Academic literature on the topic 'Calcaire – Absorption et adsorption'

The resolution IV fractional factorial design was used to study the adsorption regularity of Cu coexisted with various pollutions (Zn, Pb, Cd, Ni, atrazine, malathine, et al.) onto the sediment. The study found that the main effect and the second-order interaction effect of ten pollutions concentration had significant influence on the adsorption of Cu on the sediment. The concentration of Cu was the critical factor to the promotion of the absorption capacity of Cu in sediment, the second-order effect played the critical role in restraining the absorption of Cu. The main effect of Cd, and the second-order interaction effect include Cd, had greatly inhibited the absorption of Cu in sediment, and the contribution was over 30%, which meant there was prominent antagonism between Cu and Cd. Fractional factorial design can provide a theoretical basis for the reveal of the adsorption mechanism between the different contaminants in the water environment pollution.

Neonatal calves are born with no immunoglobulins (Igs) in the blood stream and rely on Ig from colostrum through passive immunity transfer. Unfortunately, transfer of passive immunity to neonatal calves is too often inadequate, resulting in excessive rates of morbidity and mortality. Natural zeolite is characterized by framework of linked tetra hydration enclosing open cavities in the form of channels, and cages with ion exchanger and adsorption capacity. In literature, there were reported that thermally activated natural zeolite (T-zeolite) could increase colostral IgG absorption and decrease susceptibility of neonates to infections (Sadeghi et al., 2004; Stojic et al., 1995). To our knowledge, little information is available concerning the effect of thermally activated natural zeolite on colostral IgG1, IgM and IgA absorption in neonates. Our experiment was designed to investigate the effect of thermally activated natural zeolite on colostral IgG1, IgM and IgA absorption in newborn Holstein calves.

In this research, Zn2(BDC)2(DABCO) metal–organic framework (MOF) as a solid phase was used for separation and preconcentration toxic nickel ions (Ni) from water samples by ultrasound assisted-dispersive-micro solid phase extraction coupled to electrothermal atomic absorption spectrometry (USA-D-μ-SPE/ET-AAS). The MOF nanostructure was characterized by field emission-scanning electron microscope (FE-SEM) and transmission electron microscopey (TEM) for presentation of morphology and size of MOF synthesis. By procedure, 25 mg of Zn2(BDC)2(DABCO) as MOF adsorbent was added to 25 mL of water samples and then, Ni ions chemically adsorbed based on dative bonding of nitrogen in DABCO (1,4-diazabicyclo [2.2. 2]octane); N2(C2H4)3) at pH=8. The adsorbent was separated from liquid phase by syringe cellulose acetate filters (SCAF, 0.2 μm) and Ni ions back extracted from MOF adsorbent before determined by ET-AAS. The maximum recovery of MOF for nickel ions as a physically and chemically adsorption was obtained 34.6% and 98.8% at pH=3 and 8, respectively.

Abstract. Spectral aerosol light absorption is an important parameter for the assessment of the radiation budget of the atmosphere. Although on-line measurement techniques for aerosol light absorption, such as the Aethalometer and the Particle Soot Absorption Photometer (PSAP), have been available for two decades, they are limited in accuracy and spectral resolution because of the need to deposit the aerosol on a filter substrate before measurement. Recently, a 7-wavelength (λ) Aethalometer became commercially available, which covers the visible (VIS) to near-infrared (NIR) spectral range (λ=450–950 nm), and laboratory calibration studies improved the degree of confidence in these measurement techniques. However, the applicability of the laboratory calibration factors to ambient conditions has not been investigated thoroughly yet. As part of the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia – SMOke aerosols, Clouds, rainfall and Climate) campaign from September to November 2002 in the Amazon basin we performed an extensive field calibration of a 1-λ PSAP and a 7-λ Aethalometer utilizing a photoacoustic spectrometer (PAS, 532 nm) as reference device. Especially during the dry period of the campaign, the aerosol population was dominated by pyrogenic emissions. The most pronounced artifact of integrating-plate type attenuation techniques (e.g. Aethalometer, PSAP) is due to multiple scattering effects within the filter matrix. For the PSAP, we essentially confirmed the laboratory calibration factor by Bond et al. (1999). On the other hand, for the Aethalometer we found a multiple scattering enhancement of 5.23 (or 4.55, if corrected for aerosol scattering), which is significantly larger than the factors previously reported (~2) for laboratory calibrations. While the exact reason for this discrepancy is unknown, the available data from the present and previous studies suggest aerosol mixing (internal versus external) as a likely cause. For Amazonian aerosol, we found no absorption enhancement due to hygroscopic particle growth in the relative humidity (RH) range between 40% and 80%. However, a substantial bias in PSAP sensitivity that correlated with both RH and temperature (T) was observed for 20%<RH<30% and 24°C<T<26°C, respectively. In addition, both PSAP and Aethalometer demonstrated no sensitivity to gaseous adsorption. Although very similar in measurement principle, the PSAP and Aethalometer require markedly different correction factors, which is probably due to the different filter media used. Although on-site calibration of the PSAP and Aethalometer is advisable for best data quality, we recommend a set of "best practice" correction factors for ambient sampling based on the data from the present and previous studies. For this study, the estimated accuracies of the absorption coefficients determined by the PAS, PSAP and Aethalometer were 10, 15 and 20% (95% confidence level), respectively.

