Graciela Valente - Academia.edu (original) (raw)
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University of Alicante / Universidad de Alicante
Instituto Tecnológico y de Estudios Superiores de Monterrey (ITESM)
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Papers by Graciela Valente
Applied Catalysis A: General, 2001
This work deals with the catalytic behavior of a series of Sn-MoO catalysts in the partial oxidat... more This work deals with the catalytic behavior of a series of Sn-MoO catalysts in the partial oxidation of methanol. The catalysts of different Sn:Mo ratios, were prepared by co-precipitation and they were investigated by means of dynamic experiments, test reactions (methanol-formaldehyde partial oxidation, isopropyl alcohol decomposition) and physico-chemical characterization (XRD, BET, TPD of NH 3 , TPR, XPS and EPR). It was observed that interdispersion between MoO 3 and SnO 2 favors a superficial architecture in which the Sn-Mo interaction plays a major role modifying the reactivity of the lattice oxygens and the reducibility of Mo ions and, therefore, the catalytic behavior. The partial oxidation of methanol induces a reordering of the catalyst structural organization leading to a Mo surface enrichment. The absence of chemical shifts for Sn (XPS) suggests that the O-Mo bond is mainly responsible for the methanol reaction.
El ingeniero, debe poseer el conocimiento integral de los principios básicos de las Ciencias Exac... more El ingeniero, debe poseer el conocimiento integral de los principios básicos de las Ciencias Exactas, entre las que se encuentra la Química, que incluya comprender las transformaciones permanentes de la materia, sus cambios de energía, estructura, propiedades y su relación con el entorno. En Ingeniería Civil, predecir el comportamiento químico de los materiales y de los procesos industriales en los que se ven involucrados brinda el acceso para mejorar y optimizar dichos procesos. Considerando el análisis de los rendimientos académicos de estudiantes de primer año de Ingeniería Civil, obtenidos para las cohortes 2012-2016, se adaptaron las estrategias pedagógico-didácticas en función del nuevo perfil de estudiante y de las capacidades que deben desarrollarse para lograr la competencia general de egreso. Se propuso la aplicación de nuevas estrategias que involucraran el manejo de los contenidos disciplinares desde un abordaje práctico que le permita al estudiante adquirir competencias...
Bioprecipitación mineral de hierro en perforaciones de agua en La Rioja. Iron mineral bioprecipit... more Bioprecipitación mineral de hierro en perforaciones de agua en La Rioja. Iron mineral bioprecipitaton in water wells in La Rioja. V. Calbo, O. Furlong, M. Torres Deluigi Estudios preliminares de la biolixiviación de uranio en colas de mineral de un yacimiento argentino. Preliminary studies of uranium bioleaching from mineral dumps of argentine ores.
Minerals Engineering, 2014
The extraction of lithium by means of the chlorination roasting of b-spodumene has been studied i... more The extraction of lithium by means of the chlorination roasting of b-spodumene has been studied in the temperature range from 1000 to 1100°C for periods of time from 0 to 180 min. The roasting was carried out in a fixed bed reactor using pure gaseous Cl 2 as chlorinating agent. The reactants and products were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), atomic absorption spectrometry (AAS), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The roasting of b-spodumene with pure Cl 2 at 1100°C for the period of 150 min led to quantitative extraction of lithium as lithium chloride. The solid products of the reaction of b-spodumene with Cl 2 were found to be Al 6 Si 2-O 13 (mullite), and Si 2 O (cristobalite).
Applied Catalysis A: General, 2001
This work deals with the catalytic behavior of a series of Sn-MoO catalysts in the partial oxidat... more This work deals with the catalytic behavior of a series of Sn-MoO catalysts in the partial oxidation of methanol. The catalysts of different Sn:Mo ratios, were prepared by co-precipitation and they were investigated by means of dynamic experiments, test reactions (methanol-formaldehyde partial oxidation, isopropyl alcohol decomposition) and physico-chemical characterization (XRD, BET, TPD of NH 3 , TPR, XPS and EPR). It was observed that interdispersion between MoO 3 and SnO 2 favors a superficial architecture in which the Sn-Mo interaction plays a major role modifying the reactivity of the lattice oxygens and the reducibility of Mo ions and, therefore, the catalytic behavior. The partial oxidation of methanol induces a reordering of the catalyst structural organization leading to a Mo surface enrichment. The absence of chemical shifts for Sn (XPS) suggests that the O-Mo bond is mainly responsible for the methanol reaction.
El ingeniero, debe poseer el conocimiento integral de los principios básicos de las Ciencias Exac... more El ingeniero, debe poseer el conocimiento integral de los principios básicos de las Ciencias Exactas, entre las que se encuentra la Química, que incluya comprender las transformaciones permanentes de la materia, sus cambios de energía, estructura, propiedades y su relación con el entorno. En Ingeniería Civil, predecir el comportamiento químico de los materiales y de los procesos industriales en los que se ven involucrados brinda el acceso para mejorar y optimizar dichos procesos. Considerando el análisis de los rendimientos académicos de estudiantes de primer año de Ingeniería Civil, obtenidos para las cohortes 2012-2016, se adaptaron las estrategias pedagógico-didácticas en función del nuevo perfil de estudiante y de las capacidades que deben desarrollarse para lograr la competencia general de egreso. Se propuso la aplicación de nuevas estrategias que involucraran el manejo de los contenidos disciplinares desde un abordaje práctico que le permita al estudiante adquirir competencias...
Bioprecipitación mineral de hierro en perforaciones de agua en La Rioja. Iron mineral bioprecipit... more Bioprecipitación mineral de hierro en perforaciones de agua en La Rioja. Iron mineral bioprecipitaton in water wells in La Rioja. V. Calbo, O. Furlong, M. Torres Deluigi Estudios preliminares de la biolixiviación de uranio en colas de mineral de un yacimiento argentino. Preliminary studies of uranium bioleaching from mineral dumps of argentine ores.
Minerals Engineering, 2014
The extraction of lithium by means of the chlorination roasting of b-spodumene has been studied i... more The extraction of lithium by means of the chlorination roasting of b-spodumene has been studied in the temperature range from 1000 to 1100°C for periods of time from 0 to 180 min. The roasting was carried out in a fixed bed reactor using pure gaseous Cl 2 as chlorinating agent. The reactants and products were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), atomic absorption spectrometry (AAS), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The roasting of b-spodumene with pure Cl 2 at 1100°C for the period of 150 min led to quantitative extraction of lithium as lithium chloride. The solid products of the reaction of b-spodumene with Cl 2 were found to be Al 6 Si 2-O 13 (mullite), and Si 2 O (cristobalite).