Les effets du vieillissement accéléré, comme la décoloration et la perte de propriétés mécaniques, limitent les utilisationsdes composites bois-polymère (WPC) dans les applications en extérieur. Dans la présente étude, il a été tenté d'étudier l'influence de l'utilisation de fibres délignifiées de bagasse (canne a sucre) en renfort sur les propriétés des WPC et de suivre leur effet sur le contrôle de la photo- et de la bio-dégradation (vis-à-vis des champignons et des termites). A côté des échantillons délignifiés, les effets d'une finition finition transparente ont également été étudiés sur la qualité de surface et la réduction des défauts causés par la photo- et la bio-dégradation d'échantillons pigmentés et non pigmentés. Afin de faciliter l'analyse des données et avoir des résultats plus fiables, des analyses statistiques ont été effectuées sur des données provenant de différentes techniques de mesure. Toujours dans cette étude, les effets positifs et négatifs de l'utilisation de pigments granulaires ont été étudiés. Les résultats ont montré que l'utilisation de fibres délignifiées, selon le type de solvant et le niveau de délignification, provoque des changements sur la qualité de surface et les propriétés mécaniques. En outre, les échantillons délignifiés ont montré une perte de rigidité comparés aux échantillons non-délignifiées. Après vieillissement, les échantillons délignifiés ne montraient pas de réduction du changement de couleur total causé par le vieillissement. Toutefois, les fibres délignifiées accompagnées de pigments entrainent, dans une certaine mesure, une stabilisation de la rigidité des échantillons exposés au vieillissement par rapport aux échantillons non-exposés.De plus, les échantillons avec la finition transparente ont montré des résultats très prometteurs. La finition réduit le changement de couleur total du au vieillissement, et un prétraitement de surface favorise le maintien de l'efficacité de la finition, dans toutes les étapes de la photo et la bio-dégradation. Par ailleurs, les échantillons délignifiés à 70% et les échantillons ayant subi un vieillissement montrent une plus forte biodégradation et une plus grande perte de masse par rapport aux témoins. L'étude métrologique montre que le test non-destructif par vibration est une méthode fiable pour étudier les propriétés mécaniques des WPC et les effets du vieillissement. Néanmoins, il n'a pas été montré d'effet important de la délignification sur le contrôle du vieillissement. Les études sur la corrélation entre les variables ont montré que les changements avant et après le vieillissement peuvent être prédits à partir des résultats de tests non-destructifs. / The effects of weathering, such as color fading and loss in mechanical properties, limit the performance of wood-polymer composites (WPC) in outdoor applications. In the current study, it has been tried to investigate the influence of using delignified sugar cane bagasse fibers as a reinforcement on properties of WPC and follow the effects that it cause on controlling photo and bio-degradation (fungi and termite attacks). Beside delignified samples, the effects of clear coating also have been studied on surface quality and reduction of defects caused by photo and bio-degradations of pigmented and non-pigmented samples. To facilitate the data analysis and having more reliable results, some statistical analyses have been carried out on data from different variables. Also in this study the positive and negative effects of using granule pigments in master batch of components have been investigated. Results have shown that using delignified fibers, depending on type of solvent and level of delignification, cause changes on surface qualities and mechanical properties. As well, delignified samples have shown loss in MOE compare to non-delignified samples. After weathering, none of the delignified samples had reduced the total color change caused by weathering. However delignified fibers with pigments, to some extent, stabilized the MOE in weathered samples compared to un-weathered samples. In addition, clear coated samples have shown very promising results. Total color change was reduced in coated samples and by means of pre-treatments of surface, coating remained efficient in all steps of the photo and bio-degradations. This is while the 70% delignified samples and weathered samples showed higher degradation and weight loss compared to controls and un-weathered ones. Methodology investigation did show that vibration none-destructive test is the reliable method to study the mechanical properties of WPC and weathering effects. Nevertheless, it did not show the significant effects of delignification on controlling weathering. Studies on correlation between variables have shown changes before and after weathering which can be used in further studies on modeling.

