Charlotte Hurel - Academia.edu (original) (raw)

Papers by Charlotte Hurel

MRS Proceedings, 2006

ABSTRACTSorption processes have been largely studied and modelled by considering single mineral s... more ABSTRACTSorption processes have been largely studied and modelled by considering single mineral surfaces (iron oxides, clay etc). In the case of a complex surface such as claystone, it seems important to be able to predict the behaviour of the radioactive elements in contact with the natural site. The modelling part becomes very complex if the whole minerals composing the geological media have to be taken into account. In that way, this study aims at testing various mineral mixtures, to identify the most reactive phase controlling the adsorption processes, in order to get a “simplified” system for a model calculation. Various mineral assemblages (goethite, pyrite, calcite and montmorillonite) were studied here, in contact with an anionic specie (selenium). Experiments were carried out using single, binary, ternary or quaternary solid mixtures, in order to evaluate the major reactive mineral phase. A surface complexation model was then considered to fit the experimental data. Stoichiometries and constants were extracted using FITEQL by fitting experimental results obtained on single solid in NaNO3, and used in a predictive calculation with PHREEQC for mixtures in synthetic grounwater. By doing this, we wanted to verify if the assumption that surface reactivity of single minerals keeps the same in a different environment can be used for predictive calculations.Results obtained have shown that the presence of calcite and pyrite does not influence the total amount of selenium adsorbed. Then a simplified model was proposed, taking into account only the major phase responsible for the sorption of Se.

Journal of African Earth Sciences, Jun 1, 2019

The aim of the present work was to study the application of natural clays to remove a cationic dy... more The aim of the present work was to study the application of natural clays to remove a cationic dye (methylene blue (MB) chosen as a pollutant model) from wastewater. Rhassoul-clay and Red clay investigated in this study were extracted from two different sites in Morocco. These clays have different swelling properties. A comparison of their affinity towards cationic dye help to understand the limiting factors controlling the adsorption process. Rhassoul clay and Red clay were characterized using powder X-ray diffraction, Scanning Electron Microscopy, Xray Fluorescence spectroscopy and surface area measurement (BET). The adsorption capacities of the solids were measured using batch sorption studies as a function of contact time, pH, temperature and initial concentration. Pseudo-second-order model and intraparticle diffusion model were applicables to describe the MB adsorption on both adsorbents. Langmuir and Freundlich isotherms were employed to determine adsorption mechanism. According to the results, the Langmuir model was more suitable to describe MB adsorption on both adsorbents. The maximum monolayer adsorption evaluated with this model is 166.7 mg g −1 and 18.7 mg g −1 for Rhassoulclay and Red clay, respectively. The temperature exhibited a positive effect on MB adsorption. According to Gibbs energy and enthalpy, the adsorption process was spontaneous and endothermic for both clays, but was more favorable for Rhassoul clay. Hence, Rhassoul clay exhibits much higher adsorption capacity than Red clay. The both clays studied could be potentially used for the removal of cationic dye from wastewater.

HAL (Le Centre pour la Communication Scientifique Directe), Sep 8, 2016

Journal of Applied Physics, Feb 21, 2023

Arsenic is one of the most toxic elements present in the environment, especially in water. The Wo... more Arsenic is one of the most toxic elements present in the environment, especially in water. The World Health Organization (WHO) recommends a maximum concentration of arsenic in drinkable water of 10 µg/L (10 ppb). Sensors implementing Surface Enhanced Raman Scattering (SERS) can detect chemical species at low concentrations. The aim of this study is to compare two kinds of silver-coated SERS substrates for detection and speciation of trace, trivalent and pentavalent, inorganic arsenic compounds. One type of substrates was prepared by a classical thermal evaporation technique, the second type by an electroless process. The thermally evaporated substrates allowed the detection of As(III) only, at a limit of detection (LOD) of approximately 50 mg/L, whereas As(V) could not be detected at any analyte concentration. The electroless substrates allow to differentiate As(III) and As(V) with a LOD 1 µg/L (1 ppb) equal for each valency, below WHO recommendation. The electroless substrates show a very large sensitivity across up to five orders of magnitude in terms of analyte concentration. Although the SERS intensity shows a nonlinear behaviour over this range of concentrations, these preliminary results are encouraging in the framework of the demonstration of trace As SERS sensors in drinkable water.

