Thesis (Ph. D.)--Institute of Paper Chemistry, 1953. / Includes bibliographical references (p. 106-108).

Nitrogen is known to be a limiting factor in polluted environments, however many studies overlook the potential role for nitrogen to significantly influence the removal rate and efficiency with which microorganisms can degrade aromatic hydrocarbons. In this study, inoculated and uninoculated aerated soil microcosms containing different s-triazines were examined for their ability to efficiently and rapidly treat contaminated soils containing naphthalene, nitrobenzene, and toluene (NNT), via a microbial consortium consisting of Pseudomonas, Rhodococcus, and Aeromonas. After an experimental period of 14 days, greater than 90% degradation of NNT supplemented with different s-triazines, at concentrations of 1000-3000 ppm was observed. A difference in the degradation of NNT was seen in inoculated box reactors supplemented with cyanuric acid, melamine, and atrazine in comparison to uninoculated box reactors. Combined usage of 16s rDNA and 16s rRNA analysis was then applied to study the bacterial communities, and determine the abundance and survival of inoculated strains within box reactors contaminated with NNT. The bacterial diversity within clone libraries obtained illustrated a dominance of proteobacteria and gram positive bacteria. Analysis from clone libraries also showed that inoculated strains did survive within each condition, but were not the most predominant members present in the communities. This research shows that significant removal of NNT can be achieved in two weeks with the supplementation of one of the s-triazines. However, differences in degradation and the microbial populations present within contaminated communities will be seen depending on which nitrogen sources are used and whether or not environments are bioaugmented or not.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1950. / Includes bibliographical references (p. 65-66).

Water pollution represents one of the major concerns of the modern world, after scientific and industrial development that generates hazardous organic and inorganic contaminants. Biochar (BC) has gained tremendous attention in the past decade as a cheap and efficient adsorbent for organic and inorganic contaminants from aqueous solutions. BC is considered to be a low-cost alternative to activated carbon, however, BC typically suffer performance reductions due to their low surface areas and poor mechanical properties. The main objective of this work is to develop novel biochar materials by modifying the biochar surface for the removal of organic and inorganic contaminants from water. In recent years, biochar modifications involving various methods such as, acid/base treatment, impregnation of mineral sorbents, functional groups incorporation, steam activation and magnetic modification have been widely studied. Chapter I summarizes these biochar modification methods. In Chapter II, Chitosan-Modified fast pyrolysis BioChar (CMBC) was used to remove Pb2+ from water. CMBC was made by mixing pine wood biochar with a 2% aqueous acetic acid chitosan (85% deacylated chitin) solution followed by treatment with NaOH. CMBC removed more Pb2+ than non-modified biochar suggesting that modification with chitosan generates amine groups on the biochar surface which enhance Pb2+ adsorption. Chapter III describes the fast nitrate and fluoride adsorption and magnetic separation from water on iron oxide particles dispersed on Douglas Fir biochar. Nitrate and fluoride adsorption occurred by electrostatic attraction over the wide 2 to 10 pH range. In the chapter IV, aniline and nitrobenzene removal from water was studied using magnetized and nonmagnetized Douglas Fir biochar. The adsorption of aniline and nitrobenzene occurred mainly through pi-pi electron interactions over the wide 2 to 12 pH range and H-bonding. The surface morphology, chemistry, and composition of the modified biochars were examined by SEM, SEM-EDX, TEM, PZC, XPS, XRD, FTIR, TGA, DSC, elemental analysis, and surface area measurements.

It was found that there exist three major water environments when water is dissolved in nitrobenzene. 2H NMR has proved that these solvatomers exist irrespective of whether lithium salt is added to the system. 7Li NMR experiments suggested that the first solvatomer is majority nitrobenzene, the second a mixed solvation shell consisting of nitrobenzene and water and the third solvatomer is a large water aggregated at the glass surface. The mixed solvation state is short lived and is promoted by addition of water of by supersaturating the system upon cooling. This is a high energy state and decays either into the homogenous bulk NB state or to the surface of the glass wall, depending on if glass surface is present. In the 7Li NMR experiments, the hydrophobicity of the salt, determined by the anion, affects the relative intensity of the three 7Li resonances. Addition of lithium serves to promote hydrogen bonding in the majority nitrobenzene solvatomer, as confirmed by FTIR and neutron diffraction studies. There is no evidence that it has an effect on the size of the mixed solvatomer or the water aggregate immobilized on the glass surface. A reasonable hypothesis is that lithium exchanges between the water species which are formed independent of lithium involvement. The system is summarized as follows: Below critical water concentration (~200mM) nitrobenzene/water is a homogeneous distribution of water molecules in nitrobenzene. Addition of lithium salt to such a system has two main affects. First, the lithium promotes hydrogen bonding between the dissolved water molecules, as confirmed by FTIR and neutron scattering. Second, the hydrogen bonded water may precipitate causing microheterogeneity of the system, leading to a second resonance observed in both the 2H and 7Li NMR spectra (LiNB/W). In the presence of glass, a third solvation state can nucleate at the glass surface; this solvation state has character even closer to that of bulk water (LiW). These two supplementary solvation states can be artificially induced by either adding aliquots of water or cooling.

