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Sunflower oil hydrogenation was carried out in a 2 mm diameter jacketed capillary reactor coated with a Pd/Al2O3 catalyst, mimicking a channel of a heat exchanger monolith reactor. The operating conditions were chosen to ensure Taylor flow conditions and to evaluate their impact on the reaction selectivity. CFD simulations of the experiments were performed using the unit cell approach. They accounted for the dependence of viscosity on the degree of oil saturation, kinetic laws describing the effects of pressure on cis/trans selectivity, and bubble shrinkage along the channel using a moving mesh strategy. The model captured the experimental trends, in which the fraction of monounsaturated cis fatty acids did not exceed 35% (vs 30% originally). Poor selectivity is mainly due to the strong mass transfer resistance at the catalyst wall, either from fatty acids (favoring their complete saturation) and/or from hydrogen (due to bubble shrinkage, favoring cis to trans isomerization)

A cross‐laboratory study on microbial fuel cells (MFC) which involved different institutions around the world is presented. The study aims to assess the development of autochthone microbial pools enriched from domestic wastewater, cultivated in identical single‐chamber MFCs, operated in the same way, thereby approaching the idea of developing common standards for MFCs. The MFCs are inoculated with domestic wastewater in different geographic locations. The acclimation stage and, consequently, the startup time are longer or shorter depending on the inoculum, but all MFCs reach similar maximum power outputs (55±22 μW cm−2) and COD removal efficiencies (87±9 %), despite the diversity of the bacterial communities. It is inferred that the MFC performance starts when the syntrophic interaction of fermentative and electrogenic bacteria stabilizes under anaerobic conditions at the anode. The generated power is mostly limited by electrolytic conductivity, electrode overpotentials, and an unbalanced external resistance. The enriched microbial consortia, although composed of different bacterial groups, share similar functions both on the anode and the cathode of the different MFCs, resulting in similar electrochemical output., The famous five: A cross‐laboratory study involving five institutions is presented. Each team runs a triplicate identical single chamber microbial fuel cell for 6 weeks varying only the inoculum. Electrochemical and operational parameters are collected. Microbiological analysis is carried out on the influent and effluent and on the electrodes. All the data collected are correlated by using robust statistics.

International audience; This work studies the reactivity of poly(N-vinylcaprolactam-co-vinyl acetate-co-vinylbenzyl Rose Bengal) microgels (VBRB@MG) as heterogeneous photosensitizers in a continuous-flow process for sustainable singlet oxygen sensitized photooxygenation of a bio-based molecule. Experiments were carried out in a LED-driven spiral-shaped microreactor in which slurry Taylor flows were generated, allowing accurate control of irradiation, light absorption and gas-liquid flow conditions. The benchmark photooxygenation of -terpinene was implemented in ethanol to provide a green solvent using air as a safe supply of oxygen. Swollen RB-grafted colloids formed an efficient substrate for converting -terpinene into ascaridole, providing up to high conversion with high selectivity under continuous-flow conditions, and within short residence times of a few minutes. The supported RB exhibited a reactivity similar to that of the free RB. The reactivity of the supported photosensitizer was maintained for several cycles with a reproducible level after 8 months of storage. Under experimental conditions favouring photobleaching of RB, the photobleaching level of RB was lower with the VBRB@MG colloids than with free RB, suggesting that grafting RB molecules onto the colloid can prevent their photodegradation. KEYWORDS Flow photochemistry. Singlet oxygen. Photoactive polymer colloids. Green conditions. Rose Bengal. Alpha-terpinene.

International audience; A multi-analytical methodology is implemented to characterize several sieving fractions of industrial samples of Black Mass (BM) powders originating from the thermo-mechanical treatment of cylindrical and prismatic-type spent nickel metal-hydride (Ni-MH) batteries. Elemental analyses of 17 elements (including C and O) indicate that the elemental composition of the powders (greater than93 %wt) does not depend on the battery type nor on the sieving fraction. XRD analyses evidence several phases (including Ni, NiO, CeO2 and C) but their quantification is not possible. Beyond these standard characterisations, magnetic susceptibility measurements demonstrate that the amount of metallic nickel versus nickel oxide increases with the sieving fraction, and that powders from prismatic-type batteries contain twice as much metallic nickel than cylindrical ones. Thanks to statistical analysis (based on clustering algorithms) of an electron probe µ-analysis (EPMA) compositional map, the complete methodology allows us to propose a full phase distribution for the BM particles. Three types of particles are identified and quantified. They originate from the partial oxidation of the battery components (anode active mass, anode current collector, cathode active mass and cathode current collector). The whole picture highlights the joint importance of battery ageing mechanisms, thermal deactivation and BM sieving steps on powder composition

Dynamic reactor operations will gain interest with the increase of intermittent electricity from renewable sources. Periodic operation of catalytic reactors can also be used for kinetic studies with better parameter estimation than steady-state operation. This methodology is exemplified for the case of acetylene hydrogenation over Pd/α-Al2O3 using small amplitude flow oscillations. It allows the evaluation of several elementary kinetic parameters from one set of dynamic data for a reaction mechanism based on a single catalytic site. The optimized transient model is able to reproduce the time-evolution of the reactant and product molar fractions at the outlet of a fixed bed operated with modulations of different amplitudes and frequencies. It further shows that the acetylene conversion is controlled by two steps, the hydrogen adsorption step and the hydrogenation of the surface vinyl intermediate into adsorbed ethylene

This chapter introduces the complex relationships existing among the process conditions, the microstructure and the functional properties for metal oxide films processed by metalorganic chemical vapor deposition. Amorphous aluminum oxide films are considered as a model material due to their promising barrier properties for various applications including non-volatile memories and to the extended investigation of the process and the material. The first part of the chapter considers modeling and simulation aspects of the metal-organic chemical vapor deposition (MOCVD) process with the aim to conformally cover non line of sight surfaces. The second part establishes the relationship between short range order in the films and their barrier properties.

This study aimed to investigate the key compounds involved in the aroma of French Syrah wines from the northern Rhone valley from two vintages characterized by distinct climatic conditions. The volatile composition of the wines was assessed through the determination of 76 molecules. After identifying the best matrix and best model for aroma reconstitution studies, omission tests were conducted using the Pivot© profile method. For both vintages, 35 molecules with odor activity values (OAVs) above 0.5 were identified. While remarkably high levels of 2-furfurylthiol (FFT) were reported in both wines, rotundone and 3-sulfanylhexanol (3SH) enabled the strongest discrimination between the two wines. Wine dearomatized using supercritical carbon dioxide (sCO2) was identified as the best matrix. The best models built using this matrix were composed of molecules with OAV > 5 and OAV > 10 highlighting that this dearomatization approach can be valuable to reconstitute the aroma of wine using a small number of molecules. For the cool vintage wine, the omission of rotundone and FFT had the greatest impact on the olfactive profile for non-anosmic and anosmic respondents to rotundone, respectively. 3SH, whose omission decreased the rating of the ‘fruity’ attribute, was identified as the main contributor to the aroma of Syrah wine produced in the warm vintage.

