References of "Lambert, Stéphanie"
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See detailCOPPER ADSORPTION FROM WASTEWATER USING BONE CHARCOAL
Ghrab, Sarah; Benzina, Mourad; Lambert, Stéphanie ULg

in American Journal of Applied Sciences (in press)

Bone charcoal (BC) is being developed as a treatment for decontaminating polluted water. In this study, bone charcoal was obtained by pyrolysis of cow bone. Further, for the wastewater depollution with ... [more ▼]

Bone charcoal (BC) is being developed as a treatment for decontaminating polluted water. In this study, bone charcoal was obtained by pyrolysis of cow bone. Further, for the wastewater depollution with these new materials, their performance in the elimination of copper from aqueous solutions has to be determined. The minimum time to reach the removal equilibrium by adsorption was 10 min with a maximum of copper removal equal to 9,615 mg/g. the kinetics models were applied to fit the our experimental data. Actually, they have show excellent correlations with the pseudo-second-order model wich has presented a linear correlation coefficient equal to 0.941. It was verified that the HCl desorption system has the highest efficiency. [less ▲]

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See detailTowards a large scale aqueous sol-gel synthesis of doped TiO2: Study of various metallic dopings for the photocatalytic degradation of p-nitrophenol
Mahy, Julien ULg; Lambert, Stéphanie ULg; Léonard, Géraldine ULg et al

in Journal of Photochemistry and Photobiology A : Chemistry (2016), 329

In this paper, an easy aqueous sol-gel synthesis developed previously by Mahy et al. [J. Sol-Gel Sci. Technol. (2016)] is adapted to produce highly active TiO2 catalysts doped with Fe3+, Ag+, Cu2+, Zn2 ... [more ▼]

In this paper, an easy aqueous sol-gel synthesis developed previously by Mahy et al. [J. Sol-Gel Sci. Technol. (2016)] is adapted to produce highly active TiO2 catalysts doped with Fe3+, Ag+, Cu2+, Zn2+, Cr3+, Al3+, Mn2+, and Co2+ ions and Pt metallic nanoparticles. Samples are characterized by inductively coupled plasma–atomic emission spectroscopy (ICP-AES), X-ray diffraction (XRD), Mössbauer spectroscopy, transmission electron microscopy (TEM), nitrogen adsorption–desorption measurements and diffuse reflectance spectroscopy measurements. Results show that the samples are composed of anatase-brookite TiO2 nanoparticles with a spherical shape and mean diameter of around 5-8 nm and a surface area of between about 150 - 250 m2 g-1. In each doped sample, the dopant is present in the form added during the synthesis, given that the sample has not undergone any particular treatment. Photoactivity tests show improvement in catalyst activity for Fe3+, Ag+, Cu2+, Zn2+, and Al3+ ion and Pt metallic nanoparticle dopants, while a decrease of activity is obtained for Cr3+, Mn2+ and Co2+ ion dopants. For some dopants, the activity of TiO2 doped with metallic ions and synthesized from the aqueous sol-gel process is equal or superior to the activity of the commercial photocatalyst Degussa P25. Some mechanisms are proposed to explain these modifications of activity with doping. Furthermore, cost comparison at laboratory scale showed that Zn and Cu nitrate salt dopings are clearly less expensive for a halogen light (UV/visible) or low energy light enhanced catalyst and may be considered for industrial applications. Using this method, a large scale Zn-doped TiO2 photocatalyst is synthesized with properties homologous to the lab-scale product. Results show that the aqueous sol-gel synthesis developed previously can be easily adapted for doping in order to produce an up-scalable synthesis. [less ▲]

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See detailCogelled xerogel catalysts for applications in gazeous phase
Lambert, Stéphanie ULg

Conference (2016, June 15)

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See detailAg/SiO2 and Cu/SiO2 cogelled xerogel catalysts for benzene combustion and 2-butanol deshydrogenation
Mahy, Julien ULg; Claude, Vincent ULg; Tasseroul, Ludivine ULg et al

