations in raw water with the purpose to strengthen or reject the hypothesis by: performing a literature review on sulphide soil; comparing nickel level with groundwater level; constructing a groundwater model and performing simulations. A large database is available from various investigations performed on the site from the 1940s until today. The literature review shows that the geological conditions exist for sulphide material to be present in the area, as well as several studies and investigations that confirm the suspicion of the presence of sulphide soil. Furthermore, the data points show a correlation between the groundwater level and the nickel concentration in raw water from extraction wells 17 and 20. The most obvious interpretation is the decrease in the nickel content as the groundwater level is raised, although a low groundwater level indicates high nickel levels. The modeling of the groundwater flow and mass transport shows how nickel can move from the area of suspected sulphide material to the extraction wells. An overall assessment of the project strengthens the thesis, however, more investigations are needed to exclude uncertainties inherent in the result. / Råvatten i vissa av Umeås uttagsbrunnar har uppvisat höga nickelhalter i mer än ett decennium. Orsaken är inte fastställd men det finns en tidig utredning från 2010 som misstänker sulfidlera som finns i anslutning till två bassänger som används för konstgjord infiltration. Den tidigare utredningen deklarerar vidare att urlakningen sker på grund av oxidation i omättat tillstånd när grundvattnet sänks. Dock var dataunderlaget till utredningen begränsad samt ett fåtal källhänvisningar. Idag finns över 10 års data samlat och antalet publicerade vetenskapliga artiklar som behandlar sulfidjord har ökat, vilket motiverar en uppföljning i ämnet. Detta examensarbete syftar till att bidra med ytterligare kunskap i syfte att stärka eller förkasta hypotesen genom att: utföra en litteraturstudie om sulfidjord; jämföra nickelnivå med grundvattennivå; konstruera en grundvattenmodell och utföra simuleringar. En stor databas finns tillgänglig från olika undersökningar som har gjorts på platsen från 1940-talet fram till idag.  Litteraturstudien visar att den geologiska förutsättningen finns för att sulfidjord ska finnas i området samt flera studier och undersökningar som stärker misstanken om närvaron av sulfidjord. Vidare visar resultatet av data punkter på en korrelation mellan grundvattennivån och nickelhalten i råvattnet till uttagsbrunn 17 och 20. Tydligast blir minskningen av nickelhalten när grundvattennivån höjs, även om en låg grundvattennivå indikerar höga nickelhalter. Modelleringen av grundvattenflödet och masstransporten visar hur nickel kan röra sig från området med misstänkt sulfidjord till uttagsbrunnarna. En helhetsbedömning av projektet stärker tesen, dock krävs fler undersökningar för att utesluta osäkerheter i resultatet.

The kraft pulping process is the most dominant pulping process consisting of 90% of the chemical virgin pulp production in the world. This process is extensive, especially considering the large chemical recycling, and improvements are constantly ongoing [1]. In 1966, G.H. Tomlinson II published a patent in where a white liquor of 100% sulphidity was used, i.e. only sodium sulphide (Na2S) as a cooking chemical and not sodium hydroxide (NaOH). A higher sulphidity gives an improved delignification and a stronger pulp with a higher yield. In addition, when NaOH is not used in the process, the causticizing plant can be eliminated. According to Tomlinson II, this would mean lower investment and operating costs.  The smelt from the recovery boiler undergoes leaching or evaporating to separate the sodium carbonate (Na2CO3) and Na2S. Na2CO3 recirculates to the black liquor to reduce the sulphur/sodium ratio, which is necessary for the function of the recovery boiler. A sufficiently high proportion of recirculated Na2CO3 is used to ensure that no SO2-emissions occur from the recovery boiler [2]. The purpose of this thesis is to investigate different cases of high sulphidity processes through heat and mass balances and compare it with a reference case of kraft pulp, in order to potentially find a more efficient process. The high sulphidity cases vary with e.g. dry solids content, effective alkali charge and the amount of recirculated Na2CO3. Also, a combination between the conventional kraft pulping process and high sulphidity process will be investigated. Tools for these calculations are given from AFRY and is done in excel. The focus is on the recovery boiler, since it is the most critical aspect in the process, but overall flow charts will also be made.  