International audience; Identifying, designing, deploying and maintaining accurate collaborative networks of organizations (e.g. responders in a crisis situation) are key activities in nowadays ecosystems. However, there is a lack regarding formal approaches dedicated to characterize collaborative networks of organizations. Formal descriptions of collaborative situations, that could be used, transformed, computed and exploited would be of great benefit for the quality of such collaborative networks. This article presents a model‐based AI framework for describing collaborative situations and the associated formal metamodel dedicated to be instantiated to characterize collaborative situations in a very wide range of application domains. This metamodel (describing collaborative situation between organizations) is structured according to four complementary dimensions: the context (social, physical and geographical environment), the partners (the involved organizations, their capabilities resources and relations), the objectives (the aims of the network, the goals to be the achieved and the risks to avoid, etc.) and the behaviour (the collaborative processes to be implemented by the partners to achieve the objectives in the considered context). Besides, this metamodel can be extended for some precise application domains. This article focuses on this mechanism in the specific context of crisis management.

International audience; The production of bacterial cellulose has been limited due to its high cost and low productivity. Alternative low‐cost sources of this biopolymer of high purity and biocompatibility are needed in order to benefit from its enormous potential. Kombucha tea is a trend functional beverage whose production is growing exponentially worldwide, and the bacteria present in this fermented beverage belonging to the genus Komagataeibacter are capable of producing a crystalline biofilm with interesting properties. Obtaining bacterial cellulose from Kombucha tea has already been studied, however several fermentation conditions are being optimized in order to scale‐up its production. In this study, we characterized the bacterial cellulose produced from three different Kombucha fermentation conditions. The scanning electron microscopy images revealed the crystalline structure of the biofilms. The energy‐dispersive x‐ray analysis exhibited the chemical composition of the crystals. The thermogravimetric analysis showed a rate of degradation between 490 and 560°C and the differential scanning calorimetry confirmed the presence of crystalline and amorphous regions in the bacterial cellulose samples. The results suggested that crystalline cellulose could be obtained by varying the fermentation conditions of Kombucha tea.

International audience; Purpose: Technologies with low environmental impacts and promoting renewable energy sources are required to meet the energetic demand while facing the increase of gas emissions associated to the greenhouse effect and the depletion of fossil fuels. CO2 methanation activated by magnetic heating has recently been reported as a highly efficient and innovative power-to-gas technology in a perspective of successful renewable energy storage and carbon dioxide valorisation. In this work, the life cycle assessment (LCA) of this process is performed, in order to highlight the environmental potential of the technology, and its competitivity with in respect to conventional heating technologies.Methods: The IMPACT 2002+ was used for this LCA. The process studied integrates methanation, water electrolysis and CO2 capture and separation. This “cradle-to-gate” LCA study does not consider the use of methane, which is the reaction product. The functional unit used is the energy content of the produced CH4. The LCA was carried out using the energy mix data for the years 2020 and 2050 as given by the French Agency for Environment and Energy management (ADEME). Consumption data were either collected from literature or obtained from the LPCNO measurements as discussed by Marbaix (2019). The environmental impact of the CO2 methanation activated by magnetic heating was compared with the environmental impact of a power-to-gas plant using conventional heating (Helmeth) and considering the environmental impact of the natural gas extraction.Results: It is shown that the total flow rate of reactants, the source of CO2 and the energy mix play a major role on the environmental impact of sustainable CH4 production, whereas the lifetime of the considered catalyst has no significant influence. As a result of the possible improvements on the above-mentioned parameters, the whole process is expected to reduce by 75% in its environmental impact toward 2050. This illustrates the high environmental potential of the methanation activated by magnetic heating when coupled with industrial exhausts and renewable electricity production.Conclusions: The technology is expected to be environmentally competitive compared with existing similar processes using external heating sources with the additional interest of being extremely dynamic in response, in line with the intermittency of renewable energy production.

Production of bio-succinic acid through microbial fermentation using agro-industrial waste has been observed extensively. Large scale production is now being considered since bio-succinic acid has broad range application in several industries including agricultural, food, chemical, metal, and pharmaceutical industry as a precursor, ion chelator, and or additive agent. One of promising microbes able to produce bio-succinic acid in large amount and recognized for industrial production is Actinobacillus succinogenes. However, several factors still need to be considered in order to optimize the fermentation performance. Therefore, this paper aims to review the progress of fermentation methods and discuss the fermentation strategy focused on the influences of different carbon sources, nitrogen sources, pH regulator, and fermentation configuration to the fermentation parameters including concentration, productivity and yield of bio-succinic acid. As a result, combinations of several fermentation strategies are needed to be performed to realize an efficient and effective bio-succinic acid industry. Keywords: Actinobacillus succinogenes, Agro-industrial waste, Bio-succinic acid, Fermentation strategies

International audience; In this comprehensive study, the interaction of human serum albumin (HSA) with poly(acrylic acid) (PAA) was explored using small angle X-ray scattering (SAXS) combined with chromatography. The results revealed the formation of a complex between HSA macromolecules and PAA chains but solely under some specific conditions of the ionic strength and pH of the medium. In fact, this binding was found to take place only at pH close to 5 and at low ionic strength (0.15 M). Otherwise, for a higher pH and a salt concentration of 0.75 M the HSA–PAA complex tends to dissociate completely showing the reversibility of the complexation. The assessment of the influence of the HSA/PAA molar ratio on the radius of gyration of the complex suggests that 4 HSA molecules could bind to each 100 kDa PAA chain. In addition, the Porod volume evaluation for the same range of the HSA/PAA ratio confirms this assumption. Finally, an all-atom SAXS modelling study using the BUNCH program was conducted to find a compatible model that fits the HSA–PAA complex scattering data. This model allows us to portray the HSA/PAA complex as a pearl-necklace assembly with 4 HSA molecules on the 100 kDa PAA chain.

There has been a tremendous increase in the production of ethylene over the last few decades, which has put tremendous focus on steam cracking processes and with an objective of improving its efficiency. This study, performed as a part of IMPROOF (Integrated guided Model PROcess Optimization of steam cracking Furnaces) project, is intended towards attaining that goal. Large Eddy Simulation (LES)- is at a stage of being mature enough to be used in design and optimization of processes in industrial equipments. However, the application of LES to study large flow equipments is still a technical challenge due to the high computational cost arising from numerical stiffness. In this study, a novel, chimera-based, local time stepping scheme is developed to speed up explicit time integration based LES solvers and applied (for the first time) to study the reactive flow inside a steam cracking furnace. This new numerical technique is studied for its numerical properties using Global Spectral Analysis (GSA) and the impact of local time stepping on the accuracy and resolution of the baseline numerical scheme is analyzed. The speed up obtained using this method is also ascertained with the help of canonical 2D and 3D nonreactive as well as reactive flow simulations. Numerical prediction of combustion inside a steam cracker comes with its own challenges. While detailed chemical mechanisms are ruled out from being used in simulations due to its high cost, simple global chemical mechanisms are not accurate enough to predict the flame structure and flame properties accurately. In this study, species transport equations are used with an analytically reduced chemical (ARC) mechanism. These chemical mechanisms are reduced from an up-to-date detailed mechanism using Directed Relational Graph with Error Propagation (DRGEP) technique and quasi-steady state (QSS) assumptions. The reduced mechanism is validated with respect to the detailed mechanism and experimental measurements is found to be in excellent agreement for all the flame properties of interest in this study. Radiative heat transfer is the predominant mode of heat transfer in steam cracking furnaces and hence cannot be avoided in realistic furnace simulations. In this study, the LES solver (along with the newly developed acceleration technique) is coupled with a radiative transfer equation (RTE) solver to carry out a coupled LES-RTE simulation. The approach is validated with experimental data from an axisymmetric jet diffusion flame and the experimental and numerical data is observed to be in good agreement with each other. Finally, all these methodologies are simultaneously applied to study the reactive flow occurring in the fire side of a steam cracking furnace. The LES acceleration technique speeds up the computations while ARC mechanism assists in predicting combustion reactions in an accurate manner. The radiative heat transfer effects are included by coupling the LES solver with the RTE solver as mentioned previously. Unsteady LES simulations of the combustion occurring inside the firebox is carried out. The computed and measured data for temperature and heat flux is found to be in close agreement with each other. LES of such a furnace demonstrates revealing information on the flame stabilization mechanism and the mean flame properties such as its shape and length and are discussed in this thesis. This study is intended to be a technology demonstrator by addressing three of the core challenges in the numerical modeling of steam cracking furnaces. By addressing these challenges, it is hoped that the petrochemical community is taking one step closer to using LES for their design and analysis processes in the near future.