Poster (2016, June 08)

Tars are recognized as major impurities when biomass is gazified into Syngas (mixture CO + H2) or when the methane reforming was produced from sustainaible reagents [1]. Therefore, fundamental knowledge ... [more ▼]

Tars are recognized as major impurities when biomass is gazified into Syngas (mixture CO + H2) or when the methane reforming was produced from sustainaible reagents [1]. Therefore, fundamental knowledge of catalytic oxidation and deshydrogenation mechanisms can be valuable to develop effective methods to control syngas or methane pollution. A very important concern about cogelled catalysts is the accessibility of the active centers. Because the silver and copper is located inside silica particles, there is a risk that it may not be accessible. In the case of benzene oxidation, it was observed that the specific activity (mol s-1 g-1Ag) of Ag/SiO2 and Cu/SiO2 catalysts increases when the silver or copper loading decreases (Fig. 1). In fact, visual observations by TEM showed that in samples Ag0.25, Ag0.45, Ag1.05 and Cu1.00, there are not silver or copper particles located on silica particles external surface and then the metal dispersion values are greater in these samples. So, it is the proof that Ag and Cu particles located inside the silica particles are accessible for benzene in this catalytic system. In the case of 2-butanol dehydrogenation, the specific activity of Cu/SiO2 catalysts increases when the copper loading increases or when the metal dispersion values decreases (Fig. 2). However, in Cu1.00 sample, copper particles inside silica particles only are observed by TEM. It seems that these metallic particles are accessible for 2-butanol in this catalytic system. [less ▲]

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See detailCatalytic reforming of biomass gasification tars with bi- or tri-doped catalysts optimized with organosilane precursors
Claude, Vincent ULg; Courson, Claire; Heinrichs, Benoît ULg et al

Conference (2016, June 08)

The thermochemical method called “biomass gasification” is generating emphatic interest for the production of bio-Syngas (CO + H2) since this process presents the advantage of being renewable without ... [more ▼]

The thermochemical method called “biomass gasification” is generating emphatic interest for the production of bio-Syngas (CO + H2) since this process presents the advantage of being renewable without emitting CO2. However, in practical applications, there are still some technical problems due to high tars concentration in the outlet gas which can condensate and clog the pipes. Many studies have highlighted the fact that the tar elimination via catalytic reforming seem to be the more practical and economical solution. The required properties of the catalysts are determined by its location: inside the reactor (primary catalyst) or outside of the reactor (secondary catalyst). Primary catalysts are generally robust, non-toxic, cheap and they are almost uniquely destined to fluidized bed reactors. Secondary catalysts can be used at the exit of both fluidized and fixed bed reactors. They are characterized by a tailored mesoporous shape, a controlled active site dispersion and an adapted elemental composition [1]. In this work , we decided to focus on designing materials for secondary catalytic applications, i.e. working at relatively low temperature (~650°C) with no mechanical stress. The supports were made of γ-Al2O3 synthesized via an easy Sol-Gel method. During their synthesis, these supports were doped with 10%wt of nickel and various combinations of metallic dopants (Co, Cu, Fe, Mn, Mo) in the aim of enhancing their catalytic activities and lifetime. [less ▲]

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See detailDevelopment of an easy aqueous sol-gel synthesis for large-scale film deposition methods for the manufacture of coated steel with self-cleaning properties
Mahy, Julien ULg; Léonard, Géraldine ULg; Pirard, Sophie ULg et al

Conference (2016, May 20)

In this work, a global process has been developed to produce at a large scale pure TiO2 films deposited on steel in order to get an easy-to-clean surface. This large scale process implies an easy aqueous ... [more ▼]

