20 results on '"Dafinov, Anton"'
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2. PdCu alloy nanoparticles on alumina as selective catalysts for trichloroethylene hydrodechlorination to ethylene
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Meshesha, Beteley T., Barrabés, Noelia, Llorca, Jordi, Dafinov, Anton, Medina, Francisco, and Föttinger, Karin
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- 2013
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3. Insights into palladium deactivation during advanced oxidation processes
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Crivoi, Dana Georgiana, Pinos Velez, Veronica Patricia, Osegueda Chicas, Oscar, Llorca, Jordi, García García, Francisco Javier, García Álvarez, Mayra, Medina Cabello, Francesc, Dafinov, Anton, Crivoi, Dana Georgiana, Pinos Velez, Veronica Patricia, Osegueda Chicas, Oscar, Llorca, Jordi, García García, Francisco Javier, García Álvarez, Mayra, Medina Cabello, Francesc, and Dafinov, Anton
- Abstract
A key step in creating efficient and long-lasting catalysts is understanding their deactivation mechanism(s). On this basis, the behavior of a series of Pd/corundum materials during several hydrogen adsorption/desorption cycles was studied using temperature-programmed desorption coupled with mass spectrometry and aberration-corrected transmission electron microscopy. The materials, prepared by impregnation and by sputtering, presented uniform well-dispersed Pd nanoparticles. In addition, single atoms and small clusters of Pd were only detected in the materials prepared by impregnation. Upon exposure to hydrogen, the Pd nanoparticles smaller than 2 nm and the single atoms did not present any change, while the larger ones presented a core-shell morphology, where the core was Pd and the shell was PdHx. The results suggest that the long-term activity of the materials prepared by impregnation can be attributed solely to the presence of small clusters and single atoms of Pd.
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- 2022
4. Stability of ruthenium catalysts supported by aerogel mixed oxides during the wet air oxidation of p-hydroxybenzoic acid in a continuous reactor
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Triki, Mohamed, Dafinov, Anton, Llorca, Jordi, and Medina, Francisco
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- 2012
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5. Catalytic Palladium-Based and Iron-Based Membrane Reactors: Novel Strategies of Synthesis
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Pinos-Vélez, Verónica, primary, di Luca, Carla, additional, Crivoi, Dana G., additional, Medina, Francisco, additional, and Dafinov, Anton, additional
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- 2019
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6. Processing of black liquors by UF/NF ceramic membranes
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Dafinov, Anton, Font, Josep, and Garcia-Valls, Ricard
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- 2005
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7. Catalytic Palladium-Based and Iron-Based Membrane Reactors: Novel Strategies of Synthesis
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Universitat Rovira i Virgili, Pinos-Velez, Veronica; di Luca, Carla; Crivoi, Dana G.; Medina, Francisco; Dafinov, Anton, Universitat Rovira i Virgili, and Pinos-Velez, Veronica; di Luca, Carla; Crivoi, Dana G.; Medina, Francisco; Dafinov, Anton
- Abstract
Several procedures were employed in the preparation of different Pd- and Fe-based catalytic membrane reactors (CMRs) via the normal wet impregnation method, reverse filtration of a microemulsion, sputtering method, and the precipitation of a Fe complex. Depending on the chosen procedure, the metal active phase can be found on the exterior and/or interior part of the CMR or even in its pores in concentrations between 0.05 and 2 wt %. Moreover, we have managed to implement a unique systematic process to grow hydrotalcite in the pores of a Pd-CMR. To exemplify the activity of these new CMRs, we have tested them in the peroxidation of phenol and in situ epoxidation of trans-chalcone.