L'objectif de ce travail était le développement des nanocomposites d’EVOH/zeolites à base de charges telles que les zéolites pour l’encapsulation des cellules solaires organiques, et l’étude de leur comportement photochimique. Ce travail a porté sur l’étude du mécanisme de photooxydation des copolymères d’EVOH puis sur l'impact des zéolites sur ce mécanisme. Les propriétés fonctionnelles des nanocomposites d’EVOH/zéolites ont été étudiées en prenant en compte le taux de charge et la taille des particules. Les propriétés des copolymères d’EVOH et des nanocomposites d’EVOH/zéolites comme la transparence optique, la morphologie de surface, les propriétés mécaniques et thermiques, et les propriétés d'absorption de l'eau ont été étudiées. Sur la base des résultats obtenus, les meilleurs candidats pour l'encapsulation des cellules solaires organiques ont été proposés. Le mécanisme de photooxydation des copolymères a été proposé, la photostabilité des matériaux et l'impact des zéolites sur le comportement photochimique du polymère ont été étudiés. Le test électrique de calcium et le suivi des performances des cellules solaires organiques encapsulées ont été effectués afin d'évaluer l’efficacité des matériaux étudiés comme candidats potentiels pour une encapsulation efficace et stable des cellules solaires. / The goal of this work was to develop EVOH/zeolite nanocomposites based on inorganic fillers such as zeolites for potential encapsulation of OSCs and to investigate their photochemical behaviour. The research was focused on the photooxidation mechanism of pristine EVOH copolymers and on the impact of the filler addition on this mechanism. EVOH/zeolite nanocomposites functional properties were characterised taking into account different particle sizes and filler contents. Properties of EVOH copolymers and EVOH/zeolites nanocomposites such as optical transparency, surface morphology, mechanical and thermal properties, and water uptake properties were investigated. On the basis of obtained results, the best candidate(s) for encapsulation of organic solar cells has been proposed. The chemical degradation mechanism of pristine polymers has been proposed, the materials photostability and the impact of the zeolite particles on the photochemical behaviour of the polymer have been studied. Electrical calcium test and performance of encapsulated OSCs were carried out in order to evaluate the ability of the studied materials to be used as potential candidates for efficient and stable encapsulation coatings for OSCs applications.

Dans le cadre de l'application de la directive cadre sur l'eau, la liste des substances « prioritaires » a été révisée et une nouvelle liste dite « de vigilance » a été récemment proposée pour des substances dont les connaissances sur l'exposition et la dangerosité sont à documenter. Or, les stations de traitement des eaux usées (STEU) domestiques actuelles, majoritairement des procédés secondaires biologiques, n'ont pas été conçues pour éliminer les micropolluants. Si elles en éliminent une grande partie, de nombreux micropolluants organiques (pesticides, composés pharmaceutiques, hormones, etc.) sont encore présents dans les eaux traitées. Certains procédés de traitement complémentaires (ou tertiaires) intensifs ou extensifs ont récemment été étudiés de façon à déterminer leur capacité à éliminer des micropolluants considérés comme réfractaires au traitement biologique (peu biodégradable ou faiblement sorbables sur les MES) et/ou présents en fortes concentrations dans les eaux usées brutes. Ainsi, l'oxydation par l'ozone ou par le peroxyde d'hydrogène, et l'adsorption sur charbon actif présentent des rendements supérieurs à 70% pour la majorité des pesticides et des pharmaceutiques étudiés. Concernant les procédés extensifs, de récentes études suggèrent que le rayonnement solaire pénétrant dans une colonne d'eau (ex. zone de rejet végétalisée, ZRV de type bassin) permettrait d'éliminer partiellement certains micropolluants par photodégradation (diclofénac, kétoprofène, etc.). L'objectif général de ce travail de doctorat était d'améliorer la compréhension des processus d'élimination des micropolluants organiques quantifiés en sortie de traitement secondaire par deux procédés de traitement complémentaire prometteurs : la photodégradation dans une ZRV de type bassin et l'oxydation à l'ozone mis en oeuvre par une tour d'ozonation sur une STEU réelle. Nous avons développé une méthodologie commune qui a été appliquée à l'étude de ces deux processus pour une sélection de 63 micropolluants réfractaires au traitement secondaire. La première étape a consisté à réaliser un état de l'art sur les études cinétiques