In this work, a global process has been developed to produce at a large scale pure TiO2 films deposited on steel in order to get an easy-to-clean surface. This large scale process implies an easy aqueous sol-gel process for the synthesis of the TiO2 sol. This synthesis [1] has been simplified to make easier the extrapolation towards an industrial scale. Results of TEM, photocatalytic properties, film hydrophilicity, and texture obtained with the simplified aqueous sol-gel synthesis (IsoP-TiO2 synthesis) show similar properties than those obtained with the standard aqueous sol-gel synthesis of TiO2 developed previously (HAc-TiO2 synthesis [2]). Only XRD patterns were slightly different with the presence of anatase-brookite phases in IsoP-TiO2 synthesis while anatase phase only was observed in HAc-TiO2 synthesis. Both the aqueous sol-gel synthesis of pure TiO2 and the film deposition on steel by roll-coating have been successfully extrapolated to a larger scale. Indeed, the deposition was done on a pilot line, the steel substrate is 25 cm width, and the band length is 800 m. The coating was deposited at line speed ranging from 30 to 120 m.min-1.The photocatalytic activity and the hydrophilicity of the film were found to be unchanged compared to the films produced at a laboratory scale, thus validating the production of an efficient easy-to-clean material. Even if some problems have still to be solved, this study is a hopeful first step in the development of a large scale process for self-cleaning steel production. [1] S. Mahshid, M. Askari, M.S. Ghamsari, J. Mater. Process. Technol. 189 (2007) 296–300 [2] C.M. Malengreaux, S. Douven, D. Poelman, B. Heinrichs, J.R. Bartlett, J. Sol-Gel Sci. Technol. 71 (2014) 557–570 [less ▲]

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See detailNanoparticles and microorganisms applied in groundwater decontamination
Lambert, Stéphanie ULg; Lavigne, Benoît

Conference (2016, May 13)

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See detailTailoring γ-Al2O3 supports with specific silicon precursors
Claude, Vincent ULg; Vilaseca, Miriam; Heinrichs, Benoît ULg et al

Poster (2016, May 13)

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See detailPhotocatalytic decolorization of Gentian Violet with Na-doped (SnO2 and ZnO)
Benhebal, Hadj; Chaib, Messaoud; Crine, Michel ULg et al

in Chiang Mai Journal of Sciences (2016), 42

Photocatalysis is a technique used for the purification and decolorization of water. In this work, the photocatalytic decolorization of aqueous solutions of Gentian Violet has been investigated. The ... [more ▼]

Photocatalysis is a technique used for the purification and decolorization of water. In this work, the photocatalytic decolorization of aqueous solutions of Gentian Violet has been investigated. The photocatalysts used for the study are tin dioxide (SnO2) and zinc oxide (ZnO) doped with sodium and prepared by sol-gel process. Photocatalysts were synthesised by sol-gel process and characterized by several techniques such as X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer, Emmett and Teller (BET) method and UV-vis Spectroscopy. The results of photocatalytic activity of gentian violet degradation under ultraviolet irradiation, indicated that the synthesised photocatalyst exhibit good photocatalytic performance. [less ▲]

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See detailInfluences of the aqueous synthesis way and organosilane nature on the physico-chemical properties of porous alumina
Claude, Vincent ULg; Vilaseca, Miriam; Tatton, Andrew ULg et al

in European Journal of Inorganic Chemistry (2016), 2016(11), 1678-1689

The aqueous sol-gel synthesis of γ-Al2O3 modified with different silicon precursors {trimethoxysilane, triethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylene diamine} has been investigated. Two ... [more ▼]

