There are many problems associated with the use of fossil fuels to produce fuels and chemicals, and lignocellulosic biomass stands as a promising alternative fuel/chemical feedstock. Large scale processing of biomass will likely take place in high temperature liquid water due to the low vapor pressure and polar nature of carbohydrates. However, little is known about the material stability of these catalysts in high temperature aqueous phase environments. This dissertation aims to investigate the structural integrity of some common catalytic materials under typical biomass reforming conditions. There are 3 main objectives of this study: 1) identify potentially stable candidates from commonly used materials, 2) understand the mechanism(s) by which these catalysts degrade, 3) design/modify catalysts in an effort to increase their hydrothermal stability. The two main materials investigated in this work are zeolites (faujasite, ZSM-5) and γ-Al2O3 as these are commonly used as catalysts and catalyst supports. A number of physicochemical techniques were used to characterize the materials as a function of treatment time at conditions relevant for biomass reforming. For zeolites, the major findings are that ZSM-5 framework is highly stable whereas faujasite stability depends on the Si/Al ratio, where silicon rich materials are less stable. For γ-Al2O3 based catalysts, it was found that the alumina support hydrates and undergoes a phase transformation to form crystalline boehmite (AlOOH) with a subsequent loss in surface area and Lewis acid sites. When metal particles are present on the support, the phase change kinetics are slowed. The role of metal precursor on the stability of γ-Al2O3 supported catalysts was also explored, and it was found that the precursor used in catalyst synthesis changes the boehmite formation kinetics and also affects alumina support dissolution. The final thrust aims to stabilize a Pt/γ-Al2O3 catalyst by depositing silicon on the catalyst surface. The silicon modification is effective in protecting the catalyst from boehmite formation upon exposure to hot liquid water while also stabilizing metal particles against sintering. Additionally, an increase in turnover number for hydrogen production via aqueous phase reforming of sorbitol was observed.

Air pollution by sulfur dioxide is of great concern due to its harmful effects on environment, human beings, fauna and flora. Fossil-fuel-fired power plants are one of the major sources of SO2 emissions. Typically the concentration of SO2 in the flue gases of these plants is in the range of 2000 to 20000 ppm. Flue gas desulfurisation is one of the widely practiced strategies to control SO2 emissions. Aqueous phase oxidation of sulfur dioxide catalysed by carbonaceous particles is an attractive alternative to the conventional processes for flue gas desulfurisation because, amongst other reasons, sulfuric acid, the product of aqueous phase oxidation, finds extensive application in industry. In the literature it has been reported that sulfuric acid affects the solubility of sulfur dioxide and that activated carbon catalyses aqueous phase oxidation. However there is hardly any report on the systematic evaluation of the mechanism of the heterogeneous aqueous phase oxidation of sulfur dioxide which takes into account among other factors, the effect of sulfuric acid on the solubility of SO2 (particularly, at low levels of SO2 and sulfuric acid concentrations). Therefore the objective of the present work is to evaluate systematically the aqueous phase oxidation of SO2 in ppm levels with activated carbon as catalyst in a three-phase agitated slurry reactor and to model rigorously the solubility of SO2 in ppm levels in dilute sulfuric acid solutions and to estimate the concerned parameters experimentally. Strong effect of dilute concentrations of sulfuric acid on the solubility of SO2 is analyzed in terms of the influence of the acid on the equilibrium concentrations of the ionic species (HSO3¯ and SO4¯2 formed from the hydrolysis of SO2 (aq) and the dissociation of H2SO4 respectively) in SO2 - dil. H2SO4 systems. The analysis leads to a general expression relating the partial pressure of SO2 in the gas phase to the concentration of total dissolved SO2 and the concentration of sulfuric acid in the solution. Simple equations are obtained from the general expression for the cases of zero and high concentrations of sulfuric acid in the system, which in turn lead to direct experimental determination of the parameters, Henry's law constant and the equilibrium constant of hydrolysis of SO2 (aq). The developed model predicts the present experimental data as well as the data reported in the literature very closely. The dissolution of SO2, the hydrolysis of SO2 (aq) and the dissociation of H2SO4 are found to be instantaneous. From the dependency of the parameters on temperature, the heat of dissolution of SO2 is determined to be -31.47 kJ mol"1 and the heat of hydrolysis to be 15.69 kJ mol"1. The overall heat of solubility of sulfur dioxide is therefore -15.78 kJ mol"1. Preliminary reaction experiments have