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1. Sonocatalytic degradation of EDTA in the presence of Ti and Ti@TiO2 nanoparticles

Author

Sara El Hakim, Tony Chave, and Sergey I. Nikitenko

Subjects
Sonochemistry, Sonocatalysis, EDTA, Titanium nanoparticles, Heterogeneous catalysis, Chemistry, QD1-999, Acoustics. Sound, QC221-246
Abstract

The sonocatalytic degradation of EDTA (C0 = 5 10−3 M) in aqueous solutions was studied under 345 kHz (Pac = 0.25 W mL−1) ultrasound at 22–51 °C, Ar/20%O2, Ar or air, and in the presence of metallic titanium (Ti0) or core-shell Ti@TiO2 nanoparticles (NPs). Ti@TiO2 NPs have been obtained using simultaneous action of hydrothermal conditions (100–214 °C, autogenic pressure P = 1.0–19.0 bar) and 20 kHz ultrasound, called sonohydrothermal (SHT) treatment, on Ti0 NPs in pure water. Ti0 is composed of quasi-spherical particles (30–150 nm) of metallic titanium coated with a metastable titanium suboxide Ti3O. SHT treatment at 150–214 °C leads to the oxidation of Ti3O and partial oxidation of Ti0 and formation of nanocrystalline shell (10–20 nm) composed of TiO2 anatase. It was found that Ti0 NPs do not exhibit catalytic activity in the absence of ultrasound. Moreover, Ti0 NPs remain inactive under ultrasound in the absence of oxygen. However, significant acceleration of EDTA degradation was achieved during sonication in the presence of Ti0 NPs and Ar/20%O2 gas mixture. Coating of Ti0 with TiO2 nanocrystalline shell reduces sonocatalytic activity. Pristine TiO2 anatase nanoparticles do not show a sonocatalytic activity in studied system. Suggested mechanism of EDTA sonocatalytic degradation involves two reaction pathways: (i) sonochemical oxidation of EDTA by OH·/HO2· radicals in solution and (ii) EDTA oxidation at the surface of Ti0 NPs in the presence of oxygen activated by cavitation event. Ultrasonic activation most probably occurs due to the local heating of Ti0/O2 species at cavitation bubble/solution interface.

Published
2021
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2. Modification of Olive Leaves’ Surface by Ultrasound Cavitation. Correlation with Polyphenol Extraction Enhancement

Author

Natacha Rombaut, Tony Chave, Sergey I. Nikitenko, Mohamed EI Maâtaoui, Anne Sylvie Fabiano-Tixier, and Farid Chemat

Subjects
olive leaf, microscopy, polyphenol, ultrasound, mechanism, food processing, Technology, Engineering (General). Civil engineering (General), TA1-2040, Biology (General), QH301-705.5, Physics, QC1-999, Chemistry, QD1-999
Abstract

We investigated the impact of ultrasound at 20 kHz on olive leaves to understand how acoustic cavitation could increase polyphenol extraction. Application of ultrasound to whole leaf from 5 to 60 min enabled us to increase extraction from 6.96 to 48.75 µg eq. oleuropein/mL of extract. These results were correlated with Environmental Scanning Electron Microscopy, allowing for leaf surface observation and optical microscopy of treated leaf cross sections to understand histochemical modifications. Our observations suggest that the effectiveness of ultrasound applied to extraction is highly dependent on plant structure and on how this material will react when subjected to acoustic cavitation. Ultrasound seems to impact the leaves by two mechanisms: cuticle erosion, and fragmentation of olive leaf surface protrusions (hairs), which are both polyphenol-rich structures.

Published
2020
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4. Influence of Butanol Isomerization on Photothermal Hydrogen Production over Ti@TiO2 Core-Shell Nanoparticles

Author

Sara El Hakim, Mathéo Bathias, Tony Chave, and Sergey I. Nikitenko

Subjects
photocatalysis, hydrogen production, butanol, isomers, photothermal effect, titanium, Physical and Theoretical Chemistry, Catalysis, General Environmental Science
Abstract

In this work, we reported for the first time the effect of butanol isomerization on the photothermal production of hydrogen in the presence of a noble, metal-free Ti@TiO2 core-shell photocatalyst. The experiments were performed in aqueous solutions of 1-BuOH, 2-BuOH, and t-BuOH under Xe lamp irradiation (vis/NIR: 8.4 W, UV: 0.6 W) at 35–69 °C. The increase in temperature significantly enhanced H2 formation, indicating a strong photothermal effect in the studied systems. However, in dark conditions, H2 emission was not observed even at elevated temperatures, which clearly points out the photonic origin of H2 photothermal formation. The rate of H2 production followed the order of 1-BuOH >> 2-BuOH > t-BuOH in the entire range of studied temperatures. In the systems with 1-BuOH and 2-BuOH, hydrogen was the only gaseous product measured online in the outlet carrier argon using mass spectrometry. By contrast, a mixture of H2, CH4, and C2H6 was detected for t-BuOH, indicating a C–C bond scission with this isomer during photocatalytic degradation. The apparent activation energies, Ea, with 1-BuOH/2-BuOH isomers (20–21 kJ·mol−1) was found to be larger than for t-BuOH (13 kJ·mol−1). The significant difference in thermal response for 1-BuOH/2-BuOH and t-BuOH isomers was ascribed to the difference in the photocatalytic mechanisms of these species. The photothermal effect with 1-BuOH/2-BuOH isomers can be explained by the thermally induced transfer of photogenerated, shallowly trapped electron holes to highly reactive free holes at the surface of TiO2 and the further hole-mediated cleavage of the O-H bond. In the system with t-BuOH, another mechanism could also contribute to the overall process through hydrogen abstraction from the C–H bond by an intermediate •OH radical, leading to CH3• group ejection. Formation of •OH radicals during light irradiation of Ti@TiO2 nanoparticle suspension in water has been confirmed using terephthalate dosimetry. This analysis also revealed a positive temperature response of •OH radical formation.

Published
2022
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7. Conversion of Ammonia to Hydrazine Induced by High‐Frequency Ultrasound

Author

François Jérôme, Karine De Oliveira Vigier, Anaelle Humblot, Stéphane Streiff, Laurie Grimaud, Audrey Allavena, Prince Nana Amaniampong, Tony Chave, Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Interfaces et Surfaces d'Oxydes (LISO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Eco-Efficient Products & Processes Laboratory (E2P2L), and RHODIA-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Work (thermodynamics), Materials science, Aqueous solution, Radical, Hydrazine, General Chemistry, 02 engineering and technology, General Medicine, Photochemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Catalysis, 0104 chemical sciences, Ammonia, chemistry.chemical_compound, chemistry, Degradation (geology), [CHIM]Chemical Sciences, Organic synthesis, 0210 nano-technology
Abstract

International audience; Hydrazine is a chemical of outmost importance in our society, either for organic synthesis or energy purpose. The direct conversion of NH3 to hydrazine is highly appealing but it remains a very difficult task because the degradation of hydrazine is thermodynamically more feasible than the cleavage of the N-H bond of NH3. As a result, any catalyst capable of activating NH3 will thus unavoidably decompose N2H4. Here we show that cavitation bubbles, created by ultrasonic irradiation of aqueous NH3 at a high frequency, act as micro-reactors to activate and convert NH3 to NH species, without assistance of any catalyst, yielding hydrazine at the bubble-liquid interface. The compartmentation of in situ produced hydrazine in the bulk solution, which is maintained close to 30°C, advantageously prevents its thermal degradation, a recurrent problem faced by previous technologies. This work also points towards a path to scavenge •OH radicals by adjusting the NH3 concentration.

Published
2021
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8. Deciphering the reaction mechanisms of photothermal hydrogen production using H/D kinetic isotope effect

Author

Sara El Hakim, Tony Chave, Sergey I. Nikitenko, Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM), Sonochimie dans les Fluides Complexes (LSFC), and Université de Montpellier (UM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)

Subjects
[CHIM.CATA]Chemical Sciences/Catalysis, Catalysis
Abstract

International audience; H/D kinetic isotope effect has been employed to study the mechanism of the thermally assisted photocatalytic hydrogen production over noble metal-free Ti@TiO$_2$ core–shell nanoparticles. We have found that the observed large H/D isotope separation factor (αH = 11.3 ± 1.7–6.2 ± 0.9) is due to the electron hole-mediated cleavage of OH bond. It was concluded that strong H/D isotopic selectivity is associated with significant photothermal effect.

Published
2022
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9. Simultaneous H/D and $^{13}$C/$^{12}$C anomalous kinetic isotope effects during the sonolysis of water in the presence of carbon monoxide

Author

Sergey I. Nikitenko, Tony Chave, Matthieu Virot, Rachel Pflieger, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), and Université de Montpellier (UM)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], General Materials Science, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry
Abstract

International audience; Splitting of water molecules driven by ultrasound plays a central role in sonochemistry. While studies of sonoluminescence revealed the formation of a plasma inside the cavitation bubble, much less is known about the contribution of plasma chemical processes to the sonochemical mechanisms. Herein, we report for the first time sonochemical processes in water saturated with pure CO. The presence of CO causes a large increase in the H/D kinetic isotope effect (KIE) to $\alpha_H$ = 14.6 ± 1.8 in a 10% H$_2$O/D$_2$O mixture under 20 kHz ultrasound.The anomalous H/D KIE is attributed to electron quantum tunneling in the plasma produced by cavitation. In addition, CO$_2$ formed simultaneously with hydrogen during the sonochemical process is enriched with the $^{13C}$C isotope, which indicates a VV pumping mechanism typical for non-equilibrium plasma. Both observed KIEs unambiguously point to the contribution of quantum effects in sonochemical mechanisms.

Published
2022
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10. Simultaneous H/D and

Author

Sergey I, Nikitenko, Tony, Chave, Matthieu, Virot, and Rachel, Pflieger

Abstract

Splitting of water molecules driven by ultrasound plays a central role in sonochemistry. While studies of sonoluminescence revealed the formation of a plasma inside the cavitation bubble, much less is known about the contribution of plasma chemical processes to the sonochemical mechanisms. Herein, we report for the first time sonochemical processes in water saturated with pure CO. The presence of CO causes a large increase in the H/D kinetic isotope effect (KIE) to α

Published
2021

12. Tailoring Noble Metal-Free Ti@TiO2 Photocatalyst for Boosting Photothermal Hydrogen Production

Author

Tony Chave, Sara El Hakim, Stéphanie Roualdes, Sergey I. Nikitenko, Amr A. Nada, Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Européen des membranes (IEM), and Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Hydrogen, Titanium suboxide, Nanoparticle, chemistry.chemical_element, 02 engineering and technology, engineering.material, 010402 general chemistry, 01 natural sciences, Nanomaterials, Sonohydrothermal, Photocatalysis, Hydrogen production, [CHIM.MATE]Chemical Sciences/Material chemistry, Photothermal therapy, 021001 nanoscience & nanotechnology, Nanocrystalline material, 0104 chemical sciences, Chemical engineering, chemistry, engineering, Noble metal, 0210 nano-technology
Abstract

In this work, we provide new insights into the design of Ti@TiO2photocatalyst with enhanced photothermal activity in the process of glycerol reforming. Ti@TiO2nanoparticles have been obtained by sonohydrothermal treatment of titanium metal nanoparticles in pure water. Variation of sonohydrothermal temperature allows controlling nanocrystalline TiO2shell on Ti0surface. At 100 < T < 150°C formation of TiO2NPs occurs mostly by crystallization of Ti(IV) amorphous species and oxidation of titanium suboxide Ti3O presented at the surface of Ti0nanoparticles. At T > 150°C, TiO2is also formed by oxidation of Ti0with overheated water. Kinetic study highlights the importance of TiO2nanocrystalline shell for H2generation. Electrochemical impedance spectroscopy points out more efficient electron transfer for Ti@TiO2nanoparticles in correlation with photocatalytic data. The apparent activation energy, Ea= (25–31) ± 5 kJ·mol−1, assumes that photothermal effect arises from diffusion of glycerol oxidation intermediates or from water dynamics at the surface of catalyst. Under the heating, photocatalytic H2emission is observed even in pure water.

Published
2021
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13. Modification of Olive Leaves’ Surface by Ultrasound Cavitation. Correlation with Polyphenol Extraction Enhancement

Author

Tony Chave, Natacha Rombaut, Farid Chemat, Anne Sylvie Fabiano-Tixier, Sergey I. Nikitenko, Mohamed Ei Maâtaoui, Sécurité et Qualité des Produits d'Origine Végétale (SQPOV), Avignon Université (AU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Démarche intégrée pour l'obtention d'aliments de qualité (UMR QualiSud), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)-Institut Agro - Montpellier SupAgro, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)

Subjects
[SDV.BIO]Life Sciences [q-bio]/Biotechnology, [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], mechanism, 01 natural sciences, lcsh:Technology, lcsh:Chemistry, chemistry.chemical_compound, 0404 agricultural biotechnology, Olive leaf, cavitation, Oleuropein, Microscopy, food processing, General Materials Science, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Instrumentation, Environmental scanning electron microscope, lcsh:QH301-705.5, Fluid Flow and Transfer Processes, Chromatography, business.industry, Chemistry, lcsh:T, ultrasound, Process Chemistry and Technology, 010401 analytical chemistry, Ultrasound, Extraction (chemistry), General Engineering, food and beverages, 04 agricultural and veterinary sciences, 040401 food science, lcsh:QC1-999, 0104 chemical sciences, Computer Science Applications, olive leaf, polyphenol, lcsh:Biology (General), lcsh:QD1-999, Polyphenol, lcsh:TA1-2040, Cavitation, microscopy, extraction, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], business, lcsh:Engineering (General). Civil engineering (General), lcsh:Physics
Abstract

We investigated the impact of ultrasound at 20 kHz on olive leaves to understand how acoustic cavitation could increase polyphenol extraction. Application of ultrasound to whole leaf from 5 to 60 min enabled us to increase extraction from 6.96 to 48.75 &micro, g eq. oleuropein/mL of extract. These results were correlated with Environmental Scanning Electron Microscopy, allowing for leaf surface observation and optical microscopy of treated leaf cross sections to understand histochemical modifications. Our observations suggest that the effectiveness of ultrasound applied to extraction is highly dependent on plant structure and on how this material will react when subjected to acoustic cavitation. Ultrasound seems to impact the leaves by two mechanisms: cuticle erosion, and fragmentation of olive leaf surface protrusions (hairs), which are both polyphenol-rich structures.

Published
2021
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14. Photocatalytic and Sonocatalytic Degradation of EDTA and Rhodamine B over Ti0 and Ti@TiO2 Nanoparticles

Author

Sergey I. Nikitenko, Tony Chave, Sara El Hakim, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Anatase, Materials science, organic pollutants, Nanoparticle, Ethylenediaminetetraacetic acid, 02 engineering and technology, TP1-1185, 010402 general chemistry, 01 natural sciences, Catalysis, chemistry.chemical_compound, photothermal, sonocatalysis, Oxidizing agent, Rhodamine B, titanium, Physical and Theoretical Chemistry, QD1-999, [SDE.IE]Environmental Sciences/Environmental Engineering, Chemical technology, EDTA, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Chemistry, chemistry, 13. Climate action, Photocatalysis, Degradation (geology), nanoparticles, 0210 nano-technology, [CHIM.OTHE]Chemical Sciences/Other, photocatalysis, Nuclear chemistry, rhodamine B, environmental remediation
Abstract

Herein, we report a comparative study of photocatalytic (Xe-lamp) and sonocatalytic (345 kHz power ultrasound) degradation of Ethylenediaminetetraacetic acid (EDTA) and Rhodamine B (RhB) in the presence of Ti0 and Ti@TiO2 core-shell nanoparticles (NPs). Ti@TiO2 NPs have been obtained by sonohydrothermal treatment (20 kHz, 200 °C) of commercially available Ti0 NPs in pure water. The obtained material is composed of quasi-spherical Ti0 particles (30–150 nm) coated by 5–15 nm crystals of anatase. In contrast to pristine TiO2, the Ti@TiO2 NPs exhibit the extend photo response from UV to NIR light region due to the light absorption by nonplasmonic Ti core. EDTA can be oxidized effectively by photocatalysis in the presence of Ti@TiO2 NPs. By contrast, air passivated Ti0 nanoparticles was found to be inactive in the photocatalytic process for both EDTA and RhB. Photocatalytic degradation of EDTA over Ti@TiO2 NPs exhibits strong photothermal effect, which has been attributed to the higher yield of oxidizing radicals produced by light at higher bulk temperature. The efficiency of RhB photocatalytic degradation depends strongly on RhB concentration. At [RhB] ≥ 1 × 10−3 M, its photocatalytic degradation is not feasible due to a strong self-absorption. At lower concentrations, RhB photocatalytic degradation is observed, but at lower efficiency compared to EDTA. We found that the efficient sonochemical degradation of RhB does not require the presence of any catalysts. For both processes, EDTA and RhB, sonochemical and photocatalytic processes are more effective in the presence of Ar/O2 gas mixture compared to pure Ar. The obtained results suggest that the choice of the optimal technology for organic pollutants degradation can be determined by their optical and complexing properties.

Published
2021
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15. Physical and chemical characterization of shock-induced cavitation

Author

Sergey I. Nikitenko, Tony Chave, Patrick Da Costa, Hugo Dutilleul, Laureanne Parizot, M. E. Gálvez, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Jean Le Rond d'Alembert (DALEMBERT), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Combustion, Energies Propres et Turbulence (IJLRDA-CEPT), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Shock wave, Water hammer, Work (thermodynamics), Yield (engineering), Materials science, Acoustics and Ultrasonics, Bubble, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Sonochemistry, Inorganic Chemistry, Chemical Engineering (miscellaneous), Environmental Chemistry, [CHIM]Chemical Sciences, Radiology, Nuclear Medicine and imaging, ComputingMilieux_MISCELLANEOUS, [PHYS]Physics [physics], Organic Chemistry, Mechanics, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Shock (mechanics), [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, 13. Climate action, Cavitation, 0210 nano-technology, [CHIM.RADIO]Chemical Sciences/Radiochemistry
Abstract

A strong impact on a water surface induces a shock wave propagation with a significant pressure variation leading to cavitation bubble formation. A new shock induced cavitation reactor described in this work was characterized by physical and chemical techniques. Water hammer model verification with Joukowsky approach allowed to determine the wave speed propagation and gas fraction in water submitted to shock. These values were used for frequency analysis and compared with direct bubble visualization in order to estimate the influence of the experimental parameters on the shock-induced cavitation. Thereby, the shock wave contains a broad spectrum as decomposed into frequencies. This multi-frequency nature induces heterogeneous bubbles with calculated radii of 0.01 to 3.5 mm and observed radii of 0.01 to 2.8 mm depending on experimental conditions (initial pressure, impact height, gas atmosphere). For the first time, the formation of hydroxyl radicals was proven under impact-induced cavitation. The concentration of radicals increases with increasing number of successive impacts, reaching ca. 1.3 µmol.L−1 after 500 impacts in the presence of 20% O2-Ar as saturating gas. Radical generation seems to be relatively independent of the impact height but strongly depend on the type of gas saturating water, being substantially lower in the presence of air. Moreover, radical generation increases when decreasing the initial pressure and depends on the frequency at which water is impacted by the piston. Nevertheless, yield of OH radicals during shock-induced cavitation remains much lower than that produced by power ultrasound.

Published
2020
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16. Hierarchical Porosity Tailoring of Sol–Gel Derived Pt/SiO2 Catalysts

Author

Vasile Hulea, Siglinda Perathoner, Patrick Lacroix-Desmazes, Andrés Felipe Sierra-Salazar, Sergey I. Nikitenko, Tony Chave, André Ayral, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Européen des membranes (IEM), Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Department of Industrial Chemistry and Engineering of Materials, University of Messina, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Materials science, Latex, 02 engineering and technology, Sol–gel, 010402 general chemistry, 01 natural sciences, Catalysis, Sonochemistry, Reaction rate, Hierarchical porosity, [CHIM]Chemical Sciences, p-Chloroaniline, Porosity, Sol-gel, General Chemistry, 021001 nanoscience & nanotechnology, Pt/SiO2, Selective hydrogenation, 0104 chemical sciences, Chemical engineering, p-Chloronitrobenzene, Porosity tailoring, 0210 nano-technology, Porous medium, Mesoporous material, Selectivity
Abstract

International audience; Hierarchically porous materials offer the opportunity for catalyst development in regards to improving catalytic performances. In the present work, the combination of latex synthesis, sonochemical reduction and two-step catalysed sol–gel process has been demonstrated to be a versatile method for preparing supported catalysts with tailored hierarchical porosity. This method has been used to prepare porous Pt/SiO2 catalysts with mesopore and macropore size ranges as large as 2–15 nm and 90–400 nm, respectively. These hierarchically porous catalysts presented an excellent catalytic performance for the selective hydrogenation of p-chloronitrobenzene (p-CNB) to p-chloroaniline (p-CAN). Selectivity values up to 100% at 80% conversion of p-CNB and initial reaction rates up to 74.0 molCNB/min molPt were obtained, while a commercial catalyst exhibited both a lower selectivity of 90.8% and a lower initial reaction rate of 47.7 molCNB/min molPt.

Published
2018
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17. Hierarchically porous Pd/SiO2 catalyst by combination of miniemulsion polymerisation and sol-gel method for the direct synthesis of H2O2

Author

Vasile Hulea, Andrés Felipe Sierra-Salazar, André Ayral, Salvatore Abate, Sergey I. Nikitenko, W.S. Jennifer Li, Patrick Lacroix-Desmazes, Tony Chave, Maël Bathfield, Siglinda Perathoner, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Industrial Chemistry and Engineering of Materials, University of Messina, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Hydrogen, H2O2, chemistry.chemical_element, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, Pd/SiO2, 01 natural sciences, Catalysis, Hierarchical porosity, chemistry.chemical_compound, Polymer chemistry, [CHIM]Chemical Sciences, Hydrogen peroxide, Porosity, ComputingMilieux_MISCELLANEOUS, Sol-gel, Chemistry (all), [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.MATE]Chemical Sciences/Material chemistry, General Chemistry, Miniemulsion polymerisation, 021001 nanoscience & nanotechnology, H2O2, Hierarchical porosity, Miniemulsion polymerisation, Pd/SiO2, Sol-gel, Catalysis, Chemistry (all), 0104 chemical sciences, Miniemulsion, [CHIM.POLY]Chemical Sciences/Polymers, Chemical engineering, chemistry, Polymerization, 0210 nano-technology, Selectivity
Abstract

The production of hydrogen peroxide H 2 O 2 , as an important commodity chemical, attires the attention towards greener processes such as the direct synthesis from hydrogen H 2 and oxygen O 2 , the selectivity being the biggest challenge. Since this reaction is structure-sensitive, the design of appropriate catalysts is required. We propose a novel method to prepare hierarchically porous Pd/SiO 2 catalyst by combination of miniemulsion polymerisation to prepare a Pd-containing latex template and sol-gel synthesis in controlled conditions to tailor the silica porosity. The final material displayed a surface area of 711 m 2 g −1 and a total pore volume of 0.93 cm 3 g −1 . The catalyst was evaluated with different pre-treatments in the direct synthesis of H 2 O 2 , where it exhibited structural resistance at the reaction conditions and a stable selectivity of 46 ± 1% towards H 2 O 2 .

Published
2018
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18. Engineering of silica-supported platinum catalysts with hierarchical porosity combining latex synthesis, sonochemistry and sol-gel process – II. Catalytic performance

Author

Salvatore Abate, Siglinda Perathoner, Patrick Lacroix-Desmazes, Sergey I. Nikitenko, Frans D. Tichelaar, Tony Chave, Vasile Hulea, André Ayral, Andrés Felipe Sierra-Salazar, Patricia J. Kooyman, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Delft University of Technology (TU Delft), Department of Industrial Chemistry and Engineering of Materials, University of Messina, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, chemistry.chemical_element, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, Sonochemistry, [CHIM]Chemical Sciences, Organic chemistry, General Materials Science, Porosity, Chloronitrobenzene, ComputingMilieux_MISCELLANEOUS, 010405 organic chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, General Chemistry, Microporous material, Condensed Matter Physics, 0104 chemical sciences, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Chemical engineering, Mechanics of Materials, Platinum, Selectivity, Mesoporous material
Abstract

As a follow-up of the paper “Engineering of silica-supported platinum catalysts with hierarchical porosity combining latex synthesis, sonochemistry and sol-gel process – I. Material preparation” (A.F. Sierra-Salazar, et at., Microporous Mesoporous Mater. 234 (2016) 207–214. http://dx.doi.org/10.1016/j.micromeso.2016.07.009 ), we propose waterborne Pt-based catalysts with hierarchical porosity and controlled Pt nanoparticles (NPs) distribution within the support. The materials exhibit specific surface areas and total pore volumes as high as 490 m 2 g −1 and 0.77 cm 3 g −1 , with ∼5 nm Pt NPs mainly located in the macropores. The Pt NPs were characterised using X-ray photoemission spectroscopy (XPS) and high resolution transmission electron microscopy (HR-TEM). Considering the selectivity challenge of the catalytic hydrogenation of halonitrobenzenes to produce haloanilines, which are important raw materials for several industrial products, we evaluated these hierarchically porous catalysts for the hydrogenation of p -chloronitrobenzene ( p -CNB) in batch mode to produce p -chloroaniline ( p -CAN). It was possible to obtain up to 100% selectivity at 80% conversion and initial reaction rates up to 34 mol CNB min −1 mol Pt −1 . Such selectivity was higher than that exhibited by a commercial Pt/SiO 2 catalyst (up to 92%).

Published
2018
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19. Cover Picture: Conversion of Ammonia to Hydrazine Induced by High‐Frequency Ultrasound (Angew. Chem. Int. Ed. 48/2021)

Author

Anaelle Humblot, Prince Nana Amaniampong, Laurie Grimaud, Audrey Allavena, Tony Chave, François Jérôme, Karine De Oliveira Vigier, and Stéphane Streiff

Subjects
Materials science, business.industry, Ultrasound, Hydrazine, INT, General Chemistry, Catalysis, Ammonia, chemistry.chemical_compound, chemistry, Cover (algebra), business, Nuclear chemistry, High frequency ultrasound
Published
2021
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21. Hypothesis about electron quantum tunneling during sonochemical splitting of water molecule

Author

R. Pflieger, Sergey I. Nikitenko, Timothé Di Pasquale, Tony Chave, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Acoustics and Ultrasonics, Hydrogen, chemistry.chemical_element, 02 engineering and technology, Electron, 010402 general chemistry, 01 natural sciences, 7. Clean energy, water splitting, Dissociation (chemistry), Sonochemistry, Inorganic Chemistry, Sonoluminescence, kinetic isotope effect, Kinetic isotope effect, Chemical Engineering (miscellaneous), Environmental Chemistry, Radiology, Nuclear Medicine and imaging, Quantum tunnelling, plasma, Organic Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry, Chemical physics, 0210 nano-technology, sonochemistry, quantum tunneling, Self-ionization of water
Abstract

International audience; Quantum tunneling in chemistry is often attributed to the processes at low or near room temperatures when the rate of thermal reactions becomes far less than the rate of quantum tunneling. However, in some rapid processes, quantum tunneling can be observed even at high temperatures. Herein, we report the experimental evidence for anomalous H/D kinetic isotope effect (KIE) during sonochemical dissociation of water molecule driven by 20 kHz power ultrasound measured in H 2 O/D 2 O mixtures saturated with Ar or Xe. Hydrogen released during ultrasonic treatment is enriched by light isotope. The observed H/D KIE (α=2.15-1.50) is much larger than what is calculated assuming a classical KIE for T g =5000 K (α=1.15) obtained from the sonoluminescence spectra in H 2 O and D 2 O. Furthermore, the α values sharply decrease with increasing of H 2 O content in H 2 O/D 2 O mixtures reaching a steady-state value close to α=1.50, which also cannot be explained by O-H/O-D zero-point energy difference. We suggest that these results can be understood in terms of quantum electron tunneling occurring in nonequilibrium picosecond plasma produced at the last stage of cavitation bubble collapse. Thermal homolytic splitting of water molecule is inhibited by extremely short lifetime of such plasma. On the contrary, immensely short traversal time for electron tunneling in water allows H 2 O dissociation by quantum tunneling mechanism.

Published
2020
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22. Selective radical depolymerization of cellulose to glucose induced by high frequency ultrasound

Author

Isabelle Capron, Jonathan Clarhaut, Karine De Oliveira Vigier, Ayman Karam, Tony Chave, Somia Haouache, François Jérôme, Prince Nana Amaniampong, José M. García Fernández, Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Physiopathologie des Adaptations Nutritionnelles (PhAN), Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), University of Sevilla, Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Universidad de Sevilla / University of Sevilla, ANR-16-CE07-0003,CELLOPLASM,Clivage de la liaison béta-1,4 glycosidique de la cellulose par plasma atmospherique non-thermique: mécanisme et application pour la production d'alkylglycosides(2016), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-Institut de Chimie du CNRS (INC)

Subjects
chemistry.chemical_classification, 010405 organic chemistry, Depolymerization, Radical, Glycosidic bond, General Chemistry, 010402 general chemistry, Photochemistry, 01 natural sciences, 0104 chemical sciences, Homolysis, Catalysis, chemistry.chemical_compound, Chemistry, chemistry, Degradation (geology), [CHIM]Chemical Sciences, Cellulose, Selectivity
Abstract

The depolymerization of cellulose to glucose is a challenging reaction and often constitutes a scientific obstacle in the synthesis of downstream bio-based products. Here, we show that cellulose can be selectively depolymerized to glucose by ultrasonic irradiation in water at a high frequency (525 kHz). The concept of this work is based on the generation of H˙ and ˙OH radicals, formed by homolytic dissociation of water inside the cavitation bubbles, which induce the cleavage of the glycosidic bonds. The transfer of radicals on the cellulose particle surfaces prevents the side degradation of released glucose into the bulk solution, allowing maintaining the selectivity to glucose close to 100%. This work is distinguished from previous technologies in that (i) no catalyst is needed, (ii) no external source of heating is required, and (iii) the complete depolymerization of cellulose is achieved in a selective fashion. The addition of specific radical scavengers coupled to different gaseous atmospheres and ˙OH radical dosimetry experiments suggested that H˙ radicals are more likely to be responsible for the depolymerisation of cellulose., Ultrasonic irradiation of cellulose at a high frequency induces its selective depolymerization to glucose at room temperature and atmospheric pressure within only a few minutes.

Published
2020
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23. Unconventional Pathways for Designing Silica-Supported Pt and Pd Catalysts With Hierarchical Porosity

Author

Vasile Hulea, Tony Chave, Andrés Felipe Sierra-Salazar, Salvatore Abate, Sergey I. Nikitenko, Siglinda Perathoner, Patrick Lacroix-Desmazes, André Ayral, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Department of Industrial Chemistry and Engineering of Materials, University of Messina, Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Green chemistry, Chemical process, Materials science, Software_GENERAL, Rational design, Pillar, Nanotechnology, 02 engineering and technology, [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Environmentally friendly, 0104 chemical sciences, Catalysis, [CHIM.POLY]Chemical Sciences/Polymers, 0210 nano-technology, Porosity, Hierarchical porous, ComputingMilieux_MISCELLANEOUS
Abstract

Catalysis as a pillar of green chemistry is called on to improve the performance of the current chemical processes and to develop new and sustainable processes and products. In order to tackle the current challenges in sustainable chemistry, catalyst rational design approaches are necessary. Such approaches require tailoring tools for the catalyst preparation, which should also be environmentally friendly. This chapter starts by a brief review of the techniques for texture tailoring and catalyst functionalization, highlighting the high potential of hierarchical porous catalysts. Then, a few innovative techniques for the preparation of silica-supported Pt and Pd catalysts with hierarchical porosity are described.

Published
2019
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24. Sonocatalytic oxidation of EDTA in aqueous solutions over noble metal-free Co$_3$O$_4$/TiO$_2$ catalyst

Author

Hugo Dutilleul, Laureanne Parizot, Patrick Da Costa, Tony Chave, M. E. Gálvez, Sergey I. Nikitenko, Institut Jean Le Rond d'Alembert (DALEMBERT), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Iminodiacetic acid, Formic acid, Oxalic acid, 02 engineering and technology, engineering.material, 010402 general chemistry, 01 natural sciences, Catalysis, chemistry.chemical_compound, Acetic acid, Ultrasound, Glycolic acid, General Environmental Science, Heterogeneous catalysis, Aqueous solution, [SDE.IE]Environmental Sciences/Environmental Engineering, Process Chemistry and Technology, technology, industry, and agriculture, EDTA, Advanced oxidation processes, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, engineering, Noble metal, 0210 nano-technology, Nuclear chemistry, Sonochemistry
Abstract

International audience; The sonocatalytic degradation of EDTA in aqueous solution was studied under ultrasound irradiation (345 kHz, 73 W, acoustic power 0.20 W·mL$^{−1}$, Ar and Ar/O$_2$ saturating gases, T = 20–50 °C) in the presence of Co$_3$3O$_4$/TiO$_2$ and Pt/TiO$_2$ nanocatalysts. About 90% of EDTA (C$_0$ = 5 10$^{-3}$ M) was oxidized during ultrasonic treatment at 40 °C in the presence of the Co$_3$O$_4$/TiO$_2$ catalyst and Ar/O$_2$ gas mixture. By contrast, Pt/TiO$_2$ catalyst exhibited much lower sonocatalytic activity in this system. Suggested mechanism of EDTA oxidation in the presence of Co$_3$O$_4$/TiO$_2$ catalyst involved the generation of oxidizing radicals by acoustic cavitation and Co(II)-Co(III) redox process. Quite low apparent activation energy of the sonocatalytic process (E$_a$ = 19 kJ mol$^{−1}$) was attributed to diffusion of reagents in the vicinity of the active sites of catalyst. Sonocatalytic degradation of EDTA is accompanied by formation of iminodiacetic acid, formic acid, oxalic acid, glycolic acid and acetic acid as intermediate products in an agreement with radical-driven mechanism.

Published
2019
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25. Élaboration de catalyseurs à porosité hiérarchique à base de Pt et Pd en combinant la synthèse de latex, la sonochimie et le procédé sol-gel

Author

Andrés Felipe Sierra Salazar, Tony Chave, André Ayral, Nikitenko, Sergey I., Vasile Hulea, Kooyman, Patricia J., Tichelaar, Frans D., Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), PLANES, MELISSA, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM] Chemical Sciences, [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

26. Insights into the Photothermal Hydrogen Production from Glycerol Aqueous Solutions over Noble Metal-Free Ti@TiO 2 Core-Shell Nanoparticles

Author

Tony Chave, Xavier Le Goff, Sergey I. Nikitenko, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Etude de la Matière en Mode Environnemental (L2ME), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Hydrogen, Nanoparticle, chemistry.chemical_element, 02 engineering and technology, engineering.material, 010402 general chemistry, Photochemistry, 01 natural sciences, 7. Clean energy, Catalysis, General Materials Science, Hydrogen production, Aqueous solution, Photothermal effect, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, chemistry, 13. Climate action, engineering, Photocatalysis, Noble metal, 0210 nano-technology
Abstract

International audience; Photocatalytic production of hydrogen from renewable sources with platinum group metal‐free catalysts is of great importance for environmentally friendly energetics. Herein, Ti@TiO2 core–shell nanoparticles prepared by sonohydrothermal treatment of titanium metal nanoparticles are examined for hydrogen generation from aqueous glycerol solutions under vis/NIR light irradiation. It is shown that photocatalytic reforming of glycerol in the presence of Ti@TiO2 exhibits strong photothermal effect allowing more efficient use of solar energy. Apparent activation energy equal to E act = 27 ± 2 kJ mol−1 indicates that the thermal effect is related to the diffusion of reaction intermediates at catalyst surface rather than to the activation of chemical bonds. The photoexcitation mechanism of Ti@TiO2 particles involves interband transitions in nonplasmonic Ti metal core followed by nonradiative Landau damping. Effective electron–hole separation between Ti core and nanocrystalline TiO2 anatase shell in Ti@TiO2 nanoparticles is confirmed by photoluminescence spectroscopy. In studied system, photothermal hydrogen production is not accompanied by CO2 emission indicating that glycerol is oxidized to glyceric acid without further decarboxylation.

Published
2018
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27. Ultrasound-assisted reductive dissolution of CeO2and PuO2in the presence of Ti particles

Author

Sergey I. Nikitenko, Tony Chave, Laurent Venault, Gilles Leturcq, Gauthier Jouan, Philippe Moisy, Xavier Beaudoux, Matthieu Virot, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Sonication, Inorganic chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 7. Clean energy, 01 natural sciences, Redox, 0104 chemical sciences, Corrosion, Inorganic Chemistry, chemistry.chemical_compound, Hydrofluoric acid, chemistry, Nitric acid, Reagent, 0210 nano-technology, Fluoride, Dissolution, ComputingMilieux_MISCELLANEOUS
Abstract

PuO2 is considered an important material for current and future nuclear fuel; however it is a very refractive compound towards dissolution. Among other techniques, its reprocessing can be performed via complexing dissolution in concentrated and boiling nitric acid containing hydrofluoric acid, or via oxidant dissolution in the presence of reagents with redox couples having high potentials such as Ce(iv)/Ce(iii), or Ag(ii)/Ag(i). Reductive dissolution can be performed under softer conditions and is considered an alternative to these methods which may suffer from several drawbacks (corrosion, effluent management, compatibility with nuclear waste disposal, etc.). In this study, a sonochemical and reductive approach is investigated for PuO2 dissolution under relatively mild conditions. At the first stage, the experiments are performed with CeO2 as an inactive surrogate for PuO2. The quantitative dissolution of both oxides can be achieved under ultrasound (20 kHz, 0.35-0.70 W mL(-1)) in 0.5 M HNO3/0.1 M [N2H5NO3]/2 M HCOOH sparged with Ar at 33-35 °C in the presence of Ti particles as a generating source of reductive species. Ultrasound enables the depassivation of the Ti surface (usually strongly passivated in nitric solutions) through acoustic cavitation which then allows further generation of the intermediate Ti(iii) reductive species. Dissolution rates and yields can be further increased with the injection of dilute fluoride aliquots (NH4F or HF) in the sonicated solution to favor Ti chemical depassivation. The rapid and complete dissolution of PuO2 under selected conditions is accompanied by Pu(iii) accumulation in solution.

Published
2016
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28. Effect of operational conditions on sonoluminescence and kinetics of H2O2 formation during the sonolysis of water in the presence of Ar/O2 gas mixture

Author

Tony Chave, Rachel Pflieger, Ghislain Vite, Lucie Jouve, Sergey I. Nikitenko, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Acoustics and Ultrasonics, Radical, Bubble, Organic Chemistry, Kinetics, Analytical chemistry, chemistry.chemical_element, Oxygen, Sonochemistry, Inorganic Chemistry, Sonoluminescence, chemistry, Yield (chemistry), [CHIM]Chemical Sciences, Chemical Engineering (miscellaneous), Environmental Chemistry, Radiology, Nuclear Medicine and imaging, Ultrasonic sensor, ComputingMilieux_MISCELLANEOUS
Abstract

Ultrasonic frequency is a key parameter determining multibubble sonoluminescence (MBSL) spectra of water saturated with Ar/O2 gas mixtures. At 20 kHz, the MBSL is quenched by oxygen. By contrast, at high-frequency ultrasound the maximal MBSL intensity is observed in the presence of Ar/20%O2 gas mixture. Nevertheless, oxygen has no influence on the shape of MBSL spectra. The effect of oxygen on MBSL is explained by oxygen dissociation inside the collapsing bubble which is much more effective at high ultrasonic frequency compared to 20 kHz ultrasound. In contrast to MBSL, a higher yield of H2O2 is observed in Ar/20%O2 gas mixture whatever the ultrasonic frequency. At 20°C and 20% of oxygen the maximal yield of H2O2 is observed at 204-362 kHz. The maximal yield of H2O2 is shifted to 613kHz when the bulk temperature is raised up to 40°C. Coupling of high-frequency ultrasound with mechanical stirring and intensive Ar/O2 bubbling improves H2O2 production. Comparison of MBSL and sonochemistry allowed to conclude that H2O2 is formed from non-excited OH (X(2)Π) and HO2 radicals. Finally, it was shown that at the studied conditions the efficiency of ultrasonic degassing is hardly influenced by frequency.

Published
2015
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29. Sonocatalytic degradation of oxalic acid in the presence of oxygen and Pt/TiO2

Author

Nathalie M. Navarro, Tony Chave, Aharon Gedanken, Nina Perkas, Sergey I. Nikitenko, and Patrick Pochon

Subjects
chemistry.chemical_classification, Controlled atmosphere, Aqueous solution, Inorganic chemistry, Oxalic acid, chemistry.chemical_element, General Chemistry, Oxygen, Organic compound, 6. Clean water, Catalysis, Sonochemistry, chemistry.chemical_compound, chemistry, 13. Climate action, Dispersion (chemistry)
Abstract

In order to treat aqueous effluents containing organic pollutants, several techniques can be considered depending on the organic compound concentration. Sonochemistry appears to be a promising solution to answer water remediation issue. In fact, when submitted into a liquid, ultrasound can induce the nucleation, growth, and violent collapse of vapor/gas filled bubbles. However, despite the extreme local conditions observed during acoustic cavitation, using ultrasound alone is efficient only at low concentration in organic pollutants. In the present study, 0.05 M oxalic acid degradation kinetics were followed at 40 °C under various conditions, in presence or not of Pt/TiO2 catalyst under silent conditions or ultrasound at 20 and 360 kHz. Experiments were achieved under controlled atmosphere and comparison between argon, Ar/O2 (20 vol% O2) and pure O2 conditions was performed. Oxidation rate increase of oxalic acid was measured under Ar/O2 atmosphere in presence of Pt/TiO2 catalyst due to strong dispersion effect of both low and high ultrasonic frequency and formation of chemically active species by sonolysis. High frequency ultrasonic irradiation under Ar/O2 atmosphere gives the highest kinetic increase compared to silent conditions with oxalic acid degradation rate around 13 μmol min−1 at 40 °C with 2 g L−1 of 3 wt% Pt on P25 TiO2 catalyst.

Published
2015
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30. Insights into the sonochemical synthesis and properties of salt-free intrinsic plutonium colloids

Author

David K. Shuh, Philippe Moisy, Oliver Dieste Blanco, Vincent Morosini, Thomas Dumas, Laurent Venault, Tony Chave, Christoph Hennig, Sergey I. Nikitenko, Elodie Dalodière, Matthieu Virot, Thierry Wiss, Tolek Tyliszcak, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Analyse, Géométrie et Modélisation (AGM - UMR 8088), Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), European Synchrotron Radiation Facility (ESRF), European Commission - Joint Research Centre [Karlsruhe] (JRC), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Advanced Light Source [LBNL Berkeley] (ALS), Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), European Project: 323300,EC:FP7:Fission,FP7-Fission-2012,TALISMAN(2013), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
X-ray absorption spectroscopy, Multidisciplinary, digestive, oral, and skin physiology, Kinetics, chemistry.chemical_element, Nanoparticle, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Pu(IV) colloids, 01 natural sciences, Article, XANES, 0104 chemical sciences, Plutonium, Other Physical Sciences, Colloid, chemistry, Chemical engineering, Water splitting, Biochemistry and Cell Biology, sonochemistry, 0210 nano-technology, High-resolution transmission electron microscopy
Abstract

For the first time, stable intrinsic plutonium colloid was prepared by ultrasonic treatment of PuO2 suspensions in pure water at room temperature. The yield of Pu colloid was found to increase with PuO2 specific surface area and by using reducing carrier gas mixture. Kinetic data evidenced that both chemical and mechanical effects of ultrasound strongly contribute to the mechanism of Pu colloid formation. At first, the fragmentation of initial PuO2 particles accelerates the overall process providing larger surface of contact between cavitation bubbles and solids. Furthermore, hydrogen formed during sonochemical water splitting enables reduction of Pu(IV) to more soluble Pu(III), which then reoxidizes yielding Pu(IV) colloid. Sonochemical colloid was compared with hydrolytic one using HRTEM, Pu LIII XAS, and STXM/NEXAFS (O K-edge) techniques. Both colloids are composed of quasi-spherical nanocrystalline particles of PuO2 (fcc, Fm¯3 m space group) measuring about 7 nm and 3 nm, respectively. Moreover, HRTEM revealed nanostructured morphology for initial PuO2. The EXAFS spectra of colloidal PuO2 nanoparticles were fitted using triple oxygen shell model for the first coordination sphere of Pu(IV). HRTEM and EXAFS studies revealed the correlation between the number of Pu-O and Pu-Pu contacts and atomic surface-to-volume ratio of studied PuO2 nanoparticles. The STXM/NEXAFS study indicated that the oxygen state of hydrolytic Pu colloid is influenced by hydrolyzed Pu(IV) species in much more extent than PuO2 nanoparticles of sonochemical colloid. In general, hydrolytic and sonochemical colloids can be described as core-shell nanoparticles composed of quasi stoichiometric PuO2 core and hydrolyzed Pu(IV) moieties at the surface shell.

Published
2017
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31. Thermal and sonochemical synthesis of porous (Ce,Zr)O2 mixed oxides from metal β-diketonate precursors and their catalytic activity in wet air oxidation process of formic acid

Author

Joulia Larionova, Sergey I. Nikitenko, Camille Cau, Tony Chave, Yannick Guari, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Acoustics and Ultrasonics, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, Platinum nanoparticles, 01 natural sciences, Catalysis, Inorganic Chemistry, Metal, chemistry.chemical_compound, Oleylamine, Specific surface area, Chemical Engineering (miscellaneous), Environmental Chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Radiology, Nuclear Medicine and imaging, Wet oxidation, Dissolution, ComputingMilieux_MISCELLANEOUS, Organic Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, visual_art, visual_art.visual_art_medium, 0210 nano-technology, Platinum
Abstract

Porous (Ce 0.5 Zr 0.5 )O 2 solid solutions were prepared by thermolysis ( T = 285 °C) or sonolysis (20 kHz, I = 32 W cm −2 , P ac = 0.46 W mL −1 , T = 200 °C) of Ce(III) and Zr(IV) acetylacetonates in oleylamine or hexadecylamine under argon followed by heat treatment of the precipitates obtained in air at 450 °C. Transmission Electron Microscopy images of the samples show nanoparticles of ca. 4–6 nm for the two synthetic approaches. The powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray and μ-Raman spectroscopy of solids obtained after heat treatment indicate the formation of (Ce 0.5 Zr 0.5 )O 2 solid solutions with a metastable tetragonal crystal structure for the two synthetic routes. The specific surface area of the samples varies between 78 and 149 m 2 g −1 depending on synthesis conditions. The use of Barrett–Joyner–Halenda and t -plot methods reveal the formation of mixed oxides with a hybrid morphology that combines mesoporosity and microporosity regardless of the method of preparation. Platinum nanoparticles were deposited on the surface of the mixed oxides by sonochemical reduction of Pt(IV). It was found that the materials prepared by sonochemistry exhibit better resistance to dissolution during the deposition process of platinum. X-ray photoelectron spectroscopy analysis shows the presence of Pt(0) and Pt(II) on the surface of mixed oxides. Porous (Ce 0.5 Zr 0.5 )O 2 mixed oxides loaded with 1.5 %wt. platinum exhibit high activity in catalytic wet air oxidation of formic acid at 40 °C.

Published
2014
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32. Sonochemical deposition of platinum nanoparticles on polymer beads and their transfer on the pore surface of a silica matrix

Author

Patrick Lacroix-Desmazes, Anthony Grunenwald, Sergey I. Nikitenko, Tony Chave, André Ayral, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Européen des membranes (IEM), Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), and Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)

Subjects
Materials science, Formic acid, chemistry.chemical_element, Nanotechnology, 02 engineering and technology, 010402 general chemistry, Platinum nanoparticles, 01 natural sciences, Sonochemistry, Biomaterials, chemistry.chemical_compound, Colloid and Surface Chemistry, Deposition (phase transition), Porosity, ComputingMilieux_MISCELLANEOUS, chemistry.chemical_classification, Polymer, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Chemical engineering, Polystyrene, 0210 nano-technology, Platinum
Abstract

This study reported the sonochemical deposition of platinum on the surface of polystyrene beads (PSBs) and the transfer of obtained Pt nanoparticles into a porous silica matrix using the PSB as a sacrificial template. Platinum nanoparticle deposition was ensured by the sonochemical reduction of Pt(IV) at room temperature in latex solutions containing polystyrene beads in the presence of formic acid under Ar or under Ar/CO atmosphere without any additives. After ultrasonic treatments for few hours, well dispersed Pt nanoparticles within the range of 3-5 nm deposited on PSB were obtained in both studied conditions. Samples were then mixed with TEOS, dried, and heated at 450°C to ensure the PSB removal from the silica matrix. TEM and SEM results clearly show that final silica pore size is within the same order of magnitude than initial PSB. Finally, platinum decorated silica matrix with chosen pore sizes was successfully prepared.

Published
2013
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33. Insights into the structure and thermal stability of uranyl aluminate nanoparticles

Author

Sergey I. Nikitenko, Andreas C. Scheinost, Xavier F. Le Goff, Tony Chave, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Etude de la Matière en Mode Environnemental (L2ME), Helmholtz-Zentrum Dresden-Rossendorf (HZDR), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
010405 organic chemistry, Precipitation (chemistry), Aluminate, Inorganic chemistry, chemistry.chemical_element, General Chemistry, Thermal treatment, [CHIM.MATE]Chemical Sciences/Material chemistry, Uranium, 010402 general chemistry, Uranyl, 01 natural sciences, Catalysis, 0104 chemical sciences, law.invention, X-ray absorption fine structure, chemistry.chemical_compound, chemistry, law, Materials Chemistry, Calcination, Mesoporous material
Abstract

International audience; Ultrasonically assisted hydrolytic precipitation of U(VI) in the presence of mesoporous alumina followed by thermal treatment of a solid precursor enabled the formation of crystallized uranyl aluminate (URAL) nanoparticles (NPs) dispersed in the alumina matrix. The effect of U(VI) concentration and calcination temperature on the yield of URAL NPs was studied using XRD, XAFS and HRTEM techniques. At 800 °C, URAL NPs (d ≈ 5 nm) are formed only for a low uranium loading of about 5 wt% whereas for a higher content of uranium, larger U3O8 NPs (d ≈ 20 nm) were identified as the principal uranium species. At 500 °C, URAL NPs are formed even for 25 wt% of uranium. The U LIII edge EXAFS spectra pointed out that uranyl cations in URAL are coordinated by bidentate aluminate groups. Presumably URAL is formed during the heating of the 2UO3·NH3·2H2O/AlO(OH) precursor. However, high temperature and higher content of uranium promote transformation of URAL to more thermodynamically stable U3O8. This process is accompanied by the growth of uranium NPs via the Ostwald ripening mechanism.

Published
2017
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34. SON68 nuclear glass dissolution kinetics: Current state of knowledge and basis of the new GRAAL model

Author

Jean-Eric Lartigue, B. Bonin, Tony Chave, Stéphane Gin, Yves Minet, Pierre Frugier, L. De Windt, André Ayral, Patrick Jollivet, Nicole Godon, G. Santarini, Commissariat à l'Energie Atomique, Centre de Marcoule (CEA), CEA/DEN, Service d'étude des systèmes de confinement, CEA Valrho-Marcoule, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'Etudes du Comportement à Long Terme des matériaux de conditionnement (LCLT), Département de recherche sur les technologies pour l'enrichissement, le démantèlement et les déchets (DE2D), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre de Géosciences (GEOSCIENCES), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Département de Physico-Chimie (DPC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Département de recherche sur les Procédés et Matériaux pour les Environnements complexes (DPME), Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Mines Paris - PSL (École nationale supérieure des mines de Paris)

Subjects
Nuclear and High Energy Physics, Aqueous solution, Passivation, Chemistry, [SDE.MCG]Environmental Sciences/Global Changes, Drop (liquid), Activated complex, Kinetics, Mineralogy, Thermodynamics, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Glass dissolution, Nuclear Energy and Engineering, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Silicate minerals, 0103 physical sciences, General Materials Science, 010306 general physics, 0210 nano-technology, Dissolution
Abstract

International audience; This article summarizes the present state of knowledge concerning aqueous alteration of R7T7-type nuclear containment glasses, represented mainly by the inactive reference glass designated SON68. Based on this review, we propose to describe the glass alteration kinetics up to and including the final residual rate regime by means of a new mechanistic model known as GRAAL (glass reactivity with allowance for the alteration layer). Phenomenological analysis findings are reviewed for the various glass alteration regimes: interdiffusion, initial rate, rate drop, residual rate and, under very particular circumstances, resumption of alteration. These alteration regimes are associated with predominant mechanisms. Published work interpreting and modeling these mechanisms was examined in detail. There is a broad consensus on the general mechanisms of the initial rate and even the interdiffusion regime, whereas the mechanisms controlling the rate drop remain a subject of dispute not only with regard to nuclear glasses but also for the dissolution of silicate minerals. The reaction affinity responsible for the rate drop is expressed differently by different authors and depending on the underlying theories. The disagreement concerns the nature of the phase (glass or gel) or the activated complex controlling the rate drop, which in turn determines the elements that must be taken into account in the overall affinity term. Progress in recent years, especially in identifying the mechanisms responsible for the residual rate, has shed new light on these issues, allowing us to propose new theoretical foundations for modeling the different kinetic regimes of SON68 nuclear glass dissolution. The GRAAL model considers that water diffusion in the passivating reaction zone (the gel formed under saturation conditions) is a rate-limiting step in the overall glass dissolution kinetics. Moreover, this passivation zone is a soluble phase whose stability is directly dependent on the nature of the secondary phases likely to precipitate and on the solution renewal conditions.

Published
2008
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35. Vitamin C boosts ceria-based catalyst recycling

Author

Grégory Durand, Gilles Leturcq, Xavier Beaudoux, Sergey I. Nikitenko, Tony Chave, Matthieu Virot, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut des Biomolécules Max Mousseron [Pôle Chimie Balard] (IBMM), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Avignon Université (AU)

Subjects
chemistry.chemical_classification, Inorganic chemistry, Kinetics, Oxide, Mineral acid, Polishing, Sulfuric acid, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Ascorbic acid, 01 natural sciences, Pollution, 0104 chemical sciences, Catalysis, chemistry.chemical_compound, chemistry, Environmental Chemistry, 0210 nano-technology, Dissolution, ComputingMilieux_MISCELLANEOUS
Abstract

The facile, rapid, and complete reductive dissolution of CeO2 and ceria-based oxides, known to be highly refractive materials towards dissolution, is reported for the first time in very mild conditions. Ceria samples are dissolved at room temperature under stirring in a mixture composed of ascorbic acid and a dilute mineral acid. Normalized dissolution kinetics are compared as a function of the concentration of reactants, nature of the mineral acid, firing temperature and reactive surface area of considered oxides. Since ceria dissolution can represent a promising alternative for the recycling of automotive catalysts, solid oxide fuel cells, polishing powders, organic chemistry catalysts, sensors, etc., the potential application of the proposed procedure is then studied through the dissolution of catalyst surrogates and complex oxides: Pt/CeO2, (Ce0.75Zr0.25)O2, and (Ce0.8Tb0.2)O2. Whatever the considered sample, the complete and congruent (for mixed oxides) oxide dissolution is observed in 0.5 M ascorbic acid in the presence of dilute nitric or sulfuric acid. For Pt/CeO2 samples, ceria dissolution goes with Pt aggregation which can be easily recovered from the solution after processing due to its high stability in this medium. This eco-friendly and efficient method appears very promising for catalyst recycling in comparison to conventional procedures. After rigorous characterization of the investigated oxides (BET, SEM-EDX, XRD, TGA), dissolution progress is evaluated with ICP-OES and SEM measurements. The dissolution mechanism is then investigated with UV-Vis, ATR-FTIR and ESR spectroscopies and a general dissolution mechanism is proposed.

Published
2016
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36. Photothermal Hydrogen Production Using Noble-Metal-Free Ti@TiO 2 Core–Shell Nanoparticles under Visible–NIR Light Irradiation

Author

H.P. Brau, Tony Chave, Valérie Flaud, Sergey I. Nikitenko, Camille Cau, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Etude de la Matière en Mode Environnemental (L2ME), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), and Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Anatase, Materials science, Hydrogen, Nanoparticle, chemistry.chemical_element, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, engineering.material, Photochemistry, 7. Clean energy, Catalysis, chemistry, Chemical engineering, 13. Climate action, Rutile, engineering, Photocatalysis, Noble metal, ComputingMilieux_MISCELLANEOUS, Hydrogen production
Abstract

Limiting resources of fossil fuels and environmental issues inevitably require more efficient utilization of solar energy. Photocatalytic production of hydrogen is identified as one of the most promising routes for developing clean and sustainable energy; however, engineering low-cost materials exhibiting high catalytic activity in the entire range of the solar spectrum is still a challenge. Here, for the first time, we report simple, easily scalable, and environmentally friendly synthesis of stable Ti@TiO2 core–shell nanoparticles exhibiting photocatalytic activity in hydrogen production under vis/NIR light irradiation without any noble metals. Stable to oxidation core–shell Ti@TiO2 nanoparticles have been obtained by the simultaneous actions of ultrasound and hydrothermal treatment on air-passivated titanium metal nanoparticles in pure water. The obtained material is composed of quasi-spherical Ti particles (20–80 nm) coated by 5–15 nm crystals of defect-free anatase with small amounts of rutile. In con...

Published
2015
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37. Sonochemical water splitting in the presence of powdered metal oxides

Author

Tony Chave, Philippe Moisy, Sergey I. Nikitenko, Matthieu Virot, Vincent Morosini, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Acoustics and Ultrasonics, Inorganic chemistry, Oxide, Nucleation, Nanoparticle, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Sonochemistry, Inorganic Chemistry, Metal, chemistry.chemical_compound, Mechanochemistry, Chemical Engineering (miscellaneous), Environmental Chemistry, Radiology, Nuclear Medicine and imaging, ComputingMilieux_MISCELLANEOUS, Organic Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, Chemical engineering, visual_art, visual_art.visual_art_medium, Water splitting, Particle, 0210 nano-technology
Abstract

Kinetics of hydrogen formation was explored as a new chemical dosimeter allowing probing the sonochemical activity of argon-saturated water in the presence of micro- and nano-sized metal oxide particles exhibiting catalytic properties (ThO2, ZrO2, and TiO2). It was shown that the conventional sonochemical dosimeter based on H2O2 formation is hardly applicable in such systems due to catalytic degradation of H2O2 at oxide surface. The study of H2 generation revealed that at low-frequency ultrasound (20 kHz) the sonochemical water splitting is greatly improved for all studied metal oxides. The highest efficiency is observed for relatively large micrometric particles of ThO2 which is assigned to ultrasonically-driven particle fragmentation accompanied by mechanochemical water molecule splitting. The nanosized metal oxides do not exhibit particle size reduction under ultrasonic treatment but nevertheless yield higher quantities of H2. The enhancement of sonochemical water splitting in this case is most probably resulting from better bubble nucleation in heterogeneous systems. At high-frequency ultrasound (362 kHz), the effect of metal oxide particles results in a combination of nucleation and ultrasound attenuation. In contrast to 20 kHz, micrometric particles slowdown the sonolysis of water at 362 kHz due to stronger attenuation of ultrasonic waves while smaller particles show a relatively weak and various directional effects.

Published
2015
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39. Catalytic dissolution of ceria–lanthanide mixed oxides provides environmentally friendly partitioning of lanthanides and platinum

Author

Tony Chave, Nicolas Clavier, Nicolas Dacheux, Xavier Beaudoux, Matthieu Virot, Gilles Leturcq, Sergey I. Nikitenko, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Interfaces de Matériaux en Evolution (LIME), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Lanthanide, Inorganic chemistry, Oxide, chemistry.chemical_element, 02 engineering and technology, engineering.material, 010402 general chemistry, Platinum nanoparticles, 01 natural sciences, Industrial and Manufacturing Engineering, Catalysis, chemistry.chemical_compound, Nitric acid, Materials Chemistry, [CHIM]Chemical Sciences, Dissolution, ComputingMilieux_MISCELLANEOUS, Chemistry, Metals and Alloys, 021001 nanoscience & nanotechnology, 6. Clean water, 0104 chemical sciences, engineering, Noble metal, 0210 nano-technology, Platinum
Abstract

The reductive dissolution of cerium–lanthanide mixed oxides was investigated under mild conditions in weakly acid media. The dissolution is catalyzed by platinum nanoparticles (Pt NPs) deposited onto oxide surfaces. The deposition of Pt NPs was performed by sonochemical reduction of Pt(IV). The dissolution efficiency was studied as a function of different parameters such as stirring, sonication at 20 kHz, dissolution media and oxide composition. The quantitative dissolution of these oxides can be performed in 0.25 M HNO 3 –1 M HCOOH–0.2 M [N 2 H 5 ][NO 3 ] and 0.125 M H 2 SO 4 –1 M HCOOH under stirring at 40 °C in the presence of argon, or in 0.125 M H 2 SO 4 under sonication in the presence of Ar–CO gas mixture at 40 °C. In nitric acid solutions mechanical stirring is more efficient than sonication due to the secondary denitration triggered by ultrasound. The incorporation of trivalent (Gd, Nd) or tetravalent (Tb) lanthanides into the ceria matrix resulted in faster dissolution. After dissolution, lanthanides and platinum can be separated by simple filtration. The catalytic dissolution of ceria-based mixed oxides offers a simple way of lanthanide and noble metal partitioning which could appear of interest for catalyst recycling.

Published
2015
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40. Influence of Ultrasonic Frequency on Swan Band Sonoluminescence and Sonochemical Activity in Aqueous tert -Butyl Alcohol Solutions

Author

Tony Chave, Rachel Pflieger, Sergey I. Nikitenko, Abdoul Aziz Ndiaye, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Chemistry, Bubble, Analytical chemistry, Rotational temperature, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Spectral line, 0104 chemical sciences, Surfaces, Coatings and Films, Sonochemistry, Sonoluminescence, 13. Climate action, Materials Chemistry, Electron temperature, [CHIM]Chemical Sciences, Emission spectrum, Physical and Theoretical Chemistry, Ionization energy, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

The multibubble sonoluminescence (MBSL) spectra of t-BuOH aqueous solutions submitted to power ultrasound at 20, 204, 362, and 613 kHz show emissions for the Δυ = -1 to Δυ = +2 vibrational sequences of C2* Swan system (d(3)Πg → a(3)Πu). The Δυ=+2 emission overlaps with the CH(A-X) emission band. The maximal Swan band emission is observed when the MBSL of water itself is almost completely quenched. In general, MBSL is more intense at high-frequency compared to 20 kHz ultrasound. However, in the presence of Xe, the MBSL of C2* at 20 kHz is so bright that it can be seen by the unaided eye as a blue glow in the close vicinity of the ultrasonic tip. The intensity of the C2* band emission exhibits a maximum vs t-BuOH concentration: 0.1-0.2 M at 20 kHz and (1-8) × 10(-3) M at high-frequency ultrasound. Such a huge difference is attributed to a much smaller bubble size at high ultrasonic frequency or, in other words, to a much higher bubble surface/volume ratio providing more efficient saturation of the bubble interior with t-BuOH vapors and to the fact that high frequency bubbles remain active for many more cycles than 20 kHz ones, thus accumulating more hydrocarbon decomposition products. Simulation of the emission spectra using Specair software demonstrated the absence of thermal equilibrium for C2* radicals (Tv > Tr), where Tv and Tr are the vibrational and the rotational temperature, respectively. In Ar, Tv decreases with increasing t-BuOH concentration reaching a steady value in the concentration domain that corresponds to C2* emission maximum intensity. In the presence of Xe an extremely high Tv is obtained, which is explained by the relatively low ionization potential of Xe providing a higher electron temperature of nonequilibrium plasma generated during bubble collapse. Analysis of the gaseous products of t-BuOH sonolysis reveals a significant sonochemical activity even at high t-BuOH concentration when MBSL is totally quenched, indicating that drastic conditions could be produced also within nonsonoluminescing cavitation bubbles.

Published
2014
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41. Activating Molecules, Ions, and Solid Particles with Acoustic Cavitation

Author

Matthieu Virot, Tony Chave, Sergey I. Nikitenko, Rachel Pflieger, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Materials science, General Chemical Engineering, Nucleation, Implosion, Nanoparticle, General Biochemistry, Genetics and Molecular Biology, Sonochemistry, Ion, Sonoluminescence, cavitation, colloids, Cations, Molecule, Ultrasonics, Argon, Platinum, Carbon Monoxide, Photons, Microbubbles, actinides, General Immunology and Microbiology, ultrasound, General Neuroscience, Acoustics, [CHIM.MATE]Chemical Sciences/Material chemistry, Solutions, Chemistry, nanocolloids, Chemical physics, Cavitation, Luminescent Measurements, nanoparticles, Gases, sonoluminescence, Issue 86
Abstract

International audience; The chemical and physical effects of ultrasound arise not from a direct interaction of molecules with sound waves, but rather from the acoustic cavitation: the nucleation, growth, and implosive collapse of microbubbles in liquids submitted to power ultrasound. The violent implosion of bubbles leads to the formation of chemically reactive species and to the emission of light, named sonoluminescence. In this manuscript, we describe the techniques allowing study of extreme intrabubble conditions and chemical reactivity of acoustic cavitation in solutions. The analysis of sonoluminescence spectra of water sparged with noble gases provides evidence for nonequilibrium plasma formation. The photons and the "hot" particles generated by cavitation bubbles enable to excite the non-volatile species in solutions increasing their chemical reactivity. For example the mechanism of ultrabright sonoluminescence of uranyl ions in acidic solutions varies with uranium concentration : sonophotoluminescence dominates in diluted solutions, and collisional excitation contributes at higher uranium concentration. Secondary sonochemical products may arise from chemically active species that are formed inside the bubble, but then diffuse into the liquid phase and react with solution precursors to form a variety of products. For instance, the sonochemical reduction of Pt(IV) in pure water provides an innovative synthetic route for monodispersed nanoparticles of metallic platinum without any templates or capping agents. Many studies reveal the advantages of ultrasound to activate the divided solids. In general, the mechanical effects of ultrasound strongly contribute in heterogeneous systems in addition to chemical effects. In particular, the sonolysis of PuO 2 powder in pure water yields stable colloids of plutonium due to both effects. Video Link The video component of this article can be found at

Published
2014
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42. Sonohydrothermal Synthesis of Nanostructured (Ce,Zr)O2 Mixed Oxides with Enhanced Catalytic Performance

Author

Patrick Pochon, Tony Chave, Joulia Larionova, Yannick Guari, Sergey I. Nikitenko, Camille Cau, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Chimie moléculaire et organisation du solide (CMOS), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Département RadioChimie et Procédés (DRCP), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Coprecipitation, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Hydrothermal circulation, Catalysis, Sonochemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Wet oxidation, Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, General Energy, chemistry, Mixed oxide, 0210 nano-technology, Mesoporous material, Platinum, Nuclear chemistry
Abstract

We report for the first time evidence of sonochemical activity under hydrothermal conditions. Sonolysis of H2O and D2O using 20 kHz power ultrasound at 200 °C and 13 bar in the presence of argon yields H2 and D2 respectively. Formation of hydrogen peroxide is not observed because of its thermal instability. The simultaneous sonohydrothermal treatment was used for the preparation of Ce0.5Zr0.5O2 nanocrystalline mixed oxide with external mesoporous surface area higher than that of similar material prepared by ultrasonically assisted coprecipitation followed by hydrothermal treatment. The obtained mixed oxide loaded with 1.5 wt % of platinum exhibits high activity and stability in catalytic wet air oxidation of formic acid at low temperature.

Published
2013
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43. Uranium carbide dissolution in nitric solution: Sonication vs. silent conditions

Author

Tony Chave, Sergey I. Nikitenko, Philippe Moisy, Matthieu Virot, Stéphanie Szenknect, Nicolas Dacheux, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Interfaces de Matériaux en Evolution (LIME), Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Nuclear and High Energy Physics, Nitrous acid, Sonication, Induction period, Inorganic chemistry, Kinetics, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, equipment and supplies, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Sonochemistry, chemistry.chemical_compound, Nuclear Energy and Engineering, chemistry, Nitric acid, General Materials Science, Uranium carbide, 0210 nano-technology, Dissolution, ComputingMilieux_MISCELLANEOUS
Abstract

The dissolution of uranium carbide (UC) in nitric acid media is considered by means of power ultrasound (sonication) or magnetic stirring. The induction period required to initiate UC dissolution was found to be dramatically shortened when sonicating a 3 M nitric solution (Ar, 20 kHz, 18 W cm −2 , 20 °C). At higher acidity, magnetic stirring offers faster dissolution kinetics compared to sonication. Ultrasound-assisted UC dissolution is found to be passivated after ∼60% dissolution and remains incomplete whatever the acidity which is confirmed by ICP–AES, LECO and SEM–EDX analyses. In general, the kinetics of UC dissolution is linked to the in situ generation of nitrous acid in agreement with the general mechanism of UC dissolution; the nitrous acid formation is reported to be faster under ultrasound at low acidity due to the nitric acid sonolysis. The carbon balance shared between the gaseous, liquid, and solid phases is strongly influenced by the applied dissolution procedure and HNO 3 concentration.

Published
2013
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44. Mechanism of PtIV Sonochemical Reduction in Formic Acid Media and Pure Water

Author

Tony Chave, Serge Nitsche, Sergey I. Nikitenko, Nathalie M. Navarro, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Paul Cézanne - Aix-Marseille 3, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Hydrogen, Reducing agent, Formic acid, Radical, Organic Chemistry, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Platinum nanoparticles, 01 natural sciences, Catalysis, 0104 chemical sciences, Sonochemistry, chemistry.chemical_compound, chemistry, Oxidizing agent, [CHIM]Chemical Sciences, 0210 nano-technology, Platinum, ComputingMilieux_MISCELLANEOUS
Abstract

Sonochemical synthesis of platinum nanoparticles (Pt NPs) in formic acid solutions and pure water was investigated using a 20 kHz ultrasonic irradiation. The obtained results gave new insights on the underneath Pt(IV) reduction mechanism in formic acid media under argon and in pure water under Ar/CO atmosphere. It was shown that in pure water sonochemical reduction of platinum ions occurs by hydrogen issued from homolytic water molecule split. Pt(IV) ion reduction appears to be a very slow process under argon atmosphere in pure water due to formation of oxidizing species like OH radicals and H(2)O(2) leading to reoxidation of intermediate Pt(II) ions. Sonochemical reduction is accelerated manifold in the presence of formic acid or Ar/CO gas mixture. Solution and gas-phase analyses reveal that both CO and HCOOH act as OH(.) radical scavenger and reducing agent under ultrasonic irradiation. Their ability to reduce platinum ions at room temperature is enhanced due to the local heating in the liquid shell surround the cavitation bubble. An innovative synthesis route for monodispersed Pt NPs in pure water without any templates or capping agents in the presence of Ar/CO gas mixture is then proposed. Obtained Pt NPs within the range of 2-3 nm exhibited a strong stability towards sedimentation in water. Since Ar/CO atmosphere is the only restriction of the process, this procedure can be applied in various media and is also compatible with a large array of experimental conditions.

Published
2012
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46. Glass–water interphase reactivity with calcium rich solutions

Author

Tony Chave, Stéphane Gin, Pierre Frugier, André Ayral, Laboratoire d'Etudes du Comportement à Long Terme des matériaux de conditionnement (LCLT), Département de recherche sur les technologies pour l'enrichissement, le démantèlement et les déchets (DE2D), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Département de recherche sur les Procédés et Matériaux pour les Environnements complexes (DPME), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Kinetics, chemistry.chemical_element, Mineralogy, 02 engineering and technology, Calcium, 021001 nanoscience & nanotechnology, 01 natural sciences, Water composition, chemistry, Chemical engineering, Geochemistry and Petrology, 0103 physical sciences, Calcium content, [CHIM]Chemical Sciences, Interphase, 0210 nano-technology, Saturation (chemistry), ComputingMilieux_MISCELLANEOUS
Abstract

The effect of calcium on synthetic glass alteration mechanisms has been studied. It is known that the higher the calcium content in the glass, the higher the forward rate. However, in a confined medium reaching apparent saturation state and a pH90°C around 9, synthetic calcium-bearing glasses are those with the lowest alteration rates. This work brings new and fundamental evidence toward understanding the alteration mechanisms: the rate-decreasing effect of calcium exists even if the calcium comes from the solution. Calcium from solution reacts with silica network in the hydrated layer at the glass surface. The calcium effect on the alteration kinetics is explained by the condensation of a passivating reactive interphase (PRI) whose passivating properties are strongly enhanced when calcium participates in its construction. These experiments provide new evidence of the role of condensation mechanisms in glass alteration. This better understanding of the calcium effect on glass long-term behavior will be useful both for improving glass formulations and for understanding the influence of the water composition.

Published
2011
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47. ChemInform Abstract: Potential Applications of Sonochemistry in Spent Nuclear Fuel Reprocessing: A Short Review

Author

Philippe Moisy, Laurent Venault, Tony Chave, I. Bisel, Rachel Pflieger, and Sergey I. Nikitenko

Subjects
chemistry.chemical_compound, Waste management, chemistry, Nitric acid, Neptunium, Radioactive waste, chemistry.chemical_element, General Medicine, PUREX, Uranium, Spent nuclear fuel, Sonochemistry, Plutonium
Abstract

The industrial treatment of spent nuclear fuel is based upon a hydrometallurgical process in nitric acid medium. In order to minimize the volume of radioactive waste it seems interesting to generate the reactive species in situ in such solutions using ultrasonic irradiation without addition of salt-forming reagents. This review summarizes for the first time the versatile sonochemical processes with uranium, neptunium and plutonium in homogeneous nitric acid solutions and heterogeneous systems. The dissolution of refractory solids, ultrasonically driven liquid-liquid extraction and the sonochemical degradation of the volatile products of organic solvent radiolysis issued from PUREX process are considered. Also the guidelines for required further work to ensure successful application of the studied processes at industrial scale are discussed.

Published
2011
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48. Effect of Ultrasonic Frequency on the Mechanism of Formic Acid Sonolysis

Author

Nathalie M. Navarro, Isabelle Bisel, Tony Chave, Patrick Pochon, Sergey I. Nikitenko, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Département RadioChimie et Procédés (DRCP), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Chemistry, Formic acid, Inorganic chemistry, Kinetics, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Photochemistry, 7. Clean energy, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Sonochemistry, chemistry.chemical_compound, Yield (chemistry), Materials Chemistry, Degradation (geology), [CHIM]Chemical Sciences, Ultrasonic sensor, Physical and Theoretical Chemistry, 0210 nano-technology, Argon atmosphere, ComputingMilieux_MISCELLANEOUS
Abstract

The kinetics and mechanism of formic acid sonochemical degradation were studied at ultrasonic frequencies of 20, 200, and 607 kHz under argon atmosphere. Total yield of HCOOH sonochemical degradation increases approximately 6-8-fold when the frequency increased from 20 to 200 or to 607 kHz. At low ultrasonic frequencies, HCOOH degradation has been attributed to oxidation with OH(•) radicals from water sonolysis and to the HCOOH decarboxylation occurring at the cavitation bubble-liquid interface. With high-frequency ultrasound, the sonochemical reaction is also influenced by HCOOH dehydration. Whatever the ultrasonic frequency, the sonolysis of HCOOH yielded H(2) and CO(2) in the gas phase as well as trace amounts of oxalic acid and formaldehyde in the liquid phase. However, CO and CH(4) formations were only detected under high-frequency ultrasound. The most striking difference between low-frequency and high-frequency ultrasound is that the sonolysis of HCOOH at high ultrasonic frequencies initiates Fischer-Tropsch hydrogenation of carbon monoxide.

Published
2011
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49. Potential applications of sonochemistry in spent nuclear fuel reprocessing: A short review

Author

I. Bisel, Rachel Pflieger, Philippe Moisy, Sergey I. Nikitenko, Tony Chave, Laurent Venault, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Actinoid Series Elements, Acoustics and Ultrasonics, chemistry.chemical_element, 010501 environmental sciences, 01 natural sciences, 7. Clean energy, Nitric Acid, Inorganic Chemistry, chemistry.chemical_compound, 0404 agricultural biotechnology, Nitric acid, Chemical Engineering (miscellaneous), Environmental Chemistry, [CHIM]Chemical Sciences, Radiology, Nuclear Medicine and imaging, Ultrasonics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Waste management, Chemistry, Neptunium, Organic Chemistry, Radiochemistry, Radioactive waste, 04 agricultural and veterinary sciences, Actinide, PUREX, Uranium, Nuclear Energy, 040401 food science, Spent nuclear fuel, Plutonium, Oxidation-Reduction
Abstract

The industrial treatment of spent nuclear fuel is based upon a hydrometallurgical process in nitric acid medium. In order to minimize the volume of radioactive waste it seems interesting to generate the reactive species in situ in such solutions using ultrasonic irradiation without addition of salt-forming reagents. This review summarizes for the first time the versatile sonochemical processes with uranium, neptunium and plutonium in homogeneous nitric acid solutions and heterogeneous systems. The dissolution of refractory solids, ultrasonically driven liquid-liquid extraction and the sonochemical degradation of the volatile products of organic solvent radiolysis issued from PUREX process are considered. Also the guidelines for required further work to ensure successful application of the studied processes at industrial scale are discussed.

Published
2010
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50. Acoustic Cavitation at the Water−Glass Interface

Author

Tony Chave, Dmitry G. Shchukin, Sergey I. Nikitenko, Thomas Zemb, Matthieu Virot, Helmuth Möhwald, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, business.industry, Bubble, Sonication, Ultrasound, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, General Energy, Cavitation, Microscopy, Erosion, [CHIM]Chemical Sciences, Ultrasonic sensor, Leaching (metallurgy), Physical and Theoretical Chemistry, Composite material, 0210 nano-technology, business, ComputingMilieux_MISCELLANEOUS
Abstract

Power ultrasound (20 kHz, Iac = 20−56 W cm−2) was used to investigate physical and chemical effects of acoustic cavitation at the water−glass interface. Physical effects were characterized with different techniques of microscopy (optical, SEM, AFM) and were shown to increase and evolve as a function of sonication duration according to two distinctive periods: (i) an incubation period that initiates weak points on a glass surface, which may be the result of acoustically created shock-waves, and (ii) a second period of erosion, which is related to direct impact fracture erosion of the material. Chemical analysis of water (ICP-OES), after ultrasonic treatment, clearly indicates that bubble collapse at the water−glass interface initiates not only mechanical erosion but also accelerates the leaching processes of the glass components.

Published
2010
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