The aqueous sol-gel synthesis of γ-Al2O3 modified with different silicon precursors {trimethoxysilane, triethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylene diamine} has been investigated. Two parameters have been studied: the silicon addition step and the type of silicon alkoxide. A first observation was that adding a silicon alkoxide either before or just after the precipitation step influences both the crystallinity and structure, whereas adding the alkoxide after a long agitation time only slightly modifies the support properties. It was also highlighted that due to their higher reactivity, silicon precursors with methoxy groups interact more strongly with the bulk alumina than the silicon precursors with ethoxy groups. This difference of Si location in the alumina structure permitted not only their resistance toward phase transition to be increased at high temperature, but also to stabilize them more efficiently against sintering under normal and steam conditions. Among the different silicon alkoxides tested, samples prepared with N-[3-(trimethoxysilyl)propyl]ethylene diamine showed very unusual properties. The alumina supports modified with this precursor showed grain-shaped nanocrystallites, whereas all other samples were platelet-like. As a result, this sample presented a very narrow pore diameter distribution of around 5 nm and a remarkably high specific surface area (530 m2/g). [less ▲]

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See detailEfficient P- and Ag-doped titania for the photocatalytic degradation of waste water organic pollutants
Bodson, Céline ULg; Heinrichs, Benoît ULg; Tasseroul, Ludivine ULg et al

in Journal of Alloys & Compounds (2016), 682

In this work, physico-chemical properties and photocatalytic activity of three types of dried or dried and calcined TiO2 materials, synthesized by the cogelation method, were studied: (i) a pure TiO2 ... [more ▼]

In this work, physico-chemical properties and photocatalytic activity of three types of dried or dried and calcined TiO2 materials, synthesized by the cogelation method, were studied: (i) a pure TiO2 xerogel ; (ii) TiO2 xerogels doped with Ag ; (iii) TiO2 xerogels co-doped with Ag and P. The presence of silver nanoparticles was observed by transmission electron microscopy (TEM) and the oxidation state of silver after calcination was examined by temperature-programmed reduction (TPR) measurements. The physico-chemical properties of xerogels were characterized by X-ray diffraction (XRD), diffuse reflectance UV-Vis spectroscopy (DR UV-Vis) and from nitrogen adsorption-desorption isotherms. The photocatalytic activity of the samples was quantified for the p-nitrophenol degradation under visible light. [less ▲]

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See detailFe3+/Iron Oxide/SiO2 Xerogel Catalysts for p-nitrophenol Degradation by Photo-Fenton Effects: Influence of Thermal Treatment on Catalysts Texture
Mahy, Julien ULg; Tasseroul, Ludivine ULg; Herlitscke, Marcus et al

in Materials Today: Proceedings (2016), 3(2), 464-469

Three iron xerogel catalysts were synthesized by hydrolysis and condensation of tetraethoxysilane (TEOS) and 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS) which is able to form a chelate with iron ... [more ▼]

Three iron xerogel catalysts were synthesized by hydrolysis and condensation of tetraethoxysilane (TEOS) and 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS) which is able to form a chelate with iron ions. Four thermal treatments were applied to catalysts: drying, drying-autoclaving, calcination and calcination-autoclaving. Textural characterizations show that the specific surface area is increased by calcination while materials microporosity completely collapse when using autoclaving. Based on Mössbauer spectroscopy and magnetometry measurements, only Fe3+ species were observed in xerogel catalysts. The photo-Fenton effect of these catalysts was evaluated on the degradation of p-nitrophenol in aqueous media. In the presence of H2O2, results show that this effect reachs 99% of degradation after 24 h. Mössbauer and catalytic tests are presented in another paper. [less ▲]

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See detailDoped sol–gel films vs. powders TiO2: On the positive effect induced by the presence of a substrate
Léonard, Géraldine ULg; Malengreaux, Charline; Melotte, Quentin et al

in Journal of Environmental Chemical Engineering (2016), 4

SiO2 and Ag–SiO2 doped TiO2 films and powders have been produced using a controlled sol–gel process. The dopant has been introduced using an alkoxysilane-functionalized ligand, with or without complexed ... [more ▼]