There has been a tremendous increase in the production of ethylene over the last few decades, which has put tremendous focus on steam cracking processes and with an objective of improving its efficiency. This study, performed as a part of IMPROOF (Integrated guided Model PROcess Optimization of steam cracking Furnaces) project, is intended towards attaining that goal. Large Eddy Simulation (LES)- is at a stage of being mature enough to be used in design and optimization of processes in industrial equipments. However, the application of LES to study large flow equipments is still a technical challenge due to the high computational cost arising from numerical stiffness. In this study, a novel, chimera-based, local time stepping scheme is developed to speed up explicit time integration based LES solvers and applied (for the first time) to study the reactive flow inside a steam cracking furnace. This new numerical technique is studied for its numerical properties using Global Spectral Analysis (GSA) and the impact of local time stepping on the accuracy and resolution of the baseline numerical scheme is analyzed. The speed up obtained using this method is also ascertained with the help of canonical 2D and 3D nonreactive as well as reactive flow simulations. Numerical prediction of combustion inside a steam cracker comes with its own challenges. While detailed chemical mechanisms are ruled out from being used in simulations due to its high cost, simple global chemical mechanisms are not accurate enough to predict the flame structure and flame properties accurately. In this study, species transport equations are used with an analytically reduced chemical (ARC) mechanism. These chemical mechanisms are reduced from an up-to-date detailed mechanism using Directed Relational Graph with Error Propagation (DRGEP) technique and quasi-steady state (QSS) assumptions. The reduced mechanism is validated with respect to the detailed mechanism and experimental measurements is found to be in excellent agreement for all the flame properties of interest in this study. Radiative heat transfer is the predominant mode of heat transfer in steam cracking furnaces and hence cannot be avoided in realistic furnace simulations. In this study, the LES solver (along with the newly developed acceleration technique) is coupled with a radiative transfer equation (RTE) solver to carry out a coupled LES-RTE simulation. The approach is validated with experimental data from an axisymmetric jet diffusion flame and the experimental and numerical data is observed to be in good agreement with each other. Finally, all these methodologies are simultaneously applied to study the reactive flow occurring in the fire side of a steam cracking furnace. The LES acceleration technique speeds up the computations while ARC mechanism assists in predicting combustion reactions in an accurate manner. The radiative heat transfer effects are included by coupling the LES solver with the RTE solver as mentioned previously. Unsteady LES simulations of the combustion occurring inside the firebox is carried out. The computed and measured data for temperature and heat flux is found to be in close agreement with each other. LES of such a furnace demonstrates revealing information on the flame stabilization mechanism and the mean flame properties such as its shape and length and are discussed in this thesis. This study is intended to be a technology demonstrator by addressing three of the core challenges in the numerical modeling of steam cracking furnaces. By addressing these challenges, it is hoped that the petrochemical community is taking one step closer to using LES for their design and analysis processes in the near future.

International audience; An apparent kinetic model is developed for a novel chemical vapor deposition (CVD) process of silicon oxynitride (SiO x N y) films from tris(dimethylsilyl)amine (TDMSA) and O 2 , operating at moderate temperature (600-650 • C) and at atmospheric pressure. The definition of reaction pathways and the extraction of kinetic information is based on recently reported results of the gas phase composition, complemented by solid phase characteristics obtained by spectroscopic ellipsometry (SE) and ion beam analyses (IBA). Incorporation of carbon (up to 20 at. %) is considered alongside nitrogen (up to 25 at.%) for variable O 2 flow rates (0.3-1.2 sccm). This combined gasand solid-phase analysis is utilized to identify the main gaseous species and provide insight into the deposition mechanism. A silicon-and a nitrogen-centered radical intermediates are considered as the primary species of the mechanism, based on evidence from gas phase characterizations. A third, fictitious, nitrogen-and carboncontaining molecule is also conceptualized to account for carbon incorporation. Eight chemical reactions are defined alongside their respective kinetic parameters and are implemented in the ANSYS® FLUENT® computational fluid dynamics (CFD) code. Upon validation, the model allows for the successful prediction of local deposition rates and SiO x N y film composition containing non-negligible carbon, marking it as the first kinetic model able to represent the main chemical mechanisms involved in the CVD of a four-component material. The reported combined approach could be applied to other existing or new CVD chemistries forming multicomponent thin films, favoring their implementation in original applications.

International audience; In view of a sustainable recycling process, the leaching mechanisms of nickel and rare‐earth elements (REEs) contained within industrial samples of spent nickel metal hydride battery powders were investigated in HCl and H2SO4, under mild temperature (25–60 °C) and pH (3–5.5). First, in‐depth characterization of the heterogeneous battery powder was carried out with powder XRD, SEM, electron probe microanalyzer wavelength‐dispersive spectroscopy (EPMA‐WDS) quantitative analyses of individual particles, and inductively coupled plasma optical emission spectrometry (ICP‐OES) elemental analysis. An unusual result is the identification of particles that exhibit a core–shell structure, which is related to anode active mass aging mechanisms. Then, a leaching study in a 10 L pilot‐scale reactor demonstrated the selective dissolution of REEs, with respect to nickel, at pH 3, which is attributed to 1) the kinetic inhibition of nickel metal dissolution, and 2) the specific core–shell structure of aged mischmetal particles. Furthermore, the use of H2SO4 led to coprecipitation of lanthanide–alkali double sulfates and nickel salts.

International audience; The influence of anion specificity on the faradaic efficiency relative to aluminum oxidation during electrocoagulation has been reported. While with chaotrope anions, the faradaic efficiency is higher than 1, it is lower than 1 with kosmotrope anions. The origin of this distinction has been ascribed to the ability of anions to cause pitting through the thin passive film at the aluminum surface, which depends on the varying resistance of the anions to dehydration. The influence of the nature of the cation of the supporting electrolyte on the efficiency of electrocoagulation has been investigated by comparing the same treatment of two characteristic colloidal samples. While removal efficiency is better for a positively charged latex in the presence of sodium chloride, it is better for a negatively charged oil in water emulsion in the presence of ammonium chloride. The results come from different effects of pH and its influence on aluminum species during electrocoagulation.