Past operational practices at chemical manufacturing facilities and widespread use of synthetic chemicals in agriculture, industry, and military operations have introduced many anthropogenic compounds to the biosphere. Some of them are readily biodegradable as a likely consequence of bacterial evolution of efficient degradation pathways, whereas others are partially degraded or persistent in the environment. Insight about biodegradation mechanisms and distribution of bacteria responsible provide the basis to predict the fate of synthetic chemicals in the environment and to enable bioremediation. The main focus of the research described here encompasses basic science to discover pathways and evolutionary implications of aerobic biodegradation of two specific synthetic chemicals, cis-dichloroethene (cDCE) and diphenylamine (DPA). cDCE is a suspected carcinogen that frequently accumulates due to transformation of perchloroethene and trichloroethene at many contaminated sites. Polaromonas sp. strain JS666 is the only isolate able to use cDCE as the growth substrate, but the degradation mechanism was unknown. In this study, the degradation pathway of cDCE by strain JS666 and the genes involved were determined by using heterologous gene expression, inhibition studies, enzyme assays, and analysis of intermediates. The requirement of oxygen for cDCE degradation and inhibition of cDCE degradation by cytochrome P450 specific inhibitors suggested that cytochrome P450 monooxygenase catalyzes the initial steps of cDCE degradation. The finding was supported by the observation that an E. coli recombinant expressing cytochrome P450 monooxygenase catalyzes the transformation of cDCE to dichloroacetaldehyde and small amounts of the epoxide. Both the transient accumulation of dichloroacetaldehyde in cDCE degrading cultures and dichloroacetaldehyde dehydrogenase activities in cell extracts of JS666 further support a pathway involving the degradation of cDCE through dichloroacetaldehyde. Molecular phylogeny of the cytochrome P450 gene and organization of neighboring genes suggest that the cDCE degradation pathway evolved in a progenitor capable of degrading dichloroacetaldehyde by the recruitment of the cytochrome P450 monooxygenase gene from alkane assimilating bacteria. The discovery provides insight about the evolution of the aerobic cDCE biodegradation pathway and sets the stage for field applications. DPA has been widely used as a precursor of dyes, pesticides, pharmaceuticals, and photographic chemicals and as a stabilizer for explosives, but little was known about the biodegradation of the compound. Therefore, bacteria able to use DPA as the growth substrate were isolated by selective enrichment from DPA-contaminated sediment and the degradation pathway and the genes that encode the enzymes were elucidated. Transposon mutagenesis, the sequence similarity of putative open reading frames to those of well characterized dioxygenases, and 18O2 experiments support the conclusion that the initial reaction in DPA degradation is catalyzed by a multi-component ring-hydroxylating dioxygenase. Aniline and catechol produced from the initial reaction of DPA degradation are then completely degraded via the common aniline degradation pathway. Molecular phylogeny and organization of the genes involved were investigated to provide insight about the evolution of DPA biodegradation. The fate and transport of toxic chemicals are of a great concern at several historically contaminated sites where anoxic contaminant plumes emerge into water bodies. The release of toxic chemicals to overlying water poses a potential source of environmental exposure. Bench scale studies were conducted to evaluate the impact of biodegradation on the transport of toxic chemicals across the sediment/water interface. These studies demonstrated that substantial populations of bacteria associated with organic detritus at the interface rapidly biodegrade toxic chemicals as they migrate from contaminated sediment to overlying water, suggesting that the natural attenuation processes serve as a remedial strategy for contaminated sediments and protect the overlying water.