It turns out that the amount of recirculated Na2CO3 is one of the major factors that determine the outcome of the results. An increased amount of Na2CO3, which contains inert carbon, leads to a lower heating load in the recovery boiler, resulting in too low temperatures. For the high sulphidity process to be feasible, a lower effective alkali charge is required in the digester to reduce the amount of chemicals in the process. This can be achieved through a pre-impregnation step in the digester. All high sulphidity cases also resulted in a decrease in CAPEX and OPEX compared to the reference case. The most interesting result is a combination between the high sulphidity and kraft pulping process, as the results was comparable with the reference case, but at the same time containing advantages of the high sulphidity process. / Kraftmassaprocessen är den dominerade massaframställningen bestående av 90% av världens kemiska jungfrumassa. Denna process är omfattande och förbättringar pågår ständigt, särskilt med tanke på den stora kemikalieåtervinningen [1]. 1966 publicerade G.H. Tomlinson II ett patent där en vitlut av 100% sulfiditet användes, alltså endast natriumsulfid (Na2S) och inte natriumhydroxid (NaOH) som kokkemikalie. En högre sulfiditet ger en förbättrad delignifiering och därmed en starkare massa med ett högre utbyte. När NaOH inte används i kokeriet kan dessutom kaustiseringen elimineras. Det skulle, enligt Tomlinson II, innebära lägre investerings- och driftskostnader.  Smältan som kommer ut från sodapannan genomgår en laknings- eller indunstningsprocess för att separera ut natriumkarbonatet (Na2CO3) och Na2S. Na2CO3 återcirkulerar till svartluten innan sodapannan för att på så sätt minska på svavel till natriumkvoten, vilket är nödvändigt för sodapannans funktion. En tillräckligt hög andel av Na2CO3 återcirkuleras för att inga SO2-emissioner ska förekomma [2]. Syftet med denna rapport är därför att undersöka olika fall av högsulfiditetsprocesser genom värme och massbalanser och jämföra med ett referensfall av kraftmassa, för att i slutändan undersöka en potentiellt mer effektiv process. Fallen varierar med torrhalt på svartluten, effektiv alkali laddning, och mängden återcirkulerad Na2CO3. Ett kombinerat fall mellan den konventionella kraftmassa- och högsulfiditetsprocessen kommer även att undersökas. Verktyg för dessa beräkningsbalanser fås via AFRY och används i Excel. Fokuset ligger på sodapannan då denna del av processen är avgörande för processens genomförbarhet.  Övergripande flödesscheman kommer även att göras för de olika fallen.  Det ska visa sig att mängden återcirkulerad Na2CO3 är en av de större faktorerna till förändringar i resultatet. En ökad mängd Na2CO3, som innehåller inert kol, ger en lägre värmebelastning i sodapannan, och därmed för låga temperaturer i pannan. För att högsulfiditetsprocessen ska kunna vara genomförbar krävs en lägre effektiv alkali laddning i kokeriet för att minska på mängden kemikalier i processen, detta kan göras via ett förimpregneringssteg i kokeriet. Alla högsulfiditetsfall gav även en minskning i CAPEX och OPEX jämfört med referensfallet. Mest intressant resultat gavs av en kombination mellan högsulfiditet och kraftmassaprocess, då den mest efterliknade referensfallet, men samtidigt innehåller fördelar av högsulfiditetsfallet.

La maîtrise de l’additivation est l’un des enjeux majeurs de la formulation des lubrifiants, notamment pour l’industrie automobile. La formulation d’une huile est toutefois très complexe en raison du nombre important d’additifs et des nombreuses interactions possibles entre additifs, notamment entre les additifs de surface. Les phosphites organiques et les polysulfures organiques ont déjà montré leur efficacité en tant qu’additifs de surface. Toutefois malgré leur usage répandu dans les formulations des lubrifiants automobiles, peu d’études traitent des interactions pouvant avoir lieu entre ces deux types de composés. Ce travail de thèse a pour objectif la compréhension des mécanismes d’interaction (antagonisme/synergie) pouvant exister entre les phosphites organiques et les polysulfures organiques. Pour cela, une approche originale sur la lubrification par la phase gazeuse s’est avérée très pertinente. Le couplage du Tribomètre à Environnement Contrôlé (TEC) avec les systèmes d’analyses de surface XPS/Auger a permis d’analyser les tribofilms générés in situ et d’éviter ainsi toute contamination et/ou oxydation du tribofilm avant analyse. Les molécules choisies sont les additifs de lubrification industriels (polysulfures tertaires) à faibles poids moléculaires ou alors des molécules à faible poids moléculaires ayant les mêmes fonctions chimiques que les additifs usuels : trimethyl phosphite (TMPi), dimethyl phosphite (DMPi). L’étude des réactions des tribochimiques des molécules phosphorés a permis de mettre en évidence le rôle ambivalent du DMPi qui se comporte à la fois comme un phosphite pour former un phosphure de fer et comme un phosphate. Le mécanisme formation du phosphure de fer a peu être étayé par la réalisation de calculs ab initio sur l’adsorption dissociative du TMPi sur une surface de fer. Les TPS étudiés génèrent quant à eux des