International audience; Actual requirements of the pharmaceutics industry for reliable, safe, long term storage of biopharmaceuticals imply the use of chemically inert glass vials. This can be achieved by applying a barrier coating on their internal surface. In the present work we investigate the hydrolytic resistance of amorphous alumina coatings applied by chemical vapor deposition at the interior of soda lime glass containers. Autoclaving for 60 min at 121 • C and 2 bar absolute pressure of water filled such containers according to normed tests defined by the European Pharmacopeia, reveal that the concentrations of extractables obtained from the glass and released into the solution in contact, are low. The acidification of the water inside the bottle leads to the partial delamination of a 300 nm thick alumina coating and results in a significant release of aluminum ions. This is due to the previously identified alteration of the external part of the film. In contrast, alumina layers thinner than 20 nm, show concentrations of extractables, both glass and aluminum ions, that are significantly lower than those of an uncoated bottle. This preliminary result is particularly promising. It is attributed to the transformation of the nanometric alumina coating into an aluminosilicate interdiffusion layer during the deposition process, which acts as an efficient barrier, while remaining unaffected from the interaction with the content during the shelf life of the drug.

International audience; Nanofiltration can be used to recover chemicals, like VFAs, produced by the fermentation of biomass. Solution pH is a key parameter for fermentation as well as for recovery using nanofiltration. Current work reports an experimental investigation carried out with single and mixed solutions that contain acetic, propionic, and butyric acids, at various concentrations and pHs. It is shown that retention of VFAs increases with solution pH following an S-shaped curve related to the VFA dissociation. Retentions of VFAs decrease with the concentration, the influence being negligible at low pH values and more significant at high pH values. A simple model is proposed to calculate VFAs retentions versus pH for different concentrations and a given filtration flux, considering the dissociation of VFAs and the retention of dissociated and undissociated solutes. Calculated retentions can fit well with the experimental ones, on condition to consider solutes pKa values slightly higher than theoretical ones, up to 1.24 pH units, or a variation of the membrane charge with pH, corresponding to an effective membrane pKa between 5.44 and 5.80. Both assumptions are supported by previous investigations.

International audience; Phosphorus (P) removal from the domestic wastewater is required to counter the eutrophication in receiving water bodies and is mandated by the regulatory frameworks in several countries with discharge limits within 1-2mgPL−1. Operating at higher sludge retention time (SRT) and higher biomass concentration than the conventional activated sludge process (CASP), membrane bioreactors (MBRs) are able to remove 70–98% phosphorus without addition of coagulant. In full-scale facilities, enhanced biological phosphorus removal (EBPR) is assisted by the addition of metal coagulant to ensure >95% P-removal. MBRs are successfully used for super-large-scale wastewater treatment facilities (capacity >100,000 m3d−1). This paper documents the knowledge of P-removal modeling from lab to full-scale submerged MBRs and assesses the existing mathematical models for P-removal from domestic wastewater. There are still limited studies involving integrated modeling of the MBRs (full/super large-scale), considering the complex interactions among biology, chemical addition, filtration, and fouling. This paper analyses the design configurations and the parameters affecting the biological and chemical P-removal in MBRs to understand the P-removal process sensitivity and their implications for the modeling studies. Furthermore, it thoroughly reviews the applications of bio-kinetic and chemical precipitation models to MBRs for assessing their effectiveness with default stoichiometric and kinetic parameters and the extent to which these parameters have been calibrated/adjusted to simulate the P-removal successfully. It also presents a brief overview and comparison of seven (7) chemical precipitation models, along with a quick comparison of commercially available simulators. In addition to advantages associated with chemical precipitation for P-removal, its role in changing the relative abundance of the microbial community responsible for P-removal and denitrification and the controversial role in fouling mitigation/increase are discussed. Lastly, it encompasses several coagulant dosing control systems and their applications in the pilot to full-scale facilities to save coagulants and optimize the P-removal performance.

International audience; The microbial electrochemical snorkel (MES) is a low-cost, low-maintenance technology that could considerably reduce wastewater treatment costs by reducing the need for aeration. An MES is a single electrode. The lower part, in the anoxic zone of the bioreactor, oxidizes organic matter by transferring electrons to the electrode. The upper part, in the oxic zone, releases the electrons by reducing dissolved oxygen. This study gives new insights into the correlation between the MES potential, the concentration of dissolved oxygen and COD abatement, thus enabling practical rules to be extracted for running the MES in optimal conditions, particularly for adjusting the aeration zone and frequency. Here, aeration promoted the cathodic reaction and increased the MES potential to a maximum (0.0 to 0.1 V/SCE). After aeration stopped, the potential dropped to a minimum (< -0.4 V/SCE). With 26 cm high MESs, sequential aeration at the top was not sufficient to support an effective cathodic zone, while aeration at the bottom was detrimental to the formation of the microbial anode. With MESs 48 cm high and aeration set up in the highest quarter, 30 minutes of aeration every 4.5 hours gave potential variations that were stable for weeks. The MESs continued to oxidize organic matter 30 minutes after the aeration had stopped. In this period, the MESs removed 3 to 6.3 times more COD than the control reactors. Increasing the electrode capacitance is therefore suggested as an effective way to further decrease the aeration cost by decreasing the aeration frequency.

International audience; Microbial anodes and oxygen reducing microbial cathodes were designed separately under constant polarization at +0.1 V/SCE in a hypersaline medium (NaCl 45 g/L). They were then associated to design two-compartment microbial fuel cells (MFCs). These MFCs produced up to 209 ±24 mW m-2 during a week. This was the first demonstration that hypersaline MFCs equipped with microbial cathodes can produce power density at this level. Desulfuromonas sp. were confirmed to be key species of the anodes. The efficiency of the cathodes was linked to the development of a redox system centred at +0.2 V/SCE and to the presence of Gammaproteobacteria (Alteromonadales and Oceanospirillales), especially an unclassified order phylogenetically linked to the genus Thioalobacter. Comparing the different performance of the four MFCs with the population analyses suggested that polarization at +0.1V/SCE should be maintained longer to promote the growth of Thioalobacter on the cathode and thus increase the MFC performance.

International audience; Access to critical metals required for high-performance technologies, particularly, the light rare earth elements (REEs = La, Ce, Nd, Pr), has become a major challenge for import-dependent economies such as the European Union. In this regard, the recycling of spent nickel metal hydride (Ni-MH) batteries by hydrometallurgical processes can serve as an attractive secondary source of REEs. In such processes, precipitation of REEs from pregnant leach solutions (PLS) in sulfate media using Na2SO4 is often reported. However, little consideration is given as to whether and how sodium ions influence the precipitation efficiency and selectivity. This work focuses on a better understanding of the precipitation process by coupling pilot-scale (2 L) experiments on industrially sourced PLS containing 50 g/L of Ni and 17 g/L of REEs, with thermodynamic modeling, to assess the influence of temperature (25 °C < T < 60 °C) and the Na/REEs molar ratio (0.8:1 < Na/REEs < 3.2:1). Equilibria calculations were performed using OLI Systems Inc. software whose database covers rare earth sulfate compound properties and an accurate description of the aqueous electrolytes. Highly selective precipitation was obtained at 60 °C and for a Na/REEs molar ratio of 4:1. A lanthanide-alkali solid solution was identified by multianalytical characterization.

International audience; A kinetic model for sunflower oil hydrogenation on a palladium catalyst is proposed based on Horiuty–Polanyi type mechanism and considering either a dissociative or associative adsorption of hydrogen. The derived kinetic laws allow to explain the distinct dependency of saturation and isomerization reactions on hydrogen pressure. Kinetic parameters are identified based on batch slurry hydrogenations carried out at 60–160◦C and 2–31 bar with a powdered Pd/Al2O3 catalyst. A statistical analysis is used to select the most suitable adsorption mechanism for H2. Evaluation of the Weisz–Prater modulus reveals that limitations to intraparticle diffusion occur despite the particle diameter does not exceed 40 μm.

