WorldCat Identities

Fierro, Vanessa

Overview
Works: 29 works in 37 publications in 3 languages and 217 library holdings
Genres: Conference papers and proceedings 
Roles: Thesis advisor, Other, Opponent, htt
Publication Timeline
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Most widely held works by Vanessa Fierro
Organic and carbon gels : from laboratory synthesis to applications by Nathalie Job( )

8 editions published in 2019 in English and Undetermined and held by 183 WorldCat member libraries worldwide

This expert volume provides specialized coverage of the current state of the art in carbon gels. Carbon gels represent a promising class of materials with high added value applications and many assets, like the ability to accurately tailor their structure, porosity, and surface composition and easily dope them with numerous species. The ability to obtain them in custom shapes, such as powder, beads, monoliths, or impregnated scaffolds opens the way towards numerous applications, including catalysis, adsorption, and electrochemical energy storage, among others. Nevertheless, it remains a crucial question as to which design synthesis and manufacturing processes are viable from an economic and environmental point of view. The book represents the perspectives of renowned specialists in the field, specially invited to conduct a one-day workshop devoted to carbon gels as part of the 19th International Sol-Gel Conference, SOL-GEL 2017, held on September 3rd, 2017 in Liège, Belgium. Addressing properties and synthesis through applications and industry outlook, this book represents essential reading for advanced graduate students through practicing researchers interested in these exciting materials. Authored by experts at the forefront of the latest developments in the field Covers properties and synthesis to applications and industry Thoroughly multidisciplinary in authorship and outlook Practical and comprehensive advice for those exploring the possibilities of carbon gels
Effect of the adsorption pH and temperature on the parameters of the Brouers-Sotolongo models by Taher Selmi( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Finite element simulation of nanoindentation tests using a macroscopic computational model by Mourad Khelifa( )

1 edition published in 2014 in English and held by 2 WorldCat member libraries worldwide

The severity factor as a useful tool for producing hydrochars and derived carbon materials by Asma Jeder( )

1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide

Confrontation of various adsorption models for assessing the porous structure of activated carbons by Mirosław Kwiatkowski( )

1 edition published in 2019 in English and held by 2 WorldCat member libraries worldwide

Physical meaning of the parameters used in fractal kinetic and generalised adsorption models of Brouers-Sotolongo by Taher Selmi( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Nouveaux gels organiques et carbonés dérivés de composés phénoliques naturels et synthétiques by Andrzej Szczurek( )

1 edition published in 2011 in English and held by 1 WorldCat member library worldwide

This thesis describes new carbon gels that are much cheaper than their traditional counterparts derived from resorcinol - formaldehyde (RF) resin dried with supercritical CO2 before pyrolysis, but presenting similar features. Such result was obtained through two parallel routes: (1) the search for cheap precursors able to form chemical gels having suitable densities and mechanical properties; (2) the search for alternative drying methods, such as freeze-drying and supercritical drying with acetone or ethanol. After pyrolysis, new carbon cryogels and aerogels, respectively, were obtained. Half of the work presented here is thus based on the use of (flavonoid) mimosa tannins, which are cheap natural molecules. We show that tannins allow the preparation of highly porous carbons presenting much more versatile textural characteristics, but in some cases similar to those of materials derived from RF. The latter have a production cost five times higher than that of the tannin-based carbon aerogels reported here, which are definitely the cheapest of the market
Synthèse d'essences hybrides par co-traitement de distillats de pétrole et d'huiles de pyrolyse de bio-masse en craquage catalytique by Nicolas Thegarid( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