tribofilms à base disulfure de fer. Les mélanges binaires réalisés en phase gazeuse ont permis de mettre en évidence l’importance des rapports de concentrations des vapeurs introduites et du mode d’introduction des molécules dans le tribomètre. Les résultats obtenus en tribologie en phase gazeuse ont été corroborés par des essais complémentaires en phase liquide. / Mastering the addivation is one of the biggest issues for the lubricants formulation, especially in the automobile industry. However automotive lubricants are very complex systems due to the numerous additives mixed with base oils. Many interactions can occur between additives, especially between surface additives. Organic phosphites and organic polysulphides have already demonstrated their effectiveness as surface additives. However, despite their widespread use in the formulations of automotive lubricants, few studies deal with the interactions taking place between these two types of compounds. The aim of this study is to understand the interactions, antagonistic or synergetic effect between these kinds of additives using Gas Phase Lubrication (GPL) approach. A Environmental Controlled Tribometer (TEC) was used as a tool to simulate the interaction between organophosphate additives and polysulfurous additives. In situ surface analysis was performed in the tribofilm formed during friction using of X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy(AES) in order to avoid any oxidation or air contamination. The molecules selected for the study can be same as the additive like the TPS molecules which are widely used as lubricant additives. Howeverto simulate the phosphite chemical function of phosphite additives, we need to select smaller molecule having the same chemical function. These molecules are dimethyl phosphite (DMPi), trimethylphosphate (TMPi) for simulating the phosphite chemical function and organic polysulphides (TPS44and TPS32). The study of the tribochemical reactions of organic phopshites allowed to clearly characterise the ambivalence of DMPi, which can react like a phosphite and induce iron phosphide formation or react like a phosphate. Ab initio numerical simulation on TMPi dissociative adsorption was carried out to identify the reactions pathways leading to iron phosphide formation. The tribochemical reaction of TPS44 on metallic iron surface leads to the formation of iron disulphidebased tribofilm. The binary vapours mixtures studied by GPL allowed to clearly identify the importance of the vapour concentration ratio between phosphite and polysulphide. Liquid phase experiments were also carried out to confirm the trend observed in GPL approach.

Les gisements de sulfures massifs encaissés dans les massifs hercyniens marocains des Jebilets et Guemassa sont de type (VMS) déformés et métamorphisés. Il manque toutefois une évaluation de la contribution de cette déformation à leur structuration actuelle, et l’éventuel impact de celle-ci sur le plan économique et en termes d’exploration. Par conséquent, cette contribution vise principalement à définir le contexte structural de ces minéralisations, en vue d’en déduire un modèle structural relatif au VMS de Hajjar.Le VMS de Hajjar, appartenant au domaine des Guemassa (Meseta occidentale). Il est encaissé dans des terrains d’origine volcanosédimentaire composés de pélites, de grès et de lentilles et barres calcaires intrudés par des sills et dykes felsique et basique. Les principaux corps volcaniques correspondent aux dômes rhyolitiquesLe gisement de Hajjar est composé de 3 corps minéralisés : le corps principal (CP), le corps Nord-Est (CNE) et les corps ouest et extrême ouest descenderie (CWD, CEWD). Le gisement de Hajjar est affecté par un seul plan XY d’aplatissement subvertical de directions N0 à N45. L’encaissant et les corps sulfurés présentent les mêmes assemblages métamorphiques silicatés, qui présentent soit une texture granoblastique « statique » lorsque la déformation est faible, soit des caractéristiques prés à syn-tectoniques lorsque la schistosité est fortement exprimée. La texture, les formes des biotites et d'andalousites (± cordiérite suspectée) sont typiques du métamorphisme de contact HT / BP des faciès de cornéennes. L'assemblage syntectonique est composé de quartz + chlorite + micas blancs (± calcite), et remplace partiellement les anciennes biotites et andalousites. Les données de surface du bloc N'Fis montrent la présence d'un seul plan XY subvertical orienté N130. Les biotites du métamorphisme de contact sont allongées parallèlement à la schistosité. L’ensemble des données indiquent que le VMS de Hajjar et le bloc N'Fis sont affectés par une seule schistosité qui est synchrone d’un métamorphisme de contact de HT / BP. La virgation importante de la schistosité des affleurements d'Imarine au VMS de Hajjar est dû à une importante zone de cisaillement - transpressive de direction ENE-WSW. Près de la mine Hajjar, une telle zone de