disponibles dans la littérature. Deux bases de données ont ainsi été créées pour documenter les constantes cinétiques et rendements d'élimination pour 12 micropolluants. Ce travail a permis d'avoir une vision critique sur ces données issues de la littérature, notamment en ce qui concerne le réalisme des expérimentations vis-à-vis du traitement complémentaire d'eaux usées traitées. Lors de la deuxième étape, des études à l'échelle pilote ont été menées afin d'améliorer les connaissances sur les mécanismes d'élimination par oxydation par voie directe (photons ou O3) ou bien par voie indirecte (OH●). Ainsi, la voie de dégradation majeure (directe ou indirecte) a été déterminée pour les micropolluants étudiés. L'influence de certains paramètres physico-chimiques de l'effluent (nitrates, nitrites, MES, MOD) a également été abordée. Deux modèles numériques permettant de simuler l'élimination des micropolluants par photodégradation ou oxydation à l'ozone, respectivement, ont été développés et calés à partir des résultats obtenus. Dans la troisième étape, nous avons évalué les performances d'élimination des micropolluants à l'échelle des procédés de traitement complémentaire. Les constantes cinétiques mesurées expérimentalement ont permis de classer en 3 groupe (rapide, intermédiaire et lent) 47 micropolluants selon leur cinétique de dégradation par oxydation à l'ozone et, d'autre part, 42 micropolluants selon leur cinétique de photodégradation. Enfin des prévisions effectuées avec les deux modèles ont été comparées avec les mesures sur site. Ces résultats ont confirmé leur utilisation possible comme outil d'aide à la prédiction du comportement des micropolluants en traitement complémentaire / In the context of the implementation of the Water Framework Directive, the list of "priority" substances has been revised and a new list called "vigilance" was recently proposed for substances whose knowledge on exposure and dangerousness need to be document. However, current domestic wastewater treatment plants(WWTP), mostly secondary biological processes, were not designed to eliminate micropollutants. If WWTP eliminate the most part, many organic micropollutants (pesticides, pharmaceuticals, hormones, etc.) are still present in the treated water. Some tertiary treatment processes (or complementary) intensive or extensive recently been studied to determine their ability to remove micropollutants considered refractory to biological treatment (low biodegradable or low sorption on total suspended solids (TSS)) and / or present strong concentrations in raw water. Thus, oxidation by ozone or hydrogen peroxide, and the activated carbon adsorption have removal efficiencies higher than 70% for the majority of pesticides and pharmaceuticals. On extensive processes, recent studies suggest that solar radiation penetrating the water column (eg. soil-based constructed wetlands with basin) would partially eliminate some micropollutant with significant photodegradability (diclofenac, ketoprofen, etc.). The general objective of this PhD was to improve the understanding of the removal process of organic micropollutants quantified at the output of secondary treatment by two promising complementary treatment processes: photodegradation in a basin of soil based constructed wetlands and oxidation by ozone implemented by an ozonation tower on real WWTP. We have developed a common methodology that has been applied to the study of these processes for a selection of 63 micropollutants refractory to secondary treatment. The first step was to achieve a state of the art on kinetic studies in the literature. Two databases were created to document the kinetic constants and removal efficiencies for 12 micropollutants. This work allowed to have a critical view on the data from the literature, especially regarding the realism of the experiments for complementary treatment of treated wastewater. In the second step, studies on pilot scale have been carried out to improve knowledge about the oxidative removal mechanisms by direct (O3 or photons) or indirect pathway (OH●). Thus, the major contribution of degradation (direct or indirect) was determined for all micropollutants studied and the influence of specific physicochemical parameters of the effluent (nitrates, nitrites, TSS, DOM, etc.) was discussed. Two numerical models for simulating the removal of micropollutants by photodegradation or ozone oxidation have been developed and calibrated from the results. In the third step, we evaluated the removal performance of the micropolluants in the complementary treatment processes. The experimentally measured kinetic constants were used to classify in 3 groups (fast, medium and low) 47 micropollutants according to their kinetics of degradation by oxidation with ozone and, secondly, 42 micropolluants according to their photodegradation kinetics. Finally, predictions made with both models and were compared with measurements in real scale. These results confirmed their possible use as a tool to help to predict the behavior of complementary micropolluants treatment

