CNRS Poitiers Institute of Chemistry: Materials and Natural Resources

Poitiers, France

CNRS Poitiers Institute of Chemistry: Materials and Natural Resources

Poitiers, France
SEARCH FILTERS
Time filter
Source Type

Cosenza P.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources
E3S Web of Conferences | Year: 2016

This manuscript reviews the recent developments in indirect methods used to measure soil watent content (SWC). It focuses on three types of methodological approaches: (i) high-frequency electromagnetic methodologies (dielectric methods and Ground Penetrating Radar), (ii) low-frequency electromagnetic methods (resistivity method and spectral induced polarization-SIP) and (iii) emerging methods (laboratory and ground-based nuclear magnetic resonance-NMR techniques and methods based on fiber optic temperature sensing systems). For each method the physical principles and the corresponding methodology are briefly described first, followed by the recent methodological advances. These recent advances address the following issues: (a) integration of different types of sensors to design new multi-functional devices, (b) miniaturization of low-cost and easily-installed electromagnetic sensors, (c) fusion and assimilation of data acquired from multiple modalities with different sampling rates and spatial resolutions, (d) physical understanding of spectra and distributed parameters measured by SIP and NMR methods, (e) improvement of geophysical inversion techniques combined with fast data acquisitions (4D monitoring of SWC). © 2016 The Authors.


Chatel G.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Macfarlane D.R.,Monash University
Chemical Society Reviews | Year: 2014

Ionic liquids, as reaction media, and sonochemistry are two recently developing fields of chemistry that present some similarities. Firstly, they constitute separately unconventional approaches to reaction chemistry that, in many cases, generate improvements in yield, rate and selectivity compared to classical chemistry, or even change the mechanisms or products expected. In addition, both are often associated with green chemistry concepts as a result of their properties and their possible eco-friendly uses. A recent trend has been to combine these two technologies in a range of different applications and the results demonstrate very significant and occasionally surprising synergetic effects. Here we critically review the advantages and limitations of the ionic liquid/ultrasound combination in different applications in chemistry, to understand how, and in which respects, it could become an essential tool of sustainable chemistry in the future. Many practical and theoretical aspects associated with this combination of techniques are not understood or resolved and we discus where fundamental studies might further advance this field. This journal is © the Partner Organisations 2014.


Gu Y.,Huazhong University of Science and Technology | Gu Y.,CAS Lanzhou Institute of Chemical Physics | Jerome F.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources
Chemical Society Reviews | Year: 2013

Biomass and waste exhibit great potential for replacing fossil resources in the production of chemicals. The search for alternative reaction media to replace petroleum-based solvents commonly used in chemical processes is an important objective of significant environmental consequence. Recently, bio-based derivatives have been either used entirely as green solvents or utilized as pivotal ingredients for the production of innovative solvents potentially less toxic and more bio-compatible. This review presents the background and classification of these new media and highlights recent advances in their use in various areas including organic synthesis, catalysis, biotransformation and separation. The greenness, advantages and limitations of these solvents are also discussed. © 2013 The Royal Society of Chemistry.


Royer S.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Royer S.,Laval University | Duprez D.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Can F.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | And 5 more authors.
Chemical Reviews | Year: 2014

The paper focuses on providing information about the latest advances in development and application of perovskites in heterogeneous catalytic processes. Synthesis methods of perovskites have rapidly achieved great success since their first preparation from the simple ceramic method in the 1970s. Several new synthesis routes classified as solution-mediated methods have been developed from the 1980s, including coprecipitation, complexation, sol-gel, and freeze/spray drying. Coprecipitation is used to reduce the total amount of residual carbonate with the aim of reducing the required calcinations temperature. The rate of evaporation is increased using freeze drying, allowing synthesis of solids with quite high surface areas. Another popular solution-mediated route is the sol-gel method, which is based on hydrolysis of precursors such as alkoxides, nitrates, carboxylates, acetylacetonates, chlorides, and other inorganics to generate a homogeneous solution and transforming it into a gel by densification or subsequent heat treatment.


Chatel G.,University of Alabama | Chatel G.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Rogers R.D.,University of Alabama
ACS Sustainable Chemistry and Engineering | Year: 2014

Lignin, one of the three subcomponents of lignocellulosic biomass (along with cellulose and hemicellulose), represents more than 20% of the total mass of the Earth's biosphere. However, essentially due to its complex structure, this renewable polymer derived from biomass is mainly burned as a source of energy in the pulp and paper industry. Today, the valorization of lignin into the production of chemical feedstocks represents a real challenge in terms of both sustainability and environmental protection. This review first briefly outlines the main points of this challenge and compares the different methods investigated by chemists over the past several decades, pointing out the major difficulties met. Next, the review highlights the recent use of ionic liquids (ILs) as solvents that have provided some new opportunities to efficiently convert lignin and lignin model compounds into value-added aromatic chemicals. Particular focus is given to these new strategies in terms of selectivity, separation and the unique compounds obtained for the oxidation of lignin using ILs. Finally, an assessment of the challenges that must be resolved in order for ILs to become an eco-friendly way of producing chemicals from biomass, including lignin, is proposed. © 2013 American Chemical Society.


Baranton S.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Coutanceau C.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources
Applied Catalysis B: Environmental | Year: 2013

The activity of NixCo10-x/C catalysts for the hydrogen evolution reaction (HER) was evaluated. The NixCo10-x/C (0≤ x≤ 10) nano-catalysts were synthesized by a water-in-oil microemulsion method and were then characterized by thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The control of a metal loading of ca. 30wt% on carbon was confirmed for all catalysts from TGA, while TEM images and XRD patterns revealed the formation of nickel cobalt hydroxide nano-flakes with a preferential growth along the (100) and (010) directions. The electrochemical investigations in 0.1M NaOH confirmed the interaction between nickel and cobalt in the catalytic materials, and their activity towards the HER. The catalytic activity increased regularly with the increase of the cobalt content in the NixCo10-x/C materials. The short term stability measurements performed by chronoamperometry revealed that dissolution of cobalt occurred. Hence, amongst the nickel cobalt hydroxides synthesized, Ni5Co5/C and Ni7Co3/C catalysts were found to present a good compromise between catalytic activity for the HER and stability. © 2013 Elsevier B.V.


Maciuca A.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Batiot-Dupeyrat C.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Tatibouet J.-M.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources
Applied Catalysis B: Environmental | Year: 2012

By combining non-thermal plasma and photocatalysis a synergy effect has been observed in low concentrated gaseous isovaleraldehyde oxidation in air. The study of the behavior in isovaleraldehyde oxidation by the separate processes has shown that this synergy effect could be due to the activation by UV on TiO 2 of the ozone produced by the non-thermal plasma.According to the results, plasma-photocatalysis system significantly increases the efficiency of isovaleraldehyde removal and tends to favor the complete mineralization of isovaleraldehyde. It means that plasma-photocatalysis system could be a relevant method for the removal of low concentrated volatile organic compounds from air. © 2012 Elsevier B.V.


Zhang Q.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Jerome F.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources
ChemSusChem | Year: 2013

Deconstructing cellulose: This highlight presents an emerging concept dealing with the mechanocatalytic deconstruction of biopolymers including cellulose, lignin, and lignocellulosic biomass. This dry treatment of biomass is expected to open new horizons in the field of biomass processing. In particular, mechanocatalysis is now considered as a promising entry into biorefinery. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Simoes M.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Baranton S.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Coutanceau C.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources
ChemSusChem | Year: 2012

The worldwide glycerol stocks are increasing; to make the biodiesel industry sustainable economically, this chemical could be used as a secondary primary raw material. Electric energy or hydrogen and added-value-chemical cogeneration becomes more and more an important research topic for increasing economical and industrial interests towards electrochemical technologies. Studies on glycerol electrooxidation for fuel or electrolysis cell applications are scarce. The valorisation of glycerol is generally performed by organic chemistry reactions forming, for example, esters, glycerol carbonates, ethers, acetals or ketals. Glycerol oxidation is made up of complex pathway reactions that can produce a large number of useful intermediates or valuable fine chemicals with presently limited market impact due to expensive production processes. Many of these chemical oxidation routes lead to significant amounts of undesired by-products, and enzymatic processes are limited. Converse to classical heterogeneous processes, electrocatalytic oxidation processes can be tuned by controlling the nature, composition and structure of the electrocatalyts as well as the electrode potential. Such control may lead to very high selectivity and activity, avoiding or limiting product separation steps. The coupling of glycerol oxidation to produce chemicals with the oxygen reduction reaction in a fuel cell or water reduction reaction in an electrolysis cell on Pt-free catalysts results either in coproduction of electrical energy or hydrogen for energy storage. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Criquet J.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Leitner N.K.V.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources
Radiation Physics and Chemistry | Year: 2015

The degradation of p-hydroxybenzoic acid (HBA) in aqueous solutions by ionizing radiation was studied. The phenolic pollutant was easily removed by the electron beam irradiation, as more than 80% of the initial 100. μM introduced was degraded for a dose of 600. Gy. It was shown that the addition of persulfate, producing the sulfate radical as additional reactive species, induced a change in the reaction pathway. LC-MS analyses were performed in order to identify the different by-products formed. In the absence of persulfate, the main by-product formed was 3,4-dihydroxybenzoic acid, while in presence of persulfate, 1,4-benzoquinone was detected and the hydroxylated by-products were not present. A reaction pathway of HBA degradation by hydroxyl and sulfate radicals was proposed from the identification of the chemical structure of the different by-products detected.The influences of pH and dissolved oxygen were also studied. A high decline of HBA degradation was observed at pH 11 compared to pH 4.5, this decrease was minimized in the presence of persulfate. The dissolved oxygen concentration was found to be a limiting parameter of HBA degradation, however an excess of dissolved oxygen in solution did not improve the degradation to a large extent. © 2014 Elsevier Ltd.

Loading CNRS Poitiers Institute of Chemistry: Materials and Natural Resources collaborators
Loading CNRS Poitiers Institute of Chemistry: Materials and Natural Resources collaborators