cisaillement à l’échelle régionale est reconnue pour la première fois, et constitue une caractéristique structurale-clé du district de Hajjar.La minéralisation de Hajjar est fortement déformée et métamorphisée. Elle est affectée par le plissement, la schistosité et la mylonitisation dans un contexte cisaillant. Les structures minéralisées stratiformes sous forme de rubans riches en pyrrhotite précèdent clairement la déformation et le métamorphisme de contact. D’autres structures minéralisés riche en (Zn, Cu, Pb) présentent un rubanement tectonique issu de la remobilisation par fluide de la minéralisation précoce Le stade précoce est caractérisé par la précipitation de la pyrrhotite, pyrite, arsénopyrite, sphalérite et la galène, alors que le stade syncinématique constitue l’événement concentrateur majeur caractérisé par la dissolution et la recristallisation de la paragenèse précoce avec un enrichissement en Zn, Cu. Le stade tardif post-cinématique est responsable la néoformation de sulfures, à savoir la chalcopyrite, la pyrite et quelques traces de sphalérite.Nous avons mis en évidence un épaississement tectonique dans les zones de charnières. Le métamorphisme pré à syntectonique favorise le comportement ductile et la recristallisation des sulfures (Po, Cpy et Sph). Les veines triangulaires polymétalliques à l'extrémité des lentilles de sulfures massifs sont le témoin d'une remobilisation hydrothermale assistée par un fluide pendant la déformation. L’ensemble de nos études débouche sur la proposition d’un modèle 3D tectonométamorphique pour le VMS des Guemassa et des propositions pour rechercher des extensions de la minéralisation. / The massive sulphide deposits hosted in the Moroccan Hercynian massifs of Jebilets and Guemassa are Volcanogenic Massive Sulfide (SMV), deformed and metamorphosed. However, an assessment of the contribution of this deformation to their current structure and the eventual impact on the economy and in terms of exploration is missing. Therefore, this contribution aims mainly to define the structural context of these mineralizations, in order to deduce a structural model relating to Hajjar's VMS.The VMS of Hajjar, belonging to the domain of Guemassa (Western Meseta). It is hosted in volcanosedimentary terrain composed of pelites, sandstones and lentils and limestone bars intruded by felic and basic sills and dykes. The main volcanic bodies correspond to the rhyolitic plugs.The Hajjar deposit is composed of 3 mineralized bodies: main body (CP); north-eastern body (CNE); western body (CWD) and extreme western body(CEWD.). The Hajjar deposit is affected by a single XY plane of subvertical flattening of directions N0 to N45. The host rock and sulphide bodies have the same silicate metamorphic assemblages, which exhibit either a "static" granoblastic texture when the strain is low or pre to syn-tectonic features when the foliation is strongly expressed. The texture shapes, and aggregates of the biotite and andalousite (± suspected cordierite) are typical of HT/LP “contact” metamorphism in the hornfels facies. The syn-tectonic assemblage is composed of quartz + chlorite + white micas (± calcite) and partially replaced the former biotite and andalousite blasts. The data from the N’Fis block show the occurrence of a single sub-vertical XY plane oriented N130. The biotites of contact metamorphism are elongated parallel to the foliation. These data imply that the Hajjar MSD and the N’Fis block are affected by a single foliation which encompasses a HT/LP contact metamorphism. The significant inflexion of foliation from Imarine outcrops to Hajjar VMS is due to major right-lateral ENE-trending transpressive shear zone at Hajjar. Near the Hajjar mine, such a regional shear zone is recognized for the first time, and is a structural key feature of the Hajjar district.The mineralization of Hajjar is strongly deformed and metamorphosed. It is affected by folding, foliation and mylonitic bands within a regional scale shear zone. Structures such as pyrrhotite-rich ribbons clearly pre-date the deformation and the HT/LP contact metamorphism. The early stage is characterized by the precipitation of pyrrhotite, pyrite, arsenopyrite, sphalerite, and galena, whereas the synkinematic stage constitutes major concentrator event characterized by the dissolution and recrystallization of early paragenesis with enrichment in Zn, Cu. The late post-kinematic stage is responsible for the neoformation of sulphides, namely chalcopyrite, pyrite and some traces of sphalerite.We have demonstrated a tectonic thickening within the fold hinge zone. pre-syntectonic metamorphism favors ductile behavior and sulfide recrystallization (Po, Cpy, and Sph). The polymetallic veins argue for hydrothermal fluid-assisted remobilization during deformation. All of our studies lead to the proposal of a 3D tectono-metamorphic model for the VMS of Guemassa and proposals to search extensions of the mineralization.

