Nadine Mofaddel | Rouen University (original) (raw)

Papers by Nadine Mofaddel

Research paper thumbnail of L'analyse des acides gras en électrophorèse capillaire

Research paper thumbnail of Contribution à l'étude de systèmes quaternaires : exploitation de sulfates alcalins et dédoublement de molécules chirales par formation de diastéréoisomères

Dans le cadre de la determination des domaines de cristallisation d'especes definies dans un ... more Dans le cadre de la determination des domaines de cristallisation d'especes definies dans un systeme d'ordre eleve, deux systemes quaternaires sont etudies. Le premier systeme est Na2So4 - K2SO4 – (NH4)2SO4 – H2O : l'isotherme 18°C est dresse, definissant les domaines de stabilite des differentes phases rencontrees. Le deuxieme systeme est le systeme reciproque: l'isotherme 20°C montre la possibilite de dedoublement d'un compose racemique. Une etude critique des travaux anterieurs est apportee

Research paper thumbnail of A new example of reversal of the order of migration of enantiomers, as a function of cyclodextrin concentration and pH, by cyclodextrin-modified capillary zone electrophoresis: enantioseparation of 6,6′-dibromo-1,1′-binaphthyl-2,2′-diol

Analytical and Bioanalytical Chemistry, Jul 17, 2009

Enantioseparation of 6,6′-dibromo-1,1′-binaphthyl-2,2′-diol (DBBD) by cyclodextrin-modified capil... more Enantioseparation of 6,6′-dibromo-1,1′-binaphthyl-2,2′-diol (DBBD) by cyclodextrin-modified capillary zone electrophoresis (CD-CZE) was studied using the three native α, β, and γ cyclodextrins, the three hydroxypropylated cyclodextrins (2-hydroxypropyl-α, β, and γ), heptakis-2,6di-O-methyl-β-CD (DM-β-CD), and heptakis-2,3,6-tri-Omethyl-β-cyclodextrin (TM-β-CD). First, the acidity constants of DBBD were determined using capillary electrophoresis, before performing enantioseparation. The influence of the concentrations of the studied cyclodextrins on the enantioseparation was explored and the experimental optimal concentrations were determined and compared to the theoretical optimal concentrations. Moreover, the apparent complexation constants between each studied cyclodextrin and the two DBBD enantiomers were evaluated using a non-linear curve fitting method and three linear plotting methods (x-reciprocal, y-reciprocal and double reciprocal). For TM-β-CD, the order of migration of the enantiomers of DBBD reversed as a function of TM-β-CD concentration. The influence of the nature of methylated cyclodextrin derivatives (methyl-β-CD (M-β-CD) and DM-β-CD) was then studied. Inversion of the order of migration of the enantiomers of DBBD was observed for DM-β-CD, whereas the S enantiomer of DBBD always migrated first for M-β-CD.

Research paper thumbnail of Mise en oeuvre du couplage CE / ESI / MS et exemples d’application

HAL (Le Centre pour la Communication Scientifique Directe), May 1, 2000

International audienc

Research paper thumbnail of Apport des plans d’expériences en Electrophorèse Capillaire: exemple de l’optimisation de la sensibilité en détection fluorimétrique indirecte

HAL (Le Centre pour la Communication Scientifique Directe), Mar 1, 1999

International audienc

Research paper thumbnail of Analysis of non ionic polyoxyethylenic surfactants by NACE / ESI / MS coupling

HAL (Le Centre pour la Communication Scientifique Directe), Feb 1, 2000

International audienc

Research paper thumbnail of Détermination de points isoélectriques élevés par Electrophorèse Capillaire de Zone

HAL (Le Centre pour la Communication Scientifique Directe), Mar 1, 1999

International audienc

Research paper thumbnail of Enantioseparation of binaphthol and its mono derivatives by cyclodextrin-modified capillary zone electrophoresis

Journal of Chromatography A, Nov 1, 2008

Chiral binaphthols belong to the group of most effective ligands for asymmetrical catalysis. In t... more Chiral binaphthols belong to the group of most effective ligands for asymmetrical catalysis. In this context, various binaphthols presenting original substituents have been synthesized. Their study through capillary electrophoresis is the object of this work. The literature dedicated to the separation of atropisomers by capillary electrophoresis, corresponding only to binaphthol, reveals that its enantioseparation is always delicate because of the influence of many factors and the resolutions obtained are weak. Therefore, for a structured optimization, we first successfully evaluated the acidity constants of different binaphthols by means of capillary electrophoresis. With these known physicochemical characteristics, we could successfully carry out enantiomeric separations of the different binaphthols at pH=11.5, practically in completely ionized form, in phosphate medium, and in the presence of cyclodextrin (CD), with analysis times lower than 8 minutes. The nature of CDs (α-CD, β-CD, γ-CD, hydroxypropyl-α-cyclodextrin (HP-α-CD), HP-β-CD, HP-γ-CD and trimethyl-β-CD (TM-β-CD)) and other factors in relation to enantiomeric resolution (applied voltage, nature and concentration of the electrolyte, and concentration of cyclodextrin) were optimized. These studies allowed us to determine the optimal conditions of separation (concentration and nature of CD) for each of the studied binaphthols. It is necessary to mention that, for the 1,1'binaphthyl-2,2'-diol (Binol) at pH=11.5, the S atropisomer always migrated first, regardless of the nature and concentration of the cyclodextrin used. Moreover, an inversion in elution order of the two atropisomers as a function of pH was observed with γ-CD (pH range: 10-11.5). The R atropisomer migrated first at pH=10. At pH=10.8 the migration order of the two

