Catalytic decomposition performance for O3 and NO2 in humid indoor air on a MnO /Al2O3 catalyst modified by a cost-effective chemical grafting method

International audienc

Electrostatic precipitator for fine and ultrafine particle removal from indoor air environments

International audienc

Indoor Air Quality Campaign in an Occupied Low-Energy House with a High Level of Spatial and Temporal Discretization

International audienceBackground and gaps. The topic of indoor air quality (IAQ) in low-energy buildings has received increasing interest over the past few years. Often based on two measurement points and on passive measurements over one week, IAQ studies are struggling to allow the calculation of pollutants exposure. Objectives. We would like to improve the evaluation of the health impacts, through measurements able to estimate the exposure of the occupants. Methodology. This article presents detailed IAQ measurements taken in an energy-efficient occupied house in France. Two campaigns were conducted in winter and spring. Total volatile organic compounds (TVOC), formaldehyde, the particle numbers and PM2.5, carbon dioxide (CO2), relative humidity (RH), temperature (T), ventilation airflows, and weather conditions were dynamically measured in several points. Laboratory and low-cost devices were used, and an inter-comparison was carried out for them. A survey was conducted to record all the daily activities of the inhabitants. IAQ performance indicators based on the different pollutants were calculated. Results. PM2.5 cumulative exposure did not exceed the threshold available in the literature. Formaldehyde concentrations were high, in the kitchen, where the average concentrations exceeded the threshold. However, the formaldehyde cumulative exposure of the occupants did not exceed the threshold. TVOC concentrations were found to reach the threshold. With these measurements performed with high spatial and temporal discretization, we showed that such detailed data allow for a better-quality health impacts assessment and for a better understanding of the transport of pollutants between rooms

Non-Thermal Plasma for indoor air treatment: Toluene degradation in a corona discharge at ppbv levels

International audienc

Développement d’un procédé pour l’épuration de l’air intérieur par couplage de la décharge couronne et de l’adsorption

International audienc

Etude de l'ozonation de carbones activés en grains et tissus modifiés par des traitements d’oxydation

National audienc

Investigation of Doehlert matrix conception in novel intrinsically conducting polymers based on selenium nanoparticles for wastewater treatment: Synthesis, characterization, kinetic and chemometric study

International audienceThe synthesis of robust intrinsically conducting polymers (ICPs) based on nanoparticles is becoming increasingly attractive to the research community due to the unique properties of these nanocomposites. Indeed, as organic semiconductors, ICPs combine both polymer and metal properties in a single structure. This study presents an innovative approach in which the Doehlert Matrix (DM) is applied to a novel ICP nanocomposite based on polyaniline (Pani) coupled with selenium (Se) loaded mesoporous titania (TiO2) for wastewater treatment by photocatalysis. It includes both the elaboration routes of ICP nanocomposites, characterization of materials by X-ray diffraction (XRD), BET analysis, thermogravimetric analysis (TGA), RAMAN spectroscopy and Fourier transform infrared spectroscopy (FTIR) and photodegradation of methylene blue (MB) as a representative of dye pollutant. In addition, the photocatalytic process has been optimized by a novel DM conception. The effect of the pH of the solution, the catalyst dosage and the initial pollutant concentration was investigated. The optimum conditions were found to be: initial MB concentration of 15 mg/L, the catalyst dosage of 69 mg and pH of 9.6 with an operating time of 75 min, with a coefficient of determination R2 equal to 0.9985. The removal efficiency of BM was close to 97 %. The study shows that the new ICP nanocomposites improve the photocatalytic efficiency compared to pure titania and/or pure Pani. In addition, as the ternary Pani-Se-TiO2 nanocomposite could be obtained from a low-cost synthesis, it is a very promising material for use in wastewater treatment

Stockage de chaleur thermochimique : expérimentation de différents matériaux composites innovants

International audienceThermochemical heat storage is a promising technology: it enables long-term heat storage with negligible heat loss and high energy densities. Composite sorbents based on silica, polyethylene glycol (PEG) and a thermochemical salt were developed for a transport application and studied in an open fixed-bed reactor. These composites were cycled to assess their stability and to evaluate their water sorption capacity and storage energy density. The sorption kinetics was also investigated.Le stockage de chaleur par voie thermochimique est une solution d'avenir, car il permet un stockage sur des périodes aussi longues que désiré avec une densité énergétique élevée. Des sorbants composites à base de silice, de polyéthylène glycol (PEG) et d'un sel thermochimique ont été étudiés dans un réacteur à lit fixe ouvert, pour une application de stockage de chaleur pour le transport. Ces composites ont été cyclés pour vérifier leur stabilité et évaluer leur cinétique et leur capacité de sorption, ainsi que leur densité énergétique de stockage

Suitability of Thermal Swing Adsorption for the Treatment of Siloxanes and Toluene in Biogas: An Experimental Study

International audienc

Effect of energy renovation on indoor air quality of a French school building

International audienceIndoor air quality (IAQ) and thermal comfort issues in schoolsare of particular public concern because children represent avulnerable population group to air pollution. In fact, their respiratoryand immune systems are still developing and a long-term exposureto indoor air pollutants might have a significant impact on theirhealth and scholarly. This study focuses on the effect of the energyrenovation of two classrooms which consists of the implementationof a dual flow ventilation system with high efficiency filters (F7).The classrooms are located in an alpine valley (France) known forits high level of atmospheric pollution. To do this, carbon dioxide(CO2), temperature (T), relative humidity (RH) and PM2.5 weremonitored continuously over twice two-month periods before andafter the renovation in winter 2018 and 2020, respectively. Inaddition, the ventilation airflows were measured and a dailyquestionnaire that report the information on general condition in theclassroom were recorded day-to-day. The results of these campaignsindicate that before the renovation, the two rooms were confined,estimated by IAQ index such as ICONE index which are equal to 2.The CO2 concentration reached to 4790 ppmv due to a very low airexchange rate 0.05 h-1. During the high PM2.5 levels episodesobserved in outdoor air, the low air exchange rate limited thetransport of PM2.5 from the outside to the inside of the classrooms.As a result, the percentages of concentration exceedance comparedto WHO recommendations were 23% and 17%, in class 1 and class2 respectively, while it reached 68% in outdoor air.After the renovation, the ventilation airflow was higher thanbefore renovation and reached to 2.46 h-1. As consequence, a drasticreduction of the confinement was measured with ICONE index ofclass 2 reaching to 0. The CO2 concentrations are remained low witha maximum value of 1150 ppmv. Rather the high air renewalgenerates a significant inflow of outdoor particulate pollution whichthe indoor PM2.5 concentrations range were 20-80 µg.m-3 during theoutdoor air pollution episodes. However, the indoor concentrationswere all the time lower than those observed outside withindoor/outdoor concentration ratio about 0.5. It can be assumed thatthe filtration of the supply air allowed to limit the entrance of theparticles. However, this figure should be taken with caution becauseof the complex physic associated with particle behaviours (e.g.sedimentation, resuspension, etc). In addition, it is interesting to notethat a dysfunction of the ventilation system led to a situation closeto that before renovation, both with regard to the rate of ventilationairflow, as well as the concentrations of CO2 and PM2.5