A simple and fast separation of cadmium (Cd) based on functionalized carbon nanotubes with 2,3-dimercapto-1-propanol (CNTs@DHSP) was achieved in water samples before a determination by atom trap flame atomic absorption spectrometry (AT-FAAS). In this study, Cd(II) ions were extracted by syringe filter membrane-micro solid phase extraction procedure(SFM-μ-SPE). Firstly, 20 mg of the CNTs@DHSP as solid-phase added to 20 mL of water sample in a syringe, then dispersed for 3 min after adjusting pH up to 7 and pass through SFM very slowly. After extraction, the Cd(II) ions were back-extracted from SFM/CNTs@DHSP by 1.0 mL of eluent in acidic pH. Finally, the cadmium concentration was measured by AT-FAAS. Under the optimal conditions, the linear range (2–90 µg L−1), LOD (0.75 µg L−1) and enrichment factor (19.6) were obtained (RSD<1.5%). The adsorption capacity of Cd(II) with the CNTs@DHSP was obtained about 152.6 mg g-1. The method was validated by certified reference materials (SRM, NIST) and ET-AAS in water samples.

Contamination with heavy metals and petroleum hydrocarbons is considered as an environmental problem. Thus, this research was done to evaluate the effect of montmorillonite nano-clay on the changes in petroleum hydrocarbon degradation and cadmium (Cd) concentration in plant grown in a Cd-polluted soil. Treatments consisted of two levels of montmorillonite nano-clay (0 and 1% W/W) in a Cd-polluted soil (0, 5, 10 mg Cd/kg soil) and crude oil-polluted soil (0, 1 and 2% W/W). The plant used in this study was Tall Fescue (Festuca arundinacea L.). After 20 weeks, the concentration of Cd in plants was measured by atomic absorption spectroscopy and the total petroleum hydrocarbon (TPHs) in the soil was determined using the GC-mass spectrometry. Soil respiration was determined according to the method used by Qiao et al. ANOVA was used for statistical analysis of data. The least significant difference (LSD) test was used to determine the differences between the means. The application of 1% (w/w) montmorillonite nano-clay in Cd-polluted soil (10 mg Cd) without crude oil decreased Cd concentration in plant and increased microbial respiration by 18% and 34%, respectively. In addition, the application of 1% montmorillonite nano-clay in soil polluted with 1% crude oil and 10 mg Cd enhanced TPHs degradation by 27%. The use of montmorillonite nano-clay increased Cd adsorption in soil which resulted in an increase in microbial respiration and, hence the degradability of petroleum hydrocarbon in the soil.

Abstract Microalgae species Nannochloropsis sp. can used as heavy metal biosorben because of it’s adsorption capability that caused by the active cluster which contained in that species (Sembiring et al., 2008). Chlorella sp. is one of phytoplankton species that has the bioaccumulation ability of heavy metals and easily cultivated (Arifin, 1997). Lead (Pb) is a mineral belonging to microelements, is a heavy metal and is a potentially toxic material. Water bodies that have been polluted by compounds or ions Pb because can lead to the death of aquatic biota, the number of Lead (Pb) present in water bodies exceeding the proper concentration (Palar, 2004). One way to anticipate the increasing heavy metal pollution in the water is to bioremediation. The research using experimentally, the research design used was completely randomized design (CRD) consisting of four treatments with five replications. The concentrations of heavy metals Plumbum (Pb) used is 0 ppm and 0.9 ppm. The main parameters in this study is the ability of bioremediation Plumbum (Pb) by Nannochloropsis sp. and Chlorella sp. SPSS analytics normality test results and test the ability of T 95% in Nannochloropsis sp. and Chlorella sp. in absorbing heavy metals Plumbum (Pb) concentrations of 0 ppm and 0.9 ppm indicate that the data is normal and the results obtained were significantly different / significant. While the analysis of SPSS test T on heavy metal absorption capability comparison Plumbum (Pb) concentration of 0 ppm and 0.9 ppm by Nannochloropsis sp. and Chlorella sp. showed that the results were not significantly different / non significant. On average results obtained, Nannochloropsis sp. have a higher capacity than Chlorella sp. in the bioremediation process of heavy metals Plumbum (Pb).

Abstract. Mass accommodation is an essential process for gas–particle partitioning of organic compounds in secondary organic aerosols (SOA). The mass accommodation coefficient is commonly described as the probability of a gas molecule colliding with the surface to enter the particle phase. It is often applied, however, without specifying if and how deep a molecule has to penetrate beneath the surface to be regarded as being incorporated into the condensed phase (adsorption vs. absorption). While this aspect is usually not critical for liquid particles with rapid surface–bulk exchange, it can be important for viscous semi-solid or glassy solid particles to distinguish and resolve the kinetics of accommodation at the surface, transfer across the gas–particle interface, and further transport into the particle bulk. For this purpose, we introduce a novel parameter: an effective mass accommodation coefficient αeff that depends on penetration depth and is a function of surface accommodation coefficient, volatility, bulk diffusivity, and particle-phase reaction rate coefficient. Application of αeff in the traditional Fuchs–Sutugin approximation of mass-transport kinetics at the gas–particle interface yields SOA partitioning results that are consistent with a detailed kinetic multilayer model (kinetic multilayer model of gas–particle interactions in aerosols and clouds, KM-GAP; Shiraiwa et al., 2012) and two-film model solutions (Model for Simulating Aerosol Interactions and Chemistry, MOSAIC; Zaveri et al., 2014) but deviate substantially from earlier modeling approaches not considering the influence of penetration depth and related parameters. For highly viscous or semi-solid particles, we show that the effective mass accommodation coefficient remains similar to the surface accommodation coefficient in the case of low-volatility compounds, whereas it can decrease by several orders of magnitude in the case of semi-volatile compounds. Such effects can explain apparent inconsistencies between earlier studies deriving mass accommodation coefficients from experimental data or from molecular dynamics simulations. Our findings challenge the approach of traditional SOA models using the Fuchs–Sutugin approximation of mass transfer kinetics with a fixed mass accommodation coefficient, regardless of particle phase state and penetration depth. The effective mass accommodation coefficient introduced in this study provides an efficient new way of accounting for the influence of volatility, diffusivity, and particle-phase reactions on SOA partitioning in process models as well as in regional and global air quality models. While kinetic limitations may not be critical for partitioning into liquid SOA particles in the planetary boundary layer (PBL), the effects are likely important for amorphous semi-solid or glassy SOA in the free and upper troposphere (FT–UT) as well as in the PBL at low relative humidity and low temperature.

