Doctor of Philosophy / Department of Chemical Engineering / Liang T. Fan / Walter P. Walawender Jr / Carbon adsorbents, namely, activated carbons and carbon molecular sieves, can be variously applied in the purification and separation of gaseous and liquid mixtures, e.g., in the separation of nitrogen or oxygen from air; often, carbon adsorbents also serve as catalysts or catalyst supports. The formation of carbon adsorbents entails the modification of the original internal surfaces of carbonaceous substrates by resorting to a variety of chemical or physical methods, thereby augmenting the carbonaceous substrates' adsorbing capacity. The formation of carbon adsorbents proceeds randomly, which is mainly attributable to the discrete nature, mesoscopic sizes, and irregular shapes of the substrates utilized as well as to their intricate internal surface configuration. Moreover, any process of carbon-adsorbent formation may fluctuate increasingly severely with time. It is desirable that such a process involving discrete and mesoscopic entities undergoing complex motion and behavior be explored by means of the statistical framework or a probabilistic paradigm. This work aims at probabilistic analysis, modeling, and simulation of the formation of carbon adsorbents on the basis of mechanistic rate expressions. Specifically, the current work has formulated a set of linear and non-linear models of varied complexity; derived the governing equations of the models formulated; obtained the analytical solutions of the governing equations whenever possible; simulated one of the models by the Monte Carlo method; and validated the results of solution and simulation in light of the available experimental data for carbon-adsorbent formation from carbonaceous substrates, e.g., biomass or coal, or simulated data obtained by sampling them from a probability distribution. It is expected that the results from this work will be useful in establishing manufacturing processes for carbon adsorbents. For instance, they can be adopted in planning bench-scale or pilot-scale experiments; preliminary design and economic analysis of production facilities; and devising the strategies for operating and controlling such facilities.

The primary goal of the research studies conducted was to apply statistical mechanical and computer simulation methods to describe the equilibrium behavior of hazardous dipolar/quadru-polar single-gases and mixtures confined in micro porous adsorbents. Statistical mechanical models capable of handling the energetic heterogeneity by complex electrostatic interactions between adsorbate-adsorbent and adsorbate-adsorbate electrostatic interactions were developed and studied. The heterogeneous pore shape and size of different adsorbents were taken into account by two different approaches described in the following paragraphs. Under certain conditions, the use of Mean Field Perturbation Theories (MFPTs) is more attractive than Monte-Carlo (MC) simulations because of the enhanced physical insights that they offer, as well as very low computational times required. Existing literature shows that the applications of MFPTs for studying adsorption of polar molecules were limited due to the orientation dependency of the intermolecular potentials for electrostatic interactions, that in turn poses the challenging problem of seeking analytical expressions for the various thermodynamic functions involved. Furthermore, other existing approaches of accounting for complex electrostatic interactions through hydrogen bonding have limitations due to the requirement of parameter estimation related to radial distribution functions and the critical orientation values of molecules for hydrogen bonds, which are generally obtained through MC simulations and X-ray scattering techniques. In the first stage of research efforts, an attempt was made to express angle-dependent intermolecular potentials in the form of angle-independent intermolecular potential terms by employing statistical averaging methods. In particular, the permanent dipole-dipole and permanent dipole-induced dipole intermolecular potentials were expressed as angle-averaged intermolecular potentials. Then, angle-averaged intermolecular potentials were used to predict water isotherms in nano-slit pores. Furthermore, the angle-averaged intermolecular potentials were used for a binary mixture of polar molecules (water-methanol) to predict the adsorption behavior in nano-slit pores. However, significant limitations of MFPTs arise when they are used for the study of adsorption in zeolites that exhibit irregular shaped cavities with surface heterogeneities. The latter certainly represent a future meaningful research direction. It should be pointed out, that the mean field approach allows us to predict equilibrium sorption properties in homogeneous adsorbents like graphitic carbon (slit), carbon nano tubes (cylinder) and highly siliceous faujasites (spherical) as they have regular shaped cavities. The applications of such kinds of theory remained limited due to the (generally) unknown distribution of functional sites on adsorbents of interests (mainly activated carbons and zeolites) and their locations in the adsorbent framework. The second stage of research efforts focused on models capable of incorporating surface heterogeneities and addressing complex pore geometries. The models developed relied on Grand Canonical Monte-Carlo (GCMC) simulations. In particular, two types of GCMC simulations were carried out, namely molecular and atomistic MC simulations. Both techniques were applied to simulate sorption isotherms on zeolites and activated carbon to remove mercury chloride (quadrupole), hydrogen cyanide (HCN, dipole) and methyl ethyl ketone (MEK, dipole) from air. The molecular based MC technique utilized molecular properties of the molecules namely dipole, quadrupole moments, molecular polarizability and molecule size (kinetic diameter). The molecule was considered to be a spherical shaped particle. The dispersion interactions were calculated using Vaan der Waals equation and electrostatic interactions were quantified through the multi-pole expansion method. This approach was used to simulate adsorption of HgCl2, HCN and MEK in zeolite NaX and activated carbon with functional sites namely carbonyl, hydroxyl and carboxyls. Simulation results indicated that HgCl2 sorption could be attributed to charge-induced dipole interactions for activated carbon, suggesting that sorbents with more number surface charges can be useful except for the case of carbonyls in which quadrupole moments plays a crucial role in reducing sorbent capacities, in turn implying that relative positions of positively and negatively charged cations are indeed important. However, for zeolite NaX, performance characteristics were primarily attributed to charge-quadrupole interactions and dispersion interactions. Moreover, zeolite-NaX performance characteristics for capturing HCN and MEK were attributed to dipole-Na interactions due to the relatively large dipole moments of the molecules under consideration. In the case of activated carbon, HCN sorption was governed by mainly charge-dipole and charge-induced dipole interactions, and hence, carbons with carboxyls seemed to perform better than hydroxyls and carbonyls. MEK sorption was influenced by dispersion interactions (due to the large polarizability of MEK) and charge-dipole interactions, which makes carbon with carbonyls more efficient rather than carbons with hydroxyls having the same charge densities. However, application of the aforementioned molecular approaches was limited to sorbents with regular shape cavities having some surface heterogeneity such as activated carbons. Finally, in order to account for sorbents with irregular shaped cavities, such as silicalite and mordenite, one needs to use atomistic MC simulations. The atomistic MC technique utilizes appropriate atomic sizes and charges for the molecules under consideration to quantify intermolecular forces among the adsorbate molecules and the atoms of the zeolite framework as well as activated carbon. The dispersion interactions were calculated using the Van-Der Waals equation and electrostatic interactions were quantified through a standard Coulombic equation. The bond distances among atoms were kept fixed but variations in angular movement and dihedral/torsional movements were considered, and appropriate harmonic potentials were used to account for angle bending and torsional effects. The sorption performance was evaluated for mordenite, silicalite and zeolite beta for a Si/Al ratio of 47-197 for both an HCN and MEK system. The results of HCN/MEK sorption suggested that silicalite has greater capacity than that of mordenites .In the case of MEK Zeolite beta with sodium cations, performance was better than that of mordenites and silicalites. Sorption of HCN in silicalite was observed in straight and zigzag channels, and mainly attributable to hydrogen bonding among HCN molecules. The increase in sodium cations however decreases the capacity of silicalite, zeolite beta and mordenite slightly. The sorption of MEK in mordenite was mainly observed in an 12- and 8-member ring channel. It was found that an increase in sodium cations did not increase the sorption capacity of mordenite significantly as most of the cations in mordenite were located in an 8-member ring channel where MEK molecules can not be accommodated properly due to steric effects. However, the sorption of MEK in zeolite beta seemed to be influenced by the presence of sodium cations as most of the cations are at the intersection of two 12 member rings which provide sufficient space to orient MEK molecules at the intersection and maximize electrostatic interactions. The sorption of MEK in silicalite exhibited similar trends as in the case of mordenite, as all cations were at the intersection of straight and zigzag channels . Finally, in the last Section of the Thesis, a comparative assessment was made of all three approaches in terms of their significance in applications and the ease in applying them.