Radiochimica Acta, Sep 1, 2002

Summary Sorption of elements like Cs on clay is one of the principal processes delaying their rel... more Summary Sorption of elements like Cs on clay is one of the principal processes delaying their release from deep repositories of nuclear wastes into the environment. The sorption processes taking place between non-purified natural clay material (bentonite) and synthetic groundwater (containing Ca, Mg, Na, K and carbonates) were therefore studied experimentally and modelled for Cs to determine whether thermodynamic computer codes capable of predicting the behaviour of this element in natural systems might be developed. The model used, based on the properties of a pure montmorillonite phase, incorporates the surface reactions for natural major ions and sorbing cations but does not have any adjustable parameters. The weight of each parameters used in the model is assessed. Surface reactions are classified as either major or minor, and a simplified model of Cs sorption that considers only the major processes is proposed. This simplified model might correspond to the less sophisticated thermodynamic model included in coupled geochemistry-transport models.

Biomass Conversion and Biorefinery, Mar 31, 2023

Biomass Conversion and Biorefinery, Oct 15, 2022

HAL (Le Centre pour la Communication Scientifique Directe), Nov 1, 2018

Water purification with magnetic nanoparticles 2 Advantage of nano before micro  increased speci... more Water purification with magnetic nanoparticles 2 Advantage of nano before micro  increased specific area Colloidal scale: charged colloid Pollutant molecule Molecular scale: SIROFLOC process

The effect of pH and temperature on the thermodynamics of selenium sorption on alumina and montmo... more The effect of pH and temperature on the thermodynamics of selenium sorption on alumina and montmorillonite was investigated. The equilibrium constants were obtained from batch experiments carried out at 25 and 40°C, under acidic and near to neutral conditions. Microcalorimetry was used to measure directly the enthalpy change upon sorption. These data were analysed by taking into account the different reactions that occur during the sorption process (the acid-base equilibria in the bulk solution on the one hand and the complexation equilibria between surface sites of the solid and solution species on the other hand). This was done using a simple surface model which assumes that the thermodynamic properties of the aluminol surface sites of both alumina and montmorillonite are identical. Two of the considered reactions were found to predominate, one under acidic conditions and one at near neutral pH. The microcalorimetric data allowed to check that the temperature effect on selenium sorption on alumina and montmorillonite can be correctly predicted simply using the above assumption concerning the sorption sites and by applying van't Hoff relation both to the homogeneous and heterogeneous reactions.

HAL (Le Centre pour la Communication Scientifique Directe), Nov 2, 2021

HAL (Le Centre pour la Communication Scientifique Directe), Nov 2, 2021

Research Square (Research Square), May 16, 2022

Lavandin hydrochars obtained by hydrothermal carbonization (HTC) of Lavandula distilled straw (LD... more Lavandin hydrochars obtained by hydrothermal carbonization (HTC) of Lavandula distilled straw (LDS) have been studied as an eco-friendly and economical valorization route of residual biomass from cosmetic industry into solid fuels. The critical parameters of the HTC process (temperature and retention time) were normalized to severity factor (SF). Proximate and ultimate analysis, microscopy and thermal analysis were used to characterize hydrochars surface, combustion behavior and kinetics as a function of SF, and to compare them with those of the raw lavandin sample. Results showed that preparation of lavandin hydrochars in temperature and retention time conditions providing SF close to 6 seemed to be the best compromise since under these conditions, the combustion performance of the hydrochar was close to the bituminous coal and lignite.

HAL (Le Centre pour la Communication Scientifique Directe), Nov 5, 2018

Arsenic (As) is one of the most toxic contaminants found in the environment and especially in wat... more Arsenic (As) is one of the most toxic contaminants found in the environment and especially in water. The World Health Organization decrees an As concentration less than 10 µg/L (10ppb). Established laboratory method is mass spectrometry. This technique is costly and timeintensive [1]. Other methods for As detection in water are in state of research (biosensor, electrochemical sensor, Surface Enhanced Raman Scattering sensor) (Figure1) SERS sensors are known for their high sensitivity for chemical compounds detection like pesticides [2]. In this study, we compare two kinds of silver (Ag) SERS substrates differentiating by their elaboration process. Figure 2 shows SERS results of As detection at a concentration of 10 ppb obtained with substrates made by an electroless process. Bands at 730 cm-1 and 830 cm-1 are the signature of the symmetric stretching vibrations As-O for As(3) and As(5) respectively [3] [4]. Uptake of As in water by nanostructured Ag films is discussed. Fig 2: SERS spectra of As(3) and As(5) on SERS substrates made by an electroless process