SiO2 and Ag–SiO2 doped TiO2 films and powders have been produced using a controlled sol–gel process. The dopant has been introduced using an alkoxysilane-functionalized ligand, with or without complexed silver ions. The influence of dopants on physico-chemical properties of the catalysts is studied by XRD, TEM–EDX, DRUV–vis analyses in the case of powders, while GIXRD, XPS, profilometry, UV–vis absorption analyses have been used for thin films. The photocatalytic activity has been evaluated from the degradation of methylene blue under UV-A light in the presence of the different catalysts over a period of 24 h. The detailed comparison between powders and films highlights a surprising positive effect in the case of films due to the presence of the substrate. In the case of photocatalytic powders, the presence of SiO2 or Ag–SiO2 into the TiO2 matrix has a detrimental effect on the photocatalytic activity while the opposite tendency is observed in the case of films, with best activities obtained with Ag–SiO2 doping. Different factors, in particular crystallinity modification between powders and films, have been studied to explain these opposite behaviors. In the case of powders, crystallization is hindered by SiO2 and Ag particles incorporation into the TiO2 matrix, leading to a decrease of the photocatalytic activity. In the case of thin films, probably because of the presence of a substrate, crystallization is not influenced by the presence of SiO2 and Ag particles. Therefore, the latter ones can fully play their role of electron traps leading to an enhanced photocatalytic activity. [less ▲]

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See detailPhotocatalytic decomposition of hydrogen peroxide over nanoparticles of TiO2 and Ni(II)-porphyrin doped TiO2: a relationship between activity and porphyrin anchoring mode
Tasseroul, Ludivine ULg; Pàez Martinez, Carlos ULg; Lambert, Stéphanie ULg et al

in Applied Catalysis B : Environmental (2016), 182

The nickel tetra(4-carboxyphenyl)porphyrin (TCPPNi) was chimisorbed on Degussa P25 TiO2 at different concentrations. Diffuse reflectance spectroscopy in the UV/vis region, Fourier transform infrared ... [more ▼]

The nickel tetra(4-carboxyphenyl)porphyrin (TCPPNi) was chimisorbed on Degussa P25 TiO2 at different concentrations. Diffuse reflectance spectroscopy in the UV/vis region, Fourier transform infrared spectroscopy and thermal gravimetry combined with differential scanning calorimetry measurements allowed the determination of the TCPPNi anchoring mode. At low TCPPNi concentrations, this anchoring on Degussa P25 TiO2 took place through all four carboxylic groups, while at higher concentrations the anchoring occurred through one or two carboxylic groups. For the firsttime,the effect of UV/vis light irradiation on the H2O2-degradation activity of TiO2 and TCPPNi-doped TiO2 was studied using the method of following the production of O2 by gas pressure monitoring. The activity of seven different catalysts was related to the TCPPNi anchoring mode and the percentage of TiO2 Degussa P25 coverage. An optimum degradation of H2O2 was observed for 0.0115 mol TCPPNi × g−1 P25. In that case, the TCPPNi was anchored through the four carboxylic groups, corresponding to a strong interaction with Degussa P25 TiO2. Moreover, the TCPPNi did not cover the surface completely, therefore allowing the light to reach and activate the TiO2. [less ▲]

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See detailEffet du taux de dopage sur l'activité photocatalytique de ZnO dopé par les métaux alcalins
Benhebal, Hadj; Benrabah, Boulem; Léonard, Angélique ULg et al

Conference (2015, October 16)

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See detailDegradation of p-nitrophenol and bacteria with TiO2 xerogels sensitized in situ with tetra(4-carboxyphenyl)porphyrins
Tasseroul, Ludivine ULg; Lambert, Stéphanie ULg; Eskenazi, David et al

Poster (2015, September 10)

Heterogeneous photocatalysis is widely studied for environmental applications as oxidative processes can completely destroy organic pollutants such as alkanes, pesticides, dyes, etc. and microorganisms ... [more ▼]