Les luminaires à LEDs représentent une alternative "verte" aux lampes fluorescentes et aux lampes à incandescence en répondant notamment à des critères de préservation de l'environnement : réduction de la consommation d’énergie, technologies sans mercure ni plomb et recyclables à 98%. Cependant, ces luminophores, qui sont actuellement utilisés dans les luminaires à LEDs, contiennent aujourd’hui des éléments de terres rares qui sont issus à 95% de Chine, créant de ce fait une situation de quasi-monopole et un risque réel pour le déploiement de la technologie LED dans les années à venir. Dans le cadre de cette thèse, nous nous sommes intéressés au développement de luminophores sans terres rares pour produire de la lumière blanche dans les luminaires à LEDs. Au cours de ces travaux nous avons étudié trois types de luminophores sans terres rares: luminophores organiques, luminophores hybrides (organiques-inorganiques) et quantum dots (QDs) type cœur-coquille. Les études optiques réalisées sur ces luminophores sous excitation LEDs UV ou bleue nous ont permis de déterminer leurs caractéristiques colorimétriques (IRC, T(K), PLQY(%)) et de mettre en évidence l’évolution de leurs performances dans les conditions d’usage. Pour obtenir une lumière la plus proche du blanc idéal, les luminophores les plus performants ont été sélectionnés puis mélangés en proportion adéquate avec une matrice polymère de type silicone pour conduire à un film composite offrant une émission blanche de qualité sous excitation LEDs UV ou bleue. Un autre volet de ce travail a été dédié à l’étude de la stabilité de ces luminophores (films ou poudres) en fonction du temps et de la température. L’influence de ces paramètres sur les propriétés optiques a été déterminée. Des performances optiques de 30% ont été enregistrées avec des caractéristiques photométriques intéressantes. Aussi, l’ensemble des résultats obtenus montre l’intérêt de poursuivre ces études sur les luminophores sans terres rares qui offrent des propriétés optiques intéressantes. Même s'ils ne concurrencent pas encore les luminophores inorganiques pour l’application « éclairage grand public », les luminophores sans terres rares peuvent déjà se positionner sur d’autres secteurs d’activité comme par exemple : l’éclairage d’ambiance, la signalétique le marquage anti-contrefaçons. / Lighting technologies based on light-emitting diodes have become an alternative solution over the obsolete technologies (fluorescent lamps and incandescent lamps) due to their positive key criteria of environmental conservation: reduction of energy consumption and mercury/lead-free with 98% recycling technologies. However, the rare-earth elements, which are currently used in LED lightings, are produced by China at about 95%, thereby creating a monopoly situation on the rare-earth elements’ market and also a risk to the deployment of LED technologies in coming years. In this work, we have been interested in the development of rare-earth-free luminescent materials for LED lighting applications in order to produce a white light emission. Three kinds of rare-earth-free luminescent materials have been investigated: organic phosphors, hybrid (organic-inorganic) phosphors and core-shell quantum dots (QDs). The optical studies of these phosphors recorded upon UV and/or blue excitations allow us to determine their colorimetric parameters (CRI, T(K), PLQY(%)) and to demonstrate their optical performances for use in lighting devices. In order to yield a color emission close to ideal white light, the best phosphors were selected and then introduced by mixing them in appropriate proportions into silicone polymers. Another part of this work was devoted to the studies of stability of phosphors (films or powders) under operating conditions of LEDs, moreover, variation of their optical properties as a function of time and temperature were also determined. The optical performances about 30% have been recorded with some interesting colorimetric parameters. Although these materials have presented lower photoluminescence properties compared with commercial rare-earth based inorganic phosphors for “public lighting” applications, they can already be positioned on other luminescent sectors such as indoor lighting, signage anti-counterfeit marking.

