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International audience; In this work, a solution for the treatment of toxic gases based on a photocatalytic process using TiO(2) coated on a cellulosic support, has been investigated. Here, cyclohexane was chosen as the reference for testing its removal efficiency via a continuous front flow reactor as type A anti-gas filters. The photocatalytic support was firstly characterized by EDX, to confirm its elemental composition. Then, the experiments were carried out, starting with a batch reactor in order to evaluate the degradation efficiency of the photocatalytic media, as well as the monitoring of the photocatalytic process which allowed the establishing of a carbon mass balance corresponding to the stoichiometric number of our target pollutant. The transition to a continuous treatment with a front flow reactor aims to highlight the influence of the input concentration (0.29-1.78 mM m(-3)) under different flow rates (12, 18 and 36 L min(-1)). The relative humidity effect was also investigated (from 5 to 90% of humidity) where an optimum rate was obtained around 35-45%. In addition, the mineralization rate was monitored. The major rates obtained were for a cyclohexane input concentration of 0.29 mM m(-3) in wet condition (38%) at an air flow rate of 18 L min(-1), where the CO(2) selectivity reached 77% for an abatement of 62%. In order to understand the limiting steps of the photocatalytic process, a model considering the reactor geometry and the hydraulic flow was developed. The obtained results showed that the mass transfer must be considered in the photocatalytic process for a continuous treatment. The Langmuir-Hinshelwood bimolecular model was also developed to represent the influence of the humidity.

International audience; Nowadays, air pollution is an increasingly important topic, as environmental regulations require limiting pollutant emissions. This problem requires new techniques to reduce emissions by either improving the current emission control systems and processes or installing new hybrid treatment systems. These are of broad diversity, and every system has its advantages and disadvantages. The tendency is, accordingly, to combine various techniques to achieve more acceptable and suitable treatment. Recent studies suggest that the combination of photocatalysis and plasma in a reactor can offer attractive pollutant treatment efficiency with a minimum of partially oxidized by-products than that of these processes taken separately. However, there is little review of the capability of this pairing to treat different brands of pollutants. Besides, available data concerning reactor design with flows treated 10 to 1000 times higher than those studied at the lab scale. This review paid particular attention to determine the reaction mechanisms in terms of engineering and design of combination reactors (plasma and catalysis). Likewise, we developed the effect of critical parameters such as pollutant load, relative humidity, and flow rate to understand the degradation kinetics of specific pollutants individually by using plasma and photocatalysis. Additionally, this review compares different designs of cold plasma reactors combination with heterogeneous catalysis with special attention on synergistic and antagonistic effects of using plasma and photocatalysis processes at the laboratory, pilot, and industrial scales. Therefore, the elements discussed in this review stick well to the first theme on pollution prevention of the special issue concerning pollution prevention and the application of clean technologies to promote a circular (bio) economy.

International audience; A heterogeneous catalyst, composed of an open-cell glass foam support impregnated with zerovalent ruthenium nanoparticles (loading around 0.1 wt.%), was used to remove toluene in air by catalytic ozonation. Experiments with lab-designed 2−6 cm length and 1.6 cm diameter catalysts were performed. A model based on the Langmuir–Hinshelwood mechanism, coupled with mass transfer limitations and including competitive effects between toluene and ozone, was designed. It accurately fits experimental data gathered at various temperatures (30−90 °C), gas velocities (0.0025−0.017 m s−1) and inlet ozone concentrations (6.4–11.2 g m−3). The removal of ozone and toluene was mainly ruled by the ozone concentration at low concentrations while the adsorption competition becomes significant at high ozone concentrations. Predictive simulations, at 1.0 g m−3 inlet toluene concentration, were compared in terms of investment cost, operating cost and process performances. The results highlighted the complexity of the process, which involves antagonist aims between toluene removal and the design of a compact and energy-efficient reactor. With the best operating conditions (90 °C and 46 g m−3 ozone inlet concentration), the removal of toluene reached 88% (removal rate of 0.25 g m−3 s−1) with a high ozone degradation (97%) in a moderate reactor length of 0.11 m. These good performances associated to the low cost of the catalyst's synthesis make it an efficient alternative for the removal of pollutants from air.

International audience; For potential use in air treatment by biofiltration, a new material composed of vermicompost and earthworms () was tested for the removal of a volatile organic compound (VOC), toluene. The removal rate of toluene was measured during batch experiments in presence of vermicompost only, earthworms only and a mixture of both. In the chosen experimental conditions, no mortality of earthworms was recorded and the results showed that the presence of earthworms allowed an increase in toluene removal rate (0.213 mg h) compared to vermicompost only (0.084 mg h) and earthworms only (0.136 mg h). From the experimental data, mechanisms of toluene transfer and adsorption/biodegradation by microorganisms from vermicompost and/or earthworms were proposed.

Adsorption is a commonly used technique for removal and analysis of gaseous pollutants due to its cost efficiency at low concentrations. In this work, single and competitive BTEX adsorptions were studied on three non-porous, mesoporous and microporous commercial adsorbents, namely Carbopack® B, SBA-16 and HKUST-1, respectively. For all these materials, C8 aromatics were preferentially adsorbed, preventing in some cases the adsorption of the most volatile species, i.e. benzene and toluene. This behavior indicates that the competition phenomenon is closely related to the strength of adsorbate-adsorbent interactions. Activation energies for the desorption process were determined to be 33.8 and 33.7 and 35.9 kJ/mol for Carbopack® B, SBA-16 and HKUST-1, respectively, demonstrating that stronger interactions are present in microporous materials. Among the investigated adsorbents, SBA-16 seems to be the best candidate for air treatment and analysis since it exhibited high adsorption capacity, moderate hydrophobicity, minimal roll-up and low activation energy for the desorption. The experimental results obtained illustrate the complexity of multicomponent adsorption process on materials with different porosity and surface chemistry.

Domestic activities involving household products are transient but intense indoor sources of VOCs. Once emitted, pollutants can be processed by indoor air treatment devices. To provide operational conclusions on VOC emissions and their removal by treatment systems, this study explores the issue at real scale: (i) operation of a 40 m3 experimental room, (ii) representative housecleaning action, and (iii) implementation of selected and commercially available treatment devices. The objective is to challenge the current standards by exploring the behavior of representative air treatment systems and providing a comprehensive characterization of their performances and impacts. First, VOC emissions of selected housecleaning product are characterized as a function of temperature and RH (relative humidity) in the experimental room IRINA. Limonene is identified as a tracer of household product emissions, its removal is investigated. This approach allows discriminating the device performances and identifying the contributions of sorption, photolysis, ozonolysis and photocatalysis in the removal processes. Depending on the media, sorptive and photocatalytic removal are highly contrasted. Third, gas phase side-products generated by each air treatment device are addressed at start up and after 8 h of operation. Remarkably, secondary organic aerosols are identified as side-products of limonene photocatalytic processing. Finally, respective contributions of treated limonene, gas phase and particulate side-products are evaluated through the carbon mass balance of the treatment processes. While the current standard evaluations report equivalent performances for both devices, their real scale evaluation evidence contrasted behaviors. This study shows the effectiveness of providing a comprehensive and real scale characterization of the performances of air treatment devices. It evidences the prospect of moving current experimental approaches related to indoor air investigations to realistic scale and conditions. .