- Published
- 2019
8. Preparación y caracterización de reactores catalíticos de membrana
- Author
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Pinos, Verónica, Medina, Francesc, and Dafinov, Anton
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Reactores Cataliticos De Membrana ,Tratamiento De Agua ,Catalisis ,Rcm ,Nanoparticulas De Paladio - Abstract
Los Reactores Catalíticos de Membrana, RCM, nos dan la posibilidad de optimizar diversos procesos industriales. La versatilidad que tienen los RCM reside en que pueden ejecutar varias funciones, como por ejemplo, filtración, dosificación y catálisis. Este trabajo propone cuatro formas de preparación de RCM en modo contacto interfacial, para ser evaluados en remediación ambiental. Para la preparación de RCM, se emplearon membranas comerciales de fibra hueca de corindón. Como principal fase activa se usó paladio, el cual fue depositado por diferentes métodos tales como impregnación, sputtering (pulverización catódica) y microemulsión; también se usaron nanopartículas de paladio-cobre obtenido por el método del poliol. Los reactores obtenidos fueron probados en la generación in situ de peróxido de hidrógeno y la oxidación de fenol en medio acuoso a presión atmosférica y a temperatura ambiente o a 60°C. Los mejores resultados se obtuvieron con el RCM que contenía paladio por impregnación. Los otros RCM presentaron en todos las pruebas una rápida desactivación. Catalytic Membrane Reactors, CMR, are well known because of their versatility to develop various industrial processes. This versatility lies in CMR’s ability to run many functions in a single device. These functions can be filtration, dosage and catalysis. This work proposes four ways to prepare CMRs in interface mode to be tested in environmental remediation. For the preparation of Catalytic Membrane Reactors, commercial Hollow Fiber Membranes made of corundum were used. Palladium, as the main active phase, was synthesized by different methods such as impregnation, sputtering and microemulsion. Moreover, copper palladium alloy nanoparticles were obtained by the polyol route. The reactors obtained were tested in aqueous medium, at atmospheric pressure and low reaction temperatures (< 60°C) in the following reactions: in situ generation of hydrogen peroxide and phenol oxidation. The best results were achieved with the CMR with palladium prepared by impregnation. The others CMRs showed fast deactivation in all tests. Cuenca número 16
- Published
- 2018
9. Microwave-Assisted Furfural Production Using Hectorites and Fluorohectorites as Catalysts
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Sánchez, Vladimir, primary, Dafinov, Anton, additional, Salagre, Pilar, additional, Llorca, Jordi, additional, and Cesteros, Yolanda, additional
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- 2019
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10. Preparation and characterization of catalytic membrane reactors
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Pinos Velez, Veronica Patricia, Medina, Francesc, Dafinov, Anton, Pinos Velez, Veronica Patricia, Medina, Francesc, and Dafinov, Anton
- Abstract
Catalytic Membrane Reactors, CMR, are well known because of their versatility to develop various industrial processes. This versatility lies in CMR’s ability to run many functions in a single device. These functions can be filtration, dosage and catalysis. This work proposes four ways to prepare CMRs in interface mode to be tested in environmental remediation. For the preparation of Catalytic Membrane Reactors, commercial Hollow Fiber Membranes made of corundum were used. Palladium, as the main active phase, was synthesized by different methods such as impregnation, sputtering and microemulsion. Moreover, copper palladium alloy nanoparticles were obtained by the polyol route. The reactors obtained were tested in aqueous medium, at atmospheric pressure and low reaction temperatures (< 60°C) in the following reactions: in situ generation of hydrogen peroxide and phenol oxidation. The best results were achieved with the CMR with palladium prepared by impregnation. The others CMRs showed fast deactivation in all tests.