Le reformage à la vapeur couplé à la sorption in-situ d’un composant du milieu réactionnel (sorption-enhanced steam reforming, SESR) est un procédé d’avant-garde qui permet simultanément la production d’hydrogène de très haute pureté et la capture du CO2. L'objectif principal de ce travail est le développement de nouveaux sorbants pour le CO2 applicables à hautes températures et l’étude de leur application dans SESR. Deux nouvelles méthodes de synthèse ont été proposées pour synthétiser du zirconate de lithium (Li2ZrO3), zirconate de sodium (Na2ZrO3) ainsi que des matériaux à base d’oxyde de calcium (CaO), trois catégories de sorbants capables de réagir avec le CO2 à hautes températures. L’application du Li2ZrO3 à la capture du CO2 a démontré une augmentation de l’activité du matériau produit par une nouvelle méthode de synthèse combinant un surfactant et traitement à ultrasons, comparativement au Li2ZrO3 préparé par une méthode avec surfactant seulement (sans ultrasons) ou par la méthode conventionnelle (mélange des composants en phase liquide). Néanmoins, pour des pressions partielles en CO2 inférieures à 0,75 bar, la faible cinétique de sorption du CO2 obtenue par le Li2ZrO3 limite son application au procédé SESR. En considérant l’amélioration des propriétés de sorption obtenue en appliquant la méthode combinée surfactant/ultrasons à la synthèse du Li2ZrO3, la même technique a été aussi appliquée à la synthèse du Na2ZrO3. Des résultats inattendus ont été pourtant obtenus. Le Na2ZrO3 développé par la nouvelle technique a été moins actif durant les cycles sorption/régénération que celui produit par la méthode conventionnelle, de par la faible résistance de sa structure poreuse à de très hautes températures. La nouvelle méthode de synthèse combinée surfactant/ultrasons a été aussi appliquée pour la synthèse de CaO stabilisé par du zirconium (Zr). Un rapport Zr/Ca de 0,303 a été trouvé optimal pour la production d’un sorbant présentant la meilleure stabilité et activité pour la capture de CO2. Dans les conditions sévères d’opération, les résultats ont généralement indiqué une capacité de sorption du CaO stabilisé supérieure à celle du CaO pure. Dans le but de réduire les coûts de production des sorbants, une source moins chère de CaO (calcaire naturel) a été utilisée en combinaison avec une nouvelle méthode de synthèse qui consiste dans l’acidification du calcaire par de l’acide citrique suivie par une calcination en deux étapes (argon et air). Doté d’une structure hautement poreuse, le CaO produit a révélé une stabilité nettement meilleure par rapport au calcaire, ainsi qu’une capacité accrue de sorption du CO2. La même technique de synthèse a été aussi utilisée pour développer plusieurs matériaux à base de CaO stabilisé par divers oxydes métalliques (Al, Zr, Mg et Y), afin d’améliorer la stabilité du sorbant dans les conditions opérationnelles sévères, particulièrement les hautes températures de régénération en présence de CO2. CaO stabilisé par l’aluminium (Al) ou le zirconium (Zr) a démontré une meilleure activité comparativement aux autres matériaux synthétisés, inclusivement dans des conditions sévères d’opération. L’application de ces deux types de sorbants au vaporeformage du méthane (SESMR) a été ensuite étudiée dans un réacteur à lit fixe. Pour minimiser les limitations diffusionnelles, deux matériaux hybrides sorbant-catalyseur ont été développés. NiO-CaO stabilisé par Zr, préparé par la méthode combinée surfactant/ultrasons, dont le contenu en NiO est de 20.5 % (masse) a montré une efficacité dans la production d’hydrogène de 92% lors du premier cycle de reformage, ce qui est remarquablement plus élevée que le rendement d’équilibre en H2 pour le procédé traditionnel de vaporeformage du méthane (SMR) ( 70%). La méthode acidification/calcination en deux étapes a été utilisée pour produire le deuxième matériau hybride (NiO-CaO stabilisé par Al). L’application du matériau contenant 25 % (masse) de NiO a conduit à une efficacité moyenne de production d’hydrogène de 97.3%, démontrant ainsi son grand potentiel pour le SESMR. Les résultats de ce projet de recherche ont clairement démontré que le procédé SESR est une alternative très avantageuse au procédé traditionnel de reformage à la vapeur (sans séparation in-situ de CO2) pour la production d’hydrogène de très haute pureté. Le matériau hybride sorbant-catalyseur NiO-CaO stabilisé par Al a démontré une excellente activité à long terme, en confirmant son potentiel élevé pour application dans le procédé SESMR.
Sorption-enhanced steam reforming (SESR) is a forefront technology to produce H2 clean fuel, which integrates both CO2 capture and H2 production in a single process. The main objective of this work is to develop novel high-temperature CO2 sorbents and to investigate their application in SESR operation. Special attention was given to lithium zirconate (Li2ZrO3), sodium zirconate (Na2ZrO3) and calcium oxide (CaO)-based materials, as most famous high temperature CO2 sorbents, by applying two novel synthesis techniques. The application of Li2ZrO3 in CO2 capture sorption showed an increase in activity of the material prepared by surfactant template/sonication method compared to Li2ZrO3 prepared by simple surfactant template method (without sonication) or conventional wet-mixing route. Nevertheless, porous Li2ZrO3 still suffered from slow kinetics of CO2 sorption at low CO2 partial pressure (below 0.75 bar), which can limit its application for SESMR operation. Taking into consideration the improvement of Li2ZrO3 sorption properties, the same surfactant template/sonication technique was then applied to develop porous Na2ZrO3. The behavior of the new developed Na2ZrO3 was unexpected. The samples prepared by surfactant template/sonication technique were found to be less active than the conventional Na2ZrO3 during cyclic operation, due to the low resistivity of the pore structure at the very high temperature treatment required for calcination. The same surfactant template/sonication was also applied to develop Zr-stabilized CaO sorbents. An optimum Zr/Ca ratio of 0.303 was found to maximize the stability and CO2 capture activity of the proposed Zr-stabilized CaO sorbent. The results generally showed a better CO2 capture ability of Zr-stabilized CaO sorbent in comparison with pure CaO in severe cyclic operating conditions. With the purpose of reducing the cost of sorbent production, a cheaper source of CaO (natural limestone) was also considered and a novel synthesis technique (limestone acidification by citric acid followed by two-step calcination (in Ar and air atmospheres)) was applied in order to prepare highly porous CaO structure with unique CO2 capture ability. The results revealed a much better stability and CO2 sorption activity of the developed sorbent compared to natural limestone. The same technique was employed to develop a number of metal oxide (Al, Zr, Mg and Y)-stabilized CaO sorbents in order to enhance sorbent stability in severe operating conditions, i.e., high temperature regeneration in the presence of CO2. Al and Zr-stabilized CaO showed the best activity during both mild and severe operating conditions. The performance of the developed CO2 sorbents providing the best performance in CO2 capture (Zr-stabilized and Al-stabilized CaO) were then investigated experimentally in the sorption enhanced steam methane reforming (SESMR) using a fixed-bed reactor. To minimize the diffusional limitations, a hybrid catalyst-sorbent was developed for both sorbents. The application of Zr-stabilized CaO-nickel hybrid catalyst with 20.5 wt% NiO loading, prepared by surfactant-template/sonication method, resulted in 92% H2 production efficiency for the initial SESMR cycle, which is remarkably higher than traditional steam methane reforming (SMR) equilibrium H2 yield (70 %). The second developed hybrid sorbent-catalyst (Al-stabilized CaO-NiO) was prepared using limestone acidification coupled with two-step calcination technique. The long-term application of the hybrid catalyst containing 25 wt% NiO led to an average H2 production efficiency of 97.3%, proving its high efficiency in the SESMR process. In summary, the results of this thesis show that the SESR process is as an efficient alternative of traditional steam reforming for production of highly pure H2. The Al-stabilized CaO-NiO hybrid sorbent-catalyst showed an excellent activity over long-term operation, thus confirming its very high potential for use in the SESMR process.

