2022/11/26 更新

写真a

ゲガン レジス
ゲガン レジス
Scopus 論文情報  
論文数: 0  Citation: 0  h-index: 22

Citation Countは当該年に発表した論文の被引用数

所属
理工学術院 国際理工学センター(理工学術院)
職名
准教授(任期付)
プロフィール
Two dimensional (2D) atomic crystals or nanosheets constitute exciting nanomaterials with fascinating properties and the self-organization in various liquid crystalline phases that can be used as template systems to organize further organic systems. Besides the potentialities of nanosheets in materials field, the association with other colloidal systems represents a certain challenge since it results from a fragile energy landscape with the possibility of phase segregation. My research activities aim at understanding the stability and the microstructures generated from the mixtures of inorganic particles associated with membrane phases made of surfactants, lipids and other apparent biological systems that may mimic cell envelope, as new routes to prepare biosensors and other nanomaterials.

学内研究所・附属機関兼任歴

  • 2020年
    -
    2022年

    理工学術院総合研究所   兼任研究員

学歴

  • 2018年01月
     
     

    Ability to supervise, the University of Orleans  

  • 2003年10月
    -
    2006年09月

    PhD in Physics, The University of Rennes I  

  • 2000年09月
    -
    2003年07月

    Materials Engineering School, The University of Rennes I  

  • 2002年09月
    -
    2003年06月

    Master in Physics, The University of Rennes I  

  • 1998年09月
    -
    2000年07月

    College in Chemistry, University of Rennes I  

経歴

  • 2018年04月
    -
    継続中

    Waseda University   School of Science and Engineering   Associate Professor (seconded employee from the University of Orleans in France)

  • 2007年09月
    -
    2018年03月

    University of Orleans   Department of physics   Associate Professor (Permanent)

  • 2015年04月
    -
    2015年09月

    Fukuoka Institute of Technology   JSPS visiting researcher

  • 2013年04月
    -
    2013年09月

    Waseda University   Canon Foundation visiting researcher

  • 2010年08月
    -
    2010年09月

    Waseda University   JSPS visting researcher

  • 2003年10月
    -
    2006年09月

    The University of Rennes 1   Institute of Physics   PhD student

  •  
     
     

    The University of Tokyo   Institute for Industrial Science   JSPS Post-doc Fellow

▼全件表示

 

研究分野

  • 環境負荷、リスク評価管理

  • 有機機能材料

  • 生物物理、化学物理、ソフトマターの物理

研究キーワード

  • Mesoporous materials

  • confinement effects

  • Colloidal in state materials

  • Liquid crystals

  • Layered Materials

論文

  • Preparation of double-layered nanosheets containing pH-responsive polymer networks in the interlayers and the conversion into single-layered nanosheets induced by cleavage of cross-linking points

    Takuma Kamibe, Régis Guégan, Masashi Kunitake, Takehiko Tsukahara, Naokazu Idota, Yoshiyuki Sugahara

    ACS Omega    2022年03月  [査読有り]

    DOI

  • Preparation of biocompatible hydrogels reinforced by different nanosheets

    Taiga Ito, Saki Endo, Yoshiyuki Sugahara, Ryota Tamate, Régis Guégan

    RSC Advances   12 ( 2 ) 753 - 761  2022年

     概要を見る

    Inclusion of different nanosheets derived from layered materials as a way to control the gelation of a hydrogel based on F127 tri-block copolymers functionalized with dimethacrylate (127-DMA).

    DOI

    Scopus

  • Intercalation of a Cationic Cyanine Dye Assisted by Anionic Surfactants within Mg–Al Layered Double Hydroxide

    Rina Sato, Shingo Machida, Minoru Sohmiya, Yoshiyuki Sugahara, Régis Guégan

    ACS Omega   6 ( 37 ) 23837 - 23845  2021年09月

    DOI

    Scopus

  • A kaolinite-tetrabutylphosphonium bromide intercalation compound as an effective intermediate for intercalation of bulky organophosphonium salts

    Shingo Machida, Régis Guégan, Yoshiyuki Sugahara

    Applied Clay Science   206   106038 - 106038  2021年06月

    DOI

    Scopus

    3
    被引用数
    (Scopus)
  • Performance evaluation of organoclays for the amoxicillin retention in a dynamic context

    Régis Guégan, Lydie Le Forestier

    Chemical Engineering Journal   406   126859 - 126859  2021年02月  [査読有り]

    DOI

    Scopus

    6
    被引用数
    (Scopus)
  • A novel approach to characterization of a relatively unstable intercalation compound under ambient conditions: revisiting a kaolinite-acetone intercalation compound

    Shingo Machida, Régis Guégan, Yoshiyuki Sugahara

    Dalton Transactions    2021年

     概要を見る

    <p>Characteristics of a kaolinite-acetone intercalation compound prepared using a kaolinite N-methylformamide intercalation compound (Kaol-NMF) as an intermediate were obtained by a set of techniques with attention to suppressing evaporation and...</p>

    DOI

    Scopus

  • Removal of methylene blue from aqueous solutions using a solid residue of the apple juice industry: Full factorial design, equilibrium, thermodynamics and kinetics aspects

    L.R. Bonetto, J.S. Crespo, R. Guégan, V.I. Esteves, M. Giovanela

    Journal of Molecular Structure   1224   129296 - 129296  2021年01月  [査読有り]

    DOI

    Scopus

    25
    被引用数
    (Scopus)
  • Loss of a membrane phase under soft confinement conditions imposed by a porous silica colloids network

    Miho Tanimura, Yoshiyuki Sugahara, Régis Guégan

    Colloids and Surfaces A: Physicochemical and Engineering Aspects   608   125554 - 125554  2021年01月  [査読有り]

    DOI

    Scopus

  • Use of a clay mineral and its nonionic and cationic organoclay derivatives for the removal of pharmaceuticals from rural wastewater effluents

    Tiago De Oliveira, Mohammed Boussafir, Laëtitia Fougère, Emilie Destandau, Yoshiyuki Sugahara, Régis Guégan

    Chemosphere   259   127480 - 127480  2020年11月  [査読有り]

    DOI

    Scopus

    17
    被引用数
    (Scopus)
  • Highly Efficient Surface Modification of Layered Perovskite Nanosheets with a Phosphorus Coupling Reagent Making Use of Microchannels

    Takeshi Sugaya, Régis Guégan, Naokazu Idota, Takehiko Tsukahara, Yoshiyuki Sugahara

    Langmuir   36 ( 26 ) 7252 - 7258  2020年07月  [査読有り]

    DOI

    Scopus

    3
    被引用数
    (Scopus)
  • Tuning down the environmental interests of organoclays for emerging pollutants: Pharmaceuticals in presence of electrolytes

    Régis Guégan, Tiago De Oliveira, Julien Le Gleuher, Yoshiyuki Sugahara

    Chemosphere   239   124730 - 124730  2020年01月  [査読有り]

    DOI

    Scopus

    13
    被引用数
    (Scopus)
  • Stabilization of self-assembled lipids in exfoliated organo-nanosheets

    Tomonari Tanaka, Yoshiyuki Sugahara, Régis Guégan

    Chemical Physics Letters   739   136954 - 136954  2020年01月  [査読有り]

    DOI

    Scopus

  • Preparation and Comparative Stability of a Kaolinite-Tetrabutylphosphonium Bromide Intercalation Compound for Heat and Solvent Treatments

    Shingo Machida, Régis Guégan, Yoshiyuki Sugahara

    Langmuir   35 ( 42 ) 13553 - 13561  2019年10月  [査読有り]

    DOI

    Scopus

    8
    被引用数
    (Scopus)
  • Removal of malachite green dye from aqueous solutions by a magnetic adsorbent

    C. De Marco, R. S. Mauler, T. S. Daitx, I. Krindges, A. Cemin, L. R. Bonetto, J. S. Crespo, R. Guégan, L. N. Carli, M. Giovanela

    Separation Science and Technology     1 - 13  2019年03月  [査読有り]

    DOI

    Scopus

    10
    被引用数
    (Scopus)
  • Surface modification of layered perovskite nanosheets with a phosphorus coupling reagent in a biphasic phases system

    ゲガン

    Langmuir   35 ( 20 ) 6594 - 6601  2019年  [査読有り]

  • Mobility of Pb, Zn, Ba, As and Cd toward soil pore water and plants (willow and ryegrass) from a mine soil amended with biochar

    ゲガン

    Journal of environmental management   232   117  2019年  [査読有り]

  • Removal of malachite green dye from aqueous solutions by a magnetic adsorbent

    ゲガン

    Separation Science and Technology     1-13  2019年  [査読有り]

  • Evaluation of Antibacterial Activity of Zinc-Doped Hydroxyapatite Colloids and Dispersion Stability Using Ultrasounds

    ゲガン

    Nanomaterials   9 ( 4 ) 515  2019年  [査読有り]

  • Tuning down the environmental interests of organoclays for emerging pollutants: Pharmaceuticals in presence of electrolytes

    ゲガン

    Chemosphere   239 ( 124730 ) 124730 - 124730  2019年  [査読有り]

    DOI

    Scopus

    13
    被引用数
    (Scopus)
  • Phenolic acids interactions with clay minerals: A spotlight on the adsorption mechanisms of Gallic Acid onto montmorillonite

    ゲガン

    Applied Clay Science   180 ( 105188 )  2019年  [査読有り]

  • Organoclay applications and limits in the environment

    Régis Guégan

    Comptes Rendus Chimie   22 ( 2-3 ) 132 - 141  2019年01月

     概要を見る

    © 2018 Académie des sciences This article gives an overview of the preparation, applications, and limits of organoclay materials in the environment field. Organoclays are obtained by the combination of clay minerals and surfactants (quaternary alkyl ammonium salts and others) and are appropriate candidates for the adsorption of organic contaminants such as pesticides, herbicides, and pharmaceuticals that are more and more found in the water resource despite wastewater treatments. This review article focuses on novel organoclay preparation methods based on the use of nonconventional nonionic surfactants and the interest and limits of these hybrid materials for the adsorption of organic compounds at both batch equilibrium and dynamical percolation experimental conditions.

    DOI

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    47
    被引用数
    (Scopus)
  • New Insights into the Cs Adsorption on Montmorillonite Clay from 133Cs Solid-State NMR and Density Functional Theory Calculations

    Takahiro Ohkubo, Takuya Okamoto, Katsuyuki Kawamura, Régis Guégan, Kenzo Deguchi, Shinobu Ohki, Tadashi Shimizu, Yukio Tachi, Yasuhiko Iwadate

    The Journal of Physical Chemistry A   122 ( 48 ) 9326 - 9337  2018年12月  [査読有り]

    DOI

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    11
    被引用数
    (Scopus)
  • Correction: Competitive Association of Antibiotics with a Clay Mineral and Organoclay Derivatives as a Control of Their Lifetimes in the Environment (ACS Omega (2018) 3:11 (15332-15342) DOI: 10.1021/acsomega.8b02049)

    T. De Oliveira, E. Fernandez, L. Fougère, E. Destandau, M. Boussafir, M. Sohmiya, Y. Sugahara, R. Guegan

    ACS Omega   3   18433  2018年12月  [査読有り]

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Competitive Association of Antibiotics with a Clay Mineral and Organoclay Derivatives as a Control of Their Lifetimes in the Environment

    T. De Oliveira, E. Fernandez, L. Fougère, E. Destandau, M. Boussafir, M. Sohmiya, Y. Sugahara, R. Guegan

    ACS Omega   3   15332 - 15342  2018年11月  [査読有り]

    DOI

    Scopus

    18
    被引用数
    (Scopus)
  • Removal of zinc ions using hydroxyapatite and study of ultrasound behavior of aqueous media

    Simona Liliana Iconaru, Mikael Motelica-Heino, Régis Guegan, Mihai Valentin Predoi, Alina Mihaela Prodan, Alina Mihaela Prodan, Daniela Predoi

    Materials   11  2018年08月

     概要を見る

    © 2018 by the authors. The present study demonstrates the effectiveness of hydroxyapatite nanopowders in the adsorption of zinc in aqueous solutions. The synthesized hydroxyapatites before (HAp) and after the adsorption of zinc (at a concentration of 50 mg/L) in solution (HApD) were characterized using X-ray diffraction (XRD), and scanning and transmission electron microscopy (SEM and TEM, respectively). The effectiveness of hydroxyapatite nanopowders in the adsorption of zinc in aqueous solutions was stressed out through ultrasonic measurements. Both Langmuir and Freundlich models properly fitted on a wide range of concentration the equilibrium adsorption isotherms, allowing us to precisely quantify the affinity of zinc to hydroxyapatite nanopowders and to probe the efficacy of hydroxyapatite in removal of zinc ions from aqueous solutions in ultrasonic conditions.

    DOI

    Scopus

    20
    被引用数
    (Scopus)
  • Commercial hydroxyapatite powders for lead removal from aqueous solution

    C. C. Negrila, S. L. Iconaru, M. Motelica-Heino, R. Guegan, G. Predoi, F. Barbuceanu, R. V. Ghita, C. C. Petre, G. Jiga, M. L. Badea, A. M. Prodan, D. Predoi

    AIP Conference Proceedings   1981  2018年07月

     概要を見る

    © 2018 Author(s). Nowadays, the advances in materials science have created the possibility of using nanomaterials as adsorbents in environmental technologies. This study is focused on the evaluation of C-HAp powders capacity in lead ions removal from contaminated solutions. The C-HAp powders after removal of lead (Pb2+) ions from contaminated water were characterized by X-Ray Photoelectron Spectroscopy (XPS) and Energy Dispersive X-ray analysis (EDX). The presence of lead in the hydroxyapatite powders after removal experiments was observed in the XPS general spectrum and also in the EDX spectra. In addition, the AAS studies revealed that the C-HAp powders possess a high affinity towards lead ions with an effective removal rate of 80% for an initial lead concentration of 20 mg·L-1.

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Analytical indicators to characterize Particulate Organic Matter (POM) and its evolution in French Vertical Flow Constructed Wetlands (VFCWs)

    M. Kania, M. Kania, M. Gautier, Z. Ni, E. Bonjour, R. Guégan, P. Michel, P. Jame, J. Liu, R. Gourdon

    Science of the Total Environment   622-623   801 - 813  2018年05月

     概要を見る

    © 2017 Elsevier B.V. The design of French VFCWs leads to the formation of a sludge layer at the surface of the first filters due to the retention of suspended solids from the percolation of unsettled wastewater. This layer plays a major role in the system but still little is known on its characteristics and evolutions. In this study, suspended solids and sludge deposits sampled from two French VFCW plants were analyzed by different methods in the objective to assess the evolution of particulate organic matter (POM) along the treatment chain and within the sludge layer, and identify relevant analytical indicators of these phenomena. The treatment chain included an aerobic trickling filter followed by FeCl3injection and two successive stages of filters. Thermal analyses showed that OM contents of suspended solids decreased along the treatment chain. POM in inflow suspended solids was predominantly composed of reactive, biodegradable compounds which were partly hydrolyzed and mineralized notably at the trickling filter stage. 3D fluorescence spectra collected from aqueous POM extracts confirmed the evolution of organic matter from low-molecular reactive compounds to more complex and stable structures such as humic-like substances. FTIR confirmed the mineralization of POM&#039;s reactive constituents along the treatment chain by the decrease in the intensities of the characteristics bands of aliphatic compounds or proteins, and its humification in the sludge deposits through the relative increase of the bands at 1634 cm− 1(vC = O) and 1238 cm− 1(δC = Oand/or δOH). Isotopic ratios δ2H/1H and δ15N/14N were found to be good indicators of POM evolutions. The higher values of δ2H/1H and δ15N/14N ratios measured in sludge deposits as compared to inflow suspended solids were related to POM humification and to microbial processes of POM hydrolysis and mineralization, respectively.

    DOI

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    11
    被引用数
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  • Properties of basil and lavender essential oils adsorbed on the surface of hydroxyapatite

    Daniela Predoi, Andreea Groza, Simona Liliana Iconaru, Gabriel Predoi, Florica Barbuceanu, Regis Guegan, Mikael Stefan Motelica-Heino, Carmen Cimpeanu

    Materials   11 ( 5 )  2018年04月

     概要を見る

    The research conducted in this study presented for the first time results of physico-chemical properties and in vitro antimicrobial activity of hydroxyapatite plant essential oil against Gram-positive bacteria (methicillin-resistant Staphylococcus aureus (MRSA) and S. aureus 0364) and Gram-negative bacteria (Escherichia coli ATCC 25922). The samples were studied by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy to determine the morphology and structure of the nanocomposites of hydroxyapatite coated with basil (HAp-B) and lavender (HAp-L) essential oils (EOs). The values of the BET specific surface area (SBET), total pore volume (VP) and pore size (DP) were determined. The results for the physico-chemical properties of HAp-L and HAp-B revealed that lavender EOs were well adsorbed on the surface of hydroxyapatite, whereas basil EOs showed a poor adsorption on the surface of hydroxyapatite. We found that the lavender EOs hydroxyapatite (HAp-L) exhibited a very good inhibitory growth activity. The value of the minimum inhibitory concentration (MIC) related to growth bacteria was 0.039 mg/mL for MRSA, 0.02 mg/mL for S. aureus and 0.039 mg/mL E. coli ATCC 25922. The basil EO hydroxyapatite (HAp-B) showed poor inhibition of bacterial cell growth. The MIC value was 0.625 mg/mL for the HAp-B sample in the presence of the MRSA bacteria, 0.313 mg/mL in the presence of S. aureus and 0.078 mg/mL for E. coli ATCC 25922.

    DOI

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    18
    被引用数
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  • Application of biocompatible magnetite nanoparticles for the removal of arsenic and copper from water

    S. L. Iconaru, M. Beuran, M. Beuran, C. S. Turculet, C. S. Turculet, I. Negoi, G. Teleanu, A. M. Prodan, A. M. Prodan, M. Motelica-Heino, R. Guégan, C. S. Ciobanu, G. Jiga, Daniela Predoi

    AIP Conference Proceedings   1932  2018年02月

     概要を見る

    © 2018 Author(s). The progress of nanotechnology made possible the use of nanomaterials as adsorbents and magnetic iron oxides represents one of the first generations of nanoscale materials used in environment technologies [1]. A systematic characterization of commercial magnetite (Fe3O4) is presented in this research. The commercial (Fe3O4) magnetic adsorbents were characterized by various characterizations methods such as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX). This study was also focused on the study of adsorption isotherms and the kinetics evaluation. X-ray studies indicated that As3+and Cu2+removed by Fe3O4did not seem to alter the structure of Fe3O4but they were highlighted in the EDX analysis. In addition, the SEM studies were consistent with the XRD results. The rate of adsorption of contaminants, in contaminated solutions decreases when the amount of contaminant increases in all experiments performed. The results revealed that Fe3O4nanoparticles are promising candidates which could be used as sorbents for the removal of arsenic from the marine environment, for site remediation and groundwater treatment.

    DOI

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  • Structure and Dynamics of Nonionic Surfactant Aggregates in Layered Materials

    Regis Guegan, Emmanuel Veron, Lydie Le Forestier, Makoto Ogawa, Sylvian Cadars

    LANGMUIR   33 ( 38 ) 9759 - 9771  2017年09月

     概要を見る

    The aggregation of surfactants on solid surfaces as they are adsorbed from solution is the basis of numerous technological applications such as colloidal stabilization, ore flotation, and floor cleaning. The understanding of both the structure and the dynamics of surfactant aggregates applies to the development of alternative ways of preparing hybrid layered materials. For this purpose, we study the adsorption of the triethylene glycol mono n-decyl ether (C10E3) nonionic surfactant onto a synthetic montmorillonite (Mt), an aluminosilicate clay mineral for organoclay preparation with important applications in materials sciences, catalysis, wastewater treatment, or as drug delivery. The aggregation mechanisms follow those observed in an analogous natural Mt, with the condensation of C10E3 in a bilayer arrangement once the surfactant self-assembles in a lamellar phase beyond the critical micelle concentration, underlining the importance of the surfactant state in solution. Solid-state H-1 nuclear magnetic resonance (NMR) at fast magic-angle spinning (MAS) and high magnetic field combined with(1)H-C-13 correlation experiments and different types of C-13 NMR experiments selectively probes mobile or rigid moieties of C10E3 in three different aggregate organizations: (0 a lateral monolayer, (ii) a lateral bilayer, and (iii) a normal bilayer. High-resolution H-1{Al-27} CP-H-1-H-1 spin diffusion experiments shed light on the-proximities and dynamics of the different fragments and fractions of the intercalated surfactant molecules with respect to the Mt surface. Na-23 and H-1 NMR measurements combined with complementary NMR data, at both molecular and nanometer scales, precisely pointed out the location of the C10E3 ethylene oxide hydrophilic group in close contact with the Mt surface interacting through ion dipole or van der Waals interactions.

    DOI

  • Mineralization and Preservation of an extremotolerant Bacterium Isolated from an Early Mars Analog Environment

    F. Gaboyer, C. Le Milbeau, M. Bohmeier, P. Schwendner, P. Vannier, K. Beblo-Vranesevic, E. Rabbow, F. Foucher, P. Gautret, R. Guegan, A. Richard, A. Sauldubois, P. Richmann, A. K. Perras, C. Moissl-Eichinger, C. S. Cockell, P. Rettberg, Marteinsson, E. Monaghan, P. Ehrenfreund, L. Garcia-Descalzo, F. Gomez, M. Malki, R. Amils, P. Cabezas, N. Walter, F. Westall

    SCIENTIFIC REPORTS   7  2017年08月

     概要を見る

    The artificial mineralization of a polyresistant bacterial strain isolated from an acidic, oligotrophic lake was carried out to better understand microbial (i) early mineralization and (ii) potential for further fossilisation. Mineralization was conducted in mineral matrixes commonly found on Mars and Early-Earth, silica and gypsum, for 6 months. Samples were analyzed using microbiological (survival rates), morphological (electron microscopy), biochemical (GC-MS, Microarray immunoassay, Rock-Eval) and spectroscopic (EDX, FTIR, RAMAN spectroscopy) methods. We also investigated the impact of physiological status on mineralization and long-term fossilisation by exposing cells or not to Mars-related stresses (desiccation and radiation). Bacterial populations remained viable after 6 months although the kinetics of mineralization and cell-mineral interactions depended on the nature of minerals. Detection of biosignatures strongly depended on analytical methods, successful with FTIR and EDX but not with RAMAN and immunoassays. Neither influence of stress exposure, nor qualitative and quantitative changes of detected molecules were observed as a function of mineralization time and matrix. Rock-Eval analysis suggests that potential for preservation on geological times may be possible only with moderate diagenetic and metamorphic conditions. The implications of our results for microfossil preservation in the geological record of Earth as well as on Mars are discussed.

    DOI

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    14
    被引用数
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  • Organic matter and clay interaction in a meromictic lake: Implications for source rock OM preservation (Lac Pavin, Puy-de-Dôme, France)

    Adoum Mahamat Ahmat, Mohammed Boussafir, Claude Le Milbeau, Régis Guégan, Tiago De Oliveira, Lydie Le Forestier

    Organic Geochemistry   109   47 - 57  2017年07月

     概要を見る

    © 2017 Elsevier Ltd Investigation of organic matter (OM) preservation mechanisms is crucial for understanding organic accumulation in sedimentary environments. We focus here on the contribution of organo-clay interaction in such preservation. Most studies addressing this issue deal with organo-mineral complexes which have settled, omitting consideration of early aggregation within the water column. We therefore investigated the sorption of OM on montmorillonite (Na MMt) and kaolinite (Kaol) immersed in a permanently stratified water column (Lake Pavin, France). The two types of clay samples were kept immersed for different lengths of time and characterized via analytical methods suited for the organic phase [pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), GC-MS, Fourier transform infrared spectroscopy (FT-IR) and dissolved organic carbon (DOC) analysis], as well as for the mineral phase [X ray diffraction (XRD) and microprobe elementary cartography]. Results suggest that strong organo-clay interaction occurred within the water column to a varying extent depending on water physicochemical conditions and the mineral phase typology. A higher concentration of DOC was observed in the proximal environment of the clay traps, suggesting an attractive effect induced by the clay minerals. Lipid compounds sorbed during the immersion were essentially fatty acids and aromatic compounds. Their distributions were closer to a phytoplankton signature than allochtonous pedogenetic OM. The sorption was particularly efficient in the O2transition zone, with a greater amount of OM on Na-MMt than Kaol. This was principally due to the high specific surface area and cationic exchange capacity (CEC) of the 2/1 clay mineral. Besides, XRD characterization revealed an increase in Na MMt interlayer spacing, which did not necessarily correspond to organic intercalation. The study confirms that the sorption of dissolved OM cannot alone explain the preservation of hydrocarbon-rich OM in such a lacustrine environment. Indeed, the sorbed OC was very low compared with the amount proposed by several authors as an expression of the monolayer equivalent principle.

    DOI

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    12
    被引用数
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  • Adsorption of diclofenac onto organoclays: Effects of surfactant and environmental (pH and temperature) conditions

    Tiago De Oliveira, Regis Guegan, Thomas Thiebault, Claude Le Milbeau, Fabrice Muller, Vinicius Teixeira, Marcelo Giovanela, Mohammed Boussafir

    JOURNAL OF HAZARDOUS MATERIALS   323   558 - 566  2017年02月

     概要を見る

    Among pharmaceutical products (PPs) recalcitrant to water treatments, diclofenac shows a high toxicity and remains at high concentration in natural aquatic environments. The aim of this study concerns the understanding of the adsorption mechanism of this anionic PP onto two organoclays prepared with two long-alkyl chains cationic surfactants showing different chemical-nature for various experimental pH and temperature conditions. The experimental data obtained by a set of complementary techniques (X-ray diffraction, elemental analyses, gas chromatography coupled with mass spectrometry, and Fourier transform infrared spectroscopy) and the use of Langmuir, Freundlich and Dubinin-Radushkevish equation models, reveal that organoclays show a good affinity to diclofenac which is enhanced as the temperature is under 35 degrees C and for pH above 4.5 (i.e. &gt;pKa of diclofenac) while the chemical nature of surfactant appears to play a minor role. The thermodynamic parameters derived from the fitting procedure point out the strong electrostatic interaction with organic cations adsorbed within the interlayer space in the organoclays for the adsorption of diclofenac. This study stress out the application of organoclays for the adsorption of a recalcitrant PPs in numerous aquatic compartments that can be used as a complement with activated carbon for waste water treatment. (C) 2016 Elsevier B.V. All rights reserved.

    DOI PubMed

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    110
    被引用数
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  • Advances in Functionalized Materials Research 2016

    Daniela Predoi, Mikael Motelica-Heino, Regis Guegan, Philippe Le Coustumer

    JOURNAL OF NANOMATERIALS    2017年  [査読有り]

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  • Magnetite (Fe3O4) nanoparticles as adsorbents for As and Cu removal

    Simona Liliana Iconaru, Regis Guegan, Cristina Liana Popa, Mikael Motelica-Heino, Carmen Steluta Ciobanu, Daniela Predoi

    APPLIED CLAY SCIENCE   134   128 - 135  2016年12月  [査読有り]

     概要を見る

    The aim of this study consisted to develop novel synthetic magnetite nanoparticles (nFe(3)O(4)) with preferential reactivity to trace elements (TE) for possible environmental applications as adsorbents. The synthetic magnetite materials obtained through the co-precipitation of both Fe3+ and Fe2+ ions (Fe2+ / Fe3+ = 0.5) were characterized by a set of complementary techniques: X-ray diffraction, transmission and scanning electron microscopy, Fourier transform infrared and Raman spectroscopy, and BET adsorption method. The resulting nFe(3)O(4) displayed a wide specific surface area (100 m(2) g(-1)) with particles reaching a size of about 10 nm, smaller than those of the well-crystallized commercial ones (cFe(3)O(4)) estimated at 80 nm while showing a BET surface area of 6.8 m(2) The adsorption properties of the synthetic nFe(3)O(4) magnetite nanoparticles were characterized and compared to the commercial analogous with the adsorption of both As and Cu. The equilibrium adsorption isotherms were properly fitted with Langmuir and Freundlich equation models and suggested that the developed iron oxides nanoparticles display a certain potential for removal and/or immobilization of TE from contaminated waters and/or soils, with an increase of 69.5% of the adsorbed amount compared to that of the commercial ones. (C) 2016 Elsevier B.V. All rights reserved.

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    75
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  • Confinement of a nonionic surfactant membrane within a montmorillonite as a new way to prepare organoclay materials

    ゲガン

    Mater. Res.   19 ( 6 ) 1324 - 1328  2016年11月  [査読有り]

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  • Coupled Organoclay/Micelle Action for the Adsorption of Diclofenac

    Tiago De Oliveira, Regis Guegan

    ENVIRONMENTAL SCIENCE & TECHNOLOGY   50 ( 18 ) 10209 - 10215  2016年09月  [査読有り]

     概要を見る

    A Na-smectite clay mineral (Na-Mt) was exchanged with various amounts of benzyldimethyltetradecyl ammonium chloride cationic surfactant (BDTAC) up to four times the cation exchange capacity (CEC). The adsorption properties of these organoclays as well as a coupled micelle/organoclay process were evaluated to remove an anionic pharmaceutical product, the diclofenac (DCF), recognized as a recalcitrant compound for conventional water treatments and to be poorly adsorbed onto untreated clay mineral. The DCF affinity appears to depend on the lipophilic character of organoclays in correlation to the density of intercalated BDTA and is particularly enhanced for sorbent systems with free surfactant or micelle in solution. The combination of both organclay and BDTA in excess or micelle as a one pot adsorption system appears to be the most efficient material for the sequestration of DCF and other pharmaceutical products (PPs) with a K-F Freundlich constant of 1.7 L g(-1) and no restriction of the adsorbed DCF amount as the linear adsorption isotherm shows. A BDTA hydrophobic core micelle coupled with a positive electric charge forms an organic complex with DCF that is properly intercalated within the interlayer space of BDTA-Mt organoclays as both Fourier transform infrared (FTIR) and X-ray diffraction (XRD) data supported.

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    28
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  • Zinc-rich clays in supergene non-sulfide zinc deposits

    ゲガン

    Miner. Deposita   51 ( 4 ) 467 - 490  2016年04月  [査読有り]

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    17
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  • Organic matter-clay interaction along a seawater column of the Eastern Pacific upwelling system (Antofagasta bay, Chile): implications for source rock organic matter preservation

    ゲガン

    Marine Chem.   179   23 - 33  2016年02月  [査読有り]

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    17
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  • Competitive adsorption of a pool of pharmaceuticals onto a raw clay mineral

    T. Thiebault, M. Boussafir, L. Le Forestier, C. Le Milbeau, L. Monnin, R. Guegan

    RSC ADVANCES   6 ( 69 ) 65257 - 65265  2016年  [査読有り]

     概要を見る

    The removal of a Pharmaceutically Active Compound (PhAC) pool using a well referenced clay mineral from Wyoming (SWy-2) as a geosorbent was studied for a better understanding of the environmental fate. As expected, the selected material shows its particular adsorption properties to PhAC under different experimental conditions with two main features depending on the chemical nature of the emerging micro-pollutants. Cationic PhACs, for which the driving force for their adsorption results from electrostatic interaction via the exchange with the inorganic cations of the clay mineral, are almost completely removed for all studied experimental conditions where it appears that the S/L ratio plays a minor role and the only one limitation for their removal is the cation exchange capacity of the adsorbent. In contrast, anionic and neutral PhACs are adsorbed to the clay mineral surface (silanol groups on the sheet edges, inorganic cations.) through other interactional mechanisms involving ion-dipole, van der Waals interaction, leading to a competition of all organic molecules where their chemical nature (electric charge, hydrophobicity) may also play a role in their adsorption. While the adsorption of ketoprofen, naproxen, diclofenac and salicylic acid anionic PhACs slightly increases with the increase of the S/L ratio, the removal of the neutral and the other anionic PhACs (gemfibrozil and ibuprofen) seems to be independent of that ratio and is particularly enhanced. The efficiency of the removal for a global pool of PhACs even in low S/L ratio stresses the control of the selected natural minerals on the dynamics of PhACs in the environment.

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    26
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  • Structural and Biological Assessment of Zinc Doped Hydroxyapatite Nanoparticles

    Cristina Liana Popa, Aurelien Deniaud, Isabelle Michaud-Soret, Regis Guegan, Mikael Motelica-Heino, Daniela Predoi

    JOURNAL OF NANOMATERIALS    2016年  [査読有り]

     概要を見る

    The aim of the current research work was to study the physicochemical and biological properties of synthesized zinc doped hydroxyapatite (ZnHAp) nanoparticles with Zn concentrations x(Zn) = 0 (HAp), x(Zn) = 0.07 (7ZnHAp), and x(Zn) = 0.1 (10ZnHAp) for potential use in biological applications. The morphology, size, compositions, and incorporation of zinc into hydroxyapatite were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), Raman scattering, and X-Ray Photoelectron Spectroscopy (XPS). In addition, the cytotoxicity of ZnHAp nanoparticles was tested on both E. coli bacteria and human hepatocarcinoma cell line HepG2. The results showed that ZnHAp nanoparticles (HAp, 7ZnHAp, and 10ZnHAp) have slightly elongated morphologies with average diameters between 25 nm and 18 nm. On the other hand, a uniform and homogeneous distribution of the constituent elements (calcium, phosphorus, zinc, and oxygen) in the ZnHAp powder was noticed. Besides, FTIR and Raman analyses confirmed the proper hydroxyapatite structure of the synthesized ZnHAp nanoparticles with the signature of phosphate, carbonate, and hydroxyl groups. Moreover, it can be concluded that Zn doping at the tested concentrations is not inducing a specific prokaryote or eukaryote toxicity in HAp compounds.

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    48
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  • Carbon Nanotubes-Hydroxyapatite Nanocomposites for an Improved Osteoblast Cell Response

    Sabrina Constanda, Miruna Silvia Stan, Carmen Steluta Ciobanu, Mikael Motelica-Heino, Regis Guegan, Khalid Lafdi, Anca Dinischiotu, Daniela Predoi

    JOURNAL OF NANOMATERIALS   2016   75  2016年  [査読有り]

     概要を見る

    An alternative and simple coprecipitation method was developed to obtain carbon nanotube-hydroxyapatite (CNTs:HAp) based nanocomposites. The incorporation of CNTs (in a concentration of 5% and 10% of total weight of the nanocomposite) and their impact on both structural and biological properties were studied by using a set of standard complementary biological, microscopic, and spectroscopic techniques. The characteristic peaks of carbon structure in CNTs were not observed in the CNTs-HAp composites by X-ray diffraction analysis. Moreover, FTIR and Raman spectroscopies confirmed the presence of HAp as the main phase of the synthesized CNTs: HAp nanocomposites. The addition of CNTs considerably affected the nanocomposite morphology by increasing the average crystallite size from 18.7 nm (for raw HAp) to 28.6 nm (for CNTs:HAp-10), confirming their proper incorporation. The biocompatibility evaluation of CNTs:HAp-5 and CNTs:HAp-10 nanocomposites included the assessment of several parameters, such as cell viability, antioxidant response, and lipid peroxidation, on human G-292 osteoblast cell line. Our findings revealed good biocompatibility properties for CNTs: HAp nanocomposites prepared by the coprecipitation method supporting their potential uses in orthopedics and prosthetics.

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    22
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  • Competitive adsorption of a pool of pharmaceuticals onto a raw clay mineral (vol 6, pg 65257, 2016)

    T. Thiebault, M. Boussafir, L. Le Forestier, C. Le Milbeau, L. Monnin, R. Guegan

    RSC ADVANCES   6 ( 73 ) 69312 - 69312  2016年  [査読有り]

    DOI

  • Clayey-sand filter for the removal of pharmaceuticals: Percolation experiments

    ゲガン

    Environ. Sci.: Water Res. Technol.   2 ( 3 ) 529 - 538  2016年  [査読有り]

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    21
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  • Sandwich organization of non-ionic surfactant liquid crystalline phases as induced by large inorganic K4Nb6O17 nanosheets

    R. Guegan, K. Sueyoshi, S. Anraku, S. Yamamoto, N. Miyamoto

    CHEMICAL COMMUNICATIONS   52 ( 8 ) 1594 - 1597  2016年  [査読有り]

     概要を見る

    While retaining its lamellar liquid crystal phase, K4Nb6O17 nanosheets were used as a template to sandwich and stabilize an alkylpoly(ethylene oxide) nonionic surfactant-water system showing monodomain (lamella) formation within the inorganic niobate sheets that appears to be not dependent on the surfactant liquid crystalline state in solution but more its concentration.

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    12
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  • Adsorption mechanisms of emerging micro-pollutants with a clay mineral: Case of tramadol and doxepine pharmaceutical products

    Thomas Thiebault, Regis Guegan, Mohammed Boussafir

    JOURNAL OF COLLOID AND INTERFACE SCIENCE   453   1 - 8  2015年09月  [査読有り]

     概要を見る

    A sodium exchanged smectite clay mineral (Mt) was used as geo-sorbent for the adsorption of tramadol and doxepin: two pharmaceutical products (PPs) defined as emerging pollutants due to their presence at significant concentration in numerous water compartments. The adsorption isotherms for both the temperatures of 20 and 40 degrees C and the derived data determined through the fitting procedure by using Langmuir, Freundlich and Dubinin-Radushkevich equation models explicitly pointed out that the sorption of both tramadol and doxepin is mainly driven by electrostatic interaction. The studied PPs are intercalated in a monolayer arrangement within the interlayer space through a cation exchange in stoichiometric proportion with the Na+ cations leading to adsorbed PPs amounts that match the cation exchange capacity (CEC) of Mt. Due to their hydrophobic character, additional doxepin molecules could be adsorbed by weak molecular interaction driving to an increase of the adsorbed amount beyond the CEC at low temperature (20 degrees C). The confinement of PPs within the interlayer space of Mt confirms the use of clay minerals as potential material for the wastewater treatment as well as it drives to an amorphous or glassy state, which can find echo in biopharmaceutical applications for a controlled release of PPs. (C) 2015 Elsevier Inc. All rights reserved.

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    75
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  • SYNTHESIS, CHARACTERIZATION AND CYTOTOXICITY EVALUATION ON ZINC DOPED HYDROXYAPATITE IN COLLAGEN MATRIX

    C. L. Popa, C. M. Bartha, M. Albu, R. Guegan, M. Motelica-Heino, M. C. Chifiriuc, C. Bleotu, M. L. Badea, S. Antohe

    DIGEST JOURNAL OF NANOMATERIALS AND BIOSTRUCTURES   10 ( 2 ) 681 - 691  2015年04月  [査読有り]

     概要を見る

    The goal of this study was to obtain at low temperature a functional nano-composite with characteristics similar to the natural bone by using a cost effective method. The structure and morphology of collagen coated zinc doped hydroxyapatite bio-composites (Zn:HAp-CBc) were examined by X-Ray diffraction (XRD) and Scanning Electron Microscopy (SEM). XRD analysis revealed that the unique hexagonal Ca-10(PO4)(6)(OH)(2) in P-63m space group was observed in the obtained nanocomposites Zn: HAp-CBc. The cytotoxicity of the Zn: HAp-CBc was studied on HeLa cell lines. Cell cycle distribution after treatment was examined by flow cytometry analysis. Our preliminary in vitro studies revealed that the obtained composites based on Zn doped HAp embedded in collagen matrix have excellent biocompatibility and support their further characterization by in vivo approaches and development as a biomaterial used in bone regeneration.

  • Biopolymer nanocomposites based on poly(hydroxybutyrate-co-hydroxyvalerate) reinforced by a non-ionic organoclay

    Larissa N. Carli, Tales S. Daitx, Regis Guegan, Marcelo Giovanela, Janaina S. Crespo, Raquel S. Mauler

    POLYMER INTERNATIONAL   64 ( 2 ) 235 - 241  2015年02月  [査読有り]

     概要を見る

    In this study, a nanocomposite based on a biodegradable polymer poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) reinforced by triethylene glycol mono-n-decyl ether (C10E3) non-ionic organoclay (C10E3-Mt) was prepared. The morphology and the thermal and mechanical properties of PHBV/C10E3-Mt were compared with those of PHBV nanocomposites prepared using commercial organically modified montmorillonite Cloisite((R)) 30B (OMt) and raw montmorillonite (Mt). Nanocomposites with 3wt% nanoparticles were obtained by melt processing. The high level of dispersion with improved interfacial interactions between OMt and polymer led to an increase in the thermal stability and modulus of PHBV. However, this nanocomposite presented a lower strain before fracture, typical of brittle behavior. The transmission electron microscopy and wide angle X-ray diffraction results revealed a significant increase in the interlayer spacing of clay for the PHBV/C10E3-Mt nanocomposite, which was favored by the wide expansion of the platelets of the starting non-ionic organoclay. This characteristic of C10E3-Mt, together with its hydrophobic behavior, allowed its easy incorporation in the PHBV matrix, thus improving the processing and maintaining a high modulus with increased material toughness. (c) 2014 Society of Chemical Industry

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    20
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  • Removal of methyl violet 2B dye from aqueous solution using amagnetic composite as an adsorbent

    ゲガン

    J. Water Res. Pro. Eng.   6   11 - 20  2015年  [査読有り]

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    101
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  • Nonionic organoclay: a ‘swiss army knife’ for the adsorption of micro-pollutants?

    ゲガン

    J. Colloid Interface Sci.   437 ( 1 ) 71 - 79  2015年01月  [査読有り]

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    47
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  • Systematic investigation and in vitro biocompatibility studies on mesoporous europium doped hydroxyapatite

    Cristina L. Popa, Carmen S. Ciobanu, Simona L. Iconaru, Miruna Stan, Anca Dinischiotu, Constantin C. Negrila, Mikael Motelica-Heino, Regis Guegan, Daniela Predoi

    CENTRAL EUROPEAN JOURNAL OF CHEMISTRY   12 ( 10 ) 1032 - 1046  2014年10月  [査読有り]

     概要を見る

    This paper reports the systematic investigation of europium doped hydroxyapatite (Eu:HAp). A set of complementary techniques, namely Fourier Transform Infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and the Brunauer-Emmett-Teller (BET) technique were used towards attaining a detailed understanding of Eu:HAp. The XPS analysis confirmed the substitution of Ca ions by Eu ions in the Eu:HAp samples. Secondly, Eu:HAp and pure HAp present type IV isotherms with a hysteresis loop at a relative pressure (P/P-0) between 0.4 and 1.0, indicating the presence of mesopores. Finally, the in vitro biological effects of Eu:HAp nanoparticles were evaluated by focusing on the F-actin filament pattern and heat shock proteins (Hsp) expression in HEK293 human kidney cell line. Fluorescence microscopy studies of the actin protein revealed no changes of the immunolabelling profile in the renal cells cultured in the presence of Eu:HAp nanoparticles. Hsp60, Hsp70 and Hsp90 expressions measured by Western blot analysis were not affected after 24 and 48 hours exposure. Taken together, these results confirmed the lack of toxicity and the biocompatibility of the Eu:HAp nanoparticles. Consequently, the possibility of using these nanoparticles for medical purposes without affecting the renal function can be envisaged.

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    23
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  • Effect of organic amendments on the mobility of trace elements in phytoremediated techno-soils: role of the humic substances

    N. Hattab, M. Soubrand, R. Guegan, M. Motelica-Heino, X. Bourrat, O. Faure, J. L. Bouchardon

    ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH   21 ( 17 ) 10470 - 10480  2014年09月  [査読有り]

     概要を見る

    The efficiency of aided phytostabilization using organic amendments such as ramial chipped wood (RCW) and composted sewage sludge (CSS) was studied on contaminated techno-soils, on nine experimental plots. The objective was to characterize the role of fulvic (FA) and humic acids (HA) on the mobilization of trace elements, specifically As, Cu, Mo, Pb and Zn. Results showed that the addition of CSS increased the total organic carbon and nitrogen content more than with RCW and as a result, the C/N ratio in the CSS soil was higher than in the RCW and non-amended (NE) soil, reflecting the high decomposition of soil organic matter in the CSS soil compared with the other soils. The RCW and CSS amendments increased the hydrogen index (HI) values and the oxygen index (OI) values compared with the NE soil, especially for the soil treated with CSS which contained more aliphatic than aromatic compounds. The addition of CSS to the techno-soil significantly increased the percentage of C-org associated with the HA fractions compared with the RCW and NE soils. The soil amended with CSS showed the highest E-4/E-6 ratio and the lowest E-2/E-3 ratio of FA. Zn and As were more abundant in the FA fraction than in the HA fraction, whereas Pb, Cu and Mo were more associated to HA than to FA in the treated and untreated soils, which may explain the difference in their mobility and availability.

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    36
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  • BSA and lysozyme adsorption on homoionic montmorillonite: Influence of the interlayer cation

    Mathilde Lepoitevin, Maguy Jaber, Regis Guegan, Jean-Marc Janot, Philippe Dejardin, Francois Henn, Sebastien Balme

    APPLIED CLAY SCIENCE   95 ( 396 ) 396 - 402  2014年06月  [査読有り]

     概要を見る

    This study aims to investigate the influence of interlayer cation alkali metal series (Li+, Na+, K+, Rb+, Cs+) and alkali earth metal (Mg2+, Ca2+, Ba2+) on adsorption of model proteins (lysozyme and bovine serum albumin). The localizations of both proteins and their conformational modifications in the interlayer space of the natural clay mineral were studied by X-ray diffraction, transmission electronic microscopy and fluorescence experiments. Based on Langmuir model isotherms, a strong influence of interlayer cation on maximum adsorbed amount and adsorption equilibrium constant has been observed. However the usual kosmotrope/chaotrope classification cannot be used to describe protein adsorption. (C) 2014 Elsevier B.V. All rights reserved.

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    54
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  • Characterization of Brazilian Peat Samples by Applying a Multimethod Approach

    F. Girardello, R. Guegan, V. I. Esteves, I. J. R. Baumvol, M. M. D. Sierra, J. S. Crespo, A. N. Fernandes, M. Giovanela

    SPECTROSCOPY LETTERS   46 ( 3 ) 201 - 210  2013年04月  [査読有り]

     概要を見る

    Peat is a mixture of compounds formed by the decomposition of plant residues and mineral materials that have accumulated at the bottom of ponds and flooded depressions in riverine areas. Due to their extreme heterogeneity and natural variety, the physical and chemical properties of peat can vary widely within or between deposits, and the characterization of isolated samples is still a challenging task that requires the combination of several chemical and spectroscopic methodologies. In this study, the structural characteristics of two Brazilian peat samples were evaluated using scanning electron microscopy (SEM), elemental (CHNS-O) and thermal (TGA) analysis, X-ray diffraction (XRD), and infrared (FT-IR) and solid-state C-13-nuclear magnetic resonance (C-13-NMR) spectroscopies. Although the samples originated from the same peatland, the data showed that the studied samples have distinct chemical properties and that the stage of decomposition played an important role in the differences observed.

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    16
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  • REMOVAL OF DICLOFENAC SODIUM FROM AQUEOUS SOLUTION BY ISABEL GRAPE BAGASSE

    M. Antunes, V. I. Esteves, R. Guegan, J. S. Crespo, A. N. Fernandes, M. Giovanela

    PROCEEDINGS OF THE 13TH INTERNATIONAL CONFERENCE ON ENVIRONMENTAL SCIENCE AND TECHNOLOGY    2013年  [査読有り]

     概要を見る

    A promising alternative for the treatment of effluents that contain pharmaceuticals concerns the adsorption processes that utilize agro-industrial wastes as adsorbents as a substitute for activated carbon. These processes have certain advantages from both economic and environmental points of view, such as availability, abundance, the renewable nature of the adsorbent material, and low cost. In the State of Rio Grande do Sul (Brazil), the grape bagasse is produced on a large scale. In most cases, the waste coming from wineries is disposed directly onto the soil of vineyards resulting in several environmental damages. Thus, the reuse of this biosorbent in adsorption processes can be a way to help manage solid wastes from wine industry. In view of these facts, the aim of the present work was to evaluate the adsorption capacity of the Isabel grape bagasse (Vitis labrusca x Vitis vinifera) in the removal of the DCF. In general way, it was observed that the adsorption process for DCF concentrations greater than 10.0 mg L-1 occurred in two stages. The pseudo-second-order kinetic model was more significant in the rate-controlling step in the first stage. In addition, the removal percentage (similar to 20%) was similar for all concentrations studied. For the second step, on the other hand, the intraparticle diffusion process showed the best fit to the experimental data and the removal percentage increased with increasing initial concentration of the drug (from 57 to 74%). Concerning to the equilibrium process, the Freundlich isotherm showed the best fit to the experimental results at 22 degrees C, and the adsorption of DCF onto grape bagasse presented a value of K-F and n equal to 1.72 g L-1 and 1.18, respectively. From the thermodynamic point of view, the process was exothermic, non-spontaneous, occurring with a decrease in the randomness of the system.

  • Self-assembly of a non-ionic surfactant onto a clay mineral for the preparation of hybrid layered materials

    R. Guegan

    SOFT MATTER   9 ( 45 ) 10913 - 10920  2013年  [査読有り]

     概要を見る

    The adsorption of the tri-ethylene glycol mono-n-decyl ether (C10E3) nonionic surfactant, characterized by its self-assembled lamellar phase above the critical micelle concentration (cmc), in a wide range of concentration, onto a layered clay mineral (montmorillonite) has been studied. C10E3 exhibits a high affinity for the montmorillonite (Mt) surface with an adsorption isotherm that differs strictly from previous studies on the adsorption of nonionic surfactants onto clay minerals for which a maximum of adsorption was reached below cmc. The self-organization in a lamellar phase changes the interaction potential between C10E3 and Mt, a surface that favors the aggregation of normal bilayers which expands the interlayer space at wide values (&gt;40 angstrom) while keeping the exchangeable Na+ cations conferring dual hydrophilic-hydrophobic behavior for the hybrid layered materials. Depending on the C10E3 phase state (in monomers or in a lamellar phase), the adsorption leads to four distinct surfactant arrangements (lateral layers to normal tilted bilayers) within the interlayer space of Mt. The hybrid layered materials show a thermal stability at 350 degrees C with a collapse of their interlayer space at 13 angstrom due to the degradation of the hydrocarbon chains of C10E3. FTIR during thermogravimetry analysis permits the identification of the portions of C10E3 corresponding to ethylene oxide groups in close interaction with the Mt surface.

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    27
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  • Structure, orientation and stability of lysozyme confined in layered materials

    Sebastien Balme, Regis Guegan, Jean-Marc Janot, Maguy Jaber, Mathilde Lepoitevin, Philippe Dejardin, Xavier Bourrat, Mikael Motelica-Heino

    SOFT MATTER   9 ( 11 ) 3188 - 3196  2013年  [査読有り]

     概要を見る

    The confinement of lysozyme in 3 layered materials based on montmorillonite and lamellar double hydroxides exhibiting different surface charges was studied. The protein structure and orientation in these materials were determined by X-ray diffraction, time resolved fluorescence and fluorescence anisotropy. For montmorillonite exchanged with sodium and modified with a non-ionic surfactant (tri-ethylene glycol mono n-decyl ether), the lysozyme was found to be located in the interlayer space with the "end-on" and "side-on" orientations, respectively. Conversely, no lysozyme intercalation was observed with a lamellar double hydroxide modified with an anionic surfactant (sodium octylsulfate), since the protein was adsorbed on the surface of the particles. Fourier transformed infrared spectroscopy analysis shows that lysozyme confinement in the interlayer space preserves its structure after dehydration, whereas some structural changes were observed for lysozyme adsorbed on the particle surface.

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    40
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  • New Insights into the Molecular Structures, Compositions, and Cation Distributions in Synthetic and Natural Montmorillonite Clays

    Sylvian Cadars, Regis Guegan, Mounesha N. Garaga, Xavier Bourrat, Lydie Le Forestier, Franck Fayon, Tan Vu Huynh, Teddy Allier, Zalfa Nour, Dominique Massiot

    CHEMISTRY OF MATERIALS   24 ( 22 ) 4376 - 4389  2012年11月  [査読有り]

     概要を見る

    We present a detailed investigation of the molecular structure of montmorillonite, an aluminosilicate clay with important applications in materials sciences, such as for catalysis, drug delivery, or as a waste barrier. Solid-state Si-29, Al-27, Mg-25, and H-1 nuclear magnetic resonance (NMR) measurements combined with density functional theory (DFT) calculations provide a comprehensive picture of the local structure and composition of a synthetic clay and its naturally occurring analogue. A revised composition is proposed based on NMR results that allow the identification and quantification of the signatures of otherwise undetectable noncrystalline impurities, thus largely complementing the traditional elemental analyses. Solid-state H-1 NMR at fast magic-angle spinning (MAS) and high magnetic field provide quantitative information on intra- and interlayer local environments that are crucial for the determination of the amount of Mg/Al substitution within the octahedral layer. In combination with DFT calculations of energies, it suggests that pairs of adjacent Mg atoms are unfavorable, leading to a nonrandom cationic distribution within the layers.

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    71
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  • Removal of diclofenac sodium from aqueous solution by Isabel grape bagasse

    Marjore Antunes, Valdemar I. Esteves, Regis Guegan, Janaina S. Crespo, Andreia N. Fernandes, Marcelo Giovanela

    CHEMICAL ENGINEERING JOURNAL   192   114 - 121  2012年06月  [査読有り]

     概要を見る

    The aim of the present work was to evaluate the morphologic and chemical characteristics of Isabel grape (Vitis labrusca x Vitis vinifera) bagasse and to describe the adsorption of diclofenac sodium (DCF) from aqueous solutions by this biomass. Grape bagasse constituted mainly of particles with heterogeneous shapes and sizes, and it exhibited a macroporous structure and a low specific surface area (similar to 2 m(2) g(-1)). The adsorbent material was also rich in oxygenated functional groups, especially -OH, and required an acidic pH to neutralize its surface. With respect to the adsorption of DCF, the percentage removal did not appear to depend on the initial concentration of the pharmaceutical. A pseudo-second-order kinetic model described the rate-controlling step, and the adsorption isotherms were well fitted by the Freundlich model. Concerning the thermodynamic data, the results showed that the adsorption of DCF onto grape bagasse occurred via an exothermic process accompanied by a decrease in the randomness at the solid/solution interface. Furthermore, the removal percentages of DCF ranged from 16.4% to 22.8%. (C) 2012 Elsevier B.V. All rights reserved.

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    167
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  • Confinement effects on water structure in membrane lyotropic phases

    Regis Guegan

    JOURNAL OF COLLOID AND INTERFACE SCIENCE   358 ( 2 ) 485 - 490  2011年06月  [査読有り]

     概要を見る

    The change of the water structure in aqueous solutions of the tri-ethyleneglycol mono n-decyl ether (C(10)E(3)) was studied by micro Raman scattering. The results obtained on the O-H stretching band show that the behavior of the hydrogen bonding (H-bonds) water network can be used as a probe to follow the lamellar (L(alpha)) to sponge (L(3)) phase transition. In the lamellar phase, the stack of the surfactant molecules aggregated into a two-dimensional structure (membrane) acts as a soft confinement system for the H-bond water network of which the regular tetrahedral structure is perturbed. The change of the planar organization of the membranes to a highly disordered and infinite array of bilayers in the sponge phase amplifies the surface of contact between amphiphilic surfactant and water molecules which drives a strong disruption of the regular tetrahedral H-bonding water network. (C) 2011 Elsevier Inc. All rights reserved.

    DOI

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  • CHANGES IN THE STRUCTURE OF MgxAly(OH)(z) LAYERED DOUBLE HYDROXIDES DURING THE ADSORPTION OF ORGANIC COMPOUNDS

    E. O. Butenko, E. V. Kapustina, A. E. Kapustin, V. S. Kravchenko, S. A. Gromilov, R. Guegan

    JOURNAL OF STRUCTURAL CHEMISTRY   52 ( 2 ) 436 - 438  2011年04月  [査読有り]

     概要を見る

    Changes in the structure of synthetic MgxAly(OH)(z) layered double hydroxides are studied during the sorption of organic compounds.

  • Intercalation of a Nonionic Surfactant (C10E3) Bilayer into a Na-Montmorillonite Clay

    Regis Guegan

    LANGMUIR   26 ( 24 ) 19175 - 19180  2010年12月

     概要を見る

    A nonionic surfactant, triethylene glycol mono-n-decyl ether (C10E3), characterized by its lamellar phase state, was introduced in the interlayer of a Na-montmorillonite clay at several concentrations. The synthesized organoclays were characterized by small-angle X-ray scattering in conjunction with Fourier transform infrared spectroscopy and adsorption isotherms. Experiments showed that a bilayer of C10E3 was intercalated into the interlayer space of the naturally exchanged Na-montmorillonite, resulting in the aggregation of the lyotropic liquid crystal state in the lamellar phase. This behavior strongly differs from previous observations of confinement of nonionic surfactants in clays where the expansion of the interlayer space was limited to two monolayers parallel to the silicate surface and cationic surfactants in clays where the intercalation of organic compounds is introduced into the clay galleries through ion exchange. The confinement of a bilayer of C10E3 nonionic surfactant in clays offers new perspectives for the realization of hybrid nanomaterials, since the synthesized organoclays preserve the electrostatic characteristics of the clays, thus allowing further ion exchange while presenting at the same time a hydrophobic surface and a maximum opening of the interlayer space for the adsorption of neutral organic molecules of important size with functional properties.

    DOI

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    55
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  • Chemical and spectroscopic characterization of humic acids extracted from the bottom sediments of a Brazilian subtropical microbasin

    M. Giovanela, J. S. Crespo, M. Antunes, D. S. Adamatti, A. N. Fernandes, A. Barison, C. W. P. da Silva, R. Guegan, M. Motelica-Heino, M. M. D. Sierra

    JOURNAL OF MOLECULAR STRUCTURE   981 ( 1-3 ) 111 - 119  2010年09月  [査読有り]

     概要を見る

    Humic substances (HS) perform a fundamental role in aquatic environments, exhibiting different levels of reactivity in retaining metal ions and organic pollutants Also, they control the primary production of these ecosystems and act in the carbon sequestering process. In order to improve our understanding vis-a-vis the structural and functional features of HS from aquatic systems, this study aimed to chemically and spectroscopically characterize humic acids (HA) isolated from bottom sediment samples of a stream in a Brazilian subtropical microbasin by elemental analysis, and infrared (FT-IR), ultraviolet and visible (UV-Vis) and solid-state C-13 nuclear magnetic resonance (CP-MAS C-13 NMR) spectroscopies, thermogravimetry (TG), and scanning electron microscopy (SEM) Although all samples originated from the same environment, the data showed that the HA have distinct chemical and spectroscopic properties, and that the location and characteristics of the sampling points from which the sediments were collected played an important role in the differences observed Furthermore, vascular plant matter is probably the main contributor to these samples (C) 2010 Elsevier B.V. All rights reserved

    DOI

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    82
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  • NH4-smectite: Characterization, hydration properties and hydro mechanical behaviour

    M. Gautier, F. Muller, L. Le Forestier, J. -M. Beny, R. Guegan

    APPLIED CLAY SCIENCE   49 ( 3 ) 247 - 254  2010年07月  [査読有り]

     概要を見る

    Leachates in waste landfills are characterized by the presence of ammonium ions in large excess. These ammonium ions can be exchanged with the interlayer cations in clay and modify the physical and chemical properties of clay geochemical barriers in waste landfills and drive to environmental problems. The purpose of this study was to understand the hydro-physical changes of a smectite in the presence of ammonium ions. An ammonium smectite was prepared by cation exchange from a natural montmorillonite (Wyoming). The samples were characterized and their properties were compared by the use of a set of complementary techniques (X-ray diffraction, infrared spectroscopy, N-2 adsorption desorption BET technique, thermal analysis, and percolation experiments). The main effect was a modification of the porosity and its network, and reduced crystalline swelling. These effects changed the hydraulic conductivity and macroscopic swelling of the clay. The oedometer experiments, which allow simulating the pressure on small amounts of samples, proved the strong increase of the permeability of NH4-smectite. This last point is of great importance in an environment point of view and raises questions on the impermeability behaviour on the long term of the clay geochemical barriers with the presence of ammonium ions in waste landfills. (C) 2010 Elsevier B.V. All rights reserved.

    DOI

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    54
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  • Shrinkage of microaggregates in Brazilian Latosols during drying: significance of the clay content, mineralogy and hydric stress history

    A. Reatto, A. Bruand, E. M. Silva, R. Guegan, I. Cousin, M. Brossard, E. S. Martins

    EUROPEAN JOURNAL OF SOIL SCIENCE   60 ( 6 ) 1106 - 1116  2009年12月  [査読有り]

     概要を見る

    Latosols (Oxisols, Ferralsols) are characterized by a poor soil horizon differentiation, with a strong microgranular structure formed by microaggregates 50 to 300 mu m in size. This microgranular structure is generally considered to be very stable and the shrinkage properties of microaggregates as poor or absent. The objective of our study was to analyse the shrinkage properties of microaggregates in diagnostic Bw horizons collected in Latosols with various particle size distributions and mineralogical compositions depending on their location in a regional toposequence across the Brazilian central plateau. We measured the water retention properties at -300 and -1500 kPa with a centrifugation method. The morphology and size of elementary particles were examined by transmission electron microscopy; specific surface area (SSA) was determined by nitrogen adsorption. We also determined the pore size distribution of microaggregates by the combined use of mercury intrusion and the nitrogen desorption isotherm. Our results show that microaggregates of the Latosols studied were not rigid and shrank during drying. The pore volume of the -300 and -1500 kPa-treated samples, that of the dried microaggregates and the SSA were closely related to the clay content. The mineralogy of particles &lt; 2 mu m played a secondary role in the properties studied. Our results show that microaggregate shrinkage at -300 kPa and -1500 kPa varied with the location of the Latosols in the landscape. Thus, microaggregates of Latosols located on the upper highland surface of Late Tertiary shrank less than those of the lowland surface of Late Quaternary, and this difference was attributed to their different hydric stress histories.

    DOI

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    11
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  • ADSORPTION OF A C(10)E(3) NON-IONIC SURFACTANT ON A Ca-SMECTITE

    Regis Guegan, Mathieu Gautier, Jean-Michel Beny, Fabrice Muller

    CLAYS AND CLAY MINERALS   57 ( 4 ) 502 - 509  2009年08月  [査読有り]

     概要を見る

    The transformation of clay minerals into organo-clays by surfactant intercalation is of great environmental and industrial importance because it causes the clay to attract hydrophobic contaminants and other non-polar organic compounds, but a better understanding is needed of the mechanisms by which different classes of surfactants are intercalated. The purpose of this study was to synthesize and characterize an organo-clay comprising triethylene glycol monodecyl ether (C(10)E(3)) non-ionic surfactant, which has a lamellar phase at room temperature, intercalated into Ca-montmorillonite from Wyoming (SWy-2). The C(10)E(3) non-ionic surfactant differed from previous non-ionic surfactants used in the formation of a lamellar phase in that it consisted of the stacking of molecules by hydrophobic interaction. C(10)E(3)-clay composites were characterized by complementary techniques (adsorption isotherms, X-ray diffraction, and infrared spectroscopy) and were compared to benzyldimethyltetradecyl ammonium chloride (BDTAC) cationic surfactant-clay composites for different loadings of the surfactant. For large loadings, the amount of C(10)E(3) adsorbed, which can be described by the Langmuir equation, seemed to reach a steady state close to that of the cationic surfactant. The adsorption processes of the two surfactants were different. For the cationic surfactant, the adsorption, as described in the literature, was due to ion exchange between organic cations and Ca(2+) counterions. The adsorption of C(10)E(3) did not depend on electrostatic interaction but rather was due to several interaction mechanisms (H-bonding, ion-dipole, and hydrophobic interaction). For both surfactants, the expansion was limited to two adsorbed monolayers parallel to the clay surface. The expansion of the basal spacing to 17 angstrom suggested a complete dissociation of the C(10)E(3) lamellar phase when adsorbed on the Ca-smectite. Organo-clays made using the non-ionic surfactant were stable, changing the chemical nature of clay to hydrophobic, and allowing for other cations to be exchanged, which has importance in the manufacture of new nanocomposites or geochemical barriers.

    DOI

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    28
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  • Relation between static short-range order and dynamic heterogeneities in a nanoconfined liquid crystal

    Ronan Lefort, Denis Morineau, Regis Guegan, Mohammed Guendouz, Jean-Marc Zanotti, Bernhard Frick

    PHYSICAL REVIEW E   78 ( 4 )  2008年10月

     概要を見る

    We analyze the molecular dynamics heterogeneity of the liquid crystal 4-n-octyl-4(&apos;)-cyanobiphenyl nanoconfined in porous silicon. We show that the temperature dependence of the dynamic correlation length xi(wall), which measures the distance over which a memory of the interfacial slowing down of the molecular dynamics persists, is closely related to the growth of the short-range static order arising from quenched random fields. More generally, this result may also shed some light on the connection between static and dynamic heterogeneities in a wide class of condensed and soft matter systems.

    DOI

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    30
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  • Rich polymorphism of a rod-like liquid crystal (8CB) confined in two types of unidirectional nanopores

    R. Guegan, D. Morineau, R. Lefort, W. Beziel, M. Guendouz, L. Noirez, A. Henschel, P. Huber

    EUROPEAN PHYSICAL JOURNAL E   26 ( 3 ) 261 - 273  2008年07月

     概要を見る

    We present a neutron and X-rays scattering study of the phase transitions of 4-n-octyl-4' -cyanobiphenyl (8CB) confined in unidirectional nanopores of porous alumina and porous silicon (PSi) membranes with an average diameter of 30nm. Spatial confinement reveals a rich polymorphism, with at least four different low temperature phases in addition to the smectic A phase. The structural study as a function of thermal treatments and conditions of spatial confinement allows us to get insights into the formation of these phases and their relative stability. It gives the first description of the complete phase behavior of 8CB confined in PSi and provides a direct comparison with results obtained in bulk conditions and in similar geometric conditions of confinement but with reduced quenched disorder effects using alumina anopore membranes.

    DOI

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    32
    被引用数
    (Scopus)
  • Sliding and translational diffusion of molecular phases confined into nanotubes

    R. Busselez, C. Ecolivet, R. Guegan, R. Lefort, D. Morineau, B. Toudic, M. Guendouz, F. Affouard

    INTERNATIONAL JOURNAL OF NANOTECHNOLOGY   5 ( 6-8 ) 867 - 884  2008年

     概要を見る

    The remaining dynamical degrees of freedom of molecular fluids confined into capillaries of nano to sub-nanometre diameter are of fundamental relevance for future developments in the field of nanofluidics. These properties cannot be simply deduced from the bulk one since the derivation of macroscopic hydrodynamics most usually breaks down in nanoporous channels and additional effects have to be considered. In the present contribution, we review some general phenomena, which are expected to occur when manipulating fluids under confinement and ultraconfinement conditions.

    DOI

    Scopus

    4
    被引用数
    (Scopus)
  • Incoherent quasielastic neutron scattering study of molecular dynamics of 4-n-octyl-4&apos;-cyanobiphenyl

    Ronan Lefort, Denis Morineau, Regis Guegan, Claude Ecolivet, Mohammed Guendouz, Jean-Marc Zanotti, Bernhard Frick

    PHYSICAL CHEMISTRY CHEMICAL PHYSICS   10 ( 20 ) 2993 - 2999  2008年

     概要を見る

    We report incoherent quasielastic neutron scattering experiments on the thermotropic liquid crystal 4-n-octyl-40-cyanobiphenyl. The combination of time-of-flight and backscattering data allows analysis of the intermediate scattering function over about three decades of relaxation times. Translational diffusion and uniaxial molecular rotations are clearly identified as the major relaxation processes in, respectively, the nanosecond and picosecond time scales.

    DOI

    Scopus

    10
    被引用数
    (Scopus)
  • Dynamics of 8CB confined into porous silicon probed by incoherent neutron backscattering experiments

    R. Guegan, R. Lefort, W. Beziel, D. Morineau, M. Guendouz, B. Frick

    EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS   141   29 - 34  2007年02月

     概要を見る

    Confinement in the nanochannels of porous silicon strongly affects the phase behavior of the archetype liquid-crystal 4-n-octyl-4-cyanobiphenyl (8CB). A very striking phenomenon is the development of a short-range smectic order, which occurs on a very broad temperature range. It suggests in this case that quenched disorder effects add to usual finite size and surface interaction effects. We have monitored the temperature variation of the molecular dynamics of the confined fluid by incoherent quasielastic neutron scattering. A strongly reduced mobility is observed at the highest temperatures in the liquid phase, which suggests that the interfacial molecular dynamics is strongly hindered. A continuously increasing slowdown appears on cooling together with a progressive growth of the static correlation length.

    DOI

    Scopus

    2
    被引用数
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  • Molecular dynamics of a short-range ordered smectic phase nanoconfined in porous silicon

    R. Guegan, D. Morineau, R. Lefort, A. Moreac, W. Beziel, M. Guendouz, J. -M. Zanotti, B. Frick

    JOURNAL OF CHEMICAL PHYSICS   126 ( 6 )  2007年02月

     概要を見る

    4-n-octyl-4-cyanobiphenyl has been recently shown to display an unusual sequence of phases when confined into porous silicon (PSi). The gradual increase of oriented short-range smectic (SRS) correlations in place of a phase transition has been interpreted as a consequence of the anisotropic quenched disorder induced by confinement in PSi. Combining two quasielastic neutron scattering experiments with complementary energy resolutions, the authors present the first investigation of the individual molecular dynamics of this system. A large reduction of the molecular dynamics is observed in the confined liquid phase, as a direct consequence of the boundary conditions imposed by the confinement. Temperature fixed window scans reveal a continuous glasslike reduction of the molecular dynamics of the confined liquid and SRS phases on cooling down to 250 K, where a solidlike behavior is finally reached by a two-step crystallization process. (c) 2007 American Institute of Physics.

    DOI

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    37
    被引用数
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  • Structure and relaxation processes of an anisotropic molecular fluid confined into 1D nanochannels

    R. Lefort, D. Morineau, R. Guegan, A. Moreac, C. Ecolivet, M. Guendouz

    PHILOSOPHICAL MAGAZINE   87 ( 3-5 ) 469 - 476  2007年01月

     概要を見る

    Structural order parameters of a smectic liquid crystal confined into columnar form of porous silicon are studied using neutron scattering and optical spectroscopic techniques. It is shown that both the translational and orientational anisotropic properties of the confined phase strongly couple to the one-dimensional character of the porous silicon matrix. The influence of this confinement induced anisotropic local structure on the molecular reorientations occuring in the picosecond timescale is discussed.

    DOI

    Scopus

    4
    被引用数
    (Scopus)
  • Evidence of anisotropic quenched disorder effects on a smectic liquid crystal confined in porous silicon

    R Guegan, D Morineau, C Loverdo, W Beziel, M Guendouz

    PHYSICAL REVIEW E   73 ( 1 )  2006年01月

     概要を見る

    We present a neutron scattering analysis of the structure of the smectic liquid crystal octylcyanobiphenyl (8CB) confined in one-dimensional nanopores of porous silicon films (PS). The smectic transition is completely suppressed, leading to the extension of a short-range ordered smectic phase aligned along the pore axis. It evolves reversibly over an extended temperature range, down to 50 K below the N-SmA transition in pure 8CB. This behavior strongly differs from previous observations of smectics in different one-dimensional porous materials. A coherent picture of this striking behavior requires that quenched disorder effects are invoked. The strongly disordered nature of the inner surface of PS acts as random fields coupling to the smectic order. The one-dimensionality of PS nanochannels offers perspectives on quenched disorder effects, of which observation has been restricted to homogeneous random porous materials so far.

    DOI

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    56
    被引用数
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  • Interfacial structure of an H-bonding liquid confined into silica nanopore with surface silanols

    R Guegan, D Morineau, C Alba-Simionesco

    CHEMICAL PHYSICS   317 ( 2-3 ) 236 - 244  2005年10月  [査読有り]

     概要を見る

    Molecular computer simulation has been performed on liquid methanol confined into silica cylindrical pores with diameter D = 24 angstrom. It has been motivated by recent conclusions obtained from neutron scattering experiments in similar conditions of confinement. A central issue is the influence of H-bond interactions within the fluid and between the fluid and the pore surface on the local structure of the liquid. It relies on the use of a realistic atomic description of the porous silicate and the chemical nature of the surface. A description of the interfacial interactions and the spatial correlations has been achieved in terms of energy distribution functions and density radial distribution functions. It shows that surface silanols significantly affect the spatial arrangement of the interfacial methanol molecules, which occupy half the pore volume. In addition, the effects of the surface boundary conditions propagate into the entire volume through layering and orientation order. (C) 2005 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    59
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  • Structure of liquid and glassy methanol confined in cylindrical pores

    D Morineau, R Guegan, YD Xia, C Alba-Simionesco

    JOURNAL OF CHEMICAL PHYSICS   121 ( 3 ) 1466 - 1473  2004年07月

     概要を見る

    We present a neutron scattering analysis of the density and the static structure factor of confined methanol at various temperatures. Confinement is performed in the cylindrical pores of MCM-41 silicates with pore diameters D=24 and 35 Angstrom. A change of the thermal expansivity of confined methanol at low temperature is the signature of a glass transition, which occurs at higher temperature for the smallest pore. This is evidence of a surface induced slowing down of the dynamics of the fluid. The structure factor presents a systematic evolution with the pore diameter, which has been analyzed in terms of excluded volume effects and fluid-matrix cross correlation. Conversely to the case of Van der Waals fluids, it shows that stronger fluid-matrix correlations must be invoked most probably in relation with the H-bonding character of both methanol and silicate surface. (C) 2004 American Institute of Physics.

    DOI

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    63
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▼全件表示

学内研究費(特定課題)

  • Singular colloidal organizations made of nonionic surfactants and MXene flakes

    2021年  

     概要を見る

    Organoclays (e.g. clay minerals modified by surfactants) are hybrid layeredmaterials combining a hydrophobic surface and a large interlayer space. Those materialscan be used with success as adsorbents for the removal of various types oforganic pollutants, including hydrophobic ones such as emerging pollutants(pharmaceuticals, pesticides, herbicides…). However, the final adsorptionproperties of organoclays mainly depend on the type of surfactants associatedwith the clay mineral, as well as its loadings and/or organization. The associationof a clay mineral (montmorillonite) with several nonionic surfactants ofdifferent moieties was studied and their adsorption properties was studied byfocusing on recalcitrant herbicides of diverse hydrophilic lipophilic balance. Byshowing a dual display hydrophilic and hydrophobic surface, the nonionicorganoclays (e. g. organoclays prepared with nonionic surfactants) appear as versatileadsorbents for the whole studied herbicides.&nbsp;@font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:3 0 0 0 1 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman",serif; mso-fareast-font-family:"Times New Roman";}.MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Yu Mincho"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}div.WordSection1 {page:WordSection1;}

  • Preparation of hydrogels with nanosheets as immobilization matrixes for yeasts

    2020年  

     概要を見る

    Hydrogels based on triblock co-polymers made by pluronicF127 display interesting properties: biocompatibility, gelation at roomtemperature for a possible use as embedding matrixes for bio-organisms, andfurther developments of biosensors. The inclusion of nanosheets, derivativesfrom the peeling of layered materials can give further properties(birefringence due to the anisotropy of the 2D shape particles, enhancement ofthe elastic properties) to the hybrid hydrogels. The association of clay mineralsand their organoclay derivatives in hydrogel formed with F127 and its impactson the gelation mechanisms as well as the elastic properties were investigated.The presence of hydrophobic nanosheets spreads out the gelation on a largerange of temperature, while conferring to the hybrid materials further advancedelastic properties.@font-face {font-family:"MS Mincho"; panose-1:2 2 6 9 4 2 5 8 3 4; mso-font-alt:"MS 明朝"; mso-font-charset:128; mso-generic-font-family:modern; mso-font-pitch:fixed; mso-font-signature:-536870145 1791491579 134217746 0 131231 0;}@font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-536870145 1107305727 0 0 415 0;}@font-face {font-family:"\@MS Mincho"; panose-1:2 2 6 9 4 2 5 8 3 4; mso-font-charset:128; mso-generic-font-family:modern; mso-font-pitch:fixed; mso-font-signature:-536870145 1791491579 134217746 0 131231 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman",serif; mso-fareast-font-family:"Times New Roman";}p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph {mso-style-priority:34; mso-style-unhide:no; mso-style-qformat:yes; margin-top:0cm; margin-right:0cm; margin-bottom:0cm; margin-left:42.0pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:0cm; mso-para-margin-left:4.0gd; text-align:justify; text-justify:inter-ideograph; mso-pagination:none; font-size:12.0pt; mso-bidi-font-size:11.0pt; font-family:"Times New Roman",serif; mso-fareast-font-family:"MS Mincho"; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-font-kerning:1.0pt; mso-ansi-language:EN-US;}.MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Yu Mincho"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}div.WordSection1 {page:WordSection1;}

  • Preparation of hydrogels with nanosheets as immobilization matrixes for yeasts

    2020年  

     概要を見る

    Hydrogels based on triblock co-polymers made by pluronicF127 display interesting properties: biocompatibility, gelation at roomtemperature for a possible use as embedding matrixes for bio-organisms, andfurther developments of biosensors. The inclusion of nanosheets, derivativesfrom the peeling of layered materials can give further properties(birefringence due to the anisotropy of the 2D shape particles, enhancement ofthe elastic properties) to the hybrid hydrogels. The association of grapheneoxides in hydrogel formed with F127 and its impacts on the gelation mechanismsas well as the elastic properties were investigated. The presence of largeinorganic particles spreads out the gelation on a large range of temperature,while conferring to the hybrid materials further elastic properties.@font-face {font-family:"MS Mincho"; panose-1:2 2 6 9 4 2 5 8 3 4; mso-font-alt:"MS 明朝"; mso-font-charset:128; mso-generic-font-family:modern; mso-font-pitch:fixed; mso-font-signature:-536870145 1791491579 134217746 0 131231 0;}@font-face {font-family:Century; panose-1:2 4 6 4 5 5 5 2 3 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:647 0 0 0 159 0;}@font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-536870145 1107305727 0 0 415 0;}@font-face {font-family:"\@MS Mincho"; panose-1:2 2 6 9 4 2 5 8 3 4; mso-font-charset:128; mso-generic-font-family:modern; mso-font-pitch:fixed; mso-font-signature:-536870145 1791491579 134217746 0 131231 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; text-align:justify; text-justify:inter-ideograph; mso-pagination:none; font-size:11.0pt; mso-bidi-font-size:10.0pt; font-family:"Century",serif; mso-fareast-font-family:"MS Mincho"; mso-bidi-font-family:"Times New Roman"; mso-font-kerning:1.0pt; mso-ansi-language:EN-US;}p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph {mso-style-priority:34; mso-style-unhide:no; mso-style-qformat:yes; margin-top:0cm; margin-right:0cm; margin-bottom:0cm; margin-left:42.0pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:0cm; mso-para-margin-left:4.0gd; text-align:justify; text-justify:inter-ideograph; mso-pagination:none; font-size:12.0pt; mso-bidi-font-size:11.0pt; font-family:"Times New Roman",serif; mso-fareast-font-family:"MS Mincho"; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-font-kerning:1.0pt; mso-ansi-language:EN-US;}.MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Yu Mincho"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}div.WordSection1 {page:WordSection1;}

  • Hierarchical assemblies based on liquid crystal mixtures of graphene oxides and nonionic surfactants

    2019年  

     概要を見る

    Nanosheets resulting from the peeling of inorganic layered materials can form, at low concentration in an appropriate solvent, liquid crystalline (LC) assemblies (such as nematic or lamellar phases for instance) as organic moieties do. These materials can be used as building blocks for further anisotropy and template systems to orientate other colloidal systems such as assemblies made of surfactants where synergetic effects can be expected. Thus, the colloidal mixtures resulting from a delicate balance of both repulsive and attractive forces (excluded volume, electrostatic and Van der Waals forces show interesting hierarchical assemblies that can lead to the preparation of advanced materials.

  • Novel nanostructures by mixing inorganic nanosheets and nonionic surfactants membrane as a new way to synthesize porous materials

    2018年   SUGAHARA Yoshiyuki

     概要を見る

    Two dimensional (2D) atomic crystals or nanosheets resulting from the peeling of inorganic layered materials represent exciting nanomaterials with fascinating properties and diverse potential applications for constructing novel nanomaterials. The stability of the association of dispersion of nanosheets with other colloidal objects such as organic moieties results from a fragile energy landscape with the possibility of phase segregation, and thus the study of such mixtures represents a certain challenge. Beyond the academic interests about the understanding of the stability of these colloids in solution, the association of particles associated with membrane phases made of surfactants, lipids and other apparent biological systems that can mimic cell envelope, may lead to novel microstructures that can be oriented at a macroscopic scale through the assistance of inorganic nanosheets leading to the possibility to fabricate hierarchical oriented composite films for various applications depending on the architectures of the whole colloidal objects.

 

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