En combinant expérimentations et calculs ab initio, nous proposons une étude rationnelle des mécanismes de désoxygénation de molécules modèles pertinentes (heptanoate d'éthyle et heptanal) afin de fournir des guides pour définir des systèmes catalytiques optimaux pour l'hydrotraitement de matières premières renouvelables (huiles végétales, graisses animales). L'hydrotraitement d'huiles végétales, par la réaction de désoxygénation, est une voie alternative à la transestérification et peut être envisagée pour obtenir une base gazole de haute qualité. La transformation des composés oxygénés modèles a été étudiée sous une pression totale de 1.5 MPa, à une température de 523 K, dans un réacteur à lit fixe en présence de différents sulfures de métaux de transition massiques (SMT). Cette étude a mis en évidence l'influence de la nature phase sulfure sur la sélectivité des voies de désoxygénation (hydrodésoxygénation (HDO) et/ou décarbonylation/ décarboxylation (DCO)) ainsi que la réactivité particulière du sulfure de rhodium lors de la transformation de l'heptanoate d'éthyle. À l'inverse, quelle que soit la phase sulfure utilisée, la transformation de l'heptanal suit principalement la voie HDO. Dans nos conditions réactionnelles, l'heptanal a été identifié comme un intermédiaire de cette voie de désoxygénation. L'effet promoteur du cobalt et du nickel sur l'activité du sulfure de molybdène monométallique a été observé lors de la transformation de l'heptanal. La relation entre les activités en désoxygénation et en HDO et l'énergie de liaison métal-soufre (E(MS)) calculée ab initio des solides suit une courbe en volcan. Le sulfure mixte NiMoS (0.43), qui présente une E(MS) intermédiaire (127 kJ.mol-1), est le SMT le plus actif pour les deux réactions. Le catalyseur bimétallique CoMoS (0.1) présente la sélectivité HDO/DCO la plus élevée. À l'aide des résultats catalytiques et de calculs ab initio, deux mécanismes réactionnels sont proposés pour les voies de réactions HDO et DCO / By combining well defined experiments and density functional theory (DFT) calculations, we propose a rational understanding of the deoxygenation mechanisms of relevant oxygenate molecules (ethyl heptanoate and heptanal) so as to provide guides to define optimal catalytic systems for the hydrotreating of renewable feedstocks (vegetable oils, animals fats). The hydrotreatment of vegetable oils, with the deoxygenation reaction, is an alternative route to transesterification and can be used to obtain high quality diesel. The transformation of oxygenated model compounds was studied under a total pressure of 1.5 MPa, at 523 K, in a fixed bed reactor over various unsupported transition metal sulfide catalytic phases (TMS). Results have shown the influence of the sulfide phase on the selectivity for deoxygenation reaction (hydrodeoxygenation (HDO) and/or decarbonylation/ decarboxylation (DCO)) and the specific reactivity of the rhodium sulfide for the transformation of ethyl heptanoate. The study of the transformation of heptanal shows the reaction of deoxygenation is preferentially following the HDO pathway over all the catalysts. In our reaction conditions, heptanal was identified as a reaction intermediate of this deoxygenation pathway. The promoting effect of cobalt and nickel on the activity of monometallic molybdenum sulphide was observed for the transformation of heptanal. The relation between the deoxygenation and HDO rates and the ab initio calculated sulphur-metal bond energy E(MS) in the bulk TMS is following a volcano curve. Bimetallic sulfide NiMoS (0.43), with an intermediate E(MS) (127 kJ.mol-1), is found as the most active TMS for both reactions. The maximum of the HDO/DCO selectivity is obtained for the mixed catalyst CoMoS (0.1). Thanks to catalytic results and ab initio calculations, two reaction pathways are proposed for HDO and DCO reactions

H2S é um gasotransmissor com atua regulando processos fisiológicos e fisiopatológicos. É sintetizado principalmente pelas enzimas cistationinagama-liase (CSE) e cistationina beta-sintase (CBS), ambas dependentes do co-fator 5-fosfato de pirodoxal, e que utilizam o L-cisteína como substrato. Essas enzimas estão presentes no fígado. O camundongo knockout para CBS (CBS KO) apresenta fenótipo de homocistinúria, ou seja, além da homocisteinemia apresenta estresse oxidativo, fibrose e esteatose hepática. Ademais, há estudos in vitro sugerindo um papel desse gás reduzindo a captação de glicose hepática. A hipótese desse projeto é que haja redução precoce da produção de H2S pelo fígado de camundongos alimentados com dieta hiperlipídica (DHL) e esse seja um evento anterior à instalação do fígado gorduroso ou DGHNA associada à obesidade induzida pela DHL, DIO. Para isso, avaliamos a evolução ponderal, consumo alimentar e calórico diários, a tolerância a glicose e a insulina (GTT, ITT e Kitt), a morfohistologia hepática com corantes HE e picrocirius red, expressão proteica e gênica das enzimas CBS e CSE, a quantificação do conteúdo de triglicérides, a deteção de F4/80 e a atividade de enzimas antioxidantes (catalase, GPx e arginase) em amostras de fígado de camundongos machos C57Bl6 alimentados com a DHL por 5 períodos distintos (10, 20, 40, 60 e 80 dias de dieta). Detectamos aumento da massa corporal final a partir de 20 dias de DHL. O consumo alimentar diário foi menor nos animais com a DHL, porém com maior consumo calório do que os respectivos controles. A