Le travail décrit dans cette thèse vise à produire des nanostructures bien ordonnées présentant une forte activité catalytique sur la base d’ensembles de nanoparticules de ruthénium et de fullerènes/fullerènes fonctionnalisés. Le Chapitre 1 présente une analyse bibliographique sur l’utilisation des fullerènes en catalyse hétérogène, en mettant en avant leurs propriétés particulières telles que la stabilité thermique, une grande capacité d'adsorption d'hydrogène et la capacité d’obtenir diverses coordinations. Le Chapitre 2 décrit la synthèse et la caractérisation de nanostructures Ru@C60 obtenues par la réaction de décomposition par au dihydrogène du complexe [Ru(COD)(COT)] en présence de C60. L'effet du solvant et des rapports de Ru/C60 utilisés durant la réaction ont été étudiés. Plusieurs caractérisations d’objets sphériques Ru@C60 et des calculs DFT nous permettent de proposer une voie pour leur formation. Le Chapitre 3 présente la préparation de nouveaux nano-assemblages obtenus à partir de [Ru(COD)(COT)] et de fullerènes fonctionnalisés en utilisant la même méthode décrite dans le chapitre 2. Tout d'abord la synthèse de fullerènes fonctionnalisés C66(COOH)12 est détaillée, puis la synthèse et la caractérisation des nanostructures Ru@C66(COOH)12 ont été étudiés. Le Chapitre 4 décrit l'utilisation de ces nanomatériaux en catalyse. Nous avons préparé trois Ru@fullerene: Ru@C60 dans du dichlorométhane, T-Ru@C60 dans le toluène et Ru@C66(COOH)12. Ensuite, l'activité catalytique et la sélectivité des catalyseurs préparés Ru@C60, T-Ru@C60 et Ru@C66(COOH)12 ont été étudiées pour l'hydrogénation du nitrobenzène et du cinnamaldéhyde. Des calculs DFT ont permis de rationaliser les résultats obtenus pour l'hydrogénation sélective de nitrobenzène sur Ru@C60. / The work described in this thesis aims to produce well-ordered nanostructures presenting high catalytic activity, on the bases of the assembly of ruthenium nanoparticles and fullerene/functionalized fullerene. Chapter 1 provides a review on the use of fullerene and fullerene-based materials in heterogeneous catalysis, emphasizing their specific properties such as thermal stability, high capacity for hydrogen adsorption and the ability of various coordination modes. Chapter 2 describes the synthesis and characterization of Ru@C60 nanostructures produced by the decomposition reaction of [Ru(COD)(COT)] in the presence of C60. The effect of the solvent and ratios of Ru/C60 on the course of the reaction have been investigated. Several characterizations of spherical Ru@C60 objects and DFT calculations allow us to propose a pathway for their formation. Chapter 3 presents new nano-assembly preparation based on [Ru(COD)(COT)] and functionalized fullerene using the same method as they are described in chapter 2. First, the synthesis of functionalized fullerene C66(COOH)12 is detailed, and then the synthesis and characterization of Ru@C66(COOH)12 is studied. Chapter 4 describes the use of these nanomaterials in catalysis. We have prepared three Ru@fullerene catalysts, which are Ru@C60 in dichloromethane, T-Ru@C60 in toluene, and Ru@C66(COOH)12. Then, the catalytic activity and selectivity of the prepared catalyst Ru@C60, T-Ru@C60 and Ru@C66(COOH)12 are studied for the hydrogenation of nitrobenzene and cinnamaldehyde. DFT calculations allow to rationalize the results obtained for the selective hydrogenation of nitrobenzene over Ru@C60.

The development of nanoscale heterostructure photocatalysts for the effective, direct utilization of visible light (400-750 nm, ~44% of solar spectrum) to drive important chemical conversions is a prime research area in the field of photocatalysis. Particles at nanoscale dimensions have a large surface area-to-volume ratio, expose a high number of active surface sites, and exhibit unique electronic properties (different from bulk) that are beneficial for improving the overall catalytic activity. However, the advantages of size reduction are often overshadowed by the low optical absorption (as absorption power  size3) and colloidal instability (extensive aggregation) of particles at the nanoscale. In this dissertation, we demonstrate a strategy to improve the colloidal stability and enhance the optical absorption of nano-sized semiconductor and metal nanoparticles (NPs) that exhibit weak visible light absorption. The colloidal, free-standing NPs are placed on transparent, dielectric silica nanospheres (SiOx NSs) that act as optical antenna supports, forming SiOx/NP composite nanostructures. The spherical morphology of SiOx enables scattering resonances (Fabry Perot or Whispering Gallery Modes) which enhances the local electric field on or near the surface of the NS. The NPs placed on the surface of SiOx NS interact with the locally enhanced electric field and exhibit improved optical absorption. By varying the size of the SiOx NS, the resonance wavelengths and the intensity of the local electric field enhancement can be tuned, offering the ability of such structures to effectively utilize a wide range of energies in the visible region. Composite nanostructures comprised of various classes of nanomaterials such as metal-doped semiconductor, plasmonic, and non-plasmonic metal NPs were investigated to perform the desirable solar-to-chemical transformations. First, we employed SiOx-loaded silver-doped silver chloride (SiOx/AgCl(Ag)) photocatalyst to investigate the role of metal-induced gap states in AgCl, a wide bandgap semiconductor. SiOx/AgCl(Ag) exhibit high catalytic performance and photostability after 10 cycles of the probe reaction, methylene blue (MB) degradation under visible light irradiation. The results indicate that the visible light absorption due to metal-induced gap states can be further improved by employing the SiOx NSs as supports that act as optical nanoantenna. We then studied the influence of NP size on the catalytic activity to understand the effect of size in promoting the generation and transfer of hot electrons to surface adsorbates. Our findings indicate that upon employing Ag NPs of different particle size (<10 nm and >10 nm) and normalizing for the optical absorption and moles of surface Ag atoms, the efficient generation and transfer of photoexcited hot electrons is favored in the small-sized Ag NPs (size <10 nm) than bigger Ag NPs. Next, we investigated the selective partial hydrogenation of nitroarene to N-aryl hydroxylamine using SiOx-loaded platinum (SiOx/Pt) photocatalysts. We found that change in the surface electronic structure of the small Pt NPs (size <5 nm) due to light illumination and surface modification (by adding suitable organic ligands), minimize the adsorption of the electron-rich hydroxylamine molecules and minimize their complete conversion to aniline, resulting in high N-hydroxylamine selectivity. Overall, our work shows that well-controlled composite nanostructures comprising of active catalyst loaded on dielectric SiOx NS supports that act as optical nanoantenna are a promising class of photocatalysts for driving photon-to-chemical transformations with high activity and product selectivity. / Chemistry