Heterogeneous photocatalysis is widely studied for environmental applications as oxidative processes can completely destroy organic pollutants such as alkanes, pesticides, dyes, etc. and microorganisms. The most used photocatalyst is the commercial TiO2 Degussa P25, which is composed of 80% anatase and 20% rutile and which is active when TiO2 is exposed to UV light ( < 380 nm). Recently, several studies have been performed to extend the light absorption range of TiO2 towards the visible range. In this study, TiO2-based materials doped with porphyrins, a widely used dye for the photosensibilization of TiO2, have been prepared using a sol-gel process. To stabilize the TiO2-dye interactions, free metal tetra(4-carboxyphenyl)porphyrin and nickel tetra(4-carboxyphenyl)porphyrin were introduced in situ into the TiO2 matrix during the sol-gel process rather than by grafting. Samples were thoroughly characterized by TEM, X-ray diffraction, FT-IR, DR-UV/Vis and their texture has been examined by nitrogen adsorption–desorption at 77 K. The photocatalytic activity for the degradation of p-nitrophenol and Escherichia coli and Lactobacillus rhamnosus bacteria cells in aqueous medium, under halogen lamp light have been evaluated in relation with the physico-chemical modifications induced by the doping. The low temperature vacuum drying protocol (150°C) used in the present study enabled to obtain porphyrin doped TiO2 xerogels with a high specific surface area, and containing nanoparticles composed of amorphous- and anatase-TiO2. Diffuse reflectance spectroscopy attest the presence of TCPPH2 and TCPPNi within the TiO2 matrix. In a first step, the photoactivity of the xerogels is tested for p-nitrophenol degradation. Results show that crystallinity and nature and concentration of porphyrin introduced in situ have major impact on the degradation performances. In a second step, the best xerogel for p-nitrophenol degradation has been used to degrade bacteria. This xerogel degrades E. coli and L. rhamnosus bacteria cells in less than 48 and 24 h respectively. The photocatalytic degradation of a pollutant is thus correlated to the degradation of bacteria since a xerogel doped with the TCPPNi degrades both p-nitrophenol, E. coli and L. rhamnosus. [less ▲]

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See detailEthylene polymerization mediated by nickel(II) covalently anchored to silica xerogels
Lambert, Stéphanie ULg; Sacco, Luigi

Conference (2015, September 08)

Heterogeneous catalysis is generally widely preferred for industrial applications thanks to the well-known advantages of easier product-catalyst separation and recovery of the catalyst process and, often ... [more ▼]

Heterogeneous catalysis is generally widely preferred for industrial applications thanks to the well-known advantages of easier product-catalyst separation and recovery of the catalyst process and, often, to the enhanced stability of the catalyst. But in terms of selectivity, homogeneous catalysis usually provides better results. From this point of view, the grafting of homogeneous catalysts onto a solid support seems the ideal combination in order to achieve the advantages of both heterogeneous and homogeneous catalysis, allowing the developing of more environmentally friendly and economical processes with potential application in the industry. Further, to covalently link a homogeneous onto silica (a support which is thermally, chemically and mechanically resistant, with a well defined structure) is the best way to limit metal leaching and sintering. Nitrogen-based ligands containing one of several Schiff bases have been reported to form active catalysts with “late-metal” (such as Fe, Pd, Ni,…) for the ethylene polymerization [1]. Moreover, substituted pyrazole-based organometallic complexes gave also promising results in this field. These facts let us suggest that the pyrazolylpyridine derivatives bearing a tethered trimethoxysilylated group synthesized in a previous work [2] are potentially good candidate to prepare hybrid catalyst (i.e. soluble organometallic complexes covalently bonded onto an insoluble support, in this case silica) with Ni-II, Fe-II or Pd-II for ethylene polymerization. [less ▲]

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See detailTailoring γ-Al2O3 supports with specific silicon precursors
Claude, Vincent ULg; Vilaseca, Miriam; Lambert, Stéphanie ULg

Poster (2015, September)

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