In developed countries, people spend more than 85% of their time in enclosed areas. Yet, air can carry pathogenic microorganisms such as Mycobacterium tuberculosis or Legionella pneumophila. In this context, the microbiologic quality of indoor air is an issue of common interest. Air treatment technologies for the microbial disinfection of indoor air do exist. However, most of them need external energy inputs and some do produce harmful compounds (nanoscale powders, ozone) when used. Therefore, the main goal of this thesis is to develop new antimicrobial materials for the disinfection of indoor air. These materials shall not need any energetic assistance and shall not release harmful compounds. To achieve this goal, this thesis focused on functionalizing the surface of macroscopic alumina beads. Several active compounds have been studied: manganese dioxide for its oxidizing properties, zinc oxide for its crystalline structure allowing the synthesis of nanoscale blades for the mechanical disruption of microorganisms and silver for its well-known antimicrobial ability. To assess the germicidal properties of these new materials, new test units have been designed. In particular, this thesis explored the use of tests units working in dynamic conditions with ambient air to evaluate the germicidal ability of materials in lifelike conditions.; Dans les pays développés, la population passe aujourd’hui plus de 85% de son temps en intérieur. Or l'air peut être vecteur de microorganismes pathogènes pour l'homme pouvant provoquer des maladies comme la tuberculose ou la légionellose. La qualité microbiologique de l'air intérieur est donc un enjeu d'intérêt. Des solutions existent à ce jour pour traiter l'air mais elles présentent des risques de relargage de composés néfastes (poudres nanométriques, ozone) et nécessitent le plus souvent une assistance énergétique importante. C'est pourquoi l'objectif de ces travaux de thèse est de développer des matériaux germicides pour le traitement de l’air intérieur fonctionnant sans assistance énergétique et n'émettant pas de composés nocifs pour la santé humaine. Dans ce but, les travaux se sont focalisés sur la fonctionnalisation de billes macroscopiques d'alumine par dépôt de couches nanostructurées à leur surface. Plusieurs composés actifs ont ainsi été explorés : le dioxyde de manganèse pour ses propriétés oxydantes, l'oxyde de zinc pour sa structure cristalline permettant la formation de composites pouvant endommager mécaniquement les microorganismes et l'argent pour ses propriétés germicides en tant que métal et ion métallique. Pour tester le potentiel germicide de ces matériaux, des unités pilote de test et des protocoles associés ont été créés. En particulier, cette thèse s'est focalisée sur la possibilité d'utiliser des systèmes de test en conditions dynamiques utilisant de l'air ambiant pour déterminer au mieux les capacités germicides des matériaux dans des conditions proches de leur utilisation réelle.

In developed countries, people spend more than 85% of their time in enclosed areas. Yet, air can carry pathogenic microorganisms such as Mycobacterium tuberculosis or Legionella pneumophila. In this context, the microbiologic quality of indoor air is an issue of common interest. Air treatment technologies for the microbial disinfection of indoor air do exist. However, most of them need external energy inputs and some do produce harmful compounds (nanoscale powders, ozone) when used. Therefore, the main goal of this thesis is to develop new antimicrobial materials for the disinfection of indoor air. These materials shall not need any energetic assistance and shall not release harmful compounds. To achieve this goal, this thesis focused on functionalizing the surface of macroscopic alumina beads. Several active compounds have been studied: manganese dioxide for its oxidizing properties, zinc oxide for its crystalline structure allowing the synthesis of nanoscale blades for the mechanical disruption of microorganisms and silver for its well-known antimicrobial ability. To assess the germicidal properties of these new materials, new test units have been designed. In particular, this thesis explored the use of tests units working in dynamic conditions with ambient air to evaluate the germicidal ability of materials in lifelike conditions.; Dans les pays développés, la population passe aujourd’hui plus de 85% de son temps en intérieur. Or l'air peut être vecteur de microorganismes pathogènes pour l'homme pouvant provoquer des maladies comme la tuberculose ou la légionellose. La qualité microbiologique de l'air intérieur est donc un enjeu d'intérêt. Des solutions existent à ce jour pour traiter l'air mais elles présentent des risques de relargage de composés néfastes (poudres nanométriques, ozone) et nécessitent le plus souvent une assistance énergétique importante. C'est pourquoi l'objectif de ces travaux de thèse est de développer des matériaux germicides pour le traitement de l’air intérieur fonctionnant sans assistance énergétique et n'émettant pas de composés nocifs pour la santé humaine. Dans ce but, les travaux se sont focalisés sur la fonctionnalisation de billes macroscopiques d'alumine par dépôt de couches nanostructurées à leur surface. Plusieurs composés actifs ont ainsi été explorés : le dioxyde de manganèse pour ses propriétés oxydantes, l'oxyde de zinc pour sa structure cristalline permettant la formation de composites pouvant endommager mécaniquement les microorganismes et l'argent pour ses propriétés germicides en tant que métal et ion métallique. Pour tester le potentiel germicide de ces matériaux, des unités pilote de test et des protocoles associés ont été créés. En particulier, cette thèse s'est focalisée sur la possibilité d'utiliser des systèmes de test en conditions dynamiques utilisant de l'air ambiant pour déterminer au mieux les capacités germicides des matériaux dans des conditions proches de leur utilisation réelle.

In developed countries, people spend more than 85% of their time in enclosed areas. Yet, air can carry pathogenic microorganisms such as Mycobacterium tuberculosis or Legionella pneumophila. In this context, the microbiologic quality of indoor air is an issue of common interest. Air treatment technologies for the microbial disinfection of indoor air do exist. However, most of them need external energy inputs and some do produce harmful compounds (nanoscale powders, ozone) when used. Therefore, the main goal of this thesis is to develop new antimicrobial materials for the disinfection of indoor air. These materials shall not need any energetic assistance and shall not release harmful compounds. To achieve this goal, this thesis focused on functionalizing the surface of macroscopic alumina beads. Several active compounds have been studied: manganese dioxide for its oxidizing properties, zinc oxide for its crystalline structure allowing the synthesis of nanoscale blades for the mechanical disruption of microorganisms and silver for its well-known antimicrobial ability. To assess the germicidal properties of these new materials, new test units have been designed. In particular, this thesis explored the use of tests units working in dynamic conditions with ambient air to evaluate the germicidal ability of materials in lifelike conditions., Dans les pays développés, la population passe aujourd’hui plus de 85% de son temps en intérieur. Or l'air peut être vecteur de microorganismes pathogènes pour l'homme pouvant provoquer des maladies comme la tuberculose ou la légionellose. La qualité microbiologique de l'air intérieur est donc un enjeu d'intérêt. Des solutions existent à ce jour pour traiter l'air mais elles présentent des risques de relargage de composés néfastes (poudres nanométriques, ozone) et nécessitent le plus souvent une assistance énergétique importante. C'est pourquoi l'objectif de ces travaux de thèse est de développer des matériaux germicides pour le traitement de l’air intérieur fonctionnant sans assistance énergétique et n'émettant pas de composés nocifs pour la santé humaine. Dans ce but, les travaux se sont focalisés sur la fonctionnalisation de billes macroscopiques d'alumine par dépôt de couches nanostructurées à leur surface. Plusieurs composés actifs ont ainsi été explorés : le dioxyde de manganèse pour ses propriétés oxydantes, l'oxyde de zinc pour sa structure cristalline permettant la formation de composites pouvant endommager mécaniquement les microorganismes et l'argent pour ses propriétés germicides en tant que métal et ion métallique. Pour tester le potentiel germicide de ces matériaux, des unités pilote de test et des protocoles associés ont été créés. En particulier, cette thèse s'est focalisée sur la possibilité d'utiliser des systèmes de test en conditions dynamiques utilisant de l'air ambiant pour déterminer au mieux les capacités germicides des matériaux dans des conditions proches de leur utilisation réelle.