Research paper thumbnail of Optimisation de la détection fluorimétrique indirecte en Chromatographie ElectroCinétique Micellaire en utilisant la fluorescéine comme agent de visualisation

HAL (Le Centre pour la Communication Scientifique Directe), May 1, 1997

International audienc

Research paper thumbnail of Électrophorèse Capillaire en Milieu Non Aqueux

Analusis, Mar 1, 1999

The utilisation of Capillary Electrophoresis in hydroorganic and organic media is gradually incre... more The utilisation of Capillary Electrophoresis in hydroorganic and organic media is gradually increasing since fifteen years. The influence of the physicochemical properties of ten organic solvents on the fundamental parameters commanding an electrophoretic separation, i.e. current efficiency, analysis time, resolution, is considered. The use of non aqueous media offers new attractive possibilities for the analysis of hydrophobic compounds by Capillary Electrophoresis. The choice of convenient solvent allows an easier optimisation of selectivity, particularly in the case of chiral compounds. At last, non aqueous Capillary Electrophoresis appears as a choice technique for the study of interactions in solution.

Research paper thumbnail of New analytical strategies to evaluate bioavailability of polycyclic aromatic hydrocarbons (PAH) in dissimilar soils

HAL (Le Centre pour la Communication Scientifique Directe), Jun 12, 2012

National audiencePolycyclic Aromatic Hydrocarbons (PAHs) are carcinogenic molecules mainly produc... more National audiencePolycyclic Aromatic Hydrocarbons (PAHs) are carcinogenic molecules mainly produced by the incomplete combustion of organic matter and they are found in all parts of environment. Concerning the remediation of contaminated soils and sediments, only few methods exist to assess the bioavailability of PAHs for bacterial degradation and they are not well correlated to biodegradation in real soils; however, this assessment is necessary for an effective treatment of pollution.The aim of this study is to develop a simple and rapid method for evaluating PAHs bioavailability in polluted soils by the use of non-exhaustive extraction methods that would permit to extract only labile PAHs and not the sequestrated part of PAHs (strongly sorbed on organic matter or clays), part which is not bioavailable for degradation by microorganisms. Thus, several tests were performed on two spiked soils (meadow soil, Yvetot, France and Seine river soil, Petiville, France), using aqueous phase extractions containing original additives. We tested the hydroxypropyl-β-cyclodextrin (HPCD) (Gomez-Eyles et al., 2001; Swindell and Reid, 2006), or the butan-1-ol extraction (BuOH) (Liste & Alexander, 2001) which are the two reference methods for the evaluation of bioavailability of PAHs in soils. Other assays were performed with additives such as an ionic liquid 1-hexadecyl-3-methylimidazolium bromide (HDMIm Br), the turquey red oil (TRO) or the sodium lauryl sulfate (SDS), in order to have a panel of different additives with different molecular properties, especially micellisation properties. Results of these assays did not seem to be reliable to the bioavailability of PAHs in soils. Perspectives are to study degradation kinetics of PAHs in these soils on three months and to correlate the biodegradation efficiency to PAHs bioavailability, using other additives such as new cyclodextrins or ionic liquids which form micelles in aqueous media. Other studies are also in progress to find bacterial communities responsible for the PAH degradation (by using DNA-SIP and Bioscreen technics)

Research paper thumbnail of Deciphering the role of faujasite-type zeolites as a cation delivery platform to sustain the functions of MC3T3-E1 pre-osteoblastic cells

Materials advances, 2022

Please note that technical editing may introduce minor changes to the text and/or graphics, which... more Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal's standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains.