- Published
- 2018
11. Catalytic Palladium-Based and Iron-Based Membrane Reactors: Novel Strategies of Synthesis.
- Author
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Verónica, Pinos-Vélez, di Luca, Carla, Crivoi, Dana G., Medina, Francisco, and Dafinov, Anton
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- 2019
- Full Text
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12. Development and optimization of catalytic membrane reactors for wastewater treatments
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Dafinov, Anton, Medina Cabello, Francisco, Pinos Vélez, Verónica Patricia, Dafinov, Anton, Medina Cabello, Francisco, and Pinos Vélez, Verónica Patricia
- Abstract
Different catalytic membrane reactors (CMRs) were obtained from hollow fiber membranes corundum and palladium nanoparticles obtained by different methods: Incipient wetness impregnation , sputtering , microemulsion and copper alloy by the method of the polyol. The CMRs were tested in aqueous medium, ambient pressure and ambient temperature or 60C for the in situ generation of hydrogen peroxide, oxidation and hydrogenation of phenol and ibuprofen and reduction of Cr(VI). The catalytic CMR acted as interface for the reactions between hydrogen with oxygen or organic or inorganic compound. Only the CMRs with palladium by impregnation were actives and stabilites during the tests. This behavior occurred thanks to the presence of clusters and single atoms of palladium. The lack of activity of the other kind of palladium catalysts were due to the formation of palladium hydride in the reaction conditions.
- Published
- 2016
13. Catalytic degradation of phenol with hydrogen peroxide: Heterogeneous Fenton-Like systems
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Massa, Paola Andrea, Dafinov, Anton, Fenoglio, Rosa Juana, and Medina Cabello, Francisco
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Ingeniería Química ,purl.org/becyt/ford/2.4 [https] ,Fe2O3/CeO2 ,purl.org/becyt/ford/2 [https] ,Oxidación de Fenol ,Otras Ingeniería Química ,INGENIERÍAS Y TECNOLOGÍAS ,peróxido de hidrógeno - Abstract
Se sintetizaron catalizadores de Fe2O3/CeO2 a partir de un método simple de combustión. Se estudió la influencia del contenido de hierro (5-20%), la temperatura, la concentración de H2O2 y la temperatura de calcinación (400°C-900°C) sobre la reacción de oxidación de fenol en presencia de peróxido de hidrógeno. La reacción se llevó a cabo en un reactor tipo batch a presión atmosférica, a temperaturas entre 60°C y 100°C. Sobre las muestras líquidas se realizaron determinaciones de conversión de fenol y de carbono orgánico total. Los catalizadores resultaron ser activos y selectivos en las condiciones de operación estudiadas y los de mayor contenido de Fe presentaron los mayores niveles de conversión de fenol, junto con un mayor porcentaje de pérdida de fase activa en el medio de reacción. Los catalizadores calcinados a altas temperaturas presentaron menores valores de conversión de fenol; sin embargo, el efecto más pronunciado se registró sobre los niveles de selectividad hacia productos finales. El incremento de la proporción de peróxido de hidrógeno en la reacción no produjo cambios significativos en la conversión de fenol ni en la selectividad. Fe2O3/CeO2 catalysts were synthesized with different Fe loading (5-20%), using a simple combustion preparation method. The samples were calcined at several temperatures (400-900°C), and tested in a batch reactor at atmospheric pressure, in a temperature range of 60°C-100°C, for 4 hours. The effect of different H2O2/phenol ratios was also studied. Fresh and used samples were characterized by Scanning Electronic Microscopy, Temperature Prograrnmed Reduction, X-ray Diffraction and Surface Area Measurements (BET Method). The catalysts presented considerable phenol conversion and selectivity levels, at the operation conditions. Higher phenol conversions were reached with increasing iron content of the catalytic system; however, higher Fe lixiviation levels were also detected. A reduction in the phenol conversion and, more significantly, in the selectivity towards final products was observed when samples calcined at high temperatures were used. Fil: Massa, Paola Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Dafinov, Anton. Universitat Rovira I Virgili; España Fil: Fenoglio, Rosa Juana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Medina Cabello, Francisco. Universitat Rovira I Virgili; España
- Published
- 2009
14. Catalytic wet peroxide oxidation of phenolic solutions over Fe 2O 3/CeO 2 and WO 3/CeO 2 catalyst systems
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Massa, Paola, Dafinov, Antón, Cabello, Francisco Medina, and