The aim of this thesis was to develop new solvents for the absorption of volatile organic compounds (VOC). VOC are primary air pollutants generally used as solvents and emitted directly from industries. They have adverse health effects and some of them are classified as carcinogenic. Consequently, the reduction of the emissions of these pollutants remains a major challenge to reduce air pollution. Hence, our objective was to evaluate deep eutectic solvants (DES) as absorbents for VOCs. DESs represent a new generation of solvents that is formed by simply mixing two or more compounds. They can be produced from cheap, natural and biodegradable compounds. The preparation of these solvents is easy and is 100% atom efficient. This work was divided into three parts.The first part focused on the physicochemical properties of DES, such as density and viscosity. Analysis of the infrared spectra of DES and their pure compounds showed that hydrogen bonds are essential for the formation of DES. Their polarity was studied using the Nile red probe. In addition, solubility of various gases (CO₂, CH₄ and Ar) was measured as a function of temperature. The second part dealt with the evaluation of the aborsption capacity of DESs using static headspace coupled with gas chromatography. The determination of gas/liquid partition coefficient was performed for various VOC and DES at different temperatures. In addition, the influence of VOC mixtures on DES absorption capacities was determined. DES showed high absorption capacities for a variety of VOCs, without saturation even at high concentration. A new DES-cyclodextrin system was developed and showed improved absorption capacities due to the complexation ability of the cyclodextrin. The last part was oriented towards the industrial application of DESs. The absorption capacities of DESs were evaluated using a dynamic set-up which simulated an industrial absorption column. This set-up allows the modulation of the VOC flow rate, water content and column temperature. Finally, the regeneration of the absorbent was carried out by several absorption/desorption cycles without loss of absorption capacity. In conclusion, the overall results showed that DES have characteristics that allow them to be considered as promising solvents for VOC absorption.; L(objectif de cette thèse a été de développer de nouveaux solvants d'absorption des composés organiques volatils (COV). Ces derniers sont des polluants atmosphériques primaires généralement utilisés comme solvants et émis directement par les industries. Ils induisent des effets nocifs pour la santé, et certains d'entre eux, sont classés comme cancérogènes. La réduction des émissions de ces polluants reste donc une préoccupation majeure. L'objectif de notre travail a été d'évaluer les solvants eutectiques profonds (DES) comme absorbants pour les COV. Les DES représentent une nouvelle génération de solvants. Ils sont formés par simple mélange de 2 ou plusieurs composés. Ils peuvent être produits à partir de composés économiques, naturels et biodégradables. La préparation de ces solvants est facile et permet une économie d'atome de 100%. Le travail a été divisé en trois parties.La première partie a été consacrée à la caractérisation des propriétés physico-chimiques des DES, telles que la densité et la viscosité. L'analyse des spectres infrarouge des DES et de leurs composés purs a montré une implication des liaisons hydrogène dans la formation des DES. La polarité a été étudiée à l'aide de la sonde Nile red. Enfin, la solubilité de gaz (CO₂, CH₄ and Ar) a été mesurée dans les DES en fonction de la température. La deuxième partie a porté sur l'évaluation de la capacité d'absorption des DES en utilisant la technique d'headspace statique couplée à la chromatographie en phase gazeuse. Ceci nous a permis de déterminer le coefficient de partage gaz/liquide pour les COV dans les DES à différentes températures. L'influence des mélanges de COV sur les capacités d'absorption des DES a été également déterminée. Ces derniers ont montré des capacités d'absorption élevées pour la variété de COV, sans saturation même à forte concentration. Un nouveau système DES-cyclodextrine a également été évalué. Les capacités d'absorption ont été améliorées grâce au rôle de molécule cage de la cyclodextrine. La deuxième partie a été tournée vers l'application industrielle. Nous avons évalué les capacités d'absorption des DES à l'aide d'un montage dynamique qui simule une colonne d'absorption industrielle. Cette installation permet de moduler le débit du COV, les teneurs en eau ainsi que la température de la colonne. Enfin, la régénération des DES a été effectuée par plusieurs cycles absorption/désorption sans perte de capacité d'absorption. En conclusion, l'ensemble des résultats obtenus a montré que les DES possédaient de nombreux atouts leur permettant d'être considérés comme des solvants prometteurs pour l'absorption des COV.

International audience; This study focuses on Butyraldehyde (C4H8O) degradation using catalytic ozonation oriented to the optimization of non-thermal plasma/photocatalytic coupled processes. After the first oxidation by non-thermal plasma coupled photocatalytic processes, a second oxidative step leading to the decomposition of the residual Butyraldehyde by Ozone is catalyzed by Mordenite, ZSM-5 and γ-alumina. The Butyraldehyde degradation in the presence of Ozone under operational parameters such as plasma energy, Butyraldehyde inlet concentration, relative humidity and the height of the catalytic bed are reported in detail. The optimum operating conditions found were Qair = 1 m3 h-1, [C4H8O] = 100 mg m-3, SIEplasma = 18 JL-1, for Butyraldehyde degradation mediated by ZSM-5. The formation of intermediate by-products was monitored during the degradation of Butyraldehyde in the presence of Ozone and ZSM-5 catalyst to suggest a degradation pathway. The coupling of catalytic ozonation by non-thermal plasma/photocatalysis lead to the total decomposition of Ozone when catalyzed by ZSM-5and presents a positive effect on the mineralization capacity. The pollutants degradation intermediates were identified by GC-MS and the oxidative states on the catalytic bed were characterized by XPS. © 2018 Elsevier B.V.

International audience; In hospitals, operating rooms (ORs) are very demanding in terms of the indoor air quality (IAQ) and require systems that minimize the concentrations of pollutants (microorganisms, chemical and particulate matter). Air treatment devices that use photocatalytic oxidation (PCO) could potentially be used in the OR to improve IAQ. In this work, the fate of two OR pollutants acrylonitrile (chemical found in surgical smoke) and isoflurane (an-esthetic gas) when they go through a PCO device was investigated. The experiments were conducted in a laboratory closed loop multi-pass reactor. A mathematical model was utilized to enable the calculation of one indicator (single-pass removal efficiency) for acrylonitrile and two indicators (induction period and single-pass removal efficiency) for isoflurane. The degradation efficiency was then accessed by studying the influence of environmental parameters on these indicators. The parameters that were studied are the relative humidity, presence of co-pollutants and presence of particles. The parameters were observed to have similar effects on the degradation of both compounds. Increasing relative humidity inhibited the degradation probably due to competitive adsorption. The presence of co-pollutants like nitrous oxide and acetic acid caused a possible competition for adsorption unto active sites thus decreased the degradation efficiency of acrylonitrile and isoflurane. The increase in the concentration of the co-pollutants enhances the competitive effect and further decreases the degradation efficiency of the target pollutants. Finally the presence of particles on the photocatalytic media could block active sites thereby inhibiting the degradation of acrylonitrile and isoflurane.

