Metal-organic materials (MOMs) represent a unique class of porous materials that captured a great scientific interest in various fields such as chemical engineering, physics and materials science. They are typically assembled from metal ions or metal clusters connected by multifunctional organic ligands. They represent a wide range of families of materials that varied from 0D to 3D networks: the discrete (0D) structures exemplified by metal-organic polyhedra (MOPs), cubes and nanoballs while the polymeric 1D, 2D and 3D structures exemplified by coordination polymers (CPs). Indeed, the porous 3D structures include metal-organic frameworks (MOFs), porous coordination polymers (PCPs) and porous coordination networks (PCNs). Nevertheless, MOMs are long and well-known from more than 50 years ago as exemplified by CPs that were firstly introduced in early 1960s and reviewed in 1964. However, the scientific interest toward MOMs has been enormously grown only since late 1990s, with the discovery of MOMs with novel properties, especially the high permanent porosity as exemplified by MOF-5 and HKUST-1. The inherent tunability of MOMs from the de novo design to the post-synthetic modification along with their robustness, afford numerous important families of nets "platforms" such as pcu, dia, tbo, mtn and rht topology networks. There are more than 20,000 crystal structures of MOMs in the Cambridge Structure Database (CSD). However, only a few of the networks can be regarded as families or platforms where the structure is robust, fine-tunable and inherently modular. Such robustness and inherent modularity of the platforms allow the bottom-up control over the structure "form comes before function" which subsequently facilitates the systematic study of structure/function in hitherto unprecedented way compared with the traditional screening approaches that are commonly used in materials science. In this context, we present the crystal engineering of two MOM platforms; dia and novel fsc platforms as well we introduce the novel two-step synthetic approach using trigonal prismatic clusters to build multinodal 2D and 3D MOM platforms. For the dia platform, we introduce a novel strategy to control over the level of the interpenetration of dia topology nets via solvent-template control and study the impact of the resulting different pore sizes on the squeezing of CH4, CO2 and H2 gases. New benchmark material for methane isosteric heat of adsorption was produced from this novel work. Indeed we introduce the crystal engineering of a novel versatile 4,6-c fsc platform that is formed from linking two of the longest known and most widely studied MBBs: the square planar MBB [Cu(AN)4]2+( AN = aromatic nitrogen donor) and square paddlewheel MBB [Cu2(CO2R)4] that are connected by five different linkers with different length, L1-L5. The resulting square grid nets formed from alternating [Cu(AN)4]2+ and [Cu2(CO2R)4] moieties are pillared at the axial sites of the [Cu(AN)4]2+ MBBs with dianionic pillars to form neutral 3D 4,6-connected fsc (four, six type c) nets. Pore size control in this family of fsc nets was exerted by varying the length of the linker ligand whereas pore chemistry was implemented by unsaturated metal centers (UMCs) and the use of either inorganic or organic pillars. 1,5-naphthalenedisulfonate (NDS) anions pillar in an angular fashion to afford fsc-1-NDS, fsc-2-NDS, fsc-3-NDS, fsc-4-NDS and fsc-5-NDS from L1-L5, respectively. Experimental CO2 sorption studies revealed higher isosteric heat of adsorption (Qst) for the compound with the smaller pore size (fsc-1-NDS). Computational studies revealed that there is higher CO2 occupancy about the UMCs in fsc-1-NDS compared to other extended variants that were synthesized with NDS. SiF62- (SIFSIX) anions in fsc-2-SIFSIX form linear pillars that result in eclipse [Cu2(CO2R)4] moieties at a distance of just 5.86 Å. The space between the [Cu2(CO2R)4] moieties is a strong CO2 binding site that can be regarded as being an example of a single-molecule trap; this finding has been supported by modeling studies. Furthermore, we present herein the implementation of the two-step synthetic approach for the construction of novel multinodal MOM platforms, using the trigonal prism cluster [M3(µ3-O)(RCO2)6] as a precursor to build novel stable multinodal 2D and 3D frameworks. In the first step, the bifunctional carboxylate ligands are reacted with Fe+3 or Cr+3 salts to isolate highly symmetrical decorated trigonal prismatic clusters with diverse decoration such as pyridine, amine and cyano coordinating functional groups using pyridine carboxylate, amino carboxylate, cyano carboxylate type ligands, respectively. Afterward, the isolated highly soluble trigonal prismatic salts were reacted in the second step with another metal that can act as node or linker to connect the discrete trigonal prismatic clusters to build 2D or 3D networks. Indeed, we were able to develop another novel high-symmetry Cu cluster [Cu3(µ3-Cl)(RNH2)6Cl6] by utilizing CuCl2 salt and amine decorated trigonal prismatic cluster. Two novel 3D water stable frameworks with acs and stp topologies have been afforded. Our work on the crystal engineering design and synthesis of new MOM platforms offer an exceptional level of control over the resulting structure including; the resulting topology, pore size, pore chemistry and thereby enable the control over the resulting physicochemical properties in a manner that facilitates the achieving of the desired properties.

