New activator supports for heterogeneous catalysts of olefins HTE polymerization

Cette thèse en partenariat avec Total Petrochemicals, porte sur deux grands axes: la préparation de nouveaux catalyseurs pour la polymérisation d'éthylène et l'analyse des propriétés des polyéthylènes obtenus. Face au grand nombre de combinaisons à tester et à la diversité de polymères produits, des méthodes de travail haut-débit sont indispensables pour la comparaison et la distinction de produits d'intérêt. Ainsi, le développement d'une nouvelle méthode de préparation de catalyseurs et de polymérisation en parallèle a permis de comparer directement et visuellement plusieurs complexes catalytiques suivant leur activité. Des méthodes d'analyse en parallèle ont également conduit à la comparaison de polyéthylènes produits suivant leur densité, leur température de fusion et leurs masses moléculaires. La détermination des masses moléculaires en parallèle a nécessité la conception d'un prototype de chromatographie planaire et le développement d'une nouvelle méthode d'analyse. L'ensemble de ces travaux en haut-débit a fourni un grand nombre d'informations. Le traitement statistique de cette banque de données permet d'apporter un outil de comparaison multi-paramètres et d'aide à la compréhension des relations catalyseur/propriétés de polymères.This thesis in partnership with Petrochemicals Total, is composed of two main axis: preparation of new catalysts for ethylene polymerization and analysis of the properties of polyethylenes obtained. Face to a large number of combinations being tested and the diversity of produced polymer, high-throughput methods are essential for the comparison and the distinction of products of interest. Thus, the development of a new method for the preparation of catalysts and for polymerization in parallel leads to compare directly and visually several catalytic complexes according to their activity. Methods of analysis in parallel also led to the polyethylene comparison produced according to their density, melting point and molecular masses. The determination of the molecular masses in parallel required the design of a planar prototype of chromatography and the development of a new method of analysis. The whole of this work in highthroughput provided a large number of information. The statistical processing of this data bank brings a tool of multivariate comparison and helps to the comprehension of the relations catalyst/polymer properties

Biostimulation to improve the dye biodegradation of organic dyes by activated sludge

In this work, biodegradation of organic pollutants by activated sludge (AS) in the presence of glucose (2 g/L) as an additional carbon source was studied. The AS (without pre-acclimation) was freely suspended under aerobic conditions. Three organic dyes representative of the Algerian textile industry were selected: Cibanon Navy (CN), Solophenyl Scarlet (SS) and Cibacron Green (CG). The results showed that after 10 days of incubation, AS displayed good biodegradation capabilities achieving removal percentages ranging from 50.3% to 89.4% and reduction in COD ranging from 93.1% to 98.3%. Particularly, the textile dye CN was removed up to 89% with high reduction in COD (94.7%). The microbial development stimulated by glucose achieved therefore efficiently the discoloration of contaminated solutions and pollutant degradation. Although it is assumed that dyes can be degraded only under anaerobic conditions, the wastewater treatment using AS appears therefore suitable to the removal of different types of textile dyes before final discharge

Novel and Sustainable Catalytic Ruthenium-Doped Glass Foam for Thermocatalytic Oxidation of Volatile Organic Compounds: An Experimental and Modeling Study

International audienceAn open cell foam catalyst consisting of a glass foam support impregnated with zerovalent ruthenium nanoparticles (aiming to 0.1 wt %) without washcoating was used for the first time to remove several volatile organic compounds (VOCs) by thermocatalytic oxidation. At initial concentrations between and 2 g.m(-3) and temperatures ranging from 100 to 350 degrees C, up to 100% of removal was achieved for the four VOCs tested. The ease of abatement of the VOCs with temperature had the following order: ethanol > acetone > toluene > heptane. The removal of ethanol was then modeled considering mass-transfer limitation, temperature dependency, and by-product formation. Full mineralization of ethanol can be achieved with a 30 cm length reactor at 150 degrees C and 0.010 m.s(-1). While the tortuous foam achieved efficient mass transfer, the process was still limited by this phenomenon highlighting that the efficiency of the catalyst could be improved at higher gas velocities

Enhancement of ethanol production from synthetic medium model of hydrolysate of macroalgae

International audienceAmong biomass materials available, macroalgae is a promising alternative to traditional energy crops. The absence of lignin, a high growth rate and a richness of fermentable sugars and nitrogen, are real gains for a competitive ethanol production. But the presence of salts can be an obstacle to obtain relevant performances. Experiments were carried out with a synthetic medium adjusted on algal hydrolysate composition in order to reduce resource limitations and variations of composition. The behavior of four yeast strains for ethanol production was investigated Candida guilliermondii, Scheffersomyces stipitis, Kluyveromyces marxianus and Saccharomyces cerevisiae. Glucose, which is the most abundant sugar in the targeted algal hydrolysate (Ulva spp), was completely assimilated by all of the considered strains, even in the presence of salts at levels found in macroalgal hydrolysates (0.25 M of sodium chloride and 0.21 M of sulfate). The use of peptone as nitrogen source enhanced kinetics of consumption and production. For instance, the rate of ethanol production by S. cerevisiae in the presence of peptone was six times higher than that obtained using ammonium, 0.6 and 0.1 g L−1 h−1 respectively. In the presence of salts, the rates of glucose consumption and ethanol production were lowered for the considered strains, except for K. marxianus. Nevertheless, S. cerevisiae could be the most promising strain to valorize Ulva spp hydrolysate in bioethanol, in terms of ethanol produced (7.5–7.9 g L−1) whether in the presence or in absence of salts