Waste and Biomass Valorization

HAL (Le Centre pour la Communication Scientifique Directe), Sep 4, 2016

HAL (Le Centre pour la Communication Scientifique Directe), Aug 23, 2021

HAL (Le Centre pour la Communication Scientifique Directe), 2019

HAL (Le Centre pour la Communication Scientifique Directe), Sep 10, 2018

Water-Rock Interaction, 2007

MRS Proceedings, 2006

ABSTRACTSorption processes have been largely studied and modelled by considering single mineral s... more ABSTRACTSorption processes have been largely studied and modelled by considering single mineral surfaces (iron oxides, clay etc). In the case of a complex surface such as claystone, it seems important to be able to predict the behaviour of the radioactive elements in contact with the natural site. The modelling part becomes very complex if the whole minerals composing the geological media have to be taken into account. In that way, this study aims at testing various mineral mixtures, to identify the most reactive phase controlling the adsorption processes, in order to get a “simplified” system for a model calculation. Various mineral assemblages (goethite, pyrite, calcite and montmorillonite) were studied here, in contact with an anionic specie (selenium). Experiments were carried out using single, binary, ternary or quaternary solid mixtures, in order to evaluate the major reactive mineral phase. A surface complexation model was then considered to fit the experimental data. Stoichiometries and constants were extracted using FITEQL by fitting experimental results obtained on single solid in NaNO3, and used in a predictive calculation with PHREEQC for mixtures in synthetic grounwater. By doing this, we wanted to verify if the assumption that surface reactivity of single minerals keeps the same in a different environment can be used for predictive calculations.Results obtained have shown that the presence of calcite and pyrite does not influence the total amount of selenium adsorbed. Then a simplified model was proposed, taking into account only the major phase responsible for the sorption of Se.

Journal of African Earth Sciences, Jun 1, 2019

The aim of the present work was to study the application of natural clays to remove a cationic dy... more The aim of the present work was to study the application of natural clays to remove a cationic dye (methylene blue (MB) chosen as a pollutant model) from wastewater. Rhassoul-clay and Red clay investigated in this study were extracted from two different sites in Morocco. These clays have different swelling properties. A comparison of their affinity towards cationic dye help to understand the limiting factors controlling the adsorption process. Rhassoul clay and Red clay were characterized using powder X-ray diffraction, Scanning Electron Microscopy, Xray Fluorescence spectroscopy and surface area measurement (BET). The adsorption capacities of the solids were measured using batch sorption studies as a function of contact time, pH, temperature and initial concentration. Pseudo-second-order model and intraparticle diffusion model were applicables to describe the MB adsorption on both adsorbents. Langmuir and Freundlich isotherms were employed to determine adsorption mechanism. According to the results, the Langmuir model was more suitable to describe MB adsorption on both adsorbents. The maximum monolayer adsorption evaluated with this model is 166.7 mg g −1 and 18.7 mg g −1 for Rhassoulclay and Red clay, respectively. The temperature exhibited a positive effect on MB adsorption. According to Gibbs energy and enthalpy, the adsorption process was spontaneous and endothermic for both clays, but was more favorable for Rhassoul clay. Hence, Rhassoul clay exhibits much higher adsorption capacity than Red clay. The both clays studied could be potentially used for the removal of cationic dye from wastewater.

HAL (Le Centre pour la Communication Scientifique Directe), Sep 8, 2016

Journal of Applied Physics, Feb 21, 2023

Arsenic is one of the most toxic elements present in the environment, especially in water. The Wo... more Arsenic is one of the most toxic elements present in the environment, especially in water. The World Health Organization (WHO) recommends a maximum concentration of arsenic in drinkable water of 10 µg/L (10 ppb). Sensors implementing Surface Enhanced Raman Scattering (SERS) can detect chemical species at low concentrations. The aim of this study is to compare two kinds of silver-coated SERS substrates for detection and speciation of trace, trivalent and pentavalent, inorganic arsenic compounds. One type of substrates was prepared by a classical thermal evaporation technique, the second type by an electroless process. The thermally evaporated substrates allowed the detection of As(III) only, at a limit of detection (LOD) of approximately 50 mg/L, whereas As(V) could not be detected at any analyte concentration. The electroless substrates allow to differentiate As(III) and As(V) with a LOD 1 µg/L (1 ppb) equal for each valency, below WHO recommendation. The electroless substrates show a very large sensitivity across up to five orders of magnitude in terms of analyte concentration. Although the SERS intensity shows a nonlinear behaviour over this range of concentrations, these preliminary results are encouraging in the framework of the demonstration of trace As SERS sensors in drinkable water.