Ce travail s’inscrit dans le cadre du programme de recherche pluridisciplinaire AQUAL qui vise à améliorer la qualité de l’eau sur le bassin versant de la Vesle. Cette amélioration passe par la lutte contre les pollutions diffuses en milieu rural dans ce bassin versant qui est une zone de grandes cultures et de vignobles autour de l’agglomération de Reims. L’objectif de ce travail est de déterminer les paramètres gouvernant la rétention et le transfert de deux herbicides, le terbuméton et l’isoproturon, dans les sols du bassin versant de la Vesle en région Champagne-Ardenne. Le terbuméton a été choisi en raison de sa présence chronique dans les eaux de captage alimentant la ville de Reims, malgré l’interdiction de son usage dans le traitement du vignoble champenois depuis 1998. Quant à l’isoproturon, son choix se justifie par son emploi massif en grandes cultures essentiellement dans la partie amont de la vallée de la Vesle. Onze sols ont été échantillonnés et leurs caractéristiques physico-chimiques (matière organique, calcaire, pH, CEC, détermination des phases cristallines) déterminées en combinant différentes techniques. Les différentes analyses effectuées ont mis en évidence une grande variabilité en terme de composition des sols, notamment les taux de calcaire et de matière organique. La rétention a été étudiée au laboratoire par l’intermédiaire du tracé d’isothermes d’adsorption à l’équilibre. Le calcaire et la matière organique ont été identifiés comme les paramètres majeurs gouvernant la rétention des deux pesticides étudiés : la rétention est corrélée positivement à la teneur en matière organique et négativement au taux de calcaire. Le transfert des pesticides a été étudié à travers des expériences d’élution dans des colonnes de sol reconstituées au laboratoire. Nos résultats indiquent que le lessivage du terbuméton et de l’isoproturon est favorisé dans les sols riches en calcaire et présentant de faibles teneurs en matière organique. Des modèles simples ont été proposés pour estimer les capacités de rétention et le transfert des pesticides dans les sols
This work is a part of the multidisciplinary AQUAL research program, which aims at improving the water quality in the Vesle watershed (Champagne-Ardenne area, France). This better quality of the water will be reached by controlling the diffuse pollution in the rural areas of this basin, namely the arable crops and vineyard zones around the city of Reims. Our contribution to this program consists in determining the parameters governing the retention and transfer in soils of two herbicides: (i) terbumeton used in Champagne vineyards and banned in France in 1998 but still detected in groundwaters and (ii) isoproturon currently used for the treatment of arable crops in the same area. Eleven soils were sampled and their physico-chemical properties (organic matter, lime, pH, CEC, mineralogical composition) determined using different techniques. The different techniques used showed an important variability in soils composition, notably organic matter and lime contents. Pesticide retention was studied at equilibrium through sorption isotherms. Lime and organic matter were identified as the main parameters controlling the retention of the studied pesticides in soils: retention is positively correlated with organic matter content and negatively correlated with lime content. Pesticide transfer was assessed in laboratory through elution experiments in hand-packed soil columns. Our results showed terbumeton and isoproturon leaching was favoured in highly calcareous soils presenting low organic matter contents. Simple models were proposed to assess pesticides retention and transfer in soils