International audience; The performance of a microbial electrolysis cell (MEC) supplied with domestic wastewater (dWW) is essentially limited by the kinetics of the anodic bioelectrochemical reactions and the low ionic conductivity of the electrolyte. A strategy to boost-up the anodic bioelectrochemical kinetics is to use three-dimensional (3D) microbial anodes that offer a high total anodic surface area and volume density of electroactive biofilm. In this work, a 3D multiphysics model was designed to simulate the current generation and resulting hydrogen production in double and triple-compartment MECs fed continuously with dWW. Simulations indicated that optimised 3D microbial anode geometries could simultaneously increase current and chemical oxygen demand (COD) removal by 86% compared to a 2D planar graphite electrode. At a constant CEM voltage, the current produced increased with the thickness of the 3D microbial anode up to a limiting thickness of 20 mm. Beyond this value, the current was stagnant due to the predominant ohmic drop. Current generation and COD removal could be further increased by designing 3D anode geometrical arrangements that force the dWWs to flow through the porosity of the 3D microbial anode. A gain of 20% was calculated by substituting a monolithic 3D graphite anode with a 3D anode of the same thickness (20 mm) but constructed of plates stacked on top of each other and spaced 2.5 mm apart. Finally, hydrogen production performance was additionally optimised by a further + 20% by switching from a two-compartment MEC design (anode-cathode) to a three-compartment MEC design (cathode-anode-cathode).

International audience; Yeast hulls can be used to adsorb undesirable compounds such as volatile phenols that may be present in wine. To understand this adsorption process, the properties of the cell walls and their chemical composition need to be better understood. A study was conducted using four different yeast fractions of either autolysed or high-pressure homogeniser (HPH)-crushed yeast biomasses of Saccharomyces cerevisiae and Brettanomyces bruxellensis. Near-infrared spectroscopy (FT-NIR) coupled with X-ray photoelectron spectroscopy (XPS) was used and analysed by principal component analysis (PCA). The FT-NIR spectral region of Saccharomyces and Brettanomyces statistically analysed by PCA showed a clear discrimination accounting for 76% of the variation in the data for PC1; moreover, yeast hulls prepared from the same strain and subjected to two different treatments were also separated. These methods classify yeast cell hulls (YCH) according to strain, composition and treatment applied. Our results indicate that yeast hulls obtained by autolysis are less rich in proteins than those resulting from HPH treatment due to the high pressure that releases more proteins and exposes them on the surface of the cell wall. The composition of YCH at the extreme surface is similar to that found deeper in the wall.

This work focuses on the microstructure of metallic deposits formed by galvanostatic electrodeposition inside a Hele-Shaw cell without both supporting electrolyte and flow. For a low applied current density j, the deposit grows under the form of ramified branches. As shown by Fleury (Nature, 390,, 1997), these branches are composed of small metallic crystals. This microstructure is built up by a re-nucleation process induced by the dynamics of a space charge region (non-electrically neutral solution) ahead of the growth front. When increasing j the crystal size decreases whereas the nucleation frequency increases. These latter tendencies are reversed for high j when, as experimentally observed, dendrites are formed instead of ramified branches. There must be a transition between the nucleation/growth regime (ramified branches) and the pure growth regime (dendrites). This transition is examined experimentally by carefully observing the branch microstructure by SEM. For copper and silver branches, when j is lower than a critical current density j_c (concentration-dependent), the branches are composed only of non-dendritic crystals. Whereas, when j>j_c, dendritic crystals are observed and they become the main kind of crystals constituting the branches for higher j. These observations show that the morphological transition on the pattern scale, between ramified branches and dendrites, originates from a morphological transition on the scale of the crystals constituting the branches. This latter is considered theoretically by analyzing the shape stability of the growing crystals. The Mullins & Sekerka model (shape stability of a spherical particle growing by diffusion) disagrees with these observations by predicting that the crystals are always unstable. It is proposed that the space charge layer, surrounding the growing crystals, induces a stabilizing effect.

International audience; An unconventional modelling methodology based on artificial neural networks is proposed to rapidly develop a model from data obtained during different batch experiments. The objective of the global model is to predict time evolution of concentrations of all species present in the reaction medium. For this, different recurrent neural networks are elaborated to estimate a particular species as a function of operating parameters and concentrations of all species and then assembled in a complex global model.To validate the approach, the esterification reaction of methanol by acetic acid, which presents equilibrium, has been chosen. The kinetic evolution of the chemical species during experiments conducted in batch mode are correctly represented whatever the operating conditions. Finally, the global model based on neural networks is integrated in a hybrid model. This permits to transpose the reaction to a semi-batch chemical reactor which has not been considered during the learning phase.

International audience; Continuous-flow microstructured technologies are now recognized as promising alternatives to batch processing for organic photochemistry, especially when light emitting diodes (LEDs) are employed as light sources. To evaluate and optimize productivity and energetic efficiency, the knowledge of the incident photon flux density is crucial. In this context, the objectives of the present work are dual: first, to transfer the classical actinometry method with Reinecke’s salt to a continuous-flow LED-driven spiral-shaped reactor and, second, to propose a revised one-dimensional equivalent model for the accurate determination of the incident photon flux density in this microreactor. Experimental measurements were carried out under controlled conditions. The effects of the spectral domain and radiant power emitted, the tubing length, the presence of gas-liquid Taylor flow, and the material of the support plate were especially investigated. For this purpose, an expression was established for the revised one-dimensional Cartesian model, taking into account the diffuse emission of the LED array and the reflection induced by the material of the plate in which the tubing was inserted (i.e. the reflection by the backside of the microreactor wall). In this way, the incident photon flux density could be estimated with an acceptable level of accuracy, which was not the case if the usual one-dimensional (1D) model was applied (collimated emission and no reflection).

International audience; Hemodialysis is an important therapy for treating patients with End Stage Renal Disease (ESRD). These patients visit the hospital 3 times a week and each time their blood is cleansed during 4-hour dialysis sessions using a hollow fiber membrane module; also called artificial kidney. This device mainly achieves removal of small water-soluble toxins and a limited number of middle molecules. To improve the clearance of toxins, especially middle molecules and protein bound toxins, longer treatment via nocturnal dialysis and/or the application of portable/wearable artificial kidney is required. Such therapies require application of membranes with very low fouling and very good blood compatibility. Current membranes often contain hydrophilic additives which could elute during sterilization processes and/or during long-term filtration. In this study, we propose a simple method for developing low fouling blood compatible membranes by blending of polyethersulfone (PES), a material already used for fabrication of dialysis membranes, with small amounts of SlipSkin™ (SS), a blood compatible random copolymer of hydrophilic N-vinylpyrrolidone (NVP) and hydrophobic N-butylmethacrylate (BMA). Our results show that membranes with 2 wt% of SS have high fouling resistance to proteins and middle-size molecules and very good blood compatibility, making these membranes promising for application in dialysis therapy.