Ce travail de thèse porte sur la synthèse et la caractérisation de poudres dans les plasmas radiofréquence basse pression de méthane et méthane-azote. Nous avons étudié le rôle du pourcentage d'azote dans le mélange gazeux sur la formation et la structure chimique des particules carbonées. Nous avons analysé l'influence du comportement des particules sur les caractéristiques électriques du plasma. Alors que l'incorporation d'une faible quantité d'azote au sein d'un plasma de méthane retarde la formation des particules sans modifier leur comportement au sein de la décharge, une plus grande incorporation d'azote ([N2]>30%) favorise la création des particules, modifie leur comportement au sein de la décharge et conduit à un phénomène de multi-génération pour les plasmas les plus riches en azote ([N2]>70%). Pour un mélange gazeux particulier de 30%CH4/70%N2, nous avons aussi mis en évidence la présence d'instabilités macroscopiques correspondant à un phénomène d'interactions électrostatiques entre les nuages de particules en limite de gaine cathodique et anodique. Les phénomènes de multi-générations et d'instabilités ont été corrélés avec les variations des caractéristiques électriques du plasma. Différentes techniques d'analyses (MEB, IRTF, XPS, EDAX) sont utilisées pour mettre en évidence les modifications de la taille, de la morphologie et de la composition chimique des particules. Ces analyses nous ont permis de mettre en évidence l'émergence de liaisons azotées CN (simples, doubles et triples) et NH. Pour des mélanges 10%CH4/90%N2 nous avons mesuré un rapport N/C proche de 0,5. Cette forte incorporation d'azote entraîne une graphitisation de la structure des particules.

La prise de conscience de l'importance de la gestion des déchets et de la préservation des ressources a conduit de plus en plus d'acteurs du monde agricole à s'intéresser au compostage comme mode de traitement d'effluents d'élevage ou de boues de stations d'épuration. Les filières d'utilisation de ces substrats, épandage, compostage ou autre, doivent donc être comparées. On sait en effet que l'agriculture est responsable d'une part importante des émissions d'ammoniac (NH3) et de protoxyde d'azote (N2O) et ainsi, indirectement ou directement, de l'augmentation de la concentration de N2O dans l'atmosphère. Trois séries d'expérimentations ont été menées respectivement sur des mélanges d'écorces de peuplier et de fientes de poules pondeuses, sur du fumier de poulet sans ou avec additifs et sur un mélange de paille et de boues de station d'épuration rurale, en parallèle avec un nouveau mélange d'écorces et de fientes. La première a permis de mesurer les émissions de gaz azotés d'un andain (25 m3) en cours de compostage. Elles étaient de 50% environ de l'azote initial sous forme N- NH3 et de moins de 1% sous forme N-N2O. La production de N2O était associée à des activités de nitrification/dénitrification et avait principalement lieu en phase de maturation. La seconde a révélé, pour du compostage de courte durée (1,5 mois) et en taille expérimentale (2 m3), les conditions dans lesquelles les émissions de NH3 et de N2O étaient les plus fortes ou les plus faibles et lesquelles favorisaient l'activité de dénitrification des micro-organismes. L'augmentation du rapport carbone/azote et l'addition de composés ou microorganismes adéquats font passer les pertes en NNH3 de 55 à 7% de l'azote initial. Leur effet sur la libération de N2O (0,2-0,9%) dépend de nombreux facteurs. La troisième a montré que les andains de compostage (10 et 25 m3) devaient être considérés comme des écosystèmes à part entière composés de différents compartiments (grossièrement entrée, fond, sortie et croûte) où les populations microbiennes s'organisent différemment, l'entrée étant productrice de N2O, le fond et la sortie, producteurs, en équilibre ou consommateurs suivant les moments. La taille de l'andain en expérimentation est donc une donnée capitale pour considérer les résultats comme représentatifs de la réalité.