Le paracétamol est un analgésique parmi les plus consommés dans le monde. Les synthèses actuelles de cette molécule induisent la formation de quantités non-négligeables de sels ou de produits secondaires non valorisables. En plus d'induire de faibles économies d'atomes, la présence de ces déchets engendre des surcoûts importants pour la synthèse du paracétamol dus aux lourds traitements des réactions. Les objectifs de la thèse étaient à la fois de proposer une synthèse plus respectueuse de l'environnement mais également économiquement viable. En ce sens, deux synthèses du paracétamol ont été étudiées. La première synthèse étudiée concerne la réduction sélective du nitrobenzène en p-aminophénol, l'intermédiaire clé du paracétamol. Cette synthèse nécessite typiquement une quantité importante d'acide sulfurique qui est corrosif et engendre la formation de sels (sulfate d'ammonium) importante. Un catalyseur acide recyclable à base d'oxyde de niobium a été utilisé et associé à l'acide sulfurique. Ainsi les sélectivités en aminophénol de 74 % sans catalyseur de niobium ont été améliorées à 82 % en présence de ce catalyseur. En outre, la quantité d'acide sulfurique a été réduite au minimum sans pertes significatives de sélectivité. La deuxième synthèse est la substitution de l'hydroquinone par l'acétate d'ammonium en milieu acide acétique. Cette synthèse innovante s'est révélée être particulièrement performante car elle induit la formation du paracétamol en une étape en partant d'un produit disponible en grande quantité, avec de très bons rendements et sélectivités. De plus, un test à large échelle a permis de montrer que le paracétamol produit est facilement récupérable par précipitation et l'acide acétique récupérable par distillation. Enfin, la réaction a été testée avec succès à d'autres polyhydroxybenzènes et aux naphtols / Paracetamol is an analgesic among the most consumed in the world. Currents syntheses of paracetamol induce a quantity of salts and non-reusable by-products. These wastes lead to both a low atom economy and a high process cost due to the work-ups. The main objectives of this thesis were to propose eco-friendly and competitive synthesis of paracetamol. Two syntheses have been studied. The first one was the selective reduction of nitrobenzene to p-aminophenol, the key intermediate of paracetamol. This synthesis requires a large amount of sulphuric acid which is corrosive and induces salts formation. A reusable niobium oxide-based catalyst has been associated with sulphuric acid. This association gave better selectivities to aminophenol (82%) compare to sulphuric acid alone (74%). Moreover, the quantity of sulphuric acid has been minimized without significant loss of selectivities. The second synthesis study was the hydroquinone substitution to paracetamol with ammonium acetate in acid acetic. This new synthesis is very powerful due to the one-step synthesis of paracetamol from bulk quantity available products, with very good conversion and selectivity. Moreover, a large scale synthesis has been tested which demonstrates that paracetamol and acetic acid were easily recovered by precipitation and distillation, respectively. The reaction has been successfully extended to other polyhydroxybenzenes and naphtols

<p>In electrochemical oxidation treatment of wastewater, the electrode material is an important parameter in optimizing oxidative electrochemical processes, since the mechanism and products of several anodic reactions are known to depend on the anode material. The electrochemical oxidation of benzaldehyde, nitrobenzene and m-cresol on bare boron-doped diamond (BDD) electrode was investigated. Cytochrome c was then electrochemically immobilsed onto the functionalized BDD electrode by cyclic voltammetry. Oxidation and reduction reaction mechanism of each flavonoid was studied. There was one oxidation and reduction peaks for quercitin and catechin respectively, and two oxidation and two reduction peaks for rutin. The cytochrome c modified BDD electrode showed good sensitivity for all three flavonoids and low detection limits i.e. 0.42 to 11.24 M as evaluated at oxidation and reduction peaks, respectively.</p>