International audience; Gas-expanded liquids have been studied during past years; however, the physicochemical properties of some of these fluids still need to be characterized and understood. In particular, the study of properties concerning solvation and mass transport is key for industrial applications. This work presents the characterization of eight CO2-expanded biosourced solvents: organic carbonates (dimethyl, diethyl, ethylene, and propylene carbonates), anisole, veratrole, γ-valerolactone, and 2-methyltetrahydrofuran. Two approaches have been used: spectroscopic measurements and molecular modeling. Phase equilibrium was determined for each CO2/biosourced solvent system, and then the solvatochromic probe Nile Red was used to determine changes in dipolarity/polarizability (π* Kamlet–Taft parameter) by CO2 pressure. Molecular dynamics calculations were performed to determine the density and viscosity changes with CO2 pressure. It is shown in this study that the degree of modulation of dipolarity/polarizability parameter can go from that of pure solvent (around 0.4 for linear organic carbonates) to negative values, close to that of pure CO2 at the T and P used in this study. Concerning transport properties, such as density and viscosity, a great decrease in both these properties’ values was observed after swelling of the solvent by CO2, for instance, in linear organic carbonates where density can decrease to 50% the density of pure solvent; concerning viscosity a decrease of up to 90% was measured for these compounds. It was observed that the solubility of CO2 and then modulation of properties were higher in linear organic carbonates than in the cyclic ones. This study shows once more that CO2 has a great capacity to be used as a knob for triggering changes in the physicochemical properties of green biosourced solvents that can help to implement these solvents in industrial applications.

International audience; For over 10 years, the olive oil sector has been largely studied through Life Cycle Assessment (LCA). Thus, a review of the numerous results and the different evaluated scenarios is relevant for future LCA studies on this important agro-economic sector of the Mediterranean region. The herein present work, based on scientific and technical literature aims to compare system boundaries, functional units, life cycle inventories, allocation, impact assessments, and interpretations from the currently existing LCAs of olive oil. Furthermore, an analysis of the assessment of biogenic carbon has been carried out among the reviewed papers. As a result, 23 relevant LCA studies on olive oil production or olives cultivation (for olive oil production) were identified. Analysis of the literature converged on an unequivocal environmental hotspot, the agricultural phase; which represents the most impactful phase of the olive oil life cycle, due in particular to fertilisation, pesticides treatment, and irrigation. Waste management and distribution also appear to represent a crucial issue. The comparison work made on climate change impact assessment is on the order of magnitude of 460 kg CO2-eq/ton of olive and 1.6 kg CO2-eq/L of olive oil. This study highlights the complexity of carrying out an LCA on the olive oil sector. At last, best practices and methodological recommendations were matured.

International audience; Organic clathrates, particularly those formed by hydroquinone (HQ) and gas mixtures, have been far less studied than other inclusion compounds, such as gas hydrates. In this study, experiments and molecular dynamics simulations were performed on mixed (CO2 + CH4)–HQ clathrates. Single crystals were synthesized using gas mixtures with different compositions, ranging from pure CO2 to pure CH4. The crystal structure, the guest occupancy in the clathrates, and the variation of the crystal lattice parameters according to clathrate composition were obtained by X-ray diffraction measurements. In addition, molecular dynamics simulations were performed on the same systems, with state-of-the-art molecular models and force fields. The experimental results obtained and the molecular dynamics simulation estimations were in good agreement. The clathration selectivity was also calculated on the basis of experimental results, and the composition of the solid phase was correlated with the composition of the gas phase at equilibrium. These new insights into these structures will be useful from both a fundamental and a practical point of view, particularly for further developing innovative gas separation techniques using HQ clathrates.

In this work we study the heat transport in inhomogeneous bubbly flow. The experiments were performed in a rectangular bubble column heated from one side wall and cooled from the other, with millimetric bubbles introduced through one half of the injection section (close to the hot wall or close to the cold wall). We characterise the global heat transport while varying two parameters: the gas volume fraction $\alpha = 0.4\% - 5.1 \%$, and the Rayleigh number $Ra_H=4\times10^9-2.2\times10^{10}$. As captured by imaging and characterised using Laser Doppler Anemometry (LDA), different flow regimes occur with increasing gas flow rates. In the generated inhomogeneous bubbly flow there are three main contributions to the mixing: (\textit{i}) transport by the buoyancy driven recirculation, (\textit{ii}) bubble induced turbulence (BIT) and (\textit{iii}) shear-induced turbulence (SIT). The strength of these contributions and their interplay depends on the gas volume fraction which is reflected in the measured heat transport enhancement. We compare our results with the findings for heat transport in homogeneous bubbly flow from Gvozdi{\'c} \emph{et al.} (2018). We find that for the lower gas volume fractions ($\alpha4\%$, when the contribution of SIT becomes stronger, but so does the competition between all three contributions, the homogeneous injection is more efficient.

© 2019, Australian Ceramic Society. Most methods for producing calcium phosphates involve synthetic calcium and phosphates sources. However, it has recently been proposed that calcium phosphate can be produced with bio-based calcium sources such as nacre, coral, and cuttlefish bones. One specific source of bio-based calcium is found in the Achatina snail shell, which becomes a waste product after flesh consumption. The present work aimed to assess the effectiveness of Achatina snail shells and to study the conversion kinetics in both acid and alkaline environment rich in phosphate ions. It was observed that in acidic conditions, the calcium released by the dissolution of the aragonite precipitates with the phosphate ions of reaction medium induces brushite formation which is rapidly converted into monetite. In alkaline conditions, calcium released from aragonite reacts with surrounding phosphates and carbonate ions and induces carbonated apatite precipitation. Regardless of the source of calcium used in the presence of phosphate, the conversion is carried out according to complex phenomena that involve topotactic transformation or dissolution-precipitation mechanisms.

Description of the relationship between protein structure and function remains a primary focus in molecular biology, biochemistry, protein engineering and bioelectronics. Moreover, the investigation of the protein conformational changes after adhesion and dehydration is of importance to tackle problems related to the interaction of proteins with solid surfaces. In this paper the conformational changes of wild-type Discosoma recombinant red fluorescent proteins (DsRed) adhered on silver nanoparticles (AgNPs)-based nanocomposites are explored via surface-enhanced Raman scattering (SERS). Originality in the present approach is to work on dehydrated DsRed thin protein layers in link with natural conditions during drying. To enable the SERS effect, plasmonic substrates consisting of a single layer of AgNPs encapsulated by an ultra-thin silica cover layer were elaborated by plasma process. The achieved enhancement of the electromagnetic field in the vicinity of the AgNPs is as high as 105. This very strong enhancement factor allowed detecting Raman signals from discontinuous layers of DsRed issued from solution with protein concentration of only 80 nM. Three different conformations of the DsRed proteins after adhesion and dehydration on the plasmonic substrates were identified. It was found that the DsRed chromophore structure of the adsorbed proteins undergoes optically assisted chemical transformations when interacting with the optical beam, which leads to reversible transitions between the three different conformations. The proposed time-evolution scenario endorses the dynamical character of the relationship between protein structure and function. It also confirms that the conformational changes of proteins with strong internal coherence, like DsRed proteins, are reversible.

International audience; The separation of ternary nonideal systems with multi‐azeotrope is very important because they are often found in the waste of chemical and pharmaceutical industries, which is much more difficult due to the formation of multi‐azeotrope and distillation boundary. We propose a systematic procedure for design and control of a triple‐column pressure‐swing distillation for separating ternary systems with three binary minimum azeotropes. This procedure involves thermodynamic insights, a two‐step optimization method, and effective control strategy. The separation of tetrahydrofuran (THF)/ethanol/water is used to illustrate the capability of the proposed procedure. It is found that the pressure limits in columns can be determined through the analysis of residue curve maps, distillation boundary, and isovolatility curves. The optimal triple‐column pressure‐swing distillation is generated with the minimum total annual cost (TAC) of $2.181 × 106 in sequence A. The operating conditions are well controlled approaching their desired specifications in an acceptable time when disturbances occur.