Ce travail relatif a l'adsorption et l'electrosorption (adsorption sous potentiel impose) de polluants sur charbons actifs en grains comporte trois parties : la premiere partie a pour but d'etudier l'influence sur l'interaction adsorbat-adsorbant de la nature physique et chimique du charbon actif. Les resultats obtenus, par les methodes de titrage de boehm, de chromatographie gazeuse inverse et d'une combination de ces deux methodes, ont permis d'identifier separement l'effet sur les forces d'interaction de la porosite et des groupements fonctionnels. La deuxieme partie est consacree a l'etude de l'adsorption d'herbicides et de tensioactifs sur charbon actif en grains (cag) en regime dynamique. Les resultats obtenus montrent que la capacite et la cinetique d'adsorption en flux continu sont influencees par les proprietes de l'adsorbat et celles de l'adsorbant. Les parametres utilises sont la solubilite, la charge et la concentration pour les solutes, la porosite et les proprietes acido-basiques pour l'adsorbant. La capacite d'adsorption varie lineairement avec ln t. La derniere partie s'interesse a l'etude de l'electrosorption de deux herbicides et de trois tensioactifs. Les resultats montrent, pour les herbicides atrazine et simazine, que l'application d'un potentiel negatif au cag augmente legerement l'adsorption tandis qu'un potentiel positif diminue nettement la quantite retenue. Pour les tensioactifs anionique (abs) ou non-ionique (triton n-101), l'effet d'un potentiel applique est relativement faible et difficile a interpreter. Pour le cdbac, tensioactif cationique, l'alternance de cycles positifs et negatifs donne lieu a une electrosorption reversible et comprise entre 10 et 15%.

Prevision des equilibres d'adsorption de melanges gazeux a partir de la seule connaissance des equilibres des gaz purs. Etude de l'adsorption du melange propane-propylene sur la zeolite 13x et le charbon actif microporeux a 23 et 50**(o)c et de 0,2 a 101kpa

La gestion des déchets est un problème majeur de notre société de consommation. En 2008, la France a produit 868 millions de tonnes de déchets. Aujourd’hui, un des principaux moyens de valoriser et d’éliminer nos déchets ultimes est l’incinération. Cependant, depuis la découverte des « dioxines » issues des procédés de combustion, cette technique est devenue un sujet d’inquiétude. L’application de la réglementation fixant des seuils limites à l’émission a engendré une forte diminution des émissions des sources fixes. Toutefois, il apparaît important de connaître et maîtriser en « temps réel » les taux de dioxines émis en sortie d’incinérateur. Ces travaux s'intègrent dans une étude globale d'un dispositif de mesure en ligne, "temps réel" et directe de dioxines/furannes à l'émission de sources industrielles fixes. Ils concernent plus spécifiquement l’étude de nouveaux moyens d’adsorption sélectifs de congénères toxiques vis-à-vis des autres congénères et des composés de la matrice gazeuse des rejets, matériaux qui seront implantés dans ce dispositif en ligne. Dans un premier temps, ces travaux se sont focalisés sur l'étude, la synthèse et la caractérisation de nouveaux matériaux adsorbants sélectifs de type zéolithique. Ces matériaux ont été utilisés comme supports lors de l’adsorption de dioxines en solution (2,3-DCDD et 1,2,3,4-TCDD) et ont été comparés aux adsorbants utilisés dans la norme NF EN 1948 lors du prélèvement à l’émission. Cette étude de l’adsorption de dioxines en solution dans l’isooctane a permis d’identifier la zéolithe NaX comme la plus efficace pour le piégeage sélectif des dioxines. En parallèle, un appareillage polyvalent d’adsorption/désorption thermique en ligne de dioxines en phase, gazeuse a été conçu et mis au point. Ce dispositif est couplé à un chromatographe en phase gazeuse et à un spectromètre de masse. Il permet l’analyse en ligne de flux de gaz étalon de dioxines et l’analyse de dioxines piégées dans un tube d’adsorbants. L’ensemble de ces travaux ont permis de démontrer l’intérêt d’utiliser les zéolithes pour le piégeage sélectif des dioxines en phase gazeuse dans un pré-dispositif de terrain d’adsorption/désorption thermique en ligne de dioxines à l’émission de sources fixes
Waste management is a major problem of our society where the amount of waste is still increasing. In 2008, in France, 868 million tons of waste were produced. Today, incineration is considered to be an effective method for disposing of waste. However, since the discovery dioxins generated in all waste plants, this technique becomes a topic of great concern. The authorities require a regulation of dioxin emissions lower than 0. 1 ng ITEQ. M-3 in Europe. Consequently it appears very important to measure and control in “real time” dioxin emission levels from waste incinerators. The major focus of this dissertation work centers on the development of an on-line, real time and direct monitoring technique to study stationary emission sources of dioxins/furans. It concerns the study of new classes of selective adsorbents; in relation to the complexity of the gas mixture in the incinerator’s emissions and to the possible existence of the gas phase dioxin congeners. In a first time, these works focus on study, synthesis and characterization of new selective adsorbent materials as zeolites. These materials have been used as supports for adsorption of solutions of dioxins (2,3- DCDD and 1,2,3,4-TCDD in isooctane) and they have been compared to adsorbents used in NF EN 1948 standard during emission sampling. This study shows that NaX zeolite was the best adsorbent for selective trapping on dioxins. In a second time, an analytical method for on line monitoring of gas phase dioxin at the emission of waste incinerators is designed and developed. This method is based on an adsorption/ thermal desorption device coupled to gas chromatography and mass spectrometry. The device allows the on-line analysis of the standard gas flue of dioxins and the analysis of dioxins trapped in an adsorbent tube. To conclude, these works shows the interest of use zeolites for selective trapping of gas phase dioxins in an on-line field device of adsorption/ thermal desorption of dioxins from stationary sources