La contamination des sols agricoles par la chlordécone menace la durabilité de l’élevage de plein air aux Antilles. Afin de maintenir ce dernier tout en protégeant les consommateurs de denrées animales d’origine terrestre, plusieurs stratégies sont étudiées. Ces travaux de thèse sont focalisés sur l’une d’entre elles qui consiste à séquestrer la chlordécone afin de réduire significativement sa biodisponibilité pour l’animal. La démarche expérimentale a été réalisée par étape, elle s’appuie sur trois piliers : des matières séquestrantes carbonées de type biochar ou charbon activé, l’utilisation de sols artificiels et sur le concept de biodisponibilité relative pour évaluer les performances de séquestration. Les essais conduits avec du charbon activé (à base de noyaux de dattes, de coco ou de lignite) ont montré une séquestration de la chlordécone en milieu aqueux ou chez l’animal, mais pour ce dernier cela ne fonctionne que si la chlordécone et la matrice séquestrante ont eu un temps de contact prolongé (ou maturation) avec l’ingestion par l’animal. Ces résultats montrent l’intérêt d’une séquestration in situ, à savoir directement dans le sol contaminé susceptible d’être ingéré par les animaux. Comme le charbon activé a un coût élevé, des matières carbonées a priori moins coûteuses ont été testées : des biochars à base de diverses essences de bois. Ces biochars produits à deux températures de pyrolyse (500 et 700°C) ont été caractérisés d’un point de vue physique (porosité) et sélectionnés via un test in vitro de disponibilité environnementale. Les tests in vivo (sur porcelets) n’ont pas montré que ces biochars sélectionnés étaient aptes à séquestrer efficacement la chlordécone, puisque la biodisponibilité relative n’était pas différente de un (référence = sol standard sans matière organique). La présence de tourbe dans le sol artificiel ne s’oppose pas au piégeage par les matrices carbonées exogènes. Le test in vitro utilisé et le test in vivo donnent des tendances équivalentes de réduction de la biodisponibilité relative, ce qui est intéressant dans une logique de validation du test in vitro. Ces résultats positifs montrent que la stratégie de séquestration par des matériaux hautement carbonés est possible, requiert des propriétés de microporosité et d’accès aux pores proches de celles d’un charbon activé, mais contingents des conditions expérimentales mises en œuvre ils doivent être poursuivis et validés sur des sols dits naturels / The contamination of agricultural soils by chlordecone threatens the sustainability of outdoor farming in the West Indies. In order to maintain the latter while protecting consumers of terrestrial animal products, several strategies are being studied. This thesis is focused on one of them which consists of sequestering chlordecone in order to significantly reduce its bioavailability for the animal. The experimental approach was carried out in stages, based on three pillars: biochar or activated carbon as sequestering materials, the use of artificial soils and the concept of relative bioavailability to assess sequestration performance. Tests conducted with activated charcoal (based on dates kernels, coconut or lignite) have shown that chlordecone is sequestered in an aqueous medium or in animals, but for the latter it only works if chlordecone and sequestering matrix had a prolonged contact time (or maturation) with ingestion by the animal. These results show the interest of in situ sequestration, ie directly in the contaminated soil likely to be ingested by the animals. As activated charcoal has a high cost, a priori less expensive carbonaceous materials have been tested: biochars based on various wood species. These biochars produced at two pyrolysis temperatures (500 and 700 ° C) were characterized from a physical point of view (porosity) and selected via an in vitro environmental availability test. In vivo tests (on piglets) did not show that these selected biochars were able to effectively sequester chlordecone, since the relative bioavailability was not different from one (reference = standard soil without organic matter). The presence of peat in the artificial soil does not prevent trapping by exogenous carbonaceous matrices. The in vitro test used and the in vivo test give equivalent tendencies to reduce the relative bioavailability, which is interesting in a logic of validation of the in vitro test. These positive results show that the strategy of sequestration by highly carbonaceous materials is possible, requires properties of microporosity and access to pores close to those of an activated carbon, but contingent on the experimental conditions implemented, they must be continued and validated on natural soils