Summary Objective of the study Neutropenic patients represent a growing and fragile population in our hospitals. Numerous treatments induce neutropenia in haematology wards and elsewhere. Although strict isolation is recommended during post-haematopoietic stem cell transplantation neutropenia, this may not be the current practice in other situations. In this study, our objective was to analyse what protective measures are applied in neutropenic patients in a French survey. Materiels and methods A questionnaire was sent out to infection control teams of 400 public and private French hospitals to enquire about their local recommendations regarding infection prevention in neutropenic patients. Results Among the 166 (41%) responders, 134 (81%) managed neutropenic patients. All of the centres recommended protective isolation for neutropenic patients. However, only 46 (34%) had clearly defined patients warranting specific isolation measures in terms of the level of neutropenia. All of the centres recommended several barrier measures, but these were highly variable according to the type of air treatment in the wards (note that only 72% of haematology wards are equipped with air treatment). Gowns, gloves, masks, hats and shoe covers were respectively recommended in 128 (95%), 79 (59%), 132 (98%), 87 (65%), and 34 (25%) of the establishments. Surprisingly, the recommendations vary both among hospitals and within the same hospital among different clinical wards. Conclusion In conclusion, protective measures for neutropenic patients are applied variably and urgently require a consensus to homogenize practices.

International audience; This paper concerns the study of a surface dielectric barrier discharge (SDBD) reactor designed for offering simultaneously chemical (VOC degradation) and mechanical (electro-hydrodynamic pumping) actions. It takes the form of a channel composed of active faces on which surface plasma is generated in AC sinusoidal mode with a resonant power-supply. The chemical application targeted is the flexible and low energy-cost abatement of VOC present in air at low concentration, which is a major current industrial concern for safety and environmental reasons. Regarding the mechanical action, the SDBD acts as a pump. It is able to induce flow rates reaching up to 153 L/min for a 60 W consumption with an electro-mechanical yield of 0.0133% in open configuration, while as any pump, it falls down in connected configuration; 39 L/min connected to our air treatment bench. Regarding the chemical action, five VOC are tested, two ketones: acetone and butanone, two esters: methyl-butyrate and methyl-valerate, one aldehyde: butyraldehyde. They are injected at low concentration in a continuous air flow according to two modes of injection: (i) separately at 25 ppmv, or (ii) together at 10 ppmv each one, i.e. 50 ppmv total. The air flow rate is modulated via an additional pump for investigating an extended range: 8.5–179 L/min. Thus, for a fixed 60 W consumption, the specific input energy (SIE) goes from 20 J/L to 423 J/L. As expected, the results show that as the SIE is increased, better conversion rates are achieved. Based on the experimental results, a chemical model of the SDBD reactor is proposed for providing a physical interpretation while giving information for helping the design of an optimized double-action reactor.

International audience; Indoor air quality in health care facilities is a major public health concern, particularly for immunocompromised patients who may be exposed to microbiological contaminants such as molds, mycotoxins, endotoxins, and (1,3)-ß-D-glucans. Over 2 years, bioaerosols were collected on a monthly basis in a cancer treatment center (Centre F. Baclesse, Normandy, France), characterized from areas where there was no any particular air treatment. Results showed the complexity of mycoflora in bioaerosols with more than 100 fungal species identified. A list of major strains in hospital environments could be put forward due to the frequency, the concentration level, and/or the capacity to produce mycotoxins in vitro: Aspergillus fumigatus, Aspergillus melleus, Aspergillus niger, Aspergillus versicolor, Cladosporium herbarum, Purpureocillium lilacinum, and Penicillium brevicompactum. The mean levels of viable airborne fungal particles were less than 30.530 CFU per m3 of air and were correlated to the total number of 0.30 to 20 μm particles. Seasonal variations were observed with fungal particle peaks during the summer and autumn. Statistical analysis showed that airborne fungal particle levels depended on the relative humidity level which could be a useful indicator of fungal contamination. Finally, the exposure to airborne mycotoxins was very low (only 3 positive samples), and no mutagenic activity was found in bioaerosols. Nevertheless, some fungal strains such as Aspergillus versicolor or Penicillium brevicompactum showed toxigenic potential in vitro.

International audience; Authors of the abstract come from :: University or Research Institution Submit your abstract below (400 words): Attention to indoor air quality has strongly increased over the last 30 years. VOCs are the most numerous gaseous pollutants, present in indoor air within the concentration range 1-1000 ppb. Among them, aromatics are major compounds. The photocatalytic oxidation (PCO) of VOCs is one of the most promising techniques to achieve indoor air purification. Although many studies on PCO of VOCs were published, few extensive investigations on the influence of PCO process parameters have been made yet. The aim of the present work is to assess the impact of photocatalytic media geometry on the contact time during the PCO of toluene, chosen as a typical aromatic pollutant. The residence time on the photocatalyst as a function of global flowrate was estimated by performing CFD simulations. Experiments were conducted under conditions close to real indoor atmospheres. The PCO of toluene was performed in a dynamic loop reactor with control of key process parameters: UV-light intensity, air flow rate and residence time. The initial concentration of toluene was fixed at 800 ppb. The relative humidity was set at 50% (i.e. 13 000 ppm) to be close to real indoor air conditions. The photocatalytic media was supplied by Ahlström Paper Group. Two geometries were used for the media configuration, a plane geometry and a folded one. CFD simulations were performed with ANSYS-CFX® computational fluid software. The calculations used the finite volume method on which the software is based. PCO was proved to be more efficient in the folded configuration. Three main reasons account for this efficiency increase: (i) the surface and thus the catalyst mass are higher, (ii) the residence time is longer and (iii) the quantum yield is better optimized. Simulation results showed a good homogeneity of the fluid distribution at the media surface. The superficial velocities are low, i.e. around 0.2 m/s. It is evidenced that local decrease of gases velocity through the media surface is induced by its geometry. This decrease is proportional to a local contact time increase. Consequently, this phenomenon can lead to an additional noticeable improvement of global PCO process efficiency. This work provides understanding elements to explain why some media geometry has a positive influence on the global efficiency of the PCO process. Type of presentation :: Poster Highlight 1: PCO was proved to be more efficient in the folded configuration. Highlight 2: The local decrease of gases velocity through the media surface is induced by its geometry Highlight 3: Simulation results showed good homogeneity of the fluid distribution at the media surface

SURFACES+FGI:DBI:FGA; International audience; Pt-Al2O3, Al2O3 and SnO2 were deposited as thin films on a stainless steel support that was inserted into an annular reactor and heated using an electromagnetic induction device. Possibility of an accurate temperature control was demonstrated and heating rates up to 800 degrees C min(-1) were obtained. Total abatement of 1000 ppm isopropyl alcohol (IPA) was achieved at low temperature (T50 about 80 degrees C) on 1 wt% Pt/Al2O3. Nevertheless, the strong IPA adsorption on the alumina support and the formation of large amounts of acetone dictated to select the other catalyst, SnO2. IPA 90% conversion into CO2 and H2O was then obtained at 250 degrees C with a total flow of 100 NmL min(-1) containing 1000 ppm IPA. Considering the volume of the very thin reactive sheath (hydraulic diameter about 3.6 mm), ghsv was as high as 2.6 x 10(3) h(-1). Total abatement to CO2 and H2O of high amounts of IPA (about 1 vol%) in air was achieved in less than 30 s and near-room temperature was recovered quickly when the contaminant level at the reactor inlet felled again below a given threshold (C) 2013 Elsevier B.V. All rights reserved.