La pyrolyse de la biomasse ligno-cellulosique permet la production de bio-huiles dans la perspective à court terme de carburants hybrides contenant une fraction de bio-carbone dans un carburant conventionnel d'origine fossile (essence ou diesel). Cependant, la forte concentration en oxygène dans ces huiles, leur instabilité et faible densité énergétique (comparée aux carburants fossiles) imposent des pré-traitements permettant cette co-synthèse de carburants hybrides. Ainsi, après hydrotraitement ou ajout d'un catalyseur durant la pyrolyse, ces bio-huiles peuvent être mélangées à un distillat du pétrole en vue de développer des carburants hybrides conformes aux normes européennes. Les travaux de cette thèse sont centrés sur la production d'essences hybrides par craquage catalytique. L'objectif principal est d'évaluer l'impact de la qualité des bio-huiles (nature de la pyrolyse, niveau d'hydrotraitement, ajout de catalyseurs) sur la qualité des essences produites (rendements, aromaticité, présence de résidus oxygénés etc) en présence d'une charge pétrolière de type distillat sous vide. Un réacteur en lit fixe, de type MAT, simule les conditions de fonctionnement d'une unité FCC de craquage catalytique à 500°C. Les principaux résultats sont les suivants:Une approche mécanistique indique que la conversion désoxygénante des molécules oxygénées de la bio-huile induit une surconsommation de l'hydrogène extrait des hydrocarbures lors du craquage, aboutissant à une forte concentration d'aromatiques et d'insaturés ainsi qu'à une formation excédentaire de coke. Les réactions de craquage des fragments ligno-cellulosiques des bio-huiles concernent essentiellement les sites acides extérieurs au réseau zéolithique, ce dernier permettant les transferts d'hydrogène à partir de l'intérieur du réseau où s'opère le craquage des hydrocarbures. L'incapacité à craquer certains dérivés légers de type phénoliques explique les traces de ces composés dans les essences hybrides produites. L'utilité d'un hydrotraitement couteux des huiles de pyrolyse thermique est discutée en regard d'une pyrolyse catalytique, moins onéreuse, qui produit autant de bio-huile et conduit à une production d'essence hybride équivalente, quoique que plus riche en dérivés phénoliques
Gels poreux biosourcés : production, caractérisation et applications by Gisèle Amaral-Labat( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

This manuscript presents the preparation and the characterization of highly porous monolithic materials mainly derived from natural resources. The objectives were to: (i) develop new gels, biosourced up to the 91% level; (ii) suggest alternatives to supercritical drying in CO2, and (iii) investigate properties of interest for such gels in the organic state and, in some cases, after pyrolysis for obtaining carbon gels. For those purposes, tannin and soy flour were tested as precursors, at different concentrations and different pH, and three ways of drying were used: supercritical drying, freeze drying and evaporative drying. The obtained gels were characterized in terms of density, porosity, pore size distributions and specific surface area, whether in organic or in carbon form, depending on the intended application or expected type of porosity. Mechanical and thermal properties were also measured. The obtained broad range of porous textures allowed suggesting applications such as thermal insulators, catalyst supports or electrodes for electrochemical capacitors
Développement d'un compresseur hybride d'hydrogène : électrochimique à basse pression/adsorption à haute pression by Giuseppe Sdanghi( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

The proof of concept of a non-mechanical hydrogen compressor has been carried out in the present study. It is a hybrid compressor since it consists of: (i) a first electrochemical compression step, which compresses hydrogen from 1 bar up to 40-80 bar and; (ii) a second compression step based on the thermally-driven cyclic adsorption-desorption which allows compressing hydrogen up to 700 bar. Numerical models have been developed to verify the feasibility of such a system, and their validity has been proved by the experimental data obtained with the prototypes built for each of the two compression stages. Concerning the electrochemical compressor, a current density distribution along the electrochemical was observed using a segmented cell, and the developed pseudo-2D model proved that the stability of the current density strictly depends on the local water content of the membrane. Indeed, the current density was found to decrease from 0.75 A/cm2 to 0.65 A/cm2 between the first and the last segment of the compressor, which corresponds to a decrease of the relative humidity in the inlet hydrogen flow from 90% to 55% along the gas channels at the anode side (at 0.66 A/cm2 x 0.36 V and 333 K). Concerning the adsorption-desorption compressor, the Modified Dubinin-Astakhov model (MDA) was implemented to describe hydrogen adsorption on activated carbons as a function of the temperature and the pressure. It was used along with the mass and the energy balance equations to study the feasibility of such a compressor. The results from the numerical simulation were validated with the experimental data, which were obtained using a prototype of 0.5 L, designed and built for the present study, and containing 0.135 kg of the activated carbon MSC-30 (Kansai, Japan). 30 NL/h of high-pressure hydrogen at 700 bar were obtained when introducing hydrogen at 80 bar into the compressor, previously cooled to 77 K, and when heating it up to 315 K. The proposed hybrid hydrogen compressor could be a valid alternative to traditional mechanical compressors, and it could be used in small and decentralized facilities using hydrogen as a fuel, e.g. a hydrogen refuelling station
Hollow / porous carbon spheres derived from biopolymers by Sijin Li( )

1 edition published in 2017 in English and held by 1 WorldCat member library worldwide