Research paper thumbnail of New analytical strategies to evaluate the bioavailable fraction of polycyclic aromatic hydrocarbons (PAHs) in dissimilar soils

HAL (Le Centre pour la Communication Scientifique Directe), Sep 9, 2012

International audienceDiffuse pollution of surface soils with polycyclic aromatic hydrocarbons (P... more International audienceDiffuse pollution of surface soils with polycyclic aromatic hydrocarbons (PAHs) is problematic in terms of health effects. Total PAH concentration in two different soils was assessed following an exhaustive extraction technique by MAE (microwave assisted extraction) using organic solvent mixtures. But it was demonstrated that the measure of contaminant exposure by this way is not appropriate to assess ecological risks. Moreover, it is well known that the effectiveness of in situ soil remediation processes (by degrading microorganisms) are constrained by low PAH bioavailability, due to their limited aqueous solubility and the magnitude of sorption on soils organic matter or clayey fine particles. The aim of this study was to evaluate different less exhaustive extraction methods in order to access the labile PAHs and to correlate them with bacterial degradation. Thus, aqueous-based extraction techniques using various original additives were performed. They were compared with butanol or-hydroxypropyl -cyclodextrin extractions, methods which were already described but that did not fit with our degradation tests or were too expensive. The new additives tested were original amphiphilic ionic liquids and a derivatized -cyclodextrin with micellization properties. Their critical micellar concentrations (cmc) were determined by a non-conventional method using capillary electrophoresis. These additives were introduced at 10 or 50 times their cmc in the extraction aqueous medium and time contact with soils was 24h. Desorbed PAHs, which were at trace levels, were quantified by HPLC (coupled to a fluorimetric detector) after a concentration step by SPE (solid phase extraction). Found labile PAHs were compared to PAH biodegradability (during three months) in the two studied soils in order to ensure that one of the new tested method could effectively predict the bioavailability of PAHs

Research paper thumbnail of Metal-inorganic-organic core–shell material as efficient matrices for CO2 adsorption: Synthesis, properties and kinetic studies

Journal of The Taiwan Institute of Chemical Engineers, Feb 1, 2019

A novel hydrochar-based core-shell material with improved affinity towards CO 2 was synthesized t... more A novel hydrochar-based core-shell material with improved affinity towards CO 2 was synthesized through encapsulation within ZnO shell, followed by chemical grafting to an organic moiety bearing terminal diethanolamino groups and further dispersion of Cu 0 nanoparticles. Characterization through nitrogen adsorption-desorption isotherms with BET and BJH models, SEM, TEM, zeta potential measurements, FTIR spectroscopy, DSC and XPS analyses revealed a strong influence of the modification procedure on the performance of each material in CO 2 adsorption. The resulting metal-inorganic-organic-core-shell (MIOCS) displayed compacted structure with a wide pore size distribution that imposes intraparticle diffusion as a kinetic-controlling step. Cu-MIOCS showed an appreciable CO 2 retention capacity of 5.42 mmol/g compared to many adsorbents reported so far. This affinity towards CO 2 was explained in terms of physical and non-stoichiometric CO 2 condensation. This finding is of great importance, because it demonstrates that judicious modifications of vegetal-deriving wastes such as woods and other biomasses give rise to added-value materials as low cost and efficient gas adsorbents with high affinity towards CO 2 .

Research paper thumbnail of Analytical strategies to evaluate polycyclic aromatic hydrocarbons (PAHs) bioavailability in soils; correlation with their biodegradability

HAL (Le Centre pour la Communication Scientifique Directe), Jun 24, 2013

Research paper thumbnail of Surface modification of biomaterials based on cocoa shell with improved nitrate and Cr(<scp>vi</scp>) removal

RSC Advances, 2020

The present work addresses the development of simple, low-cost and eco-friendly cocoa-shell-based... more The present work addresses the development of simple, low-cost and eco-friendly cocoa-shell-based materials for efficient removal of heavy metal hexavalent chromium (Cr(VI)), and toxic nitrate (NO 3 À) from aqueous solution. A conventional treatment process was used to purify cocoa shell (CS) into an adsorbent, followed by chemical grafting of dendrimers to promote its surface properties for nitrate and Cr(VI) removal. The morphology, surface charge, structure and stability of the new adsorbent were investigated by scanning electron microscopy, Fourier transform infrared and UV-visible spectroscopies, zeta potential, X-ray photoelectron spectrometry, and differential scanning calorimetry. The successful chemical grafting of the dendrimer (polyethyleneimine, PEI) onto purified CS was confirmed. CS-T-PEI-P proved to be a very efficient candidate for the removal of nitrate and chromium(VI). Removal of the two pollutants at different initial concentrations and pH values was studied and discussed. Sorption of chromium and nitrate was found to obey 2 nd-order kinetics and a Freundlich-type isotherm, affording an uptake adsorption of 16.92 mg g À1 for NO 3 À and 24.78 mg g À1 for Cr(VI). These results open promising prospects for its potential applications as a low cost catalyst in wastewater treatment.