International audience; The kinetic characterization of microorganisms degrading volatile organic compounds (VOCs) is difficult due to the low substrate concentration prevailing in these processes. In this work, a simple, accurate and easy-to-implement methodology was proposed to perform the kinetic characterization of VOC-degrading microorganisms. The methodology was applied to Rhodococcus erythropolis using toluene as a model VOC. Besides the assessment of traditional kinetic parameters such as the maximum specific growth rate (mu(max)), substrate half-saturation (K-s) and substrate inhibition (K-1), the methodology here proposed yielded the 46 kinetic parameter, which indicates the relative relevance of the biomass growth rate and bacterial density on the VOC mineralization performance. R. erythropolis exhibited K-s, K-1 and mu(max) values of 0.39 g m(-3), 54 g m(-3) and 0.21 h(-1), respectively. The potential of this microorganism (supporting extremely low K-s and high K-1 values) for boosting the performance of bioreactors treating low toluene concentrations was highlighted. Furthermore, alpha/beta ratios of similar to 50 to similar to 500 were recorded at initial toluene gas concentrations of 1.5-5.2 g m(-3), respectively. These alpha/beta ratios indicated that toluene mineralization under the working conditions was mainly related to the biomass growth rather than to the biomass concentration.

This study shows the development of an innovative technique for a fast and well-controlled heating of catalysts deposited as thin films on a metallic support. The use of an electromagnetic induction system fitted to an annular catalytic reactor enabled us to study some catalytic materials deposited on stainless steel. The target application was the abatement of volatile organic compounds (VOCs) in the air. Isopropyl alcohol and toluene combustion by the oxygen was studied on various thin films catalysts, i.e. : 1%Pt/Al2O3, 0,3%Pt/SnO2, 1%Pt/SnO2 et 1%Pt/YSZ. Solids were prepared by wet impregnation of the corresponding oxides by H2PtCl6 and were deposited on the stainless steel support using an electrophoretic deposition technique. The main parameters of the heating system were investigated as well as the influence on VOCs abatement of various parameters such as the thickness of catalyst film, the platinum amount and the nature of the oxide. For validation purpose, the data provided by this innovative system were also compared to the ones provided by a classical one (quartz plug-through microreactor heated in a conventional way) in a reference reaction which was CO oxidation into CO2. The system described in this study shows on the one hand a real practical interest for fast remediation of indoor air polluted by VOCs, and on the other hand is a very powerful tool for obtaining kinetic data about thin layer catalysts used in many structured reactors; Ce travail montre la mise en œuvre d'une technique originale pour le chauffage rapide et bien contrôlé de catalyseurs sous forme de films minces déposés sur un structurant métallique. L'utilisation d'un système à induction électromagnétique adapté à un réacteur catalytique de type annulaire nous a permis d'étudier un certain nombre de matériaux catalytiques, déposés sur acier inoxydable, dans une perspective d'oxydation totale en CO2 et H2O de composés organiques volatiles (COV) présents dans l'air. La combustion de l'isopropanol et du toluène par l'oxygène de l'air a été étudiée en utilisant différents catalyseurs déposés sous forme de films minces: 1%Pt/Al2O3, 0,3%Pt/SnO2, 1%Pt/SnO2 et 1%Pt/YSZ. Les solides ont été préparés par imprégnation des oxydes correspondants par H2PtCl6 puis ont été déposés sur le support d'acier inoxydable par électrophorèse. Les principaux paramètres relatifs au mode de chauffage ont été étudiés de même que l'influence sur la conversion des COV de différents facteurs tels que la quantité de catalyseur, le pourcentage de platine ou la nature du support oxyde employé. Les informations fournies par ce système innovant ont également été comparées pour validation à celles obtenues à l'aide d'un système classique (microréacteur en quartz à lit traversé chauffé de manière conventionnelle) pour une réaction de référence qui est l'oxydation de CO en CO2. Le système décrit dans cette étude présente d'une part un intérêt pratique pour le traitement rapide de contaminations accidentelles de l'air ambiant, mais est aussi un très bon moyen d'obtenir des paramètres cinétiques fiables dans le domaine des catalyseurs en films minces utilisés dans de nombreux réacteurs structurés

This study shows the development of an innovative technique for a fast and well-controlled heating of catalysts deposited as thin films on a metallic support. The use of an electromagnetic induction system fitted to an annular catalytic reactor enabled us to study some catalytic materials deposited on stainless steel. The target application was the abatement of volatile organic compounds (VOCs) in the air. Isopropyl alcohol and toluene combustion by the oxygen was studied on various thin films catalysts, i.e. : 1%Pt/Al2O3, 0,3%Pt/SnO2, 1%Pt/SnO2 et 1%Pt/YSZ. Solids were prepared by wet impregnation of the corresponding oxides by H2PtCl6 and were deposited on the stainless steel support using an electrophoretic deposition technique. The main parameters of the heating system were investigated as well as the influence on VOCs abatement of various parameters such as the thickness of catalyst film, the platinum amount and the nature of the oxide. For validation purpose, the data provided by this innovative system were also compared to the ones provided by a classical one (quartz plug-through microreactor heated in a conventional way) in a reference reaction which was CO oxidation into CO2. The system described in this study shows on the one hand a real practical interest for fast remediation of indoor air polluted by VOCs, and on the other hand is a very powerful tool for obtaining kinetic data about thin layer catalysts used in many structured reactors, Ce travail montre la mise en œuvre d'une technique originale pour le chauffage rapide et bien contrôlé de catalyseurs sous forme de films minces déposés sur un structurant métallique. L'utilisation d'un système à induction électromagnétique adapté à un réacteur catalytique de type annulaire nous a permis d'étudier un certain nombre de matériaux catalytiques, déposés sur acier inoxydable, dans une perspective d'oxydation totale en CO2 et H2O de composés organiques volatiles (COV) présents dans l'air. La combustion de l'isopropanol et du toluène par l'oxygène de l'air a été étudiée en utilisant différents catalyseurs déposés sous forme de films minces: 1%Pt/Al2O3, 0,3%Pt/SnO2, 1%Pt/SnO2 et 1%Pt/YSZ. Les solides ont été préparés par imprégnation des oxydes correspondants par H2PtCl6 puis ont été déposés sur le support d'acier inoxydable par électrophorèse. Les principaux paramètres relatifs au mode de chauffage ont été étudiés de même que l'influence sur la conversion des COV de différents facteurs tels que la quantité de catalyseur, le pourcentage de platine ou la nature du support oxyde employé. Les informations fournies par ce système innovant ont également été comparées pour validation à celles obtenues à l'aide d'un système classique (microréacteur en quartz à lit traversé chauffé de manière conventionnelle) pour une réaction de référence qui est l'oxydation de CO en CO2. Le système décrit dans cette étude présente d'une part un intérêt pratique pour le traitement rapide de contaminations accidentelles de l'air ambiant, mais est aussi un très bon moyen d'obtenir des paramètres cinétiques fiables dans le domaine des catalyseurs en films minces utilisés dans de nombreux réacteurs structurés

International audience; OBJECTIVES: This study aims at describing the evolution of the epidemiology of invasive aspergillosis (IA) in a French University Hospital focussing on nosocomial cases, in order to assess the efficiency of the environmental preventive measures which were implemented. METHODS: From 2003 to 2009, IA cases were reviewed monthly and classified according to the EORTC/MSG criteria and the origin of contamination. RESULTS: Five proven and 65 probable IA cases were diagnosed. Most of the cases (74.3%) occurred in patients with haematological malignancies. Incidences of IA and nosocomial IA (NIA) were 0.106 and 0.032 cases per 1000 admissions, respectively. All the 21 NIA cases occurred in the absence of air treatment (laminar air flow facilities or Plasmair decontamination units) and/or during construction works. The 3-month and 1-year overall survival rates were 50.6% [38.2-61.7] and 31.1% [20-42.9] respectively, and did not differ according to the origin of contamination. CONCLUSION: Nosocomial IA still accounted for a third of all IA cases diagnosed from 2003 to 2009 and mainly occurred in the absence of environmental protective measures, which were confirmed to be effective when applied. Our results show that extension and/or reinforcement of these measures is needed, especially in the haematology unit and during construction works.