Etude théorique de l'évolution morphologique du gel de silice (Rhône-Poulenc, Prolabo) sous l'action combinée de la température et de la vapeur d'adsorbat (eau, méthanol). Application à la réfrigération. Le système gel de silice-adsorbat (eau, méthanol) est très efficace dans le cas des faibles différences de température entre la source froide et la source chaude, et la source froide et la température de l'évaporateur; mais il est très sensible aux écarts de température au niveau de l'adsorbeur. La faible vitesse d'adsorption entraine quelques difficultés à utiliser ce système pour la mise en froid d'une charge. Par contre, il sera facilement utilisable pour la compensation des pertes thermiques.

Deux catalyseurs 4%Au/CeO2 ont été préparés par deux méthodes différentes : déposition-précipitation (DP) et imprégnation (Imp). L’analyse par DRX, MEB et MET a permis de mettre en évidence la présence des nanoparticules d’or dans le solide DP et des grosses particules d’or à côté de nanoparticules pour le catalyseur Imp. Dans la suite, les deux catalyseurs ont été testés dans trois réactions : oxydation totale du propène, oxydation de CO et combustion du noir de carbone. Dans les trois réactions, le catalyseur DP a représenté une meilleure activité comparée à celle du catalyseur Imp. Cette activité a été reliée à la présence des nanoparticules d’or sur la surface du catalyseur DP, à la meilleure dispersion de ces particules et enfin à la présence d’une quantité, plus importante que dans l’imprégné, de l’or chargé positivement à côté de l’or métallique et les ions O2- du réseau de CeO2. La faible activité catalytique du catalyseur Imp a été corrélée à la présence, à côté des nanoparticules, des grosses particules d’or et à la forte teneur en chlorures dans ces catalyseurs car ces derniers sont considérés comme poison catalytique. Dans l’objectif d’étudier les propriétés oxydo-réductrices, les deux catalyseurs DP et Imp, ont subi un traitement sous vide à 400°C pendant une heure avant de faire adsorber l’air sur les deux solides et les caractériser par la technique de la RPE. Deux signaux complètement différents ont été mis en évidence: un signal avec g- < g// sur le DP et un signal M avec g- > g// sur le catalyseur Imp. Le signal obtenu sur le DP a été attribué à l’espèce O2- alors l’attribution du signal M a nécessité une étude plus approfondie. L’adsorption de l’air sur les solides x%Au/CeO2 (Imp), où 0 = x= 4, a montré, par la RPE, la présence d’un signal P à côté du signal M pour les faibles teneurs en or. Suite aux résultats obtenus par l’adsorption des molécules : O2, N2, O2+N2 ou air, (O2 puis N2) ; (N2 puis O2), NO, N2O et NO2, nous avons attribué le signal P à O2- , NO2 2- ou NO3 2- et le signal M à NO, O- ou N2O-. Les produits azotés peuvent être considérés comme des produits intermédiaires ou finaux. A partir de tous les résultats obtenus, nous avons proposé des mécanismes correspondant à ces formations
Two 4%Au/CeO2 catalysts have been prepared by two different methods : deposition-precipitation (DP) and impregnation (Imp). From the XRD, SEM and TEM study, nanoparticles of gold have been evidenced in the DP catalyst and agglomerates nearby nanoparticles in the Imp solid. Compared to the Imp solid, the DP catalyst showed a better catalytic activity in the CO oxidation reaction, the total oxidation of propene and the combustion of carbon black (soots). This difference in the activity is related to the presence of well-dispersed gold nanoparticles on the DP solid surface and a significant quantity of Aun+ located nearby the metallic gold and the O2- ions of the ceria lattice. The weak activity of the Imp catalyst is correlated to the presence on the surface of gold agglomerates and an important amount of chloride ions. These latter species are known as inhibitor in calatysis. In order to elucidate the redox properties of both DP and Imp catalysts, the solids have been degassed and treated under vacuum at 400°C for 1h before the absorption of air. Therefore, the two catalysts have been studied with the EPR technique. Two signals completely different have been evidenced : the first one with g- < g// on DP and the other one, denoted M, with g- > g// on the Imp catalyst. The DP signal has been attributed to O2- species whereas, the attribution of M signal has needed of more detailed study. In fact, the adsorption of air on x%Au/CeO2 (Imp) solids, where 0 <(or egal) x <(or egal) 4, has shown using the EPR technique, the appearance of a new P signal nearby of the M signal for Au contents less than x = 2. 5. From EPR results obtained after absorption, on x%Au/CeO2 (Imp) solids, O2, N2, O2+N2 or air, O2 before N2 ; N2 before O2, NO, N2O and NO2, the P signal has been attributed to O2- , NO2 2- or NO3 2- and M signal M to NO, O- or N2O-. The Nox formed can be considered as intermediate or final products. From these results mechanisms corresponding to all the formed products have been proposed