Research paper thumbnail of Cocoa shell-deriving hydrochar modified through aminosilane grafting and cobalt particle dispersion as potential carbon dioxide adsorbent

Chemical Engineering Journal, Jun 1, 2018

This work was achieved to investigate the effect of both aminopropyltriethoxysilane (APTES) graft... more This work was achieved to investigate the effect of both aminopropyltriethoxysilane (APTES) grafting and cobalt particles incorporation on the CO 2 adsorption behavior of cocoa shell based hydrochar (HC). Electron microscopy and measurements using nitrogen adsorption-desorption isotherms showed a structure swelling after APTES grafting, followed a compaction after Co particle insertion that attenuates the surface basicity. HC-APTES-Co displayed higher CO 2 retention capacity than its metal-free counterpart, in spite of its lower basicity and porosity. CO 2 adsorption was found to obey pseudo-first order kinetics and intra-particle diffusion mechanisms due to the predominance of physical interaction. This favors CO 2 condensation of higher CO 2 amount than predicted by the stoichiometry of carbamate formation. This concept allows envisaging promising prospects for plant-deriving adsorbents intended for CO 2 concentration and valorization into added values products.

Research paper thumbnail of Entrapment and stabilization of iron nanoparticles within APTES modified graphene oxide sheets for catalytic activity improvement

Journal of Alloys and Compounds, 2019

Abstract In this work, for the first time, a grafting of 3-aminopropyltriethoxysilane (APTES) fol... more Abstract In this work, for the first time, a grafting of 3-aminopropyltriethoxysilane (APTES) followed by incorporation of iron nanoparticles (Fe-NPs) was used for the functionalization of graphene oxide (GO). Changes in stability, structural, morphological, thermal and catalytic properties of the resulting GO/APTES/Fe material were investigated by scanning electron microscopy, transmission electron microscopy, energy dispersive X-Ray, Fourier transform infrared and UV–visible spectroscopies, zeta potential measurements, X-ray photoelectron spectroscopy and differential scanning calorimetry. The average crystallite size of GO/APTES/Fe was found to decrease significantly after the post treatment, producing slight structure compaction. Iron nanoparticles were immobilized by APTES on the GO sheets, with a particle size around 50 nm. Fe insertion and APTES grafting resulted in high thermal stability of GO. As an application, GO/APTES/Fe exhibited an excellent catalytic activity in the reduction of 4-nitrophenol into 4-aminophenol. The presence of both APTES and small amount of Fe nanoparticles in GO/APTES/Fe induced a significant improvement in catalytic activity. GO/APTES/Fe also showed appreciable recyclability after four repeated uses without noticeable loss in activity. This stability was higher to those of other GO-materials. The results obtained herein open new prospects for Fe-loaded organo-graphene oxide as efficient material in catalysis and industrial applications.

Research paper thumbnail of Silver nanoparticle embedded copper oxide as an efficient core–shell for the catalytic reduction of 4-nitrophenol and antibacterial activity improvement

Dalton Transactions, 2018

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Stratégies analytiques pour évaluer la biodisponibilité des HAP dans les sols; corrélation avec leur atténuation par biodégradation

HAL (Le Centre pour la Communication Scientifique Directe), Jun 4, 2013

International audienceLes hydrocarbures aromatiques polycycliques (HAP), polluants toxiques persi... more International audienceLes hydrocarbures aromatiques polycycliques (HAP), polluants toxiques persistants, présentent un caractère de géo-accumulation. En fonction de leur forme chimique et des caractéristiques du sol, ils sont plus ou moins fortement séquestrés et l'efficacité des procédés de bioremédiation est alors intimement liée à la biodisponibilité des HAP pour les micro-organismes dégradeurs du sol. Le but de cette étude est donc de mettre au point une technique simple et rapide afin d'évaluer la biodisponibilité des HAP dans les sols. Les techniques d'extraction drastiques généralement mises en oeuvre (Soxhlet, extraction assistée par micro-ondes MAE, ou par solvants sous pression ASE) donnent la teneur pseudo-totale en HAP, mais ne permettent pas d'accéder à la fraction labile des HAP. Des méthodes d'extraction plus douces en phase aqueuse, utilisant des agents solubilisants, sont plus susceptibles d'accéder à cette fraction de HAP réellement biodisponible. Des additifs tels que des agents tensioactifs synthétiques, des émulsions, des biosurfactants (produits par des bactéries), des cyclodextrines et des liquides ioniques (LI) micellaires ont été testés sur 5 sols, de caractéristiques géochimiques très différentes (taux de matière organique, d'argiles, pH). La CMC des LI synthétisés a pu être déterminée par une technique originale, à savoir par électrophorèse capillaire en MEKC. Les capacités d'extraction en phase aqueuse, en présence des différents additifs, ont ensuite été comparées aux extractions pseudo-totales effectuées par MAE, afin d'établir si le ratio entre HAP labiles et HAP totaux était corrélé aux caractéristiques de rétention des sols. Au final, une analyse en composantes principales a permis de corréler (ou non) la biodégradation des HAP en 3 mois à certaines caractéristiques des sols, à leur biodisponibilité, à la biomasse totale et au nombre de bactéries cultivables dégradant le phénanthrène