Orientadores: Ana Flávia Nogueira, Flávio Leandro de Souza / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-27T13:00:11Z (GMT). No. of bitstreams: 1 Carminati_SaulodoAmaral_M.pdf: 3434559 bytes, checksum: 5dc1e86f14ccc0bccd7264ae9b28c11e (MD5) Previous issue date: 2015 / Resumo: O Resumo poderá ser visualizado no texto completo da tese digital / Abstract: The Abstract is available with the full electronic digital document / Mestrado / Quimica Organica / Mestre em Química

abstract: Decay of plant litter represents an enormous pathway for carbon (C) into the atmosphere but our understanding of the mechanisms driving this process is particularly limited in drylands. While microbes are a dominant driver of litter decay in most ecosystems, their significance in drylands is not well understood and abiotic drivers such as photodegradation are commonly perceived to be more important. I assessed the significance of microbes to the decay of plant litter in the Sonoran Desert. I found that the variation in decay among 16 leaf litter types was correlated with microbial respiration rates (i.e. CO2 emission) from litter, and rates were strongly correlated with water-vapor sorption rates of litter. Water-vapor sorption during high-humidity periods activates microbes and subsequent respiration appears to be a significant decay mechanism. I also found that exposure to sunlight accelerated litter decay (i.e. photodegradation) and enhanced subsequent respiration rates of litter. The abundance of bacteria (but not fungi) on the surface of litter exposed to sunlight was strongly correlated with respiration rates, as well as litter decay, implying that exposure to sunlight facilitated activity of surface bacteria which were responsible for faster decay. I also assessed the response of respiration to temperature and moisture content (MC) of litter, as well as the relationship between relative humidity and MC. There was a peak in respiration rates between 35-40oC, and, unexpectedly, rates increased from 55 to 70oC with the highest peak at 70oC, suggesting the presence of thermophilic microbes or heat-tolerant enzymes. Respiration rates increased exponentially with MC, and MC was strongly correlated with relative humidity. I used these relationships, along with litter microclimate and C loss data to estimate the contribution of this pathway to litter C loss over 34 months. Respiration was responsible for 24% of the total C lost from litter – this represents a substantial pathway for C loss, over twice as large as the combination of thermal and photochemical abiotic emission. My findings elucidate two mechanisms that explain why microbial drivers were more significant than commonly assumed: activation of microbes via water-vapor sorption and high respiration rates at high temperatures. / Dissertation/Thesis / Doctoral Dissertation Biology 2020

abstract: There is a growing consensus that photodegradation accelerates litter decomposition in drylands, but the mechanisms are not well understood. In a previous field study examining how exposure to solar radiation affects decomposition of 12 leaf litter types over 34 months in the Sonoran Desert, litter exposed to UV/blue wavebands of solar radiation decayed faster. The concentration of water-soluble compounds was higher in decayed litter than in new (recently senesced) litter, and higher in decayed litter exposed to solar radiation than other decayed litter. Microbial respiration of litter incubated in high relative humidity for 1 day was greater in decayed litter than new litter and greatest in decayed litter exposed to solar radiation. Respiration rates were strongly correlated with decay rates and water-soluble concentrations of litter. The objective of the current study was to determine why respiration rates were higher in decayed litter and why this effect was magnified in litter exposed to solar radiation. First, I evaluated whether photodegradation enhanced the quantity of dissolved organic carbon (DOC) in litter by comparing DOC concentrations of photodegraded litter to new litter. Second, I evaluated whether photodegradation increased the quality of DOC for microbial utilization by measuring respiration of leachates with equal DOC concentrations after applying them to a soil inoculum. I hypothesized that water vapor sorption may explain differences in respiration among litter age or sunlight exposure