The normal operation of the endocrine (hormonal) system can be disrupted by a number of man-made and naturally-occurring chemicals, thereby affecting those physiological processes that are under hormonal control. Such substances are called endocrine disrupting compounds (EDCs). The endocrine disruption issue has alarmed the environmental authorities since the substances involved can hinder hormonal processes causing far-reaching effects on reproduction and development in current and future human and wildlife generations. Effects on some species of fish triggered worldwide concern and initiated a research scheme which is being undertaken by various organisations e.g. United States Environmental Protection Agency (USEPA), United Kingdom Environment Agency (UKEA), Oslo and Paris Commission (OSPAR), Japan Environment Agency (JEA) and World Wildlife Fund (WWF) in order to assess the effects (present and potential), point of generation, levels of contamination and exposure limits. The findings showed that most of the oestrogens are produced by humans and animals and get discharged into river streams mainly through sewage effluents. Fish in particular have been found to be affected the most even when the oestrogenic levels in water are very low. The probability of future European legislation to eliminate hormonally active compounds from wastewaters suggests that new and alternative methods should be developed for their removal. In this work, the adsorption of 17ß-oestradiol (E2) and 17a-ethinyl oestradiol (EE2) onto several granular activated carbons and Hypersol-Macronet hypercrosslinked polymers was investigated by batch experiments after a low level detection system had been developed using Gas Chromatography Mass Spectrometry (GC/MS). Equilibrium experiments were carried out for all adsorbents to quantify the sorption capacity for E2 and EE2. For better assessment of the sorbents performance, their physical properties such as surface area, average pore diameter and micropore volume and chemical structure were characterised by N2 adsorption experiments, scanning electron microscopy (SEM), FTIR spectroscopy, elemental analysis, sodium capacity determination, pH titration, proton binding curves and zeta potential measurements. Adsorption isotherm data were fitted to the Langmuir and Freundlich equations. Activated carbons were found to be preferable to Hypersol-Macronet hypercrosslinked polymers for adsorption purposes. The adsorption of oestrogens appears to be controlled by hydrophobic interactions. Kinetic experiments were performed with different size ranges of adsorbents at different concentrations and the results were analysed by a particle diffusion model. It was found that concentration did not seem to influence the kinetics of the oestrogen sorption whereas the particle size of the adsorbents influenced the adsorption rate of both molecules. The particle diffusion model seemed to fit the data collected for the adsorption rate of 17B-oestradiool onto the adsorbents but gave a poor fit for most of the data collected for 17a-ethinyl oestradiol.

Depuis quelques temps, les enjeux énergétiques ne cessent d’apparaître en tête de liste des préoccupations actuelles pour l’avenir. La fin annoncée des énergies fossiles, à l’origine de 80% de celle que nous consommons aujourd’hui, s’accompagne naturellement par la recherche d’alternatives pour subvenir aux besoins futurs. L’intégration d’une dimension environnementale pour la mise en œuvre d’un développement durable met clairement en avant les atouts des énergies dites renouvelables qui concernent de nos jours moins de 15% de la production mondiale. Le travail proposé ici s’inscrit dans ce cadre de recherche et de proposition de sources d’énergies primaires renouvelables avec l’étude de valorisation de déchets contenant de la biomasse et plus particulièrement du cas du revêtement de sol stratifié. Parmi les diverses voies de valorisation actuelles, l’incinération avec l’ensemble des autres déchets reste le plus usité. L’inconvénient majeur réside dans la nécessité de traitement des fumées qui s’avère relativement coûteux. Il semblerait donc judicieux d’envisager une autre issue de valorisation. Le procédé proposé fait apparaître les trois étapes suivantes : une étape de prétraitement par pyrolyse à basse température (275°C) assurant une séparation des éléments azotés (précurseurs susceptibles de conduire à la formation de polluants) en altérant au minimum le matériau en vue d’une récupération maximale d’énergie lors de l’étape suivante ; une étape de valorisation énergétique, qui