In the present work, we proposed for the first time to synthesize hollow / porous carbon spheres by hydrothermal treatment and subsequent pyrolysis of templates, either natural such as fish eggs or alginate beads, or synthetic such as polymer capsules filled with xylitol-erythritol blend. Sucrose, tannin, resorcinol-formaldehyde, etc., were used as carbon precursors. The influence of the reaction conditions during the hydrothermal treatment or the pyrolysis was investigated in order to find the optimal reaction conditions and to tune the diameter and the porosity of the resultant materials. The microwave-absorbing properties of a heterostructure consisting of an ordered monolayer of hollow or porous glassy carbon spheres packed in 2D were experimentally and theoretically investigated in the Ka-band (26-37 GHz) frequency range. The first test of the hollow carbon spheres used for concentrating the solar energy and thus improving solar thermal evaporation was also carried out in this thesis
Polyphénols végétaux traités par voie humide : synthèse de carbones biosourcés hautement poreux et applications by Flavia Lega Braghiroli( )

1 edition published in 2014 in English and held by 1 WorldCat member library worldwide

Renewable resources are considered as sustainable, and sometimes cheaper, alternatives to substitute raw materials of petrochemical origin. We used tannins extracted from Mimosa barks. Tannin is an attractive precursor to synthesize new organic porous materials due to the presence of highly reactive phenolic molecules. The synthesis of these new carbon materials from tannin comprises a two-step process: the first step is a hydrothermal carbonization at moderate temperatures, 180-200°C, which allows obtaining a hydrochar, richer in carbon, and fixing other heteroatoms. These hydrochars present different morphologies as powder or gel. The second step is a carbonization at higher temperature (900°C), which allows increasing surface area (SBET), porosity as well as improving conductivity. The preparation of a porous carbon presenting mesopores perfectly defined in size and in their organization was realized by associating tannin, as carbon precursor, with a surfactant for porosity templating, the copolymer Pluronic F127. These new carbon materials were tested as electrodes of supercapacitor
Effets du dopage d'adsorbants nanoporeux par des métaux ou des semi-métaux nanodispersés sur leurs performances en stockage d'hydrogène par sorption by Sébastien Schaefer( )

1 edition published in 2016 in French and held by 1 WorldCat member library worldwide

In this PhD work, microporous carbonaceous materials decorated with metallic nanoparticles were developed in order to study the effect of nanodispersed metals on hydrogen sorption properties. Bio-sourced precursors such as sucrose, mimosa tannins or even rice straw have been used in order to promote eco-friendly, sustainable and innovating ways of synthesis. The use of hydrothermal pretreatment on tannins or sucrose allowed obtaining hydrochars that have been chemically or physically activated. Depending on synthesis parameters, these syntheses allowed to produce materials with controlled porosity. Then, the hydrogen adsorption properties of these materials were evaluated at ambient temperature as well as their textural properties. The main interest of this work was to propose a coupling between hydrogen sorption properties, from low to high pressure, and the textural properties. The textural properties were modelized using theoretical tools such as the DFT (Density Functionnal Theory). The use the different precursors and of decoration steps using supercritical carbon dioxide or hydrothermal synthesis, during which ones metallic or nitrogen containing precursors were used, allowed to obtain nickel, nitrogen or silicon doped materials without using harmful organic solvents. Finally, the decorrelation of the different adsorption contributions gave the possibility to detect and quantify the hydrogen fractions engaged in different processes such as physisorption, chemisorption and spillover. Polarized or enhanced physisorption was also detected using the same methods
Greffage de molécules azotées sur des structures carbonées à porosité hierarchisée by Assia Nouar( )

1 edition published in 2019 in French and held by 1 WorldCat member library worldwide

Nous avons étudié la chimie de surface de carbones poreux fonctionnalisés avec des oximes et amidoximes d'une part, et avec de la guanidine d'autre part. Nous avons axé ces travaux sur la compréhension et la quantification de ces fonctionnalisations par analyse thermique et plus particulièrement par thermo-désorption programmée en température couplée à la spectroscopie de masse (TPD-MS). Par la suite, nous avons évalué l'intérêt de la fonctionnalisation par la guanidine des carbones mésoporeux pour deux applications : le piégeage du CO2 et la capacité à synthétiser et stabiliser des nanoparticules métallique. Pour la première application, des tests d'adsorption du CO2 à 0°C et 20°C à 1 bar ont été réalisés sur un carbone mésoporeux oxydé sous air en présence ou non de guanidine. L'intensité des interactions (physisorption versus chimisorption) a été sondée par des calculs de chaleurs isostériques d'adsorption. Pour la seconde applications, nous avons utilisé des carbones mésoporeux oxydés en présence ou non de guanidine pour synthétiser des nanoparticules d'argent de taille inférieure à 2 nm et relativement monodisperses en taille. Des particules bimétalliques d'AgCu ont également été obtenues au sein de ces matrices carbonées mésoporeuses imprégnées par la guanidine. On a pu mettre ici en évidence un rôle bénéfique de la guanidine sur le taux de cuivre réduit. Des suivis thermiques par MET in situ ont également été réalisés afin d'évaluer la stabilité thermique de ces nanoparticules et de mieux appréhender l'intérêt de la fonctionnalisation sur les phénomènes de frittage de ces nanoparticules. Finalement, des tests catalytiques pour l'époxydation sélective du styrène ont aussi été effectués sur le matériau Ag/C. Les résultats préliminaires sont très prometteurs pour un procédé de préparation de catalyseur très simple à mettre en œuvre
Matériaux carbonés nanostructurés dérivés de tanin pour électrodes de supercondensateurs by Jimena Castro Gutiérrez( )