International audience; The purpose of the research is to make a first step towards rationalizing green polymeric membrane preparation. A holistic methodological approach based on metrics that consider technical, environmental, health and safety issues have been suggested to assess sustainability of membrane preparation. Metrics have been applied to solvent substitution in a non-solvent induced phase separation process. The flammability hazard of three shortlisted alternative solvents has substituted the reprotoxicity hazard of common solvents. The ultrafiltration cellulose diacetate membranes prepared with methyl lactate as solvent have a greater renewable intensity and require a lower number of solvents for their preparation. Trade-offs between use of resources (polymer, solvent, energy…) and membrane properties are inevitable. Further socio-economic, risk and life cycle analysis are crucial to fully integrate ecodesign in membrane preparation.

This study deals to improve the understanding of biomass thermo-chemical conversion in a dense and fast internally circulating fluidized bed. The experimental rig used in this study ran either as a dense fluidized bed or as a fast internally circulating fluidized bed. The effect of operating parameters, such as bed temperature (ranging from 750 to 850 °C), steam gas velocity (between 3 and 9.5 times the minimum fluidization velocity of bed material), steam to biomass mass ratio (ranging from 0.7 to 5.6 kg.kg −1) and biomass shape (sawdust and pellets) is investigated in both dense and fast internally circulating fluidized bed with olivine as bed material. In addition, the effect of bed material nature (olivine and sand) is also studied. Results indicated that syngas composition is strongly dependent on steam to biomass mass ratio. Moreover, it was found that syngas yield is favored by rising bed temperature and steam to biomass mass ratio while it is disadvantaged when fluidizing gas velocity increases. In addition, a greater syngas yield was obtained with olivine particles, compared to sand particles. The effect of bed material circulation flow rate was also investigated in fast internally circulating fluidized bed. Results showed that an increase in this parameter leads to a lower syngas yield. Finally, the experimental results presented in this paper were compared to ones reported in the literature and a good agreement was found.

International audience; Quasi-variational inequalities are variational inequalities in which the constraint map depends on the current point. Due to this characteristic, specific proofs have been built to prove adapted existence results. Semicontinuity and generalized monotonicity are assumed and many efforts have been made in the last decades to use the weakest concepts. In the case of quasi-variational inequalities defined on a product of spaces, the existence statements in the literature require pseudomonotonicity of the operator, a hypothesis that is too strong for many applications, in particular in economics. On the other hand, the current minimal hypotheses for existence results for general quasi-variational inequalities are quasi-monotonicity and local upper sign-continuity. But since the product of quasi-monotone (respectively, locally upper sign-continuous) operators is not in general quasi-monotone (respectively, locally upper sign-continuous), it is thus quite difficult to use these general-type existence result in the quasi-variational inequalities defined on a product of spaces. In this work we prove, in an infinite-dimensional setting, several existence results for product-type quasi-variational inequalities by only assuming the quasi-monotonicity and local upper sign-continuity of the component operators. Our technique of proof is strongly based on an innovative stability result and on the new concept of net-lower sign-continuity.

The actinobacterium strain ABH26 closely related to Saccharothrix xinjiangensis, isolated from an Algerian Saharan soil sample, exhibited highly antagonist activity against Gram-positive bacteria, yeasts and filamentous fungi. Its ability to produce antimicrobial compounds was investigated using several solid culture media. The highest antimicrobial activity was obtained on Bennett medium. The antibiotics secreted by strain ABH26 on Bennett medium were extracted by methanol and purified by reverse-phase HPLC using a C18 column. The chemical structures of the compounds were determined after spectroscopic (1H NMR, 13C NMR, 1H-1H COSY and 1H-13C HMBC spectra), and spectrometric (mass spectrum) analyses. Two new cyanogriside antibiotics named cyanogriside I (1) and cyanogriside J (2), were characterized along with three known caerulomycins, caerulomycin A (3), caerulomycin F (4) and caerulomycinonitrile (5). This is the first report of cyanogrisides and caerulomycins production by a member of the Saccharothrix genus. The minimum inhibitory concentrations (MIC) of these antibiotics were determined against pathogenic microorganisms. Keywords: Antagonistic activity, Antimicrobial compounds, Caerulomycins, Cyanogrisides, Saccharothrix xinjiangensis

International audience; This paper investigates the behavior of conductive Ti4O7 ceramic anode in different electrolytes during the degradation of the anti-inflammatory drug paracetamol (PCM) by advanced electrochemical oxidation processes mainly anodic oxidation with generation of H2O2 (AO-H2O2) and electro-Fenton (EF). Regardless of the medium, better degradation and mineralization efficiency was always observed with EF compared to AO-H2O2. The degradation of PCM was carried out by hydroxyl radical (OH) produced on the anode surface from water oxidation and mediated oxidation in the solution from oxidant species generated at the anode such as sulfate radicals and active chlorine species depending on the supporting electrolytes used, as well as OH generated homogeneously in the solution by electrochemically assisted Fenton’s reaction. Faster degradation was observed in Cl− compared to other media, but the solution was poorly mineralized. Highest total organic (TOC) removal efficiency with excellent degradation rate was attained in SO42− with either process, thus remain the best medium for advanced electrochemical wastewater treatment. Comparative studies with dimensional stable anode (DSA) and boron-doped diamond anode (BDD) showed similar trend of degradation and TOC removal efficiency with DSA anode achieving low mineralization power compared to Ti4O7 anode, whereas BDD showed slightly better efficiency than Ti4O7 in all electrolytes studied. The analysis of concentration of generated active chlorine species, especially ClO−, during AO-H2O2 decreased in the order: DSA > Ti4O7 > BDD. Therefore, the Ti4O7 electrode was found to be a promising anode material for an efficient treatment of PCM in SO42−, NO3− and ClO4− media but less effective in Cl− medium.

The influence of the chromia volatilization on the oxidation kinetics of Inconel 625 was investigated at 900 ◦C under flowing wet air (74%N2-18.5%O2-7.5%H2O) through an interdisciplinary approach, coupling experiments and gas phase simulation. Oxidation tests showed a strong decrease in the volatilization rate of lined-up samples from the inlet to the outlet of a horizontal tubular furnace. Gas phase simulation allowed to relate it to an increase in the CrO2(OH)2 partial pressure along the tube. Considering gas composition changes appears as essential to provide correct interpretation of oxidation test results in humid and oxidizing environments.

International audience; Gum arabic is a heterogeneous natural hydrocolloid commonly used in the agro-food industry to provide metastability to oil-in-water emulsions. Since aqueous solutions of gum arabic contain a complex mixture of protein/polysaccharide conjugates, the composition of interfacial films is expected to differ from the bulk composition. Here, we investigate the composition of interfacial films in oil/water emulsions stabilized by gum arabic at various concentrations, pH and salinity. Using both size exclusion and hydrophobic interaction chromatography separations, we show that the interface is enriched in protein-rich species displaying a broad range of sizes. These species are irreversibly adsorbed as monolayers at the oil/water interface. We observe that the surface coverage density, or packing, of the adsorbed species at oil/water interfaces drastically increases with both the increasing gum concentration and decreasing ionic repulsions, through increasing the ionic strength or decreasing the pH. Strikingly, these packing changes correspond to only minor composition changes in the adsorbed layer. We thus conclude that the key parameter modified in different formulations is the conformation of the adsorbed species rather than their composition distribution. These findings can be readily used to adjust the amount of gum arabic necessary to produce metastable emulsions.