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Shallow marine gas hydrates occurring above the Sulfate-Methane-Interface (SMI) often contain small amounts of H2S beside methane and other hydrocarbons, but the distribution of H2S in these natural samples is not always homogeneous. To learn more about the formation of H2Scontaining hydrates, gas hydrates with different ratios of H2S/CH4 were synthesized under various conditions. The samples were synthesized from ice and water phases, with constant feed gas compositions or controlled changes in feed gas compositions. It turns out that the detailed nature of the synthetic hydrate samples depends on the method of sample preparation. The sample prepared with gas containing small amounts of H2S (1% H2S and 99% CH4) appeared homogeneous in composition, while that prepared in a water-H2S-CH4 system with higher H2S contents was heterogeneous. The samples were analysed with Raman spectroscopy, and differential scanning calorimetry (DSC).

Formation condition data for methane hydrate in ammonia + water and ammonia + water + tetrahydrofunan (THF) systems are very important for the process development and the determination of operation condition for recycling the vent gas of ammonia synthesis using hydrates. This paper focused on the formation conditions of methane hydrate in the presence of NH3 + H2O and NH3 + H2O + THF system. Equilibrium data of methane hydrate in the temperature, pressure and concentration ranges from 277 to 291 K, 0 to 8 MPa, 1 to 5 % ammonia, were obtained. The experimental results indicate that ammonia has an inhibitive effect on hydrate formation. The higher the concentration of ammonia is, the higher the formation pressure for methane hydrate will be.

This work is part of a research project sponsored by the Italian Electricity Agency for CO2 disposal in form of hydrate. The dissociation behavior of CH4 hydrate was taken as a reference for the study of the CO2 hydrate preservation. The formation and dissociation of CO2 and CO2–THF mixed hydrates, compared to CH4 and CH4 – THF mixed hydrates, has been considered. The experimental tests were performed in a 2 liter reaction calorimeter at pressures between 0.1 and 0.3 MPa. The dissociation has been followed at temperatures from -3 °C to 0 °C for CO2 and CH4 hydrates, and from -3 °C to 10 °C for THF mixed hydrates. More than pressure, which is very important for methane hydrates, temperature affects the preservation of CO2 and CO2–THF mixed hydrates. Subcooling after formation is important for methane hydrate preservation, but it does not substantially affect CO2 hydrate stability. In the studied P, T range, CO2 hydrate does not present any anomalous self-preservation effect. The mixtures containing more ice show a slower dissociation rate. Methane hydrate requires less energy to dissociate than CO2 hydrate and, therefore, is less stable. On the contrary, the mixed CO2 – THF hydrates are less stable than the mixed methane hydrates. Modulated differential scanning calorimetry (MDSC) has been used for hydrate characterization: both CH4 and CO2 hydrates include two decomposition peaks, the first due to the melting of the ice and the second to the decomposition of the hydrate. The higher temperature of the decomposition peak of CO2 hydrate confirms its higher stability respect to CH4 hydrate.

Aquatic plants or macrophytes are known as conduits of Methane (CH4), Carbon dioxide (CO2) and Nitrous oxide (N2O) which contribute to the total fluxes of the Greenhouse gases emissions from lakes. Recent studies emphasized that the knowledge on plant mediated emissions calls for more systematic and comparative data especially in the areas of spatial and temporal variability. In this study I measured diel (24 hour) and diurnal(  daily hours only) plant mediated fluxes during four sampling sessions using chamber method from a  Swedish lake in summer 2012. The measurements were conducted on two macrophyte population patterns of mixed plant communities and Equisetum fluviatile (specie-specific) community. CH4 emissions were higher in darker hours and there were no diel correlation between CH4 fluxes and average diel temperature. CH4 fluxes varied between 0.42 mmol m-2d-1 and 2.3 mmol m-2d-1. The CO2 fluxes had negative fluxes in day and positive during the day which was logical due to macrophyte respiration and photosynthesis mechanisms. Occasional daily positive fluxes were seen (only) during the rainy hours and there were no correlation between temperature and diel CO2 fluxes. The total net CO2 exchange was 2.8mmol m-2d-1 indicating that there was more CO2 release in the littoral zone of that lake. N2O fluxes did not show any clear diel or monthly pattern and the fluxes ranged between positive and negative numbers. The N2O fluxes did not exceed 2µmol m-2 d-1 with the total average flux of 0.8µmol m-2 d-1.