1 edition published in 2020 in English and held by 1 WorldCat member library worldwide

In this thesis, the physicochemical properties of tannin-derived mesoporous carbons were studied and their electrochemical performance as electrodes for supercapacitors (SCs) was evaluated in aqueous and organic electrolytes. The main objective of this study was to develop a fast and easy, and environmentally friendly method for the synthesis of mesoporous carbons. A novel surfactant-water-assisted mechanochemical mesostructuration (SWAMM) one-pot method was developed and optimized to produce ordered and disordered mesoporous carbons (OMCs and DMCs, respectively), only by adjusting the surfactant to water weight ratio. Further physical or chemical activation of both OMCs and DMCs improved the textural properties of the materials that resulted in good SC performance, even at high charging rates, in aqueous and organic electrolytes. The in-depth characterization performed for these new materials has also led to a better understanding of the effect of order and connectivity of the micro-mesoporous structure on the development of textural properties by the different activation processes and, consequently, on the electrochemical performance of the assembled SC
Valorisation de la biomasse pour l'élaboration de carbones activés et le développement de dispositifs d'élimination et de détection de nitrates en milieu aqueux by Henriette Moussounda Boundzanga( )

1 edition published in 2020 in French and held by 1 WorldCat member library worldwide

Nitrate pollution is a major environmental problem in France, even though current solutions in wastewater treatment plants make it possible to meet current discharge standards. In the Centre-Val de Loire Region, nitrate pollution mainly affects ground water aquifers, that are naturally poorly protected due to the hydrogeological characteristics of the subsoil. The purpose of this research is to valorize the use of original agro-materials (lignocellulosic plant wastes), issued from the various specialized production chains in the Centre-Val de Loire Region, for the synthesis of "biosourced" activated carbons. Then it has the objective to develop an adsorption process to eliminate nitrates at the outlet of a wastewater treatment plant based on activated carbons.The approach and the objectives of this research were:- firstly, to study the adsorption of nitrate ions in aqueous solution on activated carbons with a focus on their adsorption capacities. To this end, commercial activated carbons having different physico-chemical characteristics in terms of porosity, surface chemistry and surface charge were selected and analyzed. In order to optimize the nitrate adsorption capacities, kinetics and isotherms of nitrate adsorption on activated carbons were carried out by investigating the influence of experimental conditions, such as the pH (acid, basic, neutral) and temperature of the aqueous medium, the mass of activated carbon and the initial nitrate concentration. The study of the kinetics and isotherms of nitrate adsorption has highlighted the importance of the pH of the solution as well as the impact of the ions present in the aqueous solution. It is shown that the latter can compete with the adsorption of nitrate ions. All the results made it possible to propose nitrate adsorption mechanisms on activated carbon:- in a second step, to synthesize activated carbons from local agricultural biomass (tomato plants, miscanthus and poplar wood) by chemical activation. During this activation process, several experimental parameters were investigated, such as the ratio between the raw material and the activating agent and the activation temperature. The objective of this work was to develop efficient and specific activated carbons for nitrate adsorption by promoting the local biomass. For the four lignocellulosic agricultural residues which were activated according to the same chemical activation protocol using phosphoric acid, it is shown that they are potentially activable to produce activated carbon for water treatment. In addition, this study showed that it was possible to predict the contribution of each component (hemicellulose, cellulose and lignin) of lignocellulosic wastes to the mass and porous properties of activated carbons issued from a phosphoric acid chemical activation process. These results confirmed and extended the use of the simple predictive calculation that allows to calculate the proportion of carbon from hemicellulose, cellulose and lignin within the final activated carbon, and, above all, to estimate the chemical activation yields from the biochemical composition of the lignocellulosic precursor.- in a third step, to study the surface functionalization of activated carbons diazonium salts grafting. The objective of this part is to establish the correlation between the chemistry of the AC surface and the adsorption of the nitrate ions. The functionalization of commercial and home-made activated carbons allowed the grafting of different chemical functions on their surface. This grafting induced significant changes in the physico-chemical characteristics and textural properties of the activated carbons studied
Synthèse et caractérisation de matériaux carbonés microporeux pour le stokage de l'hydrogène by Weigang Zhao( )