International audience; The aim of this study was to investigate the integration of nanofiltration in succinic acid production based on a fermentation. An experimental investigation was carried out with NF 45 membrane and synthetic fermentation broths of increasing complexity containing succinate salt and different impurities like inorganic salts, glucose or other organic acid salts like acetate. The influence of the operating conditions (pH, pressure…) as well as of the broth composition on the NF performances was studied. The mechanisms governing the transfer of the solutes through the membrane were investigated in order to explain the different solute retentions observed according to the fermentation broth composition. Finally, a two-step process including NF in a diafiltration mode followed by reverse osmosis was proposed to perform the purification of succinate from a synthetic fermentation broth containing acetate. It was shown that it is possible to increase the succinate purity from 85% to 99.5% while maintaining the total yield higher than 92%.

De très nombreuses bactéries sont capables de connecter leur métabolisme avec une électrode qu’elles utilisent comme accepteur ou donneur d’électrons. Quelques études ont mis en lumière des processus similaires avec des levures. Pour l’heure, de tels transferts d’électrons extracellulaires n’ont pas été décrits avec les cellules animales, bien que de multiples résultats expérimentaux laissent penser qu’ils pourraient exister. Ces travaux de thèse ont eu pour objectif d’explorer la capacité de cellules animales à échanger des électrons avec des électrodes. L’étude par voltammétrie cyclique de cellules MRC-5 et Vero adhérées à la surface d’électrodes en carbone a mis en évidence leurs effets catalytiques différents sur la réduction électrochimique du dioxygène. La culture de cellules Vero sur des électrodes de carbone polarisées a démontré que les potentiels entre -0,15 et 0,25 V/ECS ne permettent pas l’adhésion des cellules, bien qu’ils ne semblent engendrer aucune réaction résiduelle significative au niveau des électrodes. Au potentiel appliqué de 0,45 V/ECS, un courant d’oxydation a été enregistré pendant plusieurs jours en présence de cellules Vero adhérées à la surface de l’électrode. La génération de courant d’oxydation est strictement conditionnée par la présence de dioxygène, suggérant une origine mitochondriale des électrons. La forte diminution du courant en l’absence de glutamine conduit à certaines hypothèses sur les voies métaboliques impliquées dans le transfert d’électrons extracellulaire.

International audience; Several homogeneous photo-based advanced oxidation processes - namely photolysis, photo- oxidation and photo-Fenton oxidation - were investigated for the elimination of ibuprofen in water. The effects of several operating parameters, such as the lamp type (low or medium pressure mercury, xenon-arc), the concentration of hydrogen peroxide (0.5 to 7 times the stoichiometric amount required for mineralization) and the concentration of Fenton reagent, were quantified. Photo-Fenton oxidation was also combined with low-frequency sonication to investigate possible synergistic interactions. Ibuprofen degradation under ultraviolet photolysis and ultraviolet/hydrogen peroxide oxidation followed pseudo-first-order kinetics with respect to the pollutant concentration and the apparent rate constant increased with lamp power (6-10 W) and oxidant concentration. Photo-Fenton oxidation under ultraviolet light (L1 lamp, 254 nm, 6 W) and visible light (L2 lamp, 360-740 nm, 150 W) led to complete ibuprofen removal after 3 h, but the mineralization yield of the L1/Fenton process (82%) was higher than that of the L2/Fenton process (59%) because of the effects of ultraviolet/hydrogen peroxide oxidation in the former. Coupling L2/Fenton with sonication improved the degradation rate of the molecule at low Fenton reagent concentration, but the beneficial effect of ultrasound on ferrous iron regeneration vanished when the iron to ibuprofen molar ratio was close to 1. An overall reaction scheme for ibuprofen degradation is proposed based on the transformation products detected during these processes.

International audience; Animal cells from the Vero lineage and MRC5 human cells were checked for their capacity to catalyse the electrochemical oxygen reduction reaction (ORR). The Vero cells needed 72 hours’ incubation to induce ORR catalysis. The cyclic voltammetry curves were clearly modified by the presence of the cells with a shift of ORR of 50 mV towards positive potentials and the appearance of a limiting current (59 μA.cm-2). The MRC5 cells induced considerableORR catalysis after only 4 h of incubation with a potential shift of 110 mV but with large experimental deviation. A longer incubation time, of 24 h, made the results more reproducible with a potential shift of 90 mV. The presence of carbon nanotubes on the electrode surfaceor pre-treatment with foetal bovine serum or poly-D-lysine did not change the results. These data are the first demonstrations of the capability of animal and human cells to catalyse electrochemical ORR. The discussion of the possible mechanisms suggests that these pioneering observations could pave the way for electrochemical biosensors able to characterize the protective system of cells against oxidative stress and its sensitivity to external agents.

International audience; The main environmental impact of olive oil production is the disposal of residues such as pomace and water vegetation. During the olive oil extraction process, the olive stone is milled and discharged within the olive pomace. However, olive stone flour can be valorized as filler for poly‐meric composites. A life cycle assessment of the olive pomace valorization was carried out by fo‐cusing on the manufacturing process of a biocomposite made of two different thermoplastic matri‐ces, i.e., polyethylene and polypropylene. The functional unit is the production of 1 m2 of a lath made of an olive pomace‐based biocomposite. The analysis was carried out with the SimaPro PhD 9.1.1.1 software, and the database used for the modeling was Ecoinvent 3.6. The obtained results reveal that the hotspot of the whole process is the twin‐screw compounding of the olive stone frac‐tion, with the polymeric matrix and coupling agent, and that human health is the most affected damage category. It represents 89% for both scenarios studied: olive stone fraction/polypropylene (OSF/PP) and olive stone fraction/polyethylene (OSF/PE). Further research directions include the use of biosourced polymer matrices, which could reduce the impact of olive pomace‐based compo‐site manufacturing.

The chemical or mechanical performance of amorphous SiO2 films depend on intrinsic physicochemical properties, which are intimately linked to atomic and molecular arrangements in the Si–O–Si network. In this context, the present work focuses on a comprehensive description of SiO2 films deposited from a well-established chemical vapor deposition process involving tetraethyl-orthosilicate, oxygen and ozone, and operating at atmospheric pressure in the range 400–550 °C. The connectivity of the silica network is improved with increasing the deposition temperature (Td) and this is attributed to the decreased content of hydrated species through dehydration-condensation mechanisms. In the same way, the critical load of delamination increases with increasing Td thanks to the silicon substrate oxidation. The utilization of a O2/O3 oxidizing atmosphere involving the oxidation of intermediates species by O2, O3 and O., allows increasing the deposition rate at moderate temperatures, while minimizing carbon, H2O and silanol contents to extremely low values (4.5 at.% of H). The SiOx stoichiometry and Td interplay reveals two distinct behaviors before and above 450 °C. The best corrosion resistance of these films to standard P-etching test is obtained for the minimum silanol content and the best network molecular ordering, with an etching rate of 4.0 ± 0.1 A/s at pH = 1.5. The elastic modulus and hardness of the films remain stable in the investigated range of deposition temperature, at 64.2 ± 1.7 and 7.4 ± 0.3 GPa respectively, thanks to the low content in silanol groups.