Papers by Gérald Pourcelly
Journal of Computational and Applied Mathematics
A planar cubic Bézier curve segment that is a spiral, i.e., its curvature varies monotonically wi... more A planar cubic Bézier curve segment that is a spiral, i.e., its curvature varies monotonically with arc-length, is discussed. Since this curve segment does not have cusps, loops, and inflection points (except for a single inflection point at its beginning), it is suitable for applications such as highway design, in which the clothoid has been traditionally used. Since it is
Desalination, Volume 200, Issues 1-3, pp. 752-753
Desalination, Vol. 199 - Issues 1-3, pp. 62-63
Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1990
The high frequency electrical resistance of a Nafion ® 117 perfluorosulphonic membrane has been m... more The high frequency electrical resistance of a Nafion ® 117 perfluorosulphonic membrane has been measured by means of the ac impedance technique. Using a mercury cell, the variations of the membrane conductance as a function of the degree of swelling and of the nature of ...
Journal of Membrane Science, 2015
The results of an investigation of the mechanical properties of a perfluorosulfonic acid MF-4SC m... more The results of an investigation of the mechanical properties of a perfluorosulfonic acid MF-4SC membrane (Russian analogue of Nafion s ) in the H þ and Na þ ion forms at different relative humidity (RH) values ranging from 0% to 95% are presented in this article. The dependences of Young's modulus and the proportional limit stress on RH reach a maximum at RH ¼ 32-58%. The influence of the strain on the ionic conductivity measured in parallel and perpendicular directions to the strain is studied. The conductivity of membranes strained within the region of irreversible deformation is lower than the conductivity of the initial membrane but relaxes and increases up to the values of the initial membrane 2 h after the straining. The conductivity of broken membranes maintained at RH ¼ 9% is higher than the conductivity of the initial membranes under similar conditions. Anisotropy is observed in the ion transport of broken membranes. At RH 432%, the conductivity measured parallel to the straining is higher than that measured perpendicular to the straining, while at RH r32%, the conductivity is higher in the perpendicular direction. Explanations of the processes occurring during the straining and following relaxation of the membranes are proposed.
Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1991
The electrical transport properties of sulphuric acid in a Nafion 117 perfluorosulphonic membrane... more The electrical transport properties of sulphuric acid in a Nafion 117 perfluorosulphonic membrane have been studied. Using a mercury cell, the conductivity of the membrane was determined by ac impedance measurements as a function of the degree of swelling and of the amount of sorbed species. The excellent permselectivity of the Nafion 117 membrane to protons was confirmed. By means of radiotracer measurements; the transport number of chemical species bearing a sulphur atom was determined; it was lower than 2% regardless of the amount of sorbed acid or the applied current density. The electro-osmotic fhrx of water was measured by means of an electro-electrodialysis device. The coefficient of the first dissociation step of molecular sulphuric acid to HSO; within the membrane was calculated as a function of the amount of sorbed acid species; it was found to be less than those observed for hydrohalogenic acids. This dissociation coefficient decreased from 0.42 to 0.22 when the concentration of the sorbed sulphuric acid varied from 0.005 to 0.16 mole per sulphonic site. 0022-0728/91/$03.50 6 1991 -Blsevier Sequoia S.A.
Chemical, Pharmaceutical, Food, and Biotechnological Applications, 2008
Journal of Membrane Science, 2014
ABSTRACT Pulsed electric field (PEF) can affect positively the membrane scaling mitigation and th... more ABSTRACT Pulsed electric field (PEF) can affect positively the membrane scaling mitigation and the intensification of electrodialytic (ED) process. Recent studies considered the use of PEF with relatively long pulse/pause conditions (5–40 s). The present work was focused on the application of specific PEF conditions with short pulse/pause duration as a following perspective step in improving demineralization. Therefore, in this study six conditions were tested (1 s/0.33 s, 1 s/1 s, 2 s/0.5 s, 2 s/0.67 s, 3 s/0.33 s, 3 s/1 s) in order to investigate the influence of short PEF lapses and to find the optimum among all PEF conditions. Results indicate that PEF conditions of 2 s/0.5 s and 2 s/0.67 s allowed the highest demineralization rates. A decrease of scaling on the cation-exchange membrane surface in comparison with previous data was observed in all PEF conditions. In addition, absence of scaling on the anion-exchange membrane was observed for the first time in such extreme conditions of demineralization and solution composition. These results highlighted the successful use of short pulse/pause lapses during electrodialysis.
Electrochimica Acta, 2015
Procedia Engineering, 2012
Journal of electroanalytical chemistry
Palabras clave: Electro-electrodialisis, tratamiento de superficies, reciclado, ácido crómico. La... more Palabras clave: Electro-electrodialisis, tratamiento de superficies, reciclado, ácido crómico. La reducción de costos en los procesos de fabricación es una vías para aumentar la competitividad de las empresas. Si esta reducción de costos se realiza mediante la recuperación y reciclado de materia primas además de la reducción de costos, conseguiremos una reducción de los residuos producidos en el proceso de fabricación. Mediante la introducción de un proceso de electro-electrodialisis(EED) en los procesos de cromado, conseguimos la recuperación, purificación y concentración del ácido crómico arrastrado a las aguas de lavado en las instalaciones de cromado. La recuperación de ácido crómico obtenida por EED es de hasta un noventa por ciento del total de crómico arrastrado y su pureza le hace apto para ser reciclado directamente al proceso de fabricación. El proceso de EED tiene lugar sin la adicción de productos químicos auxiliares, y la simplicidad del proceso hace que sea fácilmente adaptable a las instalaciones de cromado existentes.
Electrochimica Acta, 2015
ABSTRACT The electrochemical decomposition of methanol for hydrogen production has been carried o... more ABSTRACT The electrochemical decomposition of methanol for hydrogen production has been carried out at several temperatures (25 to 85 °C) and different methanol concentrations (0.1 to 10 M in 0.5 M H2SO4) using a DMFC hardware working as a Proton Exchange Membrane Electrolysis Cell (PEMEC). Conversely to most of recent studies which investigated the effect of working parameters (cell voltage, methanol concentration, flow rate of reactants, temperature, etc.) on the hydrogen evolution rate, this work is focussed on the analysis of the kinetics of methanol oxidation at the anode using the hydrogen cathode as a reference electrode. In this way it was possible to analyse the cell voltage (corrected from the ohmic drop) as a function of the logarithm of the imposed current density. A Tafel analysis of these plots allowed us to estimate the kinetics parameters of methanol oxidation, i.e. the charge transfer coefficient α of the rate determining step and the heat of activation ΔH* of the overall process. The values obtained for these parameters (α ≈ 0.5 to 0.6, ΔH* ≈ 50-60 kJ mol−1) are similar to those published in the literature and as deduced from the analysis of methanol oxidation both on smooth Pt-Ru electrodes and on Pt-Ru nanoparticles supported on carbon powders.
Desalination and Water Treatment, 2014
It is known that the behavior of a membrane with homogeneous and heterogeneous surface under the ... more It is known that the behavior of a membrane with homogeneous and heterogeneous surface under the same current density is different. In order to find out this difference, a twodimensional non-stationary model of mass transfer through electrically inhomogeneous surface of ion-exchange membrane under direct current is proposed. In this paper, the general formulation of the boundary conditions at the conductive sections has the form of the integral function of the local current density. The problem was solved by applying an electric current stream function, which is quite similar to the stream function in hydrodynamics. For the first time, it is proved that the distribution of current lines over the conductive sections of the membrane is not uniform. It is shown experimentally and theoretically that the shape of chronopotentiograms and electrochemical impedance spectra changes with changing conductive portion of the ion-exchange membrane surface.
Journal of Applied Electrochemistry, 1999
The electrogenerated mediator oxidation process is capable of oxidizing organic compounds to the ... more The electrogenerated mediator oxidation process is capable of oxidizing organic compounds to the final step, producing CO2. It requires the use of separate compartments for the anode and cathode. A considerable electric charge is necessary to decompose long carbon chains and high-intensity electrochemical reactors are needed for use at industrial scale. A variety of porous and microporous ceramic separators (frits)
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Papers by Gérald Pourcelly