clearly indicated that SO2 (aq) does not react and HSO3¯ is the only reactant for aqueous phase oxidation of sulfur dioxide catalysed by activated carbon. The non-reactant SO2 (aq) deactivates the oxidation reaction by competing with HSO3¯ for adsorption on the active sites of the catalyst particles. However the catalyst particles become saturated with SO2 (aq) beyond a certain value of its concentration (saturation limit), which depends on temperature. A mechanism is proposed based on these observations to develop a rate model. The rate model also takes into account the effect of the concentration of the product sulfuric acid on the solubility of sulfur dioxide. The model predicts first order in HSO3¯ , half order in dissolved oxygen and a linear deactivation effect of 5O2(ag). The oxidation reaction is evaluated experimentally at various levels of the operating variables such as temperature and the concentrations of sulfur dioxide and oxygen in the inlet gas. In all experiments a pseudo steady-state region is observed where the gas phase concentration of SO2 reaches a steady value but the concentrations of HSO3¯ and total S (VI) in the liquid phase continue to change. Pseudo steady-state considerations lead to the determination of the initial estimates of the parameters of the rate model namely, the rate constant and the deactivation constant. These parameters are estimated from the transient profiles of the product (sulfuric acid) by solving the model equations by Runge-Kutta method along with Marquardt's non-linear parameter estimation algorithm. The predictions of the model with the estimated parameters match very well with the experimentally observed concentration profiles of S(VI) and HSO3 in the liquid phase and SO2 in the gas phase. The deactivation constant in the saturation range is independent of temperature and is 0.27, which indicates that the intrinsic rate constant is about four times greater than the observed rate constant. From Arrhenius equation-type dependency of the parameters on temperature, the activation energy for the oxidation reaction is determined to be 93.55 kJ mol"1 and for deactivation to be 21.4 kJ mol"1. The low value of activation energy for deactivation suggests a weak dependency of the deactivation on temperature, which perhaps is due to the weak nature of the chemisorption of SO2 (aq) on carbon.

Multiple hydrocarbon phases are observed during miscible gas floods. The possible phases that result from a gas flood include a vapor phase, an oleic phase, a solvent-rich phase, a solid phase, and an aqueous phase. The solid phase primarily consists of aggregated asphaltene particles. Asphaltenes can block pore throats or change the formation wettability, and thereby reduce the hydrocarbon mobility. The dissolution of injected gas into the aqueous phase can also affect the gas flooding recovery because it reduces the amount of gas available to contact oil. This is more important in CO₂ flooding as the solubility of CO₂ in brine is much higher than hydrocarbons. In this research, we developed efficient and fast multi-phase equilibrium calculation algorithms to model phase behavior of asphaltenes and the aqueous phase in the compositional simulation of gas floods. The PC-SAFT equation of state is implemented in the UTCOMP simulator to model asphaltene precipitation. The additional computational time of PC-SAFT is substantially decreased by improving the root finding algorithm and calculating the derivatives analytically. A deposition and wettability alteration model is then integrated with the thermodynamic model to simulate dynamics of precipitated asphaltenes. Asphaltene deposition is shown to occur with pressure depletion around the production well and/or with gas injection in the reservoir domain that is swept by injected gas. It is observed that the profile of the damaged area by asphaltene deposition depends on the reservoir fluid. A general strategy is proposed to model the phase behavior of CO₂/hydrocarbon/water systems where four equilibrium phases exist. The developed four-phase reduced flash algorithm is used to investigate the effect of introducing water on the phase behavior of CO₂/hydrocarbon mixtures. The results show changes in the phase splits and saturation pressures by adding water to these CO₂/hydrocarbon systems. We used a reduced flash approach to reduce the additional computational time of the four-phase flash calculations,. The results show a significant speed-up in flash calculations using the reduced method. The computational advantage of the reduced method increases rapidly with the number of phases and components. We also decreased the computational time of the equilibrium calculations in UTCOMP by changing the sequential steps in the flash calculation where it checks the previous time-step results as the initial guess for the current time-step. The improved algorithm can skip a large number of flash calculation and stability analyses without loss of accuracy. / text