The main objective of this work was to study the potential of three-dimension beta silicon carbide (β-SiC) alveolar foams for use as photocatalyst support, targeting the implementation of structured photocatalytic reactors for air treatment. Medium surface area β-SiC alveolar foams were synthesized according to the Shape Memory Synthesis concept, consisting in the controlled carburization of a preshaped polyurethane foam. First, the degradation of three model pollutants (methylethylketone, ammonia and hydrogen sulfide) was performed over TiO2 thin layers in a flow-through reactor for selecting three photocatalysts of interest – Hombikat UV100, PC500 and P25 TiO2 – among six commercial standards. The powderly photocatalysts were further immobilized onto β-SiC foams. After an optimization step in terms of mean cell size, light transmission, photocatalyst nature and weight content as well as of the immobilization method, the TiO2/β-SiC foam photocatalytic media was characterized and its photocatalytic behaviour was compared in a single-pass mode as well as in a recirulation mode inside a 2 m3 chamber, to those obtained on a TiO2 thin layer and with a well-known commercial photocatalytic felt media made from quartz fibers supporting sol-gel TiO2. The photocatalytic media elaborated with β-SiC alveolar foams exhibited superior performances compared to that of the commercial felt standard. The foams acted as static mixing within the reactor and allowed a more efficient use of the reactor volume, by increasing the photocatalyst density per reactor volume unit, while maintaining however a suitable illumination within the reactor core as well as very low pressure drops.; L’objectif principal de ce travail a été d’étudier le potentiel de mousses alvéolaires tridimensionnelles en carbure de silicium de forme béta (β-SiC) comme support de photocatalyseur, dans le but de mettre au point des réacteurs photocatalytiques structurés pour le traitement de l’air. Ces mousses alvéolaires de β-SiC de surface spécifique moyenne et de porosité très ouverte sont obtenues par la synthèse dite à mémoire de forme (Shape Memory Synthesis), consistant en la carburation contrôlée d’une mousse alvéolaire de polyuréthane préformée. Une étude de la dégradation de trois polluants sur des films minces en mode de lit léchant (la méthyléthylcétone, l’ammoniac et le sulfure d’hydrogène) a tout d’abord permis de sélectionner trois photocatalyseurs d’intérêt parmi six références commerciales avant d’être immobilisés sur les mousses de β-SiC. Après une étape d’optimisation en termes de taille d’alvéoles, de nature et quantité de photocatalyseur, le média photocatalytique TiO2/mousses de β-SiC a été caractérisé et ses performances comparées en mode mono-passage ainsi qu’en mode de recirculation du flux dans une enceinte de 2 m3, à celles d’un film mince de TiO2 et d’un média photocatalytique commercial de référence. Le média photocatalytique TiO2/mousses de β-SiC présente des performances nettement améliorées par rapport à celles du média référent. Les mousses jouent un rôle de mélangeur statique et permettent une meilleure utilisation du volume du réacteur, en augmentation la densité de photocatalyseur par unité de volume tout en maintenant une illumination du cœur du réacteur acceptable ainsi que des pertes de charge très limitées.

International audience; This study deals with the application of vapour permeation on the abatement of air polluted with VOC, from low to medium concentrations. Toluene, butadiene and propylene were chosen as model compounds. On a first part of the study, the permeation of single VOC, binary and ternary VOC/air mixtures was performed at different flow rates and VOC concentrations. The permeate flux, permeance, enrichment factor, separation efficiency and the recovery were determined. The experimental results were compared to those obtained with a mathematical model, allowing the calculation of the membrane area required to eliminate 95% of the feed VOC content.

International audience; A general research program, focusing on activated carbon fiber cloths (ACFC) and felt for environmental protection was performed. The objectives were multiple: (i) a better understanding of the adsorption mechanisms of these kinds of materials; (ii) the specification and optimization of new processes using these adsorbents; (iii) the modeling of the adsorption of organic pollutants using both the usual and original approaches; (iv) applications of ACFC in industrial processes. The general question was: how can activated carbon fiber cloths and felts be used in air treatment processes for the protection of environment. In order to provide an answer, different approaches were adopted. The materials (ACFC) were characterized in terms of macro structure and internal porosity. Specific studies were performed to get the air flow pattern through the fabrics. Head loss data were generated and modeled as a function of air velocity. The performances of ACF to remove volatile organic compounds (VOCs) were approached with the adsorption isotherms and breakthrough curves in various operating conditions. Regeneration by Joule effect shows a homogenous heating of adsorber modules with rolled or pleated layers. Examples of industrial developments were presented showing an interesting technology for the removal of VOCs, such as dichloromethane, benzene, isopropyl alcohol and toluene, alone or in a complex mixture.

International audience; This study assesses the potential of ozonation and advanced oxidation process O(3)/H(2)O(2) to enhance the dimethyldisulfide (DMDS) mass transfer in a compact chemical scrubber developed for air treatment applications. Theoretical calculations, through Hatta number and enhancement factor evaluations for two parallel irreversible reactions, were compared to experimental data and enabled the description of the mass transfer mechanisms. These calculations required the determination of the kinetic constant of the DMDS oxidation by molecular ozone ( [Formula: see text] ) and the measurement of the hydroxyl radical concentration within the scrubber. The competitive kinetic method using the 1,2-dihydroxybenzene (resorcinol) enabled to determine a value of the kinetic constant [Formula: see text] of 1.1×10(6)M(-1)s(-1) at 293K. Then, experiments using para-chlorobenzoic acid in solution allowed measuring the average hydroxyl concentration in the scrubber between the inlet and the outlet depending on the chemical conditions (pH and inlet O(3) and H(2)O(2) concentrations). High hydroxyl radical concentrations (10(-8)M) and ratio of the HO°-to-O(3) exposure (R(ct)≈10(-4)) were put in evidence.

International audience; Photocatalytic oxidation (PCO) is a technique developed for the removal of volatile organic compounds (VOC) in indoor air. The originality of this work is to investigate PCO performances under experimental conditions equivalent to indoor air in terms of VOC concentrations and relative humidity. Toluene was chosen as the model compound. Oxidation of this compound was followed in static conditions for 12 h to study: (i) oxidation kinetics, (ii) formation/disappearance of reaction intermediates and by-products. Experiments were conducted with initial concentrations of toluene ranging from 50 to 800 ppb, both under dry air and under wet air (50% RH).Seventeen reaction intermediates were detected and quantified in the gas phase (benzaldehyde, cresols, aldehydes, ketones...). Their temporal profiles are used to compare the reaction mechanism of toluene PCO at ppm level (classical literature) and at ppb level (this study). These temporal profiles clearly show that some intermediates, such as acetaldehyde and acrolein, can either disappear with slow kinetics or accumulate in the air. In addition, the presence of water vapor,although it accelerates toluene oxidation, does not induce significant effect on the nature of reaction intermediates. All these results lead to the justification for future studies of PCO to select typical indoor air concentrations in order to draw reliableconclusions about the performance and behavior of the systems of air treatment by photocatalysis.; Lʼoxydation photocatalytique (OPC) est une technique développée pour lʼélimination des composés organiques volatils (COV) présents dans lʼair intérieur. Lʼoriginalité de ces travaux réside dans lʼétude des performances de lʼOPC dans des conditions expérimentales reproduisant lʼair intérieur en termes de niveaux de concentrations en COV et dʼhumidité relative. Le toluène a été retenu comme composé modèle. Lʼoxydation de ce composé a été suivie en conditions statiques pendant 12 h afin dʼétudier : (i) sa cinétique dʼoxydation ; (ii) la formation/disparition des intermédiaires réactionnels et sous-produits. Lʼétude a été réalisée pour des concentrations initiales en toluène comprises entre 50 et 800 ppb, à la fois en air sec et en air humide (50 % RH). Dix-sept intermédiaires réactionnels ont été détectés et quantifiés en phase gazeuse (benzaldéhyde, crésols, aldéhydes, cétones…). Leurs profils temporels permettent de comparer le mécanisme réactionnel de lʼOPC du toluène à lʼéchelle de la ppm (littérature classique) et à lʼéchelle de la ppb (cette étude). Ces profils temporels montrent clairement que certains des intermédiaires, tels que lʼacétaldéhyde ou lʼacroléine, peuvent soit disparaître avec une cinétique très lente, soit sʼaccumuler dans lʼair. En outre, la présence dʼeau, bien quʼelle accélère lʼoxydation du toluène, nʼinduit pas dʼeffet notable sur la nature des intermédiaires réactionnels. Lʼensemble de ces résultats justifie de conduire à lʼavenir les études dʼOPC à des concentrations correspondant à lʼair intérieur afin de tirer des conclusions fiables sur les performances et le comportement des systèmes de traitement dʼair par photocatalyse.