glicemia basal foi maior nos animais com DHL desde os 10 dias, com exceção o grupo com 40 dias. Houve maior intolerância à glicose desde 10 dias de DHL seguida de resistência à insulina a partir de 20 dias de DHL. Foi detectada presença de vacúolos intracelular nos hepatócitos a partir de 20 dias de DHL, no entanto, a presença de hepatócitos comprometidos foi de aproximadamente 2% aos 20 dias da DHL, cerca de 5% aos 40 dias da DHL e aproximadamente 60% com 60 e 80 dias da DHL. Aos 80 dias de DHL foi detectada balonização de hepatócitos, presença de infiltrado inflamatório identificado pelo aumento da marcação com F4/80, maior detecção de fibras colágenas nos espaços vasculares e aumento da atividade da enzima sérica AST. Houve redução para aproximadamente 50% da produção do H2S nas amostras de fígado dos animais a partir de 40 dias da DHL, porém sem relação clara com as modificações detectadas na expressão das enzimas CBS e CSE. Diante desses dados, concluímos que a DHL leva à intolerância à glicose, seguida de aumento da massa corporal e resistência ao efeito hipoglicemiante da insulina e que o desenvolvimento de fígado gorduroso é um evento mais tardio. Vimos que o espectro da DGHNA desenvolvida apresenta características de esteato-hepatite incipiente, com balonização dos hepatócitos, infiltrado inflamatório presente, discreto aumento de deposição de fibras colágenas e aumento da enzima hepática circulante AST. A redução da produção do gás apareceu após a instalação da resistência à insulina, mas anterior ao estabelecimento da DGHNA. Portanto, concluímos que a alteração na produção hepática do H2S pode ser um evento precoce associado ao desenvolvimento da DGHNA e que merece ser investigado seu potencial papel na progressão de estatose a EHNA com fibrose e cirrose. No entanto, será importante buscar um outro modelo animal para estudo dessa evolução. / Hydrogen sulfide (H2S) is a gaseous signaling molecule that regulates a variety of physiological and pathophysiological processes. It is primarily synthesized by cystathionine-gamma-lyase (CSE) and cystathionine beta-synthase (CBS), which are expressed in the liver, require 5\'-pyrodoxal phosphate as a co-factor, and use L-cysteine as a substrate. Interestingly, CBS knockout (CBS KO) mice present homocystinuria and associated homocysteinemia, as well as oxidative stress, fibrosis and hepatic steatosis. Furthermore, in vitro studies suggest that this gas reduces hepatic glucose uptake. It was hypothesized that mice fed a high fat diet (HFD) would display an early reduction H2S production by the liver and that this event would occur prior to the establishment of fatty liver or NAFLD, which is associated with diet induced obesity (DIO). Towards the goal of gaining a better understanding of H2S production during the onset and progression of DIO, male C57B16 mice were fed a HFD for 10, 20, 40, 60 or 80 days. During the experimental period, weight evolution, daily food and caloric intake, as well as glucose and insulin tolerance (GTT, ITT and Kitt) were evalauted. At the end of each time period hepatocyte morphology was assessed by HE and picrocirius red staining, CBS and CSE gene and protein expression were evaluated, triglyceride content was quantified, F4/80 antigen was detected and antioxidant enzyme (catalase, GPx and arginase) activites were determined. The results showed that mice fed a HFD for 20 days or longer presented an increase in final body weight. All of the HFD groups presented reduced daily food intake, but higher caloric intake, when compared to their respective controls. All of the animals fed a HFD had increased basal glycemia levels, with the exception of the group fed the diet for 40 days. Reduced glucose tolerance and insulin resistance were observed after consuming the HFD for 10 and 20 days, respectively. Intracellular vacuoles were detected in the hepatocytes after 20 days of the HFD. The amount of compromised hepatocytes increased from 2% after 20 days of the HFD, to about 5% after 40 days, to approximately 60% after 60 and 80 days. After consuming the HFD for 80 days, there was an observed ballooning of hepatocytes, increased F4/80 detection indicating the presence of inflammatory infiltrates, increased collagen fiber detection in the vascular spaces, and increased serum AST activity. There was a ~50% reduction in H2S production in the liver samples from animals fed a HFD for 40 days; however, there was no clear relationship with the alterations detected in CBS and CSE gene or protein expression. Based on the results, it was concluded that an HFD promotes glucose intolerance, followed by increased body mass and insulin resistance and that the development of fatty liver occurs later. Additionally, the spectrum of the developed NAFLD presented incipient steatohepatitis characteristics, such as: hepatocyte ballooning, inflammatory infiltrate, a slight increase in collagen fiber deposition, and an increase in circulating liver AST levels. The reduction in H2S gas production appeared after the installation of insulin resistance, but prior to the establishment of NAFLD. Therefore, we conclude that alterations in hepatic H2S production may be an early event associated with the onset of NAFLD and that its potential role in the progression of steatosis and NASH with fibrosis and cirrhosis deserves to be investigated. However, it will be important to evaluate this evolution in other animal models.