constitue le centre du procédé, par une pyrolyse à haute température (1000°C). L’énergie est obtenue par l’intermédiaire du gaz de synthèse ; et une étape de valorisation matière sous deux aspects avec l’obtention de produits à valeur ajoutée (panneaux de particules et charbons actifs) dont l’entrée dans le bilan économique global d’une installation industrielle pourrait s’avérer intéressante / Since a few years, energy challenges are appearing at the top of the list of the current concerns for the future. The forecasted end of fossil fuels, at the origin of 80% of currently consumed energy, is obviously accompanied by research about alternatives to provide for the future needs. The integration of an environmental care concerning the implementation of a sustainable development puts clearly ahead the assets of renewable energies which constitutes nowadays less than 15% of the worldwide production. Work suggested here deals with this scope of research and proposal for renewable primary energy sources with the recovery study of waste containing biomass and more precisely the case of laminated flooring. Among the various current recovering ways, incineration with the whole waste remains the most used one. The main drawback deals with the need for smoke treatment, the cost of which can be really high. It would thus seem to be judicious to look for another recovering issue. The suggested process is divided in the three following steps: - A pretreatment step through low temperature pyrolysis (275°C) making it possible a nitrogenous components separation of the elements (precursor able to form pollutants species) in deteriorating the fuel the less as possible to provide a maximum energy recovery in the following stage.- An energy recovery step, which constitutes the main goal of the process, through a high temperature pyrolysis (1000°C). Energy is recovered via syngas.- A material recovery step through two aspects in order to produce added-value material (particle boards and activated carbon), the consideration of which in the global economic assessment of an industrial installation could be interesting

Les effluents industriels sont constitués de molécules de natures très diverses, plus ou moins réfractaires aux classiques traitements biologiques. Les normes de rejets évoluant régulièrement vers des contraintes de plus en plus sévères, il semble aujourd'hui nécessaire de proposer des solutions complémentaires pour atteindre de hauts rendements d'épuration. Le premier procédé mis en oeuvre dans ce travail est l'adsorption sur charbon actif. Le caractère novateur de cette technique se situe dans l'utilisation de charbons actifs fabriqués à partir de boues de stations d'épuration d'eaux usées. La seconde méthode est un procédé hybride innovant combinant adsorption et photocatalyse avec TiO2. Les eaux industrielles ciblées sont les effluents colorés, représentés par la tartrazine, et les effluents phénolés représentés par le phénol, l'acide p-hydroxybenzoïque, le p-chlorophénol er le p-nitrophénol. Pour traiter par adsorption les eaux chargées en phénols, plusieurs charbons actifs commerciaux et six charbons de boues ont été utilisés. Il ressort de cette première étude que, malgré leurs faibles surfaces spécifiques, certains charbons de boues présentent des performances très satisfaisantes. Le procédé séquentiel combinant adsorption et photocatalyse a été réalisé avec plusieurs matériaux: un tissu Ahlstrom contenant du charbon et du TiO2, un charbon actif avec dépôt de TiO2 par MOCVD puis un mélange de charbon actif et TiO2 en poudre. Des résultats prometteurs ont été obtenus pour dégrader la tartrazine, en particulier avec le TiO2 déposé sur charbon actif montrant que la proximité de sites d'adsorption et photocatalytique améliore les performances de l'oxydation / In order to explore a new sequential process for water treatment its two steps, adsorption on activated carbon and in situ photocatalytic oxidative regeneration, were investigated successively. Several commercial activated carbons (AC) and sewage sludge based activated carbons (SBAC) were tested with several phenols and one dye as pollutants. Despite low BET surface SBAC exhibits convenient adsorption properties. Photocatalysis on TiO2 was carried out with several materials to achieve activated carbon adsorption- egeneration process: a multilayer tissue with fixed granular AC and TiO2 on a sheet, a composite with TiO2, CVD deposited on AC, and AC-TiO2 powder mixture for comparison. Promising results were obtained especially with TiO2 deposited on AC proving the vicinity of adsorption and photocatalytic sites to be beneficial