Ce travail a porté sur la conversion du méthane en hydrogène par les procédés de vaporeformage et reformage à sec, utilisant de nouvelles formulations de catalyseurs afins d'augmenter la sélectivité en produit désiré (H₂), de réduire la production du monoxyde de carbone (CO) et défavoriser la formation de coke. Deux familles de catalyseurs, à base de nickel et de ruthénium supportés par la cérine et/ou l'alumine, ont été évaluées dans ces réactions. Il a été montré que les catalyseurs à base de ruthénium supportés par l'alumine présente une bonne activité catalytique et une très bonne résistance au dépôt de coke dans les réactions de reformage du méthane. La cérine joue un rôle déterminant dans les catalyseurs à base de nickel en favorisant la dispersion de la phase active et évitant la formation des agglomérats. Parallèlement, une inhibition de la formation de coke est observée grâce aux propriétés redox du solide. Les travaux ont porté également sur l'amélioration de la formulation des catalyseurs monométalliques, et un catalyseur bimétallique (Ru-Ni/CeO₂-Al₂O₃) actif, sélectif et stable pour la production d'hydrogène à partir du méthane a été mis au point. L'ajout d'un deuxième métal en faible teneur (0,5%) aide à maintenir le Ni sous sa forme actif empêchant la formation de coke sur la surface du catalyseur. Pour les deux réactions étudiées, les excellentes performances obtenues proviennent essentiellement de l'ajustement des paramètres de réaction et les paramètres de préparation des catalyseurs, ce qui ouvre de réelles perspectives d'application industrielle. / This work has focused on the methane conversion by steam reforming and dry reforming processes, through new catalyst formulations in order to increase the selectivity of expected products (H₂), to reduce carbon monoxide production (CO) and to limit the coke formation. Two categories of catalysts were evaluated in these reactions : nickel-based catalysts and ruthenium-based catalysts supported by ceria and/or alumina. It has been reported that the ruthenium-based catalysts supported by alumina provide important catalytic activity and high resistance to coke deposition in the methane reforming reactions. Ceria played a determining role in the nickel-based catalysts by enhancing the active phase dispersion without agglomerates and coke formation. Works have also continued on the improvement of the monometallic catalyst and an active bimetallic catalyst (Ru-Ni/CeO₂-Al₂O₃), selective and stable in hydrogen production from methane has been developed. The addition of a second metal helps maintaining Ni in its active form, preventing the coke formation on the catalyst surface. For the two considered reactions, the excellent performance was largely due to the adjustment of the reactions and catalyst parameters offering a real potential industrial application.

M.Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology / Water contaminated with non-biodegradable organics is becoming increasing problematic as it has a hazardous effect on human health and the aquatic environment. Therefore, the removal of organic contaminants is of importance and an active heterogeneous Fenton catalyst is thus required. The literature indicates that a bimetallic oxide Fenton catalyst is more active than an iron oxide catalyst. This study focused on increasing the activity of iron-based Fenton catalysts with the addition of transition metals such as manganese, cobalt and copper and optimizing the preparation method. In this study, bimetallic oxide (Fe-Cu, Fe-Mn, Fe-Co) and monometallic oxide (Fe, Cu, Mn,Co) catalysts supported on silica SiO2 where prepared by incipient wetness impregnation. The total metal oxide contents were kept constant. The catalysts where calcined in two different ways, in a conventional oven and in a microwave. These catalysts were characterized with XRD, XPS and CV and were tested for the degradation of methylene blue dye at 27°C. The catalysts calcined in a microwave oven had a higher catalytic activity than those prepared in a conventional oven. The bimetallic oxide catalysts outperformed the mono- metallic oxide catalysts in the degradation of methylene blue. The Fe2MnOx prepared by microwave energy were the most active catalyst yielding the highest percentage of degradation of methylene blue dye (89.6%) after 60 minutes. The relative amounts of manganese and iron oxide were varied while keeping the total metal content in the catalyst the same. The optimum ratio of Fe to Mn was 1:7.5 since it yielded the most active catalyst. A 96.6 % removal of methylene blue was achieved after 1 hour of degradation. Lastly this ratio 1Fe:7.5Mn was prepared by varying different microwave power (600, 700 and 800 W) and irradiation time (10, 20 and 30 min). The optimum microwave power and irradiation time was 800W and 10 min with the methylene blue percentage removal of 96.6 % after 1 hour of degradation.

Les aminopeptidases sont des cibles thérapeutiques importantes pour plusieurs maladies, car elles sont impliquées dans divers processus physiologiques et pathologiques comme la progression tumorale, l'angiogenèse, et certaines infections (virales, bactériennes, et parasitaires). Il en existe deux classes : les aminopeptidases avec un ion métallique (Aminopeptidase N [APN ou CD13] et leukotrien A4 hydrolase [LTA4H]) et les aminopeptidases avec deux ions métalliques (Aminopeptidase de l'Aeromonas proteolytica [APaero], Leucine Aminopeptidase cytosolique [LAPc] et Méthionine aminopeptidase 1 ou 2 [MetAP]). Deux types de composés dérivés des amino-benzosubérones ont été envisagés pour inhiber sélectivement chacune de ces classes d'aminopeptidases. L'étude des relations structures-activités (RSA) nous a permis de découvrir une molécule très puissante et sélective de l'APN (Ki 60 pM). L'APN est une enzyme monométallique considérée aujourd'hui comme une nouvelle cible pour la lutte contre le cancer car son inhibition bloque le processus de l'angiogenèse et donc la progression tumorale. L'étude d'une nouvelle classe de molécules trisubstituées dérivées des amino­benzosubérones a abouti à la découverte d'une seconde molécule active et sélective des enzymes bimétalliques notamment l'APaero (Ki 10 nM). / The aminopeptidases are important therapeutic targets for several diseases, because they are implied in various physiological and pathological processes like the tumoral progression, the angiogenesis, and certain infections (viral, bacterial, and parasitic). There are two classes: aminopeptidases with one metal ion (Aminopeptidase N [APN or CD13] and leukotriene A4 hydrolase [LTA4H]) and aminopeptidases with two metal ions (Aminopeptidase of Aeromonas proteolytica [APaero], cytosolic leucine aminopeptidase [LAPc] and Methionine aminopeptidase 1 or 2 [MetAP]). Two types of compounds of amino-benzosuberone derivatives were envisaged to inhibit selectively each one of these classes of aminopeptidases. The study of the structure-activity relationship (SAR) enabled us to discover a very powerful and selective molecule of the APN (Ki 60 pM). The APN is a monometallic enzyme considered today as a new target for the fight against cancer because its inhibition blocks the angiogenesis process and thus the tumoral progression. The study of a new class of trisubstituted molecules derived from the amino-benzosuberone led us to discover another molecule which is active and selective of the bimetallic enzymes in particular APaero (Ki 10 nM).