Development of a Sustainable Heterogeneous Catalyst Based on an Open-Cell Glass Foam Support: Application in Gas-Phase Ozone Decomposition

International audienceHeterogeneous catalysts were synthesized with a glass foam support mainly composed of recycled glass and impregnated with zerovalent ruthenium nanoparticles (aiming to 0.1 wt % ruthenium). Different glass foams were developed, playing on the nature and quantity of foaming/doping agents, as well as the operating conditions (heat temperature and time of heating). They were characterized in terms of open porosity, pore diameter, wettability, and pressure drops. High open porosity can be achieved (between 73% and 92%) with mean pore diameter up to 0.55 mm, resulting in the lowest pressure drops measured among all glass foams. The deposit of zerovalent ruthenium nanoparticles was confirmed by transmission electron microscopy images and changes in surface charge showed by zeta potential determination. Finally, the removal of ozone from air at room temperature and inlet concentration of 9 g Nm(-3) was performed to prove the catalyst activity. Up to 52% of ozone decomposition was achieved in less than 13 s of residence time. The activity did not seem to be linked with the characteristics (open porosity and mean pore size) of the glass foams, but it was shown that the external mass transfer was still limiting the process performances in the range of superficial gas velocity tested (4 mm s(-1) to 11 mm s(-1))

Green Macroalgae Hydrolysate for Biofuel Production: Potential of Ulva rigida

International audienceIn this study, the green macroalgae Ulva rigida, which contains 34.9% carbohydrates, underwent treatment with commercial hydrolytic enzymes. This treatment yielded a hydrolysate that contained 23 ± 0.6 g·L−1 of glucose, which was subsequently fermented with Saccharomyces cerevisiae. The fermentation process resulted in an ethanol concentration of 9.55 ± 0.20 g·L−1. The optimal conditions for ethanol production by S. cerevisiae were identified as follows: non-sterilized conditions, an absence of enrichment, and using an inoculum size of 118 mg·L−1. Under these conditions, the fermentation of the green macroalgal hydrolysate achieved a remarkable conversion efficiency of 80.78%. The ethanol o/t ratio, namely the ratios of the experimental to theoretical ethanol produced, for Scheffersomyces stipitis, Candida guilliermondii, Kluyveromyces marxianus, and S. cerevisiae after 48 h of fermentation were 52.25, 63.20, 70.49, and 82.87%, respectively. Furthermore, S. cerevisiae exhibited the best outcomes in terms of ethanol production (9.35 g·L−1) and conversion efficiency (80.78%) after 24 h (optimal time) of fermentation

ISOLATION AND IDENTIFICATION OF YEAST STRAINS FROM SUGARCANE MOLASSES, DATES AND FIGS FOR ETHANOL PRODUCTION UNDER CONDITIONS SIMULATING ALGAL HYDROLYSATE

International audienceYeast strains were isolated from sugar cane molasses (S1), dates (S2) and figs (S3) and the ethanol production was evaluated in batch condition. A comparison was made with the yeast Saccharomyces cerevisiae. The strains showed tolerant characteristics to stressful conditions like salinity and ethanol. The isolated strains produced ethanol; at 20 h of fermentation ethanol yields were 0.38-0.39 g.g-1 , and the productivities were almost 0.58 g.L-1. S. cerevisiae and S1 tolerated up to 14% (v/v) of ethanol; while interestingly the isolates S2 and S3 were highly tolerant, up to 20% (v/v) ethanol. Thus, S2 and S3 could serve as potential strains for ethanol fermentation, with 0.27 and 0.29 g.g-1 yield of ethanol in the presence of 1.37 mol.L-1 NaCl. These values were higher than the value obtained using the yeast of reference and S1 (0.16 g.g-1). Co-cultures of S2 and S3 enhanced the ethanol production, increasing the yield of ethanol by 12.5% compared with the single culture. The strains were identified as species S.cerevisiae, and S2 and S3 were very similar. For an application in the valorization of biomass such as green macro-algae, some assays were done on a synthetic model medium of hydrolysate of macro-algae and the strains S2 and S3 demonstrated excellent fermentative performances

Secreted surfactant protein A from fetal membranes induces stress fibers in cultured human myometrial cells

International audienceIn the present study, we investigated the ability of human fetal membranes (amnion and choriodecidua) to regulate human maternal uterine cell functions through the secretion of surfactant protein (SP)-A and SP-D at the end of pregnancy. We detected the expression of both SP-A (SP-A1 and SP-A2) and SP-D by quantitative reverse transcription polymerase chain reaction. Immunohistochemistry revealed that human fetal membranes expressed both SP-A and SP-D. By Western blot analysis, we demonstrated that SP-A protein expression was predominant in choriodecidua, whereas the amnion predominantly expressed SP-D. Only the secretion of SP-A was evidenced in the culture supernatants of amnion and choriodecidua explants by immunodot blot and confirmed by Western blot. Exogenous human purified SP-A induced stress fiber formation in cultured human myometrial cells via a pathway involving Rho-kinase. Conditioned medium from choriodecidua and amnion explants mimicked the SP-A effect. Treatment of myometrial cells with SP-A-depleted conditioned medium from choriodecidua or amnion explants failed to change the actin dynamic. These data indicate that SP-A released by human fetal membranes is able to exert a paracrine regulation of F-actin filament organization in myometrial cells