Attractive particle interactions which lead to the hetero-aggregation or 'sliming' of silicate clay gangue and valuable sulphide mineral particles are encountered in a number of hydrometallurgical and flotation processes. Sliming leads to poor recovery of the valuable minerals and high recovery of the clay gangue minerals in flotation concentrates. In the present work, the hetero-aggregation mechanism of hydrophilic mica clay mineral sericite (or muscovite) and hydrophobic chalcocite was investigated by probing the particle interactions and the prevailing interfacial chemistry under dispersion conditions where the individual chalcocite and sericite particles displayed negative zeta potentials. The mitigation/suppression of the hetero-aggregation was examined via the prudent control of dispersion conditions and pulp chemistry (i.e., pH modification and solution speciation control) and the use of two, anionic, polymeric dispersants with different molecular weight and functionality (carboxylate-substituted polyacrylamide, Cyquest 3223 and sulphonate-substituted polymaleic acid, P80 co-polymers) as dispersants. The adsorption behaviour of both polymers onto both minerals under industrially relevant suspension conditions have been quantified in terms of the polymer adsorption density and the adsorbed layer characteristics. These interfacial layer properties which impact on the mineral particles' zeta potentials and interactions, and also underpin the dispersion efficacy of polymers were characterized, using interfacial and solution analytical methods and TM-AFM imaging analysis.

[Truncated abstract] As mineral deposits continue to be mined, the non economic gangue materials such as sulphides (e.g. pyrite) that are extracted as part of the ore body or overburden are deposited within the waste rock and/or milled tailings. As a result of natural weathering processes, these reactive materials represent a potential hazard to surrounding environments. A major consequence, resulting from mine-waste impoundments containing sulphidic materials, relates to the offsite movement of low pH leachates containing elevated concentrations of metal ions posing a contamination threat. The processes and mechanisms acting in the formation of acid mine drainage (AMD) are highly variable and, to a high extent, controlled by climatic conditions as the main driver of water flow and wetness of the system which in turn determines the availability of oxygen as well as water for pyrite weathering. In particular, this thesis is based on the hypothesis that in semiarid and arid climates the acid production may be water … The experiments were repeated at different water contents ranging from 0.24 to 0.33 cm3 cm-3. Breakthrough curves (BTC) of Li+, K+, Ca2+, Mg2+, Na+ and pH were measured and described with models of different complexities. This included the use of a simple linear and non-linear isotherms for Li+ alone, a binary Li+ - K+ ion exchange, and a complete multicomponent chemical equilibrium description of ion transport. The latter, by including dissolution of primary minerals which released base cations such as Mg2+, Ca2+ and K+ explained some of the elution patterns of base cations for which the Li+ - K+ exchange was the dominant process. Furthermore, under unsaturated water flow conditions, retardation of Li+ increased with decreasing water content. Thus solute mobility in mafic rock tailings appears to decrease under strongly unsaturated water flow conditions.