Ce travail a pour objectif l'etude electrochimique des electrodes a pate de carbone modifiees par l'introduction sur solide non electroactif de molecules organiques. La premiere partie est consacree a l'adsorption de molecules d'alizarine s et de pyrocatechol sur alumine. Les voltamperogrammes ont ete traces et les rendements de la reaction electrochimique ont ete evalues. Une relation lineaire entre la quantite d'electricite et la masse de molecules organiques presentes dans l'electrode a ete trouvee. Dans une seconde partie, nous decrivons l'etude des molecules organiques ayant des proprietes complexantes adsorbees sur alumine: dithizone, 8-hydroxyquinoleine et 1,10 phenanthroline. L'incorporation a ete faite en evaporant le solvant ou a ete dissous le complexant. La poudre a ete utilisee pour la preparation de l'electrode a pate de carbone. Les preconcentrations des ions metalliques dans des cellules separees ont ete realisees a circuit ouvert pendant un temps fixe, puis la determination voltamperometrique a ete effectuee. Les ions pb#2#+ et cd#2#+ ont ete determines avec l'electrode qui contient de la dithizone. Une relation lineaire est obtenue entre le courant de pic et la concentration pour le plomb. Les determinations realisees pour le cadmium sont similaires. Quelques essais ont ete effectues en utilisant le nujol comme liant, le plomb a ete determine. Dans ce cas il a ete necessaire d'activer prealablement l'electrode pour pouvoir preconcentrer cet ion. Le courant de pic est lineaire avec la concentration. Des essais similaires ont ete faits avec la 8-hydroxyquinoleine et la 1,10 phenanthroline pour etudier la reponse des ions cd#2#+, pb#2#+, hg#2#+, co#2#+ et fe#2#+

Development of intelligent and ecological energy absorption systems (EAS) is important to various fields such as automotive (vehicle suspensions, bumpers, engine mounts), construction (protections against seismic and wind-induced vibrations), and defense (parachuted objects, armors). Usual EAS use composites, shape-memory alloys and foams. Recently, liquid adsorption/desorption in/from nanoporous solids was employed to develop high-performance nano-EAS. Energy loss is based on the well-known capillary phenomenon: external work must be done to spread a non-wetting liquid on a solid surface. Nano-EAS provide considerably higher dissipated energies, about 1–10J/g at deformability of 30–70%, compared with the energy absorption of Ti-Ni alloys, about 0.01–0.05J/g at deformability of 5–8%. For water against hydrophobic nanoporous silica gel (artificial sand), the nano-EAS become ecological; they can be also made intelligent by thermo-electrical control. Relative to thermal effects, Qiao et al. have investigated, for nanoporous silica gel with insufficient coverage of the alkyl-based hydrophobic coating, the problem of hysteresis recovery by increasing the temperature in the range 20∼80°C. Energy loss capacity reduced severely after the first loading-unloading cycle, so, the hysteresis was found as irreversible. Shape of the first hysteresis, the accessible specific pore volume and the desorption pressure were almost unaffected by the temperature change. At temperature augmentation the second hysteresis was partially recovered and when the temperature exceeded 50°C the system became almost fully reusable. Water inflow was found as governed by Laplace-Washburn equation but the outflow process was perceived as thermally aided. On the other hand, Eroshenko et al. have contradictorily obtained for nanoporous silica gel with full coverage of the alkyl-based hydrophobic coating, a stable hysteresis at repeated working cycles. Adsorption pressure decreased and desorption pressure increased at temperature augmentation, this producing a reduction of the hysteresis area and damping. However, the accessible specific pore volume was found as thermally unaffected. Oppositely, both the in- and out-flows were found as governed by Laplace-Washburn equation. In this work, for nanoporous silica gels with partial and full coverage of the alkyl and fluorocarbon based hydrophobic coatings, the thermal effects on the hysteresis and damping performances are studied. Test rig used is a compression-decompression chamber introduced inside of an incubator that allows temperature adjustment in the range of −10∼50°C. Results reveal that, depending on the hydrophobic coating coverage, findings reported by Qiao et al. and Eroshenko et al. are in fact not contradictory but complementary. However, as expected, the accessible specific pore volume was found to decrease at temperature reduction. In order to explain all these apparently opposite experimental findings, a model based on the water cluster size distribution versus temperature, the pore size distribution of silica gel and the ability of water molecules to form hydrogen bonds with the uncovered hydroxyl groups on the solid surface is proposed.