International audience; Petroleum transformation industries have applied membrane processes for solvent and hydrocarbon recovery as an economic alternative to reduce their emissions and reuse evaporated components. Separation of the volatile organic compounds (VOCs) (toluene-propylene-butadiene) from air was performed using a poly dimethyl siloxane (PDMS)/α-alumina membrane. The experimental set-up followed the constant pressure/variable flow set-up and was operated at ~21 °C. The membrane is held in a stainless steel module and has a separation area of 55 × 10−4 m². Feed stream was set to atmospheric pressure and permeate side to vacuum between 3 and 5 mbar. To determine the performance of the module, the removed fraction of VOC was analyzed by Gas Chromatography/Flame Ionization Detector (GC/FID). The separation of the binary, ternary and quaternary hydrocarbon mixtures from air was performed at different flow rates and more especially at low concentrations. The permeate flux, permeance, enrichment factor, separation efficiency and the recovery extent of the membrane were determined as a function of these operating conditions. The permeability coefficients and the permeate flux through the composite PDMS-alumina membrane follow the order given by the Hildebrand parameter: toluene > 1,3-butadiene > propylene. The simulated data for the binary VOC/air mixtures showed fairly good agreement with the experimental results in the case of 1,3-butadiene and propylene. The discrepancies observed for toluene permeation could be minimized by taking into account the effects of the porous support and an influence of the concentration polarization. Finally, the installation of a 0.02 m2 membrane module would reduce 95% of the VOC content introduced at real concentration conditions used in the oil industry.

Desiccant evaporative systems are heat driven at moderate temperature and are usually coupled with solar collectors or with waste heat. The performance of desiccant systems is very sensitive to outside conditions and to the efficiency of the system components. In this paper the impact of these factors on the performance of two configurations of desiccant systems is investigated through simulation. First, a model of a desiccant air handling unit is briefly presented and validated experimentally. Then different efficiency combinations are studied and the critical efficiencies are derived. Finally, a comparison of the conventional and the recirculation configurations is made, based on outside conditions.

The NO2 removal performance of Fe-modified H-BEA and H-ZSM-5 has been investigated in detail by means of in situ and operando FTIR spectroscopy. The surface characterization using NO2 and NO as probe molecules revealed important contributions of redox processes involving Fe3+-OH and/or α-oxygen species as well as Fe2+-NO species. In these anhydrous conditions, the NO2 storage performance is mainly due to the disproportion of NO2 leading to NO+ and nitrate species. However, under flow and in the presence of humidity, and thus in more realistic conditions, nitrates and NO+ formation are suppressed. The main mechanism responsible for the wet NO2 removal consists in the formation of both adsorbed nitric acid and gaseous NO. According to the proposed mechanism, a strong positive water-effect is established: the total suppression of NO2 in the presence of humidity together with the formation of NO, which is less toxic than NO2, makes the investigated zeolites promising candidates for efficient materials used in indoor air treatment.

International audience; A catalytic, silicon-based, microstructured reactor was developed for the catalytic oxidation of volatile organic compounds, with the aim of small-scale localized air treatment. The microreactor was based on the stacking of microstructured platelets, and the active catalyst phase, i.e., platinum, was deposited onto the walls of the microchannels by the thermal evaporation technique. The experimental setup allowed testing the efficiency of the catalytic microreactor. The deep oxidation of acetone (as a target compound) in air was carried out at increasing temperatures, resulting in ignition curves. Wide ranges of inlet acetone concentrations (500–8000 ppmv) and space velocities (18,700–201,000 h–1) were studied. Regarding acetone oxidation, the catalytic microreactor was found to exhibit high performances in terms of conversion, selectivity, and temperatures required to reach 50 and 95 % conversions.

International audience; In order to obtain a system as efficient for collecting particles with a size less than 10 μm (PM10) as removing volatile organic compounds (VOCs), prototype fibrous media containing activated carbon fibers (ACF) associated with non-adsorptive fibers such as cellulose (C) and polyester (PET) fibers have been developed. Influence of process operating parameters on toluene adsorption and particle filtration efficiency was investigated. Particularly, effect of type and ratio of non-adsorptive fibers, degree of beating of cellulose fibers and addition of binders was studied and the impact on physical properties of the medium and its performances for adsorption and particle collection was analyzed.

New inorganic composite materials (ICM) were prepared combining a diatomite (Kieselguhr) from Algerian origin and charcoal from pine. After pyrolysis at 850 °C and chemical treatment with HCl, several techniques were used for the characterization of the obtained ICM. X-ray diffraction patterns and FT-Infrared spectroscopy showed that calcium carbonates, initially present as impurities in the natural Kieselguhr, have totally disappeared after treatment. A phase transition for diatomite was observed from quartz, dolomite and amorphous phase to cristobalite after mixture with charcoal. According to the nitrogen adsorption-desorption analysis, the surface properties of diatomite were found to be profoundly affected by the presence of charcoal. Indeed, the surface increased from 5 to 405 m2/g. The obtained products also exhibit a hydrophobic characteristic, contrary to the hydrophilic nature of the initially used diatomite material. These new ICM seem to be promising materials for use as industrial adsorbents in different applications like for the wastewater and air treatment, and for solvent recuperation.

International audience; Dimethyldisulfide (DMDS) degradation and mineralization were carried out in a continuous flow reactor using TiO2-P25 or ZnO as photocatalysts. The efficiency of the disappearance and of the mineralization of the DMDS showed to be very sensitive to the molar flow of the sulphur compounds. In our study, we have evaluated the limit average mineralization rate of DMDS per Watt emitted (for TiO2-P25). Catalyst deactivation has been observed after several hours of complete DMDS mineralization, which was expressed by the decrease of CO2 concentration and the appearance of residual DMDS on the outlet side of the reactor. This phenomenon is due to the inhibition of active sites on the catalyst by the formation of sulfates as final sulphur-compounds (determined by ionic chromatography). The FT-IR analysis, performed on catalyst in presence of high DMDS flow, indicated the presence of partial oxidation products such as sulfoxides, sulfones, sulfonates, sulfates and carbonyl groups. All of these disappearing after static irradiation, except for sulfate according to ionic chromatography analysis. The effect of humidity is shown; the data indicated that a detrimental effect occurs depending on the DMDS/H2O concentration ratio. Comparison of the disappearance and of the mineralization of DMDS in presence of TiO2-P25, commercial ZnO or home made nano-ZnO catalysts is presented and discussed. Nano-ZnO material, prepared at low temperature, showed an efficiency close to that of TiO2-P25 while no activity was detected in the presence of commercial ZnO.