The motivation of this thesis is to understand the physical properties of semiconductor quantum dots (QDs) and to get insight on the basic physics of charge separation in composites made from QDs with graphene oxide (GO)/organic semiconductors. The flexion phonon interactions is one of fundamental issues in solid state physics, which has a significant effect on both electrical and optical properties of solid state materials. This thesis investigates the physical properties of aqueous grown QDs through exciton-phonon coupling and non-radiative relaxation of excited carriers which have been carried out by temperature dependent photoluminescence spectroscopy. Several e orts have been made in order to understand the basic physics of photo induced charge separation in the hybrid systems made from QDs with graphene oxide and organic semiconductors. Investigations on the photoconductivity of the devices made from these hybrid composites have been carried out keeping the motive of its application in nanotechnology. This thesis work is presented in six chapters inclusive of summary and directions for future work. Chapter 1 discusses the background knowledge and information of the general properties of semiconductor nanostructures, QDs and their hybrid nanocomposites. Chapter 2 deals with the sample preparation and experimental techniques used in this thesis. Chapter 3 elaborates the exciton-phonon scattering and nonradiative relaxations of excited carriers in visible emitting cadmium telluride QDs with help of temperature and size dependent photoluminescence. Chapter 4 presents the investigations on time resolved photoluminescence dynamics and temperature dependent photoluminescence properties of near infrared (NIR) emitting mercury cadmium telluride (CdHgTe). Chapter 5 discusses the importance of NIR emitting silver sulphide (Ag2S) QDs and gives insight of nonradiative recombinations through defect/trap states. Chapter 6 investigates the excited state interactions between CdHgTe QDs and GO. Chapter 7 focuses on the understanding of basic physics of charge separation/transfer between poly (3hexylthiophene) and Ag2S QDs. Chapter 1: Semiconductor nanostructures have attracted significant scientific attention due to their fundamental physical properties and technological interests. Quasi zero dimensional nanocrystals or quantum dots (QDs) have shown unique optical and electrical properties compared to its bulk counterpart. These QDs show discrete energy levels due to the quantum confinement effect hence known as arti cial atoms. Large surface to volume ratio in these QDs is expected to play a crucial role in determing the photo-physical properties. Temperature dependent photoluminescence is a powerful tool for understanding the role of the large surface area on exciton recombination process in QDs. Inorganic QDs combined with different materials like graphene oxide or organic semiconductors forms an exciting class of synthetic materials which integrates the properties of organic and inorganic semiconductors. It is quite important to understand the basic physics of electronic interactions in these composites for its future application in many elds. Chapter 2: Synthesis of the inorganic QDs, graphene oxide, composites and fabrication of devices is an important and integral part of this thesis. Hydrothermal and three necked ask technique is adopted to get highly dispersible colloidal quantum dots in solvents. Synthesis of graphene oxide from graphite through oxidation and ultrasonication has been carried out to obtain homogenous dispersed graphene oxide in water. Structural properties have been studied by techniques like X ray diffraction, Raman spectroscopy, X ray photoelectron spectroscopy and high resolution transmission electron microscopy. Morphological properties are studied by atomic force microscopy and transmission electron microscopy. Optical properties are investigated by absorption spectroscopy, steady state and time resolved photoluminescence spectroscopy. Photoconductivity characteristics are analyzed to understand the basics of enhanced current in the various devices made from QDs composites. Chapter 3:Investigations on exciton phonon coupling and nonradiative relaxations in various sizes of visible light emitting cadmium telluride (CdTe) QDs size have been presented. Due to the large surface area, QDs are prone to have defect/trap states which can affect the exciton relaxation. Hence, understanding the role of such defect/trap states on photoluminescence is very essential for achieving the optimum optical properties. Temperature dependent (15 300 K) photoluminescence has been used to understand nonradiative relaxation of excited carriers. Thermally activated processes and multiple phonons scattering is thoroughly investigated to understand the quenching of photoluminescence with temperature. The strength of exciton-phonon coupling is investigated which determines the variation in energy bandgap of QDs with temperature. Role of exciton phonon scattering is also discussed to understand the basic physics of photoluminescence line width broadening in QDs. Chapter 4 and 5: This part of thesis focuses on the size and temperature pho-toluminescence properties of near infra red emitting ternary alloyed CdHgTe and Ag2S QDs. Near infrared emitting semiconductor quantum dots (QDs) have attracted significant scientific and technological interests due to their potential applications in the fields of photosensor, solar energy harvesting cells, telecommunication and biological tissue imaging etc. Structural and photophysical properties of CdHgTe QDs have been analyzed by high resolution transmission electron microscopy, X rayphotoelectron microscopy, photoluminescence decay kinetics and low temperature photoluminescence. Investigations on the nonradiative recombinations through trap/defects states and exciton phonon coupling are carried out in colloidal Ag 2S QDs which emits in the range of 1065 1260 nm. Particularly, the photoluminescence quenching mechanism with increasing temperature is analyzed in the presence of multiple nonradiative relaxation channels, where the excited carriers are thermally stimulated to the surface defect/trap states of QDs. Chapter 6 and 7: The aim of these chapters is to understand the basic physics of photo induced charge separation in the hybrid systems made from the inorganic QDs with graphene oxide and organic semiconductors. In chapter 6, CdHgTe QDs are decorated on graphene oxide sheets through physisorption. The excited state electronic interactions have been studied by optical and electrical characterizations in these CdHgTe QDs GO hybrid systems. In chapter 7, investigations are carried out for understanding the basic physics of charge separation in the composites of Ag2S QDs and poly (3hexylthiophene 2,5 diyl)(P3HT). These composites of inorganic organic materials are made by simple mixing with help of ultrasonication technique. Steady state and time resolved photoluminescence measurements are used as powerful technique to gain insight of energy/charge transfer process between P3HT and Ag2S QDs. Furthermore, investigations have been carried out on the photoconductivity of the devices made from these hybrid composites keeping the motive of its application in nanotechnology. Chapter 8: The conclusions of the work presented in this thesis are coherently summarized in this chapter. Thoughts and prospective for future directions are also summed up.