Research studies on the adsorption kinetics are conducted in order to determine the absorption time of heavy metals on coffee grounds from liquid. The models of adsorption kinetics and adsorption diffusion are based on mathe-matical models (Cho et al. 2005). The adsorption kinetics can provide information on the mechanisms occurring be-tween adsorbates and adsorbents and give an understanding of the adsorption process. In the mathematical modelling of processes, Lagergren’s pseudo-first- and pseudo-second-order kinetics and the intra-particle diffusion models are usually applied. The mathematical modelling has shown that the kinetics of the adsorption process of heavy metals (copper (Cu) and lead (Pb)) is more appropriately described by the Lagergren’s pseudo-second-order kinetic model. The kinetic constants (k2Cu = 0.117; k2Pb = 0,037 min−1) and the sorption process speed (k2qeCu = 0.0058–0.4975; k2qePb = 0.021–0.1661 mg/g per min) were calculated. After completing the mathematical modelling it was calculated that the Langmuir isotherm better reflects the sorption processes of copper (Cu) (R2 = 0.950), whilst the Freundlich isotherm – the sorption processes of lead (Pb) (R2 = 0.925). The difference between the mathematically modelled and experimen-tally obtained sorption capacities for removal of heavy metals on coffee grounds from aqueous solutions is 0.059–0.164 mg/l for copper and 0.004–0.285 mg/l for lead. Residual concentrations of metals in a solution showed difference of 1.01 and 0.96 mg/l, respectively.

AbstractNanoparticles as part of nanotechnology have drawn the attention for its great potential of increasing oil recovery. From authors' previous studies (Li et al., 2013a), wettability alteration was proposed as one of the main Enhanced Oil Recovery (EOR) mechanisms for nanoparticles fluid, as adsorption of nanoparticles on pore walls leads to wettability alteration of reservoir. We conducted a series of wettability measurement experiments for aged intermediate-wet Berea sandstone, where the core plugs were treated by different concentration and type of nanoparticles fluid. Nanoparticles transport experiments also were performed for core plugs with injection of varying concentration and type of nanoparticles fluid. Pressure drop across the core plug during injection was recorded to evaluate nanoparticles adsorption and retention inside core, as well as desorption during brine postflush. Both hydrophilic silica nano-structure particles and hydrophilic silica colloidal nanoparticles were utilized in above two experiments.The results of wettability alteration experiments indicated that hydrophilic nanoparticles have ability of making intermediate-wet Berea sandstone to be more water wet, and basically the higher concentration the more water wet will be. And different type of nanoparticles has different effect on the wettability alteration process. For nanoparticles transport experiments, the results showed that the nanoparticles undergo both adsorption and desorption as well as retention during injection. Pressure drop curves showed that absorption and retention of nano-structure particles inside core was significant while colloidal nanoparticles did not adsorb much. Permeability impairment was observed during nano-structure particles fluid injection, but on the contrary colloidal nanoparticles dispersion injection made core more permeable.

Prolongation of the aPTT in a mixture of a patient’s plasma with normal plasma is characteristic for the presence of a coagulation inhibitor. Since inhibitors directed against individual blood coagulation factors differ in their clinical significance from a lupus anticoagulant (LA), a fast and reliable distinction from each-other would be highly desirable. The test presented which is based on the absorption of antiphospholipid antibodies by use of a stable phospholipid adsorbent largely fullfills this demand.Method 1. Preparation of the LA-adsorbent (modified acc. to Steck et al., Science 168:255, 1970): Fresh human RBC (bl. gr. 0, in 0.5% EDTA) are washed (NaCl, 0.15m / phosphate buffer,0.005m, pH8.0) and lysed in phosphate buffer alone. The membranes are washed with the same buffer (centrifugations: 40’000g, lOmin, 4°C) and incubated 60 min on ice in phosphate buffer, 0.0005m. After centrifugation, the sediment is resuspended in an equal volume of buffer (0.0005m, with merthiolate 0.1%), homogenized and centrifuged in portions of lml; the supernatant is carefully removed. The adsorbent, stored at 4°C in capped tubes, is stable for at least three months.2. Performance of test: To 600ul of patient’s plasma mixed with 600ul normal plasma (citrated), 12ul of heparin (501U/ml) are added. 600ul of the mixture are given to the LA-adsorbent, vorte-xed, incubated (room temp., 30min) and centrifuged (40’000g). From the supernatant as well as the not adsorbed portion of the plasma mixture, heparin is eliminated by adding ECTEOLA-cellulose. After centrifugation, aPTT is determined in both supernatant samples. Results The test is positive, i.e. LA is present, if aPTT is shortened by at least 5 sec after treatment with LA-adsorbent. *not diluted; other samples are mixed 1:1 with normal plasma

Dye sensitized solar cells (DSSCs) are promising photovoltaic devices as they offer advantages such as low cost and easy for fabrication et al. The key part of the original DSSC is a sintered film of nanoparticles which has a large surface area for the absorption of dyes. It has been reported that boundaries of nanoparticles diminish the efficiency of charge transport in the nanoparticle network, and lead to charge–carrier recombination. The one dimensional morphology of the nanofiber is believed to improve electron transport efficiency without sacrificing the high specific surface area for the adsorption of dyes. In this paper, TiO2 nanofibers are used to replace TiO2 nanoparticles in the DSSC. The film of nanofibers was synthesized by electrospinning process and collected on the transparent conductive glass substrate. The precursor used for the electrospinning of the nanofiber consists of titanium (IV) isopropoxide, acetate acid, ethanol and polyvinylpyrrolidone(PVP). After the electrospinning process, nanofibers were pretreated at 120°C for 2 hours and annealed at 500°C in atmosphere for another 2 hours. Then DSSC with the film of TiO2 nanofibers were assembled and characterized through electrical measurements. Open circuit voltage of 0.7V and short circuit current densities of 0.45mA/cm2 were achieved.