Radiochimica Acta, Sep 1, 2002

Summary Sorption of elements like Cs on clay is one of the principal processes delaying their rel... more Summary Sorption of elements like Cs on clay is one of the principal processes delaying their release from deep repositories of nuclear wastes into the environment. The sorption processes taking place between non-purified natural clay material (bentonite) and synthetic groundwater (containing Ca, Mg, Na, K and carbonates) were therefore studied experimentally and modelled for Cs to determine whether thermodynamic computer codes capable of predicting the behaviour of this element in natural systems might be developed. The model used, based on the properties of a pure montmorillonite phase, incorporates the surface reactions for natural major ions and sorbing cations but does not have any adjustable parameters. The weight of each parameters used in the model is assessed. Surface reactions are classified as either major or minor, and a simplified model of Cs sorption that considers only the major processes is proposed. This simplified model might correspond to the less sophisticated thermodynamic model included in coupled geochemistry-transport models.

Biomass Conversion and Biorefinery, Mar 31, 2023

Biomass Conversion and Biorefinery, Oct 15, 2022

HAL (Le Centre pour la Communication Scientifique Directe), Nov 1, 2018

Water purification with magnetic nanoparticles 2 Advantage of nano before micro  increased speci... more Water purification with magnetic nanoparticles 2 Advantage of nano before micro  increased specific area Colloidal scale: charged colloid Pollutant molecule Molecular scale: SIROFLOC process

The effect of pH and temperature on the thermodynamics of selenium sorption on alumina and montmo... more The effect of pH and temperature on the thermodynamics of selenium sorption on alumina and montmorillonite was investigated. The equilibrium constants were obtained from batch experiments carried out at 25 and 40°C, under acidic and near to neutral conditions. Microcalorimetry was used to measure directly the enthalpy change upon sorption. These data were analysed by taking into account the different reactions that occur during the sorption process (the acid-base equilibria in the bulk solution on the one hand and the complexation equilibria between surface sites of the solid and solution species on the other hand). This was done using a simple surface model which assumes that the thermodynamic properties of the aluminol surface sites of both alumina and montmorillonite are identical. Two of the considered reactions were found to predominate, one under acidic conditions and one at near neutral pH. The microcalorimetric data allowed to check that the temperature effect on selenium sorption on alumina and montmorillonite can be correctly predicted simply using the above assumption concerning the sorption sites and by applying van't Hoff relation both to the homogeneous and heterogeneous reactions.

HAL (Le Centre pour la Communication Scientifique Directe), Nov 2, 2021

HAL (Le Centre pour la Communication Scientifique Directe), Nov 2, 2021

Research Square (Research Square), May 16, 2022

Lavandin hydrochars obtained by hydrothermal carbonization (HTC) of Lavandula distilled straw (LD... more Lavandin hydrochars obtained by hydrothermal carbonization (HTC) of Lavandula distilled straw (LDS) have been studied as an eco-friendly and economical valorization route of residual biomass from cosmetic industry into solid fuels. The critical parameters of the HTC process (temperature and retention time) were normalized to severity factor (SF). Proximate and ultimate analysis, microscopy and thermal analysis were used to characterize hydrochars surface, combustion behavior and kinetics as a function of SF, and to compare them with those of the raw lavandin sample. Results showed that preparation of lavandin hydrochars in temperature and retention time conditions providing SF close to 6 seemed to be the best compromise since under these conditions, the combustion performance of the hydrochar was close to the bituminous coal and lignite.

HAL (Le Centre pour la Communication Scientifique Directe), Nov 5, 2018

Arsenic (As) is one of the most toxic contaminants found in the environment and especially in wat... more Arsenic (As) is one of the most toxic contaminants found in the environment and especially in water. The World Health Organization decrees an As concentration less than 10 µg/L (10ppb). Established laboratory method is mass spectrometry. This technique is costly and timeintensive [1]. Other methods for As detection in water are in state of research (biosensor, electrochemical sensor, Surface Enhanced Raman Scattering sensor) (Figure1) SERS sensors are known for their high sensitivity for chemical compounds detection like pesticides [2]. In this study, we compare two kinds of silver (Ag) SERS substrates differentiating by their elaboration process. Figure 2 shows SERS results of As detection at a concentration of 10 ppb obtained with substrates made by an electroless process. Bands at 730 cm-1 and 830 cm-1 are the signature of the symmetric stretching vibrations As-O for As(3) and As(5) respectively [3] [4]. Uptake of As in water by nanostructured Ag films is discussed. Fig 2: SERS spectra of As(3) and As(5) on SERS substrates made by an electroless process

Waste and Biomass Valorization

HAL (Le Centre pour la Communication Scientifique Directe), Sep 4, 2016

HAL (Le Centre pour la Communication Scientifique Directe), Aug 23, 2021

HAL (Le Centre pour la Communication Scientifique Directe), 2019

HAL (Le Centre pour la Communication Scientifique Directe), Sep 10, 2018

Water-Rock Interaction, 2007