Unconformity-type uranium deposits from the Athabasca Basin are considered to be the result of mixing between oxidized basinal brines and basement-derived reduced fluids/gases, and/or reduced basement rocks. Graphite and/or its breakdown products are suggested to be responsible for uranium mineralization by acting as a reductant that could trigger deposition of uranium. Also, graphite is considered to be indicative of basement structures; being often concentrated along structures which can be identified as electromagnetic (EM) conductors. Thus, exploration for uranium deposits is often focused on the search for EM conductors. Underlying the sedimentary rocks of the basin in the Dufferin Lake zone are variably graphitic pelitic schists (VGPS); altered to chlorite and hematite (Red/Green Zone: RGZ), and locally bleached equivalents near the unconformity during paleoweathering or later fluid interactions. These altered zones are texturally similar rocks within “graphite-depleted zones” as the unconformity is approached. Both zones are characterized by a lower concentration of carbon and sulfur, with the bleached zone showing higher concentrations of uranium and boron, the latter corresponding to high dravite content. The major element composition of the graphite-bearing pelitic schists and altered equivalents (RGZ) are similar. Raman analyses indicate that well-ordered carbon species (graphite to semi-graphite) are present in the pelitic schists, with both types more common within shear zones. In contrast, only rare low-ordered carbon species (carbonaceous matter) were detected in the graphite-depleted samples within the RGZ. This variation is interpreted to be the result of graphite consumption by oxidizing fluids migrating downward from the Athabasca Group. This graphite consumption may have resulted in the production of a mobile reductant (gas or fluid), which may have played a subsequent role in the deposition of uranium mineralization. Secondary fluid inclusions (FI) examined in different quartz vein generations using microthermometry and Raman analysis, provide an indication of the fluids that have interacted with these rocks. Monophase vapor are the dominant type of fluid inclusions in the VGPS, whereas aqueous two-phase (L+V) and three-phase (L+V+Halite) FI occur in the RGZ. CH4-dominant and N2-dominant FI identified using Raman could be the result of fluid(s) interaction with the graphitic lithologies. This would have generated the breakdown of graphite to CH4 and associated feldspars/micas to NH4/N2. CH4, N2 and H2 (resulting from the decomposition of NH4+) represent possible reductants of uranium-bearing brines. Two brines in the RGZ: a regional basinal fluid and an evolved fluid possibly related to U mineralization; similar to other nearby deposits, are observed. These suggest that the basinal brines have circulated in the basement rocks and have been able to evolve by interaction with the basement rocks to possibly be related to uranium mineralization.

Many agricultural biogas stations process predominantly phytomass specifically grown for power engineering purposes as a primary raw material. This results in gradual increase of maize proportion in sowing sequences at the exclusion of traditional area-specific crops, which presents various potential negative effects. The aim of study is to evaluate the substitution of maize with wheat straw in the anaerobic fermentation process from the biotechnological and economic viewpoint. For this purpose, wheat straw pellets were pretreated using the high-pressure extruder in compliance with UV CZ 21314 at different runtime parameters. Cumulative methane (CH4) production in quarter-mode operation simulation, based on the extrusion pressure, cycle duration and fermentation temperature, was the main evaluation criteria. Optimal run time parameters were derived from the approximation ? extrusion pressure 1,35 MPa, reaction time 210 s, in order to achieve maximal CH4 production at mesophilic fermentation temperature (38 °C). For fermentation temperature 48 °C, optimal pressure 1,25 MPa and cycle duration 180 s were approximated. The discount rate of Net Present Value (NPV) was established as a main comparative criterion considering overall executive, legislative and technological aspects of analyzed biological effects. Based on these findings suggest, wheat straw extrusion is interesting, unconventional and profitable technology in the field of biogas production.