Contaminated sites are found all around the world. In order to contain these contaminants, engineers propose capping the contaminated sediments with a sand cap. When capping these contaminants, the sand causes consolidation to occur and could cause a slope failure if the contaminants were on a slope. Investigating the properties of these contaminated sediments allows for proper analysis of a slope failure. The primary objective of this research was to determine the shear strength of contaminated sediments. Since soil samples from actual contaminated sites are highly variable and difficult to explain, the soil used in this research project was mixed and controlled in the lab. A mixture of Kaolinite, water and mineral oil (NAPL, non-aqueous phase liquid) was used for the specimens. Different oil amounts were placed into the specimens to create different scenarios. The different oil combinations included: 100% water, 100% oil, 90% oil, 70% oil, and 50% oil. All of the specimens were fully saturated, and the specimens that had less than 100% oil contained water in the remaining percentage. Consolidated Undrained and Consolidated Drained triaxial tests were performed on the specimens. The constructed specimens were subjected to consolidation stages ranging from 0.6psi to 29psi in confining pressure. The main focus of the study was on low confining pressures. After consolidation the specimens were sheared either undrained or drained. Both tests were utilized in order to see the difference in the pore pressures generated. Failure envelopes were developed for the different oil contents that contained three dimensions included the shear strength, the effective stress, and the pore pressure difference between the pore oil pressures and the pore water pressures. Also, the behavior of oil-dominated versus water-dominated was determined. Results from the 100% water specimens were comparable to previous data. The shear strength for the 100% oil specimens was higher than the 100% water specimens, but lower than the 90% oil and 70% oil specimens. The 50% oil specimens resulted in a great deal of variability on whether the specimen was water-dominated or oil-dominated. The main conclusion was that the Kaolinite had an increase in strength with the introduction of mineral oil. / text

Degassing and in situ formation of a mobile gas phase takes place when an aqueous phase equilibrated with a gas at a pressure higher than the subsurface pressure is injected in water-saturated porous media. This process, which has been termed supersaturated water injection (SWI), is a novel and hitherto unexplored means of introducing a gas phase into the subsurface. Herein is a first macroscopic account of the SWI process on the basis of continuum scale simulations and column experiments with CO2 as the dissolved gas. A published empirical mass transfer correlation (Nambi and Powers, Water Resour Res, 2003) is found to adequately describe the non-equilibrium transfer of CO2 between the aqueous and gas phases. Remarkably, the dynamics of gas-water two-phase flow, observed in a series of SWI experiments in homogeneous columns packed with silica sand or glass beads, are accurately predicted by traditional two-phase flow theory which allows the corresponding gas phase relative permeability to be determined. A key consequence of the finding, that the displacement of the aqueous phase by gas is compact at the macroscopic scale, is consistent with pore scale simulations of repeated mobilization, fragmentation and coalescence of large gas clusters (i.e., large ganglion dynamics) driven entirely by mass transfer. The significance of this finding for the efficient delivery of a gas phase below the water table in relation to the alternative process of in-situ air sparging and the potential advantages of SWI are discussed. SWI has been shown to mobilize a previously immobile oil phase in the subsurface of 3-phase systems (oil, water and gas). A macroscopic account of the SWI process is given on the basis of continuum-scale simulations and column experiments using CO2 as the dissolved gas and kerosene as the trapped oil phase. Experimental observations show that the presence of oil ganglia in the subsurface alters gas phase mobility from 2-phase predictions. A corresponding 3-phase gas relative permeability function is determined, whereas a published 3-phase relative permeability correlation (Stone, Journal of Cana Petro Tech, 1973) is found to be inadequate for describing oil phase flow during SWI. A function to predict oil phase relative permeability is developed for use during SWI at high aqueous phase saturations with a disconnected oil phase and quasi-disconnected gas phase. Remarkably, the dynamics of gas-water-oil 3-phase flow, observed in a series of SWI experiments in homogeneous columns packed with silica sand or glass beads, are accurately predicted by traditional continuum-scale flow theory. The developed relative permeability function is compared to Stone’s Method and shown to approximate it in all regions while accurately describing oil flow during SWI. A published validation of Stone’s Method (Fayers and Matthews, Soc of Petro Eng Journal, 1984) is cited to validate this approximation of Stone’s Method.