treatments. Therefore, I assessed water vapor sorption of litter over an 8-day incubation in high relative humidity. Water vapor sorption rates over 1 and 8 days were slower in decayed than new litter and not faster in photodegraded than other decayed litter. However, I found that 49-78% of the variation in respiration could be explained by the relative amount of water litter absorbed over 1 day compared to 8 days, a measure referred to as relative water content. Decayed and photodegraded litter had higher relative water content after 1 day because it had a lower water-holding capacity. Higher respiration rates of decayed and photodegraded litter were attributed to faster microbial activation due to greater relative water content of that litter. / Dissertation/Thesis / Masters Thesis Biology 2019

In this thesis the optical changes of beers and model beer solutions during their photodegradation were studied. The optical changes - change of absorbance - were measured on the prototype of apparatus COLORTURB and were correlated with sensory tested intensity of the lightstruck flavour of beer and with riboflavin content in samples. High correlation between the lightstruck flavour intensity, the loss of absorbance at the wavelength of 450 nm and the riboflavin content loss was found. The partial recovery of the absorbance for both beers and model beer solutions was found and was attributed to the riboflavin photoproducts transformation. Powered by TCPDF (www.tcpdf.org)

Inorganic colloidal synthesis, without a doubt, lies at the foundation of many contemporary areas of nanoscience and nanotechnology. At the advent of the 21st century, much progress has been made in the size, shape / morphological control and surface engineering of metal oxides resulting in a diverse library of macroscopic crystal architectures with well-defined surface properties. In this thesis, we start by introducing the self-assembly of the iron(oxy-, hydro-)xide while briefly reviewing some fundamental concepts of solid-state chemistry. Specific information on the family of iron oxide and iron(oxy-, hydro-)xide, as relevant to crystalline phase control, has been highlighted to direct our discussion of the synthesis of diverse crystal morphologies. Furthermore, we briefly underline and discuss the kinetic and thermodynamic control of colloidal crystal morphologies through reasonably established knowledge of anisotropic growth rates in the perspective of iron oxides' facets or crystalline planes. Lastly, we review the state-of-the-art wet chemical synthetic approaches, while using different iron(oxy-, hydro-)xide crystals as examples, for the purpose of explaining our synthetic work of choice. The main work of this thesis is entirely focused on the "facile synthesis and fine morphological tuning of branched hematite (??-Fe2O3) crystals for photodegradation of azo-type dyes".. We would discuss the crucial parameters for fine morphological tuning in the context of controlling the anisotropic growth rates of branched ??-Fe2O3 crystals instead of phase transformation. In our work, we have significantly improved the synthesis of dendritic "feather-like" and "starfish-like" for their size reduced variants for use in photocatalysis.

Wastewater reclamation and reuse have been increasingly practiced as sustainable strategies to meet water demands, particularly in regions threatened by water shortages. However, one of the biggest challenges for reusing wastewater effluents (WEs) as irrigation water is to remove emerging organic contaminants such as persistent and potentially bioaccumulated per- and polyfluoroalkyl substances (PFAS), whose presence may result in adverse impacts on crops, soils, aqueous ecosystems, and human health. Photocatalysis is an effective and promising technique to remediate PFAS in aqueous media. This dissertation aims to: i) Develop a novel, environmental-friendly, and low-cost treatment process for PFAS removal and degradation for water reuse; ii) Optimize the experimental conditions and investigate the removal mechanisms of PFAS with different structures in this novel process; iii) Scale up this treatment process and apply it to treatment of WEs in a point-of-use (POU) system. First, ultraviolet (UV) C /nanoscale zero-valent iron (nZVI, Fe0 nanoparticles (NPs)) system is used for the first time to induce PFAS photocatalytic removal from aqueous solution. Oxidative and/or