Research paper thumbnail of L'analyse des acides gras en électrophorèse capillaire

Research paper thumbnail of Contribution à l'étude de systèmes quaternaires : exploitation de sulfates alcalins et dédoublement de molécules chirales par formation de diastéréoisomères

Dans le cadre de la determination des domaines de cristallisation d'especes definies dans un ... more Dans le cadre de la determination des domaines de cristallisation d'especes definies dans un systeme d'ordre eleve, deux systemes quaternaires sont etudies. Le premier systeme est Na2So4 - K2SO4 – (NH4)2SO4 – H2O : l'isotherme 18°C est dresse, definissant les domaines de stabilite des differentes phases rencontrees. Le deuxieme systeme est le systeme reciproque: l'isotherme 20°C montre la possibilite de dedoublement d'un compose racemique. Une etude critique des travaux anterieurs est apportee

Research paper thumbnail of A new example of reversal of the order of migration of enantiomers, as a function of cyclodextrin concentration and pH, by cyclodextrin-modified capillary zone electrophoresis: enantioseparation of 6,6′-dibromo-1,1′-binaphthyl-2,2′-diol

Analytical and Bioanalytical Chemistry, Jul 17, 2009

Enantioseparation of 6,6′-dibromo-1,1′-binaphthyl-2,2′-diol (DBBD) by cyclodextrin-modified capil... more Enantioseparation of 6,6′-dibromo-1,1′-binaphthyl-2,2′-diol (DBBD) by cyclodextrin-modified capillary zone electrophoresis (CD-CZE) was studied using the three native α, β, and γ cyclodextrins, the three hydroxypropylated cyclodextrins (2-hydroxypropyl-α, β, and γ), heptakis-2,6di-O-methyl-β-CD (DM-β-CD), and heptakis-2,3,6-tri-Omethyl-β-cyclodextrin (TM-β-CD). First, the acidity constants of DBBD were determined using capillary electrophoresis, before performing enantioseparation. The influence of the concentrations of the studied cyclodextrins on the enantioseparation was explored and the experimental optimal concentrations were determined and compared to the theoretical optimal concentrations. Moreover, the apparent complexation constants between each studied cyclodextrin and the two DBBD enantiomers were evaluated using a non-linear curve fitting method and three linear plotting methods (x-reciprocal, y-reciprocal and double reciprocal). For TM-β-CD, the order of migration of the enantiomers of DBBD reversed as a function of TM-β-CD concentration. The influence of the nature of methylated cyclodextrin derivatives (methyl-β-CD (M-β-CD) and DM-β-CD) was then studied. Inversion of the order of migration of the enantiomers of DBBD was observed for DM-β-CD, whereas the S enantiomer of DBBD always migrated first for M-β-CD.

Research paper thumbnail of Mise en oeuvre du couplage CE / ESI / MS et exemples d’application

HAL (Le Centre pour la Communication Scientifique Directe), May 1, 2000

International audienc

Research paper thumbnail of Apport des plans d’expériences en Electrophorèse Capillaire: exemple de l’optimisation de la sensibilité en détection fluorimétrique indirecte

HAL (Le Centre pour la Communication Scientifique Directe), Mar 1, 1999

International audienc

Research paper thumbnail of Analysis of non ionic polyoxyethylenic surfactants by NACE / ESI / MS coupling

HAL (Le Centre pour la Communication Scientifique Directe), Feb 1, 2000

International audienc

Research paper thumbnail of Détermination de points isoélectriques élevés par Electrophorèse Capillaire de Zone

HAL (Le Centre pour la Communication Scientifique Directe), Mar 1, 1999

International audienc

Research paper thumbnail of Enantioseparation of binaphthol and its mono derivatives by cyclodextrin-modified capillary zone electrophoresis

Journal of Chromatography A, Nov 1, 2008

Chiral binaphthols belong to the group of most effective ligands for asymmetrical catalysis. In t... more Chiral binaphthols belong to the group of most effective ligands for asymmetrical catalysis. In this context, various binaphthols presenting original substituents have been synthesized. Their study through capillary electrophoresis is the object of this work. The literature dedicated to the separation of atropisomers by capillary electrophoresis, corresponding only to binaphthol, reveals that its enantioseparation is always delicate because of the influence of many factors and the resolutions obtained are weak. Therefore, for a structured optimization, we first successfully evaluated the acidity constants of different binaphthols by means of capillary electrophoresis. With these known physicochemical characteristics, we could successfully carry out enantiomeric separations of the different binaphthols at pH=11.5, practically in completely ionized form, in phosphate medium, and in the presence of cyclodextrin (CD), with analysis times lower than 8 minutes. The nature of CDs (α-CD, β-CD, γ-CD, hydroxypropyl-α-cyclodextrin (HP-α-CD), HP-β-CD, HP-γ-CD and trimethyl-β-CD (TM-β-CD)) and other factors in relation to enantiomeric resolution (applied voltage, nature and concentration of the electrolyte, and concentration of cyclodextrin) were optimized. These studies allowed us to determine the optimal conditions of separation (concentration and nature of CD) for each of the studied binaphthols. It is necessary to mention that, for the 1,1'binaphthyl-2,2'-diol (Binol) at pH=11.5, the S atropisomer always migrated first, regardless of the nature and concentration of the cyclodextrin used. Moreover, an inversion in elution order of the two atropisomers as a function of pH was observed with γ-CD (pH range: 10-11.5). The R atropisomer migrated first at pH=10. At pH=10.8 the migration order of the two

Research paper thumbnail of Optimisation de la détection fluorimétrique indirecte en Chromatographie ElectroCinétique Micellaire en utilisant la fluorescéine comme agent de visualisation

HAL (Le Centre pour la Communication Scientifique Directe), May 1, 1997

International audienc

Research paper thumbnail of Électrophorèse Capillaire en Milieu Non Aqueux

Analusis, Mar 1, 1999

The utilisation of Capillary Electrophoresis in hydroorganic and organic media is gradually incre... more The utilisation of Capillary Electrophoresis in hydroorganic and organic media is gradually increasing since fifteen years. The influence of the physicochemical properties of ten organic solvents on the fundamental parameters commanding an electrophoretic separation, i.e. current efficiency, analysis time, resolution, is considered. The use of non aqueous media offers new attractive possibilities for the analysis of hydrophobic compounds by Capillary Electrophoresis. The choice of convenient solvent allows an easier optimisation of selectivity, particularly in the case of chiral compounds. At last, non aqueous Capillary Electrophoresis appears as a choice technique for the study of interactions in solution.

Research paper thumbnail of New analytical strategies to evaluate bioavailability of polycyclic aromatic hydrocarbons (PAH) in dissimilar soils

HAL (Le Centre pour la Communication Scientifique Directe), Jun 12, 2012

National audiencePolycyclic Aromatic Hydrocarbons (PAHs) are carcinogenic molecules mainly produc... more National audiencePolycyclic Aromatic Hydrocarbons (PAHs) are carcinogenic molecules mainly produced by the incomplete combustion of organic matter and they are found in all parts of environment. Concerning the remediation of contaminated soils and sediments, only few methods exist to assess the bioavailability of PAHs for bacterial degradation and they are not well correlated to biodegradation in real soils; however, this assessment is necessary for an effective treatment of pollution.The aim of this study is to develop a simple and rapid method for evaluating PAHs bioavailability in polluted soils by the use of non-exhaustive extraction methods that would permit to extract only labile PAHs and not the sequestrated part of PAHs (strongly sorbed on organic matter or clays), part which is not bioavailable for degradation by microorganisms. Thus, several tests were performed on two spiked soils (meadow soil, Yvetot, France and Seine river soil, Petiville, France), using aqueous phase extractions containing original additives. We tested the hydroxypropyl-β-cyclodextrin (HPCD) (Gomez-Eyles et al., 2001; Swindell and Reid, 2006), or the butan-1-ol extraction (BuOH) (Liste & Alexander, 2001) which are the two reference methods for the evaluation of bioavailability of PAHs in soils. Other assays were performed with additives such as an ionic liquid 1-hexadecyl-3-methylimidazolium bromide (HDMIm Br), the turquey red oil (TRO) or the sodium lauryl sulfate (SDS), in order to have a panel of different additives with different molecular properties, especially micellisation properties. Results of these assays did not seem to be reliable to the bioavailability of PAHs in soils. Perspectives are to study degradation kinetics of PAHs in these soils on three months and to correlate the biodegradation efficiency to PAHs bioavailability, using other additives such as new cyclodextrins or ionic liquids which form micelles in aqueous media. Other studies are also in progress to find bacterial communities responsible for the PAH degradation (by using DNA-SIP and Bioscreen technics)

Research paper thumbnail of Deciphering the role of faujasite-type zeolites as a cation delivery platform to sustain the functions of MC3T3-E1 pre-osteoblastic cells

Materials advances, 2022

Please note that technical editing may introduce minor changes to the text and/or graphics, which... more Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal's standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains.

Research paper thumbnail of New analytical strategies to evaluate the bioavailable fraction of polycyclic aromatic hydrocarbons (PAHs) in dissimilar soils

HAL (Le Centre pour la Communication Scientifique Directe), Sep 9, 2012

International audienceDiffuse pollution of surface soils with polycyclic aromatic hydrocarbons (P... more International audienceDiffuse pollution of surface soils with polycyclic aromatic hydrocarbons (PAHs) is problematic in terms of health effects. Total PAH concentration in two different soils was assessed following an exhaustive extraction technique by MAE (microwave assisted extraction) using organic solvent mixtures. But it was demonstrated that the measure of contaminant exposure by this way is not appropriate to assess ecological risks. Moreover, it is well known that the effectiveness of in situ soil remediation processes (by degrading microorganisms) are constrained by low PAH bioavailability, due to their limited aqueous solubility and the magnitude of sorption on soils organic matter or clayey fine particles. The aim of this study was to evaluate different less exhaustive extraction methods in order to access the labile PAHs and to correlate them with bacterial degradation. Thus, aqueous-based extraction techniques using various original additives were performed. They were compared with butanol or-hydroxypropyl -cyclodextrin extractions, methods which were already described but that did not fit with our degradation tests or were too expensive. The new additives tested were original amphiphilic ionic liquids and a derivatized -cyclodextrin with micellization properties. Their critical micellar concentrations (cmc) were determined by a non-conventional method using capillary electrophoresis. These additives were introduced at 10 or 50 times their cmc in the extraction aqueous medium and time contact with soils was 24h. Desorbed PAHs, which were at trace levels, were quantified by HPLC (coupled to a fluorimetric detector) after a concentration step by SPE (solid phase extraction). Found labile PAHs were compared to PAH biodegradability (during three months) in the two studied soils in order to ensure that one of the new tested method could effectively predict the bioavailability of PAHs

Research paper thumbnail of Metal-inorganic-organic core–shell material as efficient matrices for CO2 adsorption: Synthesis, properties and kinetic studies

Journal of The Taiwan Institute of Chemical Engineers, Feb 1, 2019

A novel hydrochar-based core-shell material with improved affinity towards CO 2 was synthesized t... more A novel hydrochar-based core-shell material with improved affinity towards CO 2 was synthesized through encapsulation within ZnO shell, followed by chemical grafting to an organic moiety bearing terminal diethanolamino groups and further dispersion of Cu 0 nanoparticles. Characterization through nitrogen adsorption-desorption isotherms with BET and BJH models, SEM, TEM, zeta potential measurements, FTIR spectroscopy, DSC and XPS analyses revealed a strong influence of the modification procedure on the performance of each material in CO 2 adsorption. The resulting metal-inorganic-organic-core-shell (MIOCS) displayed compacted structure with a wide pore size distribution that imposes intraparticle diffusion as a kinetic-controlling step. Cu-MIOCS showed an appreciable CO 2 retention capacity of 5.42 mmol/g compared to many adsorbents reported so far. This affinity towards CO 2 was explained in terms of physical and non-stoichiometric CO 2 condensation. This finding is of great importance, because it demonstrates that judicious modifications of vegetal-deriving wastes such as woods and other biomasses give rise to added-value materials as low cost and efficient gas adsorbents with high affinity towards CO 2 .

Research paper thumbnail of Analytical strategies to evaluate polycyclic aromatic hydrocarbons (PAHs) bioavailability in soils; correlation with their biodegradability

HAL (Le Centre pour la Communication Scientifique Directe), Jun 24, 2013

Research paper thumbnail of Surface modification of biomaterials based on cocoa shell with improved nitrate and Cr(<scp>vi</scp>) removal

RSC Advances, 2020

The present work addresses the development of simple, low-cost and eco-friendly cocoa-shell-based... more The present work addresses the development of simple, low-cost and eco-friendly cocoa-shell-based materials for efficient removal of heavy metal hexavalent chromium (Cr(VI)), and toxic nitrate (NO 3 À) from aqueous solution. A conventional treatment process was used to purify cocoa shell (CS) into an adsorbent, followed by chemical grafting of dendrimers to promote its surface properties for nitrate and Cr(VI) removal. The morphology, surface charge, structure and stability of the new adsorbent were investigated by scanning electron microscopy, Fourier transform infrared and UV-visible spectroscopies, zeta potential, X-ray photoelectron spectrometry, and differential scanning calorimetry. The successful chemical grafting of the dendrimer (polyethyleneimine, PEI) onto purified CS was confirmed. CS-T-PEI-P proved to be a very efficient candidate for the removal of nitrate and chromium(VI). Removal of the two pollutants at different initial concentrations and pH values was studied and discussed. Sorption of chromium and nitrate was found to obey 2 nd-order kinetics and a Freundlich-type isotherm, affording an uptake adsorption of 16.92 mg g À1 for NO 3 À and 24.78 mg g À1 for Cr(VI). These results open promising prospects for its potential applications as a low cost catalyst in wastewater treatment.

Research paper thumbnail of Cocoa shell-deriving hydrochar modified through aminosilane grafting and cobalt particle dispersion as potential carbon dioxide adsorbent

Chemical Engineering Journal, Jun 1, 2018

This work was achieved to investigate the effect of both aminopropyltriethoxysilane (APTES) graft... more This work was achieved to investigate the effect of both aminopropyltriethoxysilane (APTES) grafting and cobalt particles incorporation on the CO 2 adsorption behavior of cocoa shell based hydrochar (HC). Electron microscopy and measurements using nitrogen adsorption-desorption isotherms showed a structure swelling after APTES grafting, followed a compaction after Co particle insertion that attenuates the surface basicity. HC-APTES-Co displayed higher CO 2 retention capacity than its metal-free counterpart, in spite of its lower basicity and porosity. CO 2 adsorption was found to obey pseudo-first order kinetics and intra-particle diffusion mechanisms due to the predominance of physical interaction. This favors CO 2 condensation of higher CO 2 amount than predicted by the stoichiometry of carbamate formation. This concept allows envisaging promising prospects for plant-deriving adsorbents intended for CO 2 concentration and valorization into added values products.

Research paper thumbnail of Entrapment and stabilization of iron nanoparticles within APTES modified graphene oxide sheets for catalytic activity improvement

Journal of Alloys and Compounds, 2019

Abstract In this work, for the first time, a grafting of 3-aminopropyltriethoxysilane (APTES) fol... more Abstract In this work, for the first time, a grafting of 3-aminopropyltriethoxysilane (APTES) followed by incorporation of iron nanoparticles (Fe-NPs) was used for the functionalization of graphene oxide (GO). Changes in stability, structural, morphological, thermal and catalytic properties of the resulting GO/APTES/Fe material were investigated by scanning electron microscopy, transmission electron microscopy, energy dispersive X-Ray, Fourier transform infrared and UV–visible spectroscopies, zeta potential measurements, X-ray photoelectron spectroscopy and differential scanning calorimetry. The average crystallite size of GO/APTES/Fe was found to decrease significantly after the post treatment, producing slight structure compaction. Iron nanoparticles were immobilized by APTES on the GO sheets, with a particle size around 50 nm. Fe insertion and APTES grafting resulted in high thermal stability of GO. As an application, GO/APTES/Fe exhibited an excellent catalytic activity in the reduction of 4-nitrophenol into 4-aminophenol. The presence of both APTES and small amount of Fe nanoparticles in GO/APTES/Fe induced a significant improvement in catalytic activity. GO/APTES/Fe also showed appreciable recyclability after four repeated uses without noticeable loss in activity. This stability was higher to those of other GO-materials. The results obtained herein open new prospects for Fe-loaded organo-graphene oxide as efficient material in catalysis and industrial applications.

Research paper thumbnail of Silver nanoparticle embedded copper oxide as an efficient core–shell for the catalytic reduction of 4-nitrophenol and antibacterial activity improvement

Dalton Transactions, 2018

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Stratégies analytiques pour évaluer la biodisponibilité des HAP dans les sols; corrélation avec leur atténuation par biodégradation

HAL (Le Centre pour la Communication Scientifique Directe), Jun 4, 2013

International audienceLes hydrocarbures aromatiques polycycliques (HAP), polluants toxiques persi... more International audienceLes hydrocarbures aromatiques polycycliques (HAP), polluants toxiques persistants, présentent un caractère de géo-accumulation. En fonction de leur forme chimique et des caractéristiques du sol, ils sont plus ou moins fortement séquestrés et l'efficacité des procédés de bioremédiation est alors intimement liée à la biodisponibilité des HAP pour les micro-organismes dégradeurs du sol. Le but de cette étude est donc de mettre au point une technique simple et rapide afin d'évaluer la biodisponibilité des HAP dans les sols. Les techniques d'extraction drastiques généralement mises en oeuvre (Soxhlet, extraction assistée par micro-ondes MAE, ou par solvants sous pression ASE) donnent la teneur pseudo-totale en HAP, mais ne permettent pas d'accéder à la fraction labile des HAP. Des méthodes d'extraction plus douces en phase aqueuse, utilisant des agents solubilisants, sont plus susceptibles d'accéder à cette fraction de HAP réellement biodisponible. Des additifs tels que des agents tensioactifs synthétiques, des émulsions, des biosurfactants (produits par des bactéries), des cyclodextrines et des liquides ioniques (LI) micellaires ont été testés sur 5 sols, de caractéristiques géochimiques très différentes (taux de matière organique, d'argiles, pH). La CMC des LI synthétisés a pu être déterminée par une technique originale, à savoir par électrophorèse capillaire en MEKC. Les capacités d'extraction en phase aqueuse, en présence des différents additifs, ont ensuite été comparées aux extractions pseudo-totales effectuées par MAE, afin d'établir si le ratio entre HAP labiles et HAP totaux était corrélé aux caractéristiques de rétention des sols. Au final, une analyse en composantes principales a permis de corréler (ou non) la biodégradation des HAP en 3 mois à certaines caractéristiques des sols, à leur biodisponibilité, à la biomasse totale et au nombre de bactéries cultivables dégradant le phénanthrène