The procedures coupling a catalyst and a plasma at atmospheric pressure present a promising solution for atmospheric depolluting; more specifically for the processing of VOCs. In particular, the low energetic cost of this technique is highly interesting for minor concentrations (odor treatments), which are difficult to treat with usual methods. Among the catalysts available for the given purpose, TiO2 (a photocatalyst) is of advantage thanks to its low cost, its non toxicity and especially thank to its excellent selectivity in CO2. The combination with plasma could improve the processing speed which is slow using photocatalysis alone. The plasma/TiO2 synergy has just been studied since 2000. The aim of this work consists in the identification of the mechanisms responsible for this phenomenon. The physical and chemical contributions from the discharge, from porosity and from TiO2's photocatalytic activity were therefore separately scrutinized. In order to accomplish this, an non conventional approach was adopted to study a discharge at atmospheric pressure (DBD) as well as a discharge at low pressure (pulsed DC) permitting the use of infrared laser diagnosctics for in situ measurements resolved in time.; Les procédés de couplage d'un plasma à pression atmosphérique et d'un catalyseur représentent une solution prometteuse pour la dépollution atmosphérique, ou plus spécifiquement pour le traitement des Composés Organiques Volatils. En particulier, le faible coût énergétique de cette technique la rend très intéressante pour les petites concentrations (traitement d'odeurs), difficiles à traiter avec les techniques habituelles. Parmi les catalyseurs qui peuvent être employés, le TiO2 (photocatalyseur) est avantageux pour son faible coût, sa non toxicité, et surtout son excellente sélectivité en CO2. Le couplage avec un plasma pourrait améliorer la vitesse de traitement qui est très lente en photocatalyse seule. La synergie plasma/TiO2 est étudiée depuis 2000 seulement. Le but de ce travail est d'identifier les mécanismes responsables de cette synergie en séparant les contributions de la décharge, de la porosité et de l'activité photocatalytique du TiO2. Pour y parvenir, une approche originale à été utilisée en étudiant à la fois une décharge à pression atmosphérique (DBD) et une décharge à basse pression (DC pulsée) autorisant l'utilisation de diagnostics lasers infra-rouge pour effectuer des mesures in situ résolues en temps.

The procedures coupling a catalyst and a plasma at atmospheric pressure present a promising solution for atmospheric depolluting; more specifically for the processing of VOCs. In particular, the low energetic cost of this technique is highly interesting for minor concentrations (odor treatments), which are difficult to treat with usual methods. Among the catalysts available for the given purpose, TiO2 (a photocatalyst) is of advantage thanks to its low cost, its non toxicity and especially thank to its excellent selectivity in CO2. The combination with plasma could improve the processing speed which is slow using photocatalysis alone. The plasma/TiO2 synergy has just been studied since 2000. The aim of this work consists in the identification of the mechanisms responsible for this phenomenon. The physical and chemical contributions from the discharge, from porosity and from TiO2's photocatalytic activity were therefore separately scrutinized. In order to accomplish this, an non conventional approach was adopted to study a discharge at atmospheric pressure (DBD) as well as a discharge at low pressure (pulsed DC) permitting the use of infrared laser diagnosctics for in situ measurements resolved in time., Les procédés de couplage d'un plasma à pression atmosphérique et d'un catalyseur représentent une solution prometteuse pour la dépollution atmosphérique, ou plus spécifiquement pour le traitement des Composés Organiques Volatils. En particulier, le faible coût énergétique de cette technique la rend très intéressante pour les petites concentrations (traitement d'odeurs), difficiles à traiter avec les techniques habituelles. Parmi les catalyseurs qui peuvent être employés, le TiO2 (photocatalyseur) est avantageux pour son faible coût, sa non toxicité, et surtout son excellente sélectivité en CO2. Le couplage avec un plasma pourrait améliorer la vitesse de traitement qui est très lente en photocatalyse seule. La synergie plasma/TiO2 est étudiée depuis 2000 seulement. Le but de ce travail est d'identifier les mécanismes responsables de cette synergie en séparant les contributions de la décharge, de la porosité et de l'activité photocatalytique du TiO2. Pour y parvenir, une approche originale à été utilisée en étudiant à la fois une décharge à pression atmosphérique (DBD) et une décharge à basse pression (DC pulsée) autorisant l'utilisation de diagnostics lasers infra-rouge pour effectuer des mesures in situ résolues en temps.

WOS:000240293500005; International audience; Due to their good adsorption capacities, woven activated carbon filters are promising materials for the removal of volatile organic compounds (VOC) and odors in air treatment applications. As these fibrous media can easily be implemented in various filtration configurations, their use in a combined filter device for VOC and particulate matter (PM) removal is considered. For this purpose, experiments are performed to characterize their collection efficiencies versus particle size and mass loading for the removal of particulate matter smaller than 10 mu m. The specific fiber arrangement, due to multi-fiber yam weaving, prevents the use of initial collection efficiency models developed for non-woven media. This study aims to characterize collection efficiency during loading and to model initial collection efficiency in a woven structure made of multi-fiber yams. (C) 2005 Elsevier Ltd. All rights reserved.

International audience; The absorption of oxygen in aqueous-organic solvent emulsions was studied in a laboratory-scale bubble reactor at a constant gas flow rate. The organic and the gas phases were dispersed in the continuous aqueous phase. Volumetric mass transfer coefficients (k(L)a) of oxygen between air and water were measured experimentally using a dynamic method. It was assumed that the gas phase contacts preferentially the water phase. It was found that addition of silicone oils hinders oxygen mass transfer compared to air-water systems whereas the addition of decane, hexadecane and perfluorocarbon PFC40 has no significant influence. By and large, the results show that, for experimental conditions (organic liquid hold-up

Volatile organic compounds (VOC) entail nuisances for humans and the natural environment. Increasing strict rules force the industrials to set up equipments of air treatment ofr their VOC charged effluents. This work studies the technical feasibility of an innovative hybrid process among the at present available techniques: the coupling of an absorption process and a membrane separation, pervaporation. The various aspects of this process are examined: choice of the absorbent, study of hydrodynamics and mass transfer in a packed column, separation of pollutants contained in the absorbent by pervaporation, coupling of the two processes. At the end, an analysis of the process underlines main parameters and their impact on the coupling efficiency. It is shown that hybrid process turns out feasible., Les composés organiques volatils (COV) sont source de nuisances pour l'Homme et le milieu naturel. Des réglementations de plus en plus strictes imposent d'équiper les unités industrielles d'un procédé de traitement des effluents gazeux chargés en COV lorsque cela est nécessaire. Ce travail étudie la faisabilité technique d'un procédé hybride innovant parmi les techniques actuellement disponibles : le couplage d'un procédé d'absorption et un procédé membranaire, la pervaporation. Les différents aspects de ce procédé sont examinés : choix de l'absorbant, étude de l'hydrodynamique et du transfert de matière en colonne garnie, séparation des polluants contenus dans l'absorbant par pervaporation, couplage des deux procédés. Au final, une analyse du procédé met en lumière les grandeurs influentes et leur impact sur l'efficacité du couplage. Il est montré que le procédé hybride s'avère faisable techniquement.