reductive degradation of three representative PFAS - perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorooctane sulfonate (PFOS) was achieved using Fe0 NPs under UVC light both with and without presence of oxygen. However, no PFAS removal was observed either under visible light and in the dark, and much lower PFAS degradation was achieved under UVA light. Higher degradation and defluorination efficiencies were obtained for longer chain PFNA compared to PFOA, and higher degradation and defluorination of PFAS were achieved without presence of O2 compared to with O2. The degradation of PFOA and PFOS followed first order reaction kinetics with the highest efficiencies achieved of 97.6, >99.9, and 98.5% without presence of O2 for PFOA, PFNA, and PFOS, respectively. The degradation efficiencies increased with the increase of nZVI concentrations in the range of 1-100 mg/L. The degradation efficiency of PFOA using bare Fe0 NPs was higher than that using 1% PVP-coated Fe0 NPs in the initial 6 h. Second, the removal mechanism of PFAS in UVC/Fe0 NPs system was obtained by testing the concentrations of iron ions (Fe2+/Fe3+), intermediate products, and reactive oxygen species (ROS, e.g., ·O2- and ·OH) generated, and conducting ROS quenching experiments. The proposed degradation pathway of PFCAs (PFNA and PFOA) was initiated from PFOA/PFNA oxidation by transferring an electron of the carboxylate terminal group of PFOA/PFNA to the Fe(III)-carboxylate complex, then followed by decarboxylation−hydroxylation−elimination−hydrolysis (DHEH) pathway and the accompanying CO2 and F− release. The generated shorter chain PFCAs also underwent degradation with time in the system. This proposed degradation pathway was confirmed by the formation of shorter chain PFCAs, e.g. PFHpA, PFHxA, PFPeA, and PFBA, F- ions, and rapid consumption of Fe3+. For PFOS, besides H/F exchange pathway and chain-shortening (DHEH pathway) to form short chain PFAS during PFCA degradation, desulfonation to form PFOA followed by PFOA degradation also happened. These pathways were suggested by the formation of intermediates — trace amount of shorter chain PFCAs, 6:2 FTS, PFHpS, and F- ions. ·O2- and ·OH were not involved in PFOA degradation in the UVC/Fe0 NPs system with presence of O2, while they may be involved in PFOS degradation, e.g., desulfonation to form PFOA, which were suggested by the results of quenching experiments. And introducing H2O2 into the UVC/Fe0 NPs system resulted in lower PFOA degradation efficiency and defluorination efficiency, which also indicated that ·OH may not be involved in PFOA degradation. Hydrated electrons e-aq that can be involved in desulfonation, defluorination, and C-C bond scission processes were likely quenched by the presence of oxygen to reduce the degradation and defluorination efficiencies; plus, presence of Fe0 NPs may promote the generation of hydrated electrons. Last, UVC/Fe0 NPs system was used to degrade PFAS from WEs in both bench scale and in a scale up POU system. The degradation efficiencies of PFAS in WEs from both wastewater treatment plants (WWTP) were lower than that in deionized water, likely reflecting the complex compositions in the environmental media. Optimal degradation efficiencies of 90±1%, 88±1%, and 46±2% were obtained for PFNA, PFOS, and PFOA, respectively, each starting from 0.5 µg/L using bare Fe0 at pH 3.0 after 2 h. PFAS removal and bacterial inactivation were achieved simultaneously in the POU system using Fe0 NPs without and with rGO support under UVC irradiation in WEs, although the PFAS levels were still above the regulation levels for discard. These pilot tests provided more data and experiences for the real applications of UVC/Fe0 NP system to PFAS contaminated wastewater or other water matrix treatment. Overall, this research demonstrated a cost-effective and environment-friendly method — UVC/Fe0 NPs method for PFAS (i.e., PFOA, PFNA, and PFOS) degradation from WEs for water reuse both with and without presence of oxygen. The possible degradation mechanisms of PFAS with different structures were obtained by testing the concentrations of iron ions, intermediate products, and reactive oxygen species (ROS) involved in the reactions. The developed technology can be potentially applied to treat other environmental media (e.g., groundwater, landfill leachate) that are contaminated by PFAS from previous anthropogenic activities.