1 edition published in 2012 in English and held by 1 WorldCat member library worldwide

This thesis describes the preparation, the characterisation and the performances in terms of hydrogen storage capacity of activated carbons designed for such application. The objective was to develop materials that might be able to meet or approach the storage capacity targeted by the US Department of Energy for 2015, i.e. 5.5 wt. % with respect to the whole storage system. With this aim in view, the researches reported here focused on: (1) investigation and understanding of experimental conditions for preparing such adsorbents; (2) optimization of their porous texture for hydrogen storage; (3) correlations between hydrogen storage capacity and textural parameters (surface area, pore volumes and pore size distributions); (4) investigation of materials doping by nitrogen and metal nanoparticles. Storage capacities of 6.6 % in weight with respect to adsorbent at 77K and 4 MPa on one hand, and of 1 wt. % at 298K and 20 MPa on the other hand, were obtained in the present thesis, among the highest reported so far in the open literature
Récupération du tungstène à partir d'un skarn à faible contraste de séparation : apport de la modélisation moléculaire dans la flottation des minéraux calciques by Yann Foucaud( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

Nowadays, skarns represent more than 40% of the global resources in tungsten, which has been classified as a critical raw material in the European Union. In particular, the Tabuaço deposit constitutes an archetype of tungsten skarns and contains high amounts of calcium minerals, including fluorite, apatite, and vesuvianite, in close association with scheelite (CaWO4). According to their similar surface properties, the separation of these minerals by flotation with fatty acids is significantly difficult and, therefore, remains a scientific challenge. In this study, which has been conducted within the framework of the FAME H2020 European project, an economic, environment friendly, and transferable process has been developed for the Tabuaço ore to demonstrate the feasibility of the tungsten skarns processing. In the froth flotation process, the Na2CO3/Na2SiO3 system has exhibited the best efficiency in terms of gangue minerals depression due to considerable synergistic effects that have been subsequently described by statistical, spectroscopic, and atomistic methods. Meanwhile, the influence of the ratios between different carboxylic acids in the collector formulations (Tall Oil Fatty Acids) has been assessed to improve the flotation selectivity. In addition, the enhanced gravity separation (Falcon centrifuge concentrator) has been investigated, optimised, and combined with the flotation to produce a marketable scheelite concentrate assaying 63% WO3 with 59% recovery. Besides, to gain understanding in the molecular mechanisms involved in the flotation process, the fluorite and scheelite interfaces have been modelled using the density functional theory. This study has allowed to characterise the hydration state of these minerals, which display different affinities for water molecules. Furthermore, the adsorption of fatty acids on fluorite has been studied to unravel the adsorption mechanisms of these molecules on calcium minerals, confirmed by experimental investigations
Optimisation de mousses de carbone dérivées de tannin par l'étude et la modélisation de leurs propriétés physiques by Maxime Letellier( )

1 edition published in 2015 in French and held by 1 WorldCat member library worldwide

In this PhD work, alveolar materials in the form of carbon cellular and/or reticulated foams were produced in order to study and to model their physical properties. Cellular carbon foams were obtained by pyrolysis under nitrogen flow of rigid foams mainly derived from biomass-based tannins and furfuryl alcohol. The structures of these foams were tailored through the modification of the formulation of their organics precursors. The reticulated foams, only comprising a solid skeleton made of struts without cell walls, were prepared from polymeric commercial foams through a template method. The structures of all of these materials were thoroughly characterised by using different methods such as electron microscopy and X-ray microtomography. The physical properties of these foams were investigated through mechanical, acoustic, thermal and electromagnetic measurements. Mechanical characterisations were carried out in quasi-static compression through a comparative study with or without plates glued to the samples surfaces. The acoustic tests were done with a 2-microphones impedance tube and through air resistivity measurements. The thermal conductivity was investigated by Hot Disk and Laser flash methods, the latter being coupled with thermal expansion and heat capacity measurements. The electromagnetic characterisations were performed in a wide range of frequencies, from 20 Hz to terahertz and far infrared through LRC-meter, network analyser and waveguides, and terahertz and infrared spectrometers. This work allowed studying precisely the influence of different structural parameters such as density and cell size, interconnectivity and shape, as well as tortuosity, on the physical properties of foams. It was finally possible, depending on the cases, to check the validity of existing models, to suggest improvements or limitations, or to observe new phenomena
 
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Alternative Names
Vanessa Fierro chimiste

Vanessa Fierro researcher

Vanessa Fierro ricercatrice

Vanessa Fierro wetenschapper

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