Functional water-soluble polymers find applications in a variety of fields including waste-water treatment, pharmaceuticals, cosmetics, drug delivery, and hygiene. Despite the increased demand for these products, understanding of their synthesis by free-radical aqueous-phase polymerization has lagged behind that of polymers produced in organic solvents. In this doctoral work, the free-radical batch and semibatch aqueous-phase polymerization of N-vinylpyrrolidone (NVP), N-vinylformamide (NVF), N-vinylimidazole (NVI) and quaternized vinylimidazole (QVI), as well as NVP polymerized in n-butanol, has been studied. Kinetic models are developed to describe monomer conversion and polymer molecular weight (MW) behaviour of these systems. The expressions developed from independent pulsed-laser studies for propagation (kp) and termination (kt) rate coefficients, including their variation with monomer concentration and conversion, are shown to provide an excellent description of aqueous-phase NVP polymerization. Polymerization of NVP in butanol and of NVF in water are well-represented by the base NVP model, with differences in polymerization rate and polymer MWs simply accounted for by the differences in kp for the systems, indicating that the kt behaviour must be quite similar. The NVI/QVI study demonstrates the importance of a pH-dependent degradative addition reaction to monomer for NVI, with polymerization behaviour identical to that of QVI for pH 1, an effect captured in the model developed to describe the system. The aqueous-phase copolymerization of NVP and NVF was also studied, and reactivity ratios were determined to be very close to unity. This information was combined with the kp and kt expressions used to describe NVP and NVF homopolymerizations, with no other additional parameters required to model the copolymerization rate, copolymer composition and copolymer MW. This result demonstrates that the improved homopolymerization knowledge of these water-soluble monomers can be easily extended to understand their behaviour in copolymerization. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2011-12-21 16:05:14.904

Στόχος της μεταπτυχιακής διατριβής αποτέλεσε η πειραματική μελέτη φαινομένων μεταφοράς μάζας από υγρά μη υδατικής φάσης (NAPLs) σε δισδιάστατα πορώδη δοκίμια. Τα υγρά μη υδατικής φάσης αποτελούνται από υδρογονάνθρακες οι οποίοι διαλύονται μερικώς στο νερό. Αποτελούν τη συχνότερα εμφανιζόμενη πηγή μόλυνσης των υπόγειων υδροφορέων και είναι ιδιαίτερα επιβλαβή για τον άνθρωπο. Ο κύριος διαχωρισμός των NAPLs σε κατηγορίες γίνεται με βάση την πυκνότητά τους σε σύγκριση με αυτή του νερού. Έτσι, υπάρχουν τα Light NAPLs (LNAPLs), τα οποία είναι ελαφρύτερα από το νερό με αποτέλεσμα να επιπλέουν στην επιφάνειά του και τα Dense NAPLs (DNAPLs), τα οποία είναι βαρύτερα από το νερό και διαπερνούν τη μάζα του μέχρι να συναντήσουν κάποιο αδιαπέραστο στρώμα. Η πειραματική διάταξη που χρησιμοποιήθηκε αποτελούνταν από γυάλινα δισδιάστατα πορώδη δοκίμια που είχαν κατασκευαστεί με τη λιθογραφική μέθοδο. Με τη βοήθεια αντλίας τα δοκίμια τροφοδοτούνταν με σταθερή παροχή και σε κατάλληλη χρονική στιγμή γινόταν η εισαγωγή του ρύπου στο δοκίμιο. Στη συνέχεια με τη βοήθεια φωτογραφικής μηχανής λαμβάνονταν στιγμιότυπα σε καθορισμένες χρονικές στιγμές και με γραφικές μεθόδους υπολογιζόταν η μεταφορά μάζας. Στο πρώτο κεφάλαιο, περιέχονται εισαγωγικά στοιχεία για τη δομή και τη φύση των υγρών μη υδατικής φάσης καθώς και οι επιπτώσεις τους στο περιβάλλον. Επίσης, γίνεται μια σύντομη αναφορά στο φαινόμενο της διαχύσεως και στο πρώτο πείραμα που παρατηρήθηκε η διάχυση από τον Dalton και περιγράφεται με συντομία το πείραμα που διεξήχθη. Στο δεύτερο κεφάλαιο, γίνεται εκτενής περιγραφή όλων των στοιχείων των υγρών μη υδατικής φάσης και αναλύεται η κίνηση των υγρών αυτών σε όλα τα είδη εδάφους. Επίσης, εξηγείται η διαφορετική συμπεριφορά που αυτά εμφανίζουν στα διάφορα μέσα με βάση τις φυσικές τους ιδιότητες και επίσης παρουσιάζονται οι πρώτες μαθηματικές σχέσεις που δικαιολογούν την κίνησή τους αυτή. Στο τέλος του κεφαλαίο αναφέρονται και χημικές διεργασίες που συμβαίνουν στο υπέδαφος και επηρεάζουν την κίνηση των NAPLs. Στο τρίτο κεφάλαιο περιγράφεται το φαινόμενο μεταφοράς μάζας στο νερό αλλά και σε πορώδη μέσα. Αναφέρονται και περιγράφονται οι σημαντικότεροι και απαραίτητοι τύποι που περιγράφουν τη μεταφορά μάζας και αναλύονται όλοι οι όροι που παίρνουν μέρος στη σύνταξη των τύπων αυτών. Τέλος, αναφέρονται κάποια πειράματα στα οποία χρησιμοποιήθηκαν οι τύποι που περιέχονται στη θεωρία. Στο τέταρτο κεφάλαιο, περιγράφεται η προετοιμασία της πειραματικής διαδικασίας και αναφέρεται ο τεχνικός εξοπλισμός που χρησιμοποιήθηκε για τη διεξαγωγή της. Περιγράφονται όλα τα στάδια του πειράματος με λεπτομέρειες στις διάφορες μεθόδους που χρησιμοποιήθηκαν για τη κατασκευή και τον υπολογισμό των ιδιότητων των δοκιμίων. Επίσης, γίνεται περιγραφή της λειτουργίας του προγράμματος Comsol που χρησιμοποιήθηκε κατά το σχεδιασμό των δοκιμίων. Στο πέμπτο κεφάλαιο, παρουσιάζονται τα αποτελέσματα της πειραματικής διαδικασίας σε μορφή πινάκων και διαγραμμάτων. Τα αποτελέσματα αναλύονται και περιγράφονται με λεπτομέρεια προβλήματα που προέκυψαν κατά τη διεξαγωγή των πειραμάτων. Τέλος εξάγονται συμπεράσματα και γίνονται υποδείξεις για την περαιτέρω διερεύνηση του φαινομένου. / The aim of this Master thesis was the experimental study of mass transfer phenomena of non-aqueous phase liquids (NAPLs) in two-dimensional porous specimens. The liquid non-aqueous phase consisting of hydrocarbons which partially dissolve in the water. Are the most frequently occurring source of contamination of aquifers and is particularly harmful to humans. The main distinction of NAPLs into categories is based on the density compared to that of water. Thus, there are the Light NAPLs (LNAPLs), which is lighter than water so that float on the surface and Dense NAPLs (DNAPLs), which are heavier than water and penetrate the mass of up to meet a impermeable layer . The experimental setup used consisted of two-dimensional porous glass specimens were manufactured with lithographic method. With the pump cores fed with a constant flow and at an appropriate time was the introduction of the pollutant in the essay. Then with the help of camera footage taken at fixed times and graphical methods estimated the mass transfer. In the first chapter, contained introduction to the structure and nature of the non-aqueous phase liquids and their impact on the environment. Also, there is a brief reference to the effect of diffusion in the first experiment observed the diffusion of the Dalton and briefly describes the experiment conducted. The second chapter is a detailed description of all elements of non-aqueous phase liquids and analyzed the movement of fluids across all kinds of terrain. It also explains the different behavior they show in various media based on physical properties and also presents the first mathematical relationships that justify this movement. At the end of the chapter lists and chemical processes occurring in the soil and affect the movement of NAPLs. The third chapter describes the phenomenon of mass transfer in water and in porous media. Listed and described the most important and necessary formulas describing mass transfer and analyze all terms that take part in the preparation of these types. Finally, some experiments indicated that used types contained in the theory. The fourth chapter describes the preparation of the experimental procedure and specifying the equipment used to conduct it. Describes all stages of the experiment in detail the various methods used to construct and calculate the properties of the samples. Also, there is a description of the operation of the program Comsol used in the design of essays. The fifth chapter presents the results of the experimental procedure in the form of tables and diagrams. The results are analyzed and described in detail problems encountered in conducting the experiments. Finally conclusions are drawn and suggestions are made for further investigation of the phenomenon.

Dramatic increases in the price of crude oil, and consequently, transportation fuels, coupled with increased environmental concerns have resulted in rapid growth in biodiesel production. Thus, so does production of the primary coproduct, glycerol, which has become a worrying factor because for every ton of biodiesel produced, are generated 100 Kg of glycerol. Because this reality research has been developed to search alternatives for the use of glycerol. So, an application for this alcohol is the search for value-added chemicals such as propylene glycol and others. Reactions of aqueous phase reforming of glycerol were performed without the addition of hydrogen and streaming using monometallic catalysts of Re and Pt and bimetallic Pt-Re all supported on carbon Black . We used an aqueous solution of glycerol feeding 80% m / m, temperature of 275°C and 30 bar pressure. WHSV was varied and the content thus evaluating Re, its influence on the Pt catalysts, the stability and activity. The catalysts was characterized for temperature-programmed reduction (TPR); chemisorption of CO studies; temperature-programmed desorption-CO (TPD-CO); temperature-programmed desorption-isopropylamine (TPD-IPA). Studies of RTP for the bimetallic catalysts Pt-Re showed that rhenium interacts strongly with the platinum and possibly, precursor species are formed bimetallic alloy. CO chemisorption experiments resulted in the formation of the alloys of Pt-Re / C. The results of TPD-CO demonstrated that the addition of Re to the catalyst Pt / C changes the surface of Pt and collaborates with the weakening of bond strength of the CO molecule to the sites involved. Through the catalytic reactions studied and a qualitative analysis of chromatograms from high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GCMS) was possible to verify from the reaction of aqueous phase reforming of glycerol, the formation 1,2-propanediol and other products. / O grande aumento no preço do petróleo e conseqüentemente o transporte de combustíveis, juntamente com as preocupações ambientais resultaram em um rápido crescimento na produção de biodiesel. Assim, o mesmo acontece com a produção do subproduto, o glicerol, o qual se tornou um fator preocupante já que para cada tonelada de biodiesel obtido, são gerados 100 Kg de glicerol. Devido a esta realidade pesquisas vem sendo desenvolvidas para buscar alternativas para a utilização deste excedente. Dentro deste contexto, uma aplicação para este álcool é a busca de produtos químicos de valor agregado como o propanodiol e outros. Reações de reforma líquida do glicerol foram realizadas sem a adição de hidrogênio e em fluxo contínuo utilizando catalisadores monometálicos de Re e Pt e bimetálicos Pt-Re todos suportados em carbono Black . Foi utilizada uma solução aquosa de alimentação de glicerol 80 % m/m, temperatura de 275ºC, e pressão 30 bar. Variou-se o WHSV e teor de Re avaliando, portanto a influência deste sobre os catalisadores de Pt, a estabilidade e atividade. Os catalisadores foram caracterizados por redução à temperatura programada (RTP) quimissorção de CO, dessorção de CO à temperatura programada (DTP-CO) e dessorção de isopropilamina à temperatura programada (DTP-IPA). Os estudos de RTP para os catalisadores bimetálicos de Pt-Re demonstraram que o rênio interage fortemente com a platina e que possivelmente, espécies precursoras de ligas bimetálicas são formadas. Experimentos de quimissorção de CO resultaram na formação de ligas para os catalisadores de Pt-Re/C. Os resultados de DTP-CO demonstraram que a adição de Re ao catalisador de Pt/C altera a superfície da Pt e colabora com o enfraquecimento da força de ligação da molécula do CO aos sítios envolvidos. Através dos testes catalíticos estudados e uma análise qualitativa dos cromatogramas de cromatografia líquida de alta eficiência (CLAE) e cromatografia gasosa acoplada ao espectrômetro de massas (CG/MS), foi possível verificar a partir da reação de reforma líquida do glicerol, a formação 1,2-propanodiol e outros produtos. / Mestre em Química

L'oxydation des composés organiques émis dans l'atmosphère est progressive et conduit à la formation d'une multitude de composés organiques secondaires. Ces composés organiques secondaires (COS) peuvent être hydrosolubles et donc réagir dans la phase aqueuse atmosphérique. La communauté scientifique s'intéresse actuellement à l'impact environnemental de la réactivité de la matière organique atmosphérique en phase aqueuse. Des études récentes montrent par exemple que ces modifications pourraient entraîner une augmentation de la production d'aérosol organique secondaire (AOS). Pour explorer les effets de la réactivité aqueuse, une modélisation détaillée de la dissolution des COS et de leur oxydation aqueuse a été menée dans ce travail. Cette modélisation repose sur l'extension du générateur de schémas chimiques explicites GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere).La fraction soluble des COS est peu connue. Il est donc nécessaire de la quantifier en fonction du contenu en eau liquide. GECKO-A permet de générer des schémas explicites d'oxydation en phase gazeuse. Pour intégrer la dissolution des composés organiques formés, leurs constantes de Henry ont été documentées. Le faible nombre de données disponibles (600) comparé au très grand nombre d'espèces secondaires formées (>103) demande d'estimer empiriquement la majorité des constantes de Henry. Nous avons eu recours à une méthode d'estimation de type structure-propriété développée au LISA, GROMHE (GROup contribution Method for Henry's law Estimates). Ceci a permis de décrire le transfert de masse de toutes les espèces solubles générées lors de l'oxydation de trois précurseurs d'intérêt atmosphérique : l'isoprène, l'octane et l'α-pinène. Pour un contenu en eau liquide typique d'un aérosol déliquescent, seule une très faible fraction des COS est dissoute. Cependant, nous avons montré qu'une proportion significative des COS est susceptible de se dissoudre dans une phase aqueuse nuageuse. La dissolution et la réactivité des COS issus de l'oxydation des composés à chaîne longue doivent donc être représentées dans les modèles. Pour décrire la réactivité aqueuse des composés organiques dissous, un module de réactivité aqueuse a été ajouté à GECKO-A. La génération des mécanismes d'oxydation aqueuse repose sur l'écriture d'un protocole d'oxydation systématique. En s'appuyant sur les connaissances disponibles, ce protocole définit les règles d'oxydation et d'estimation des constantes inconnues. Implémenté dans GECKO-A, il permet dorénavant d'écrire des schémas d'oxydation multiphasique explicites pour les composés organiques. Pour l'instant, les espèces précurseur sont limitées en longueur de chaîne carbonée à cause de la taille des schémas générés. Le traitement de l'octane et de l'α-pinène est par exemple impossible. Néanmoins, à partir du mécanisme généré pour l'isoprène, le modèle a été utilisé pour explorer l'impact de la réactivité aqueuse sous différentes conditions environnementales. La réactivité aqueuse modifie significativement la distribution du carbone entre les phases ainsi que la spéciation de la matière organique dans les deux phases. Nous avons en particulier montré une production importante de diacides carboxyliques, espèces régulièrement identifiées dans la phase particulaire lors de mesures de terrain. Le mécanisme généré permet pour la première fois d'identifier environ 360 voies de formation différentes pour l'acide oxalique / The atmospheric oxidation of organic compounds is progressive and leads to the formation of a myriad of secondary organic compounds. These secondary organic compounds (SOC) can be hydrosoluble and react in the atmospheric aqueous phase. The scientific community is currently interested in the environmental impact of the atmospheric organic matter aqueous phase reactivity. For example, recent studies show that these modifications could increase the secondary organic aerosol (SOA) production. In order to explore effects of the aqueous reactivity, this work consists of a detailed modeling study of the SOC dissolution and their aqueous oxidation. The modeling is based on the extension of the explicit chemical schemes generator GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere).There is little known about the soluble fraction of SOC. It is thus needed to quantify it as a function of the liquid water content. GECKO-A enables the generation of explicit oxidation schemes for the gas phase. To integrate the dissolution of produced organic compounds, their Henry's law constants have been documented. The low number of available data (600) compared to the large number of formed secondary species (>103) requires the empirical estimate of the majority of Henry's law constants. We relied on an estimate method based on a structure-activity relationship developed at LISA, GROMHE (GROup contribution Method for Henry's law Estimates). This allowed us to describe the mass transfer of every soluble species generated during the oxidation of three precursors of atmospheric interest: isoprene, octane and α-pinene. For a liquid water content typical of a deliquescent aerosol, only a very small fraction of SOC is dissolved. However, we showed that a significant proportion of SOC could dissolve in a cloud aqueous phase. Dissolution and reactivity of SOC produced from the oxidation of long chain compounds need to be represented in models. In order to describe the aqueous reactivity of dissolved organic compounds, a aqueous reactivity module was added to GECKO-A. The generation of aqueous oxidation mechanisms is based on the writing of a systematic oxidation protocol. Supported by available knowledge, this protocol defines rules for oxidation and estimates of unknown constants. Implemented in GECKO-A, it now enables us to write multiphase explicit oxidation schemes for organic compounds. For now, precursor species are limit in the carbon skeleton length by the size of generated schemes. Treatment of octane and α-pinene is for example impossible. Nevertheless, from the mechanism generated for isoprene, the model has been used to explore the aqueous reactivity impact under different environmental conditions. Aqueous reactivity modifies significantly the carbon distribution between phases as well as the organic matter speciation in both phases. In particular, we showed an important production of carboxylic diacids, species that are regularly identified in the particulate phase during field measurements. For the first time, the generated mechanism allows the identification of approximately 360 different formation pathways for oxalic acid

京都大学 / 0048 / 新制・課程博士 / 博士(地球環境学) / 甲第18487号 / 地環博第121号 / 新制||地環||25(附属図書館) / 31365 / 京都大学大学院地球環境学舎環境マネジメント専攻 / (主査)教授 勝見 武, 准教授 田中 周平, 准教授 乾 徹 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM