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132 results on '"Pérez-Maqueda, L. A."'

1. Effects of mechanical treatment and exchanged cation on the microporosity of vermiculite

Author

De Haro, M. C. Jimenez, Blanes, J. M. Martınez, Poyato, J., Perez-Maqueda, L. A., Lerf, A., and Perez-Rodrıguez, J. L.

Subjects
Condensed Matter - Materials Science
Abstract

The influence of the interlayer cations, sonication and grinding on surface area of the vermiculite from Santa Olalla has been studied. For untreated samples the surface area increases with the size of the exchanged cation and only the samples with the largest cations (NH+ and K+) show some microporosity. Sonication produces an increase of the surface area but the amount of micropores remains almost unchanged. Grinding leads to a significant increase of the surface area and of the microporosity. In the ground samples the percentage of micropores contributing to the surface area is influenced by the interlayer cation and the extent of N2 penetration by the water kept in the sample at a given degassing temperature. From transmission electron microscopy, thermogravimetry and XRD (d00l diffraction peaks) it can be concluded that grinding produces imperfections in crystal ordering, some alteration in the crystal edges, and a significant release of loosely bound water at temperatures up to 450 8C. These effects are responsible for the high surface area and microporosity measured by the N2 adsorption.

Published
2024
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4. SCTA and Kinetics

Author

Criado, J. M., Pérez-Maqueda, L. A., Simon, Judit, editor, Sørensen, O. Toft, editor, and Rouquerol, J., editor

Published
2003
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34. Physico-geometric kinetics of complex solid-state reactions

Author

Koga, Nobuyoshi, Pérez-Maqueda, L. A., Favergeon, Loïc, Muravyev, N. V., Yamada, S., Hiroshima University, Graduate School of Education, Institute of Materials Science of Seville, CSIC - University of Seville, University of Sevilla, École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT), Université de Lyon, Centre National de la Recherche Scientifique (CNRS), Laboratoire Georges Friedel (LGF-ENSMSE), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Centre Sciences des Processus Industriels et Naturels (SPIN-ENSMSE), Département Procédés de Transformations des Solides et Instrumentation (PTSI-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences [Moscow] (RAS), Department of Applied Chemistry, National Defense Academy of Japan (NDA), École des Mines Saint-Étienne, Association Française de Calorimétrie et d’Analyse Thermique (AFCAT), Hiroshima University - Graduate School of Education, C.S.I.C.-University of Sevilla - Institute of Materials Science, and Lillouch, Fatima

Subjects
[SPI.GPROC] Engineering Sciences [physics]/Chemical and Process Engineering, solid-state reaction, kinetic analysis, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Thermal analysis, overlapping multistep process
Abstract

National audience; Kinetic analysis of the solid-state reaction using thermal analysis (TA) is the established scientific tool and widely applied to many technological processes. However, many solid-state reactions proceed with complex behavior regulated by heterogeneous characteristics. Rather simple solid-state reactions should be described by considering consecutive physico-geometrical processes such as surface reaction–reaction interface shrinkage and nucleation–growth. Further, the surface product layer produced by the reaction regulates diffusion of gases that contribute to the reaction as reactant and product. The mass transfer phenomena influence on the rate behavior and sometimes impede the reaction. Formation of diffusion path in the surface product layer is necessary for the reactivation. As the result, the overall reaction proceeds as the multistep reaction caused by the physico-geometrical constraints. The concurrent or consecutive chemical reactions occurring in the solid-state exhibit more complex kinetic behavior. For these reactions, the comparing reaction steps can indicate differently signed TA signals, i.e., mass loss versus mass gain and exothermic versus endothermic effects. For extending basic kinetic theory and the kinetic calculation methods using TA data to be applicable to the complex solid-state reactions, detailed case studies for the selected reaction processes that exhibit different physico-chemical and physico-geometrical complexities are necessary. In this presentation, the cutting-edge of the kinetic analysis for the complex solid-state reactions is briefly reviewed with special attentions to (i) kinetic deconvolution analysis, (ii) induction period–surface reaction–phase boundary controlled reaction model, and (iii) impact of the evolved gas on the overall kinetics.

Published
2018

35. Logic and strategy for the kinetic analysis of complex solid-state reactions

Author

Koga, Nobuyoshi, Pérez-Maqueda, L. A., Favergeon, Loïc, Muravyev, N. V., Yamada, S., Hiroshima University, Graduate School of Education, Institute of Materials Science of Seville, CSIC - University of Seville, École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT), Université de Lyon, Centre National de la Recherche Scientifique (CNRS), Laboratoire Georges Friedel (LGF-ENSMSE), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Centre Sciences des Processus Industriels et Naturels (SPIN-ENSMSE), Département Procédés de Transformations des Solides et Instrumentation (PTSI-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences [Moscow] (RAS), National Defense Academy of Japan (NDA), The Japan Society of Calorimetry and Thermal Analysis, The Committee of Chemical Thermodynamics and Thermal Analysis of Chinese Chemical Society, Prof. Takayoshi Kimura (Kindai Univ.), Prof. Hatsumi Aki (Fukuoka Univ.), Hiroshima University - Graduate School of Education, C.S.I.C.- University of Sevilla - Institute of Materials Science, Russian Academy of Sciences - Semenov Institute of Chemical Physics, National Defense Academy of Japan - Department of Applied Chemistry, and Lillouch, Fatima

Subjects
[SPI.GPROC] Engineering Sciences [physics]/Chemical and Process Engineering, kinetic analysis, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, solid-state reactions, general approach
Abstract

International audience; Kinetic description of the complex solid-state reactions is a challenging task, because of the overall process compraizing different heterogeneous reaction steps occuring concecutively or concurrently. For extending basic kinetic theory and the kinetic calculation methods using thermoanalytical data established for the single-step reaction to be applicable to the complex solid-state reactions, detailed case studies for the selected reaction processes with different physico-chemical and physico-geometrical complexities are neccessary. In this presentation, the cutting-edge of the kinetic analysis for the complex solid-state reactions are briefly reviewed and the strategy for contributing toward the provision of theoretical foundation of the kinetic analysis for the complex solid-state reactions are discussed with a special attention to the role of the kinetic deconvolution analysis.

Published
2017

49. Thermal decomposition of NH 4 +-vermiculite from Santa Olalla (Huelva, Spain) and its relation to the metal ion distribution in the octahedral sheet

Author

Pérez-Rodríguez, J. L., Poyato, J., Haro, M. C. Jiménez de, Pérez-Maqueda, L. A., and Lerf, A.

Abstract

The investigation of the NH 3 loss in the NH 4 +-vermiculite (Santa Olalla) by thermogravimetry, evolved gas analysis, chemical analysis, X-ray diffraction and IR spectroscopy is reported here. The mass loss during heating takes place in two steps at about 650 and 825 °C. Additionally, the releases of H 2O and NH 3 occurs simultaneously. The experimental results indicate that the protons remaining in the interlayer space after NH 3 removal trigger the H 2O release. X-ray diffraction shows that during the decomposition of NH 4 +-vermiculite there are two domains with different interlayer spaces at ~9 and ~10 Å. As the decomposition proceeds, the intensity of the 9 Å peak increases at the expense of the second one. The change in the IR-stretching modes of the structural OH groups during heating indicates that the OH groups surrounded by 3Mg 2+ or 2Mg 2+Fe 2+ are released at lower temperatures than those with environments like 2Mg 2+Fe 3+, 2Mg 2+Al 3+ or more complex ones.

Published
2004
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50. On the evaluation of the nonisothermal kinetic parameters of (GeS<INF>2</INF>)<INF>0.3</INF>(Sb<INF>2</INF>S<INF>3</INF>)<INF>0.7</INF> crystallization using the IKP method

Author

Budrugeac, P., Criado, J. M., Gotor, F. J., Malek, J., Pérez-Maqueda, L. A., and Segal, E.

Abstract

The isoconversional method suggested by Friedman and the invariant kinetic parameters method (IKP) were used in order to examine the kinetics of the nonisothermal crystallization of (GeS2)0.3(Sb2S3)0.7. The objective of the paper is to show the usefulness of the IKP method both for determining the activation parameters as well as the model of the investigated process. It was shown that the kinetic triplet [(E, A, f(α), where E is the activation energy, A is the preexponential factor, and f(α) is the differential function of conversion], which results through the application of the IKP method, depends on the set of kinetic models considered. For different sets of kinetic models, proportional values of f(α) are obtained. A criterion for the selection of this set, the use of which lead to the true kinetic triplet corresponding to the analyzed process (E = 163.2 kJ mol−1; A = 2.47 × 1012 min−1 and the Avrami-Erofeev model, Am, for m = 2.5–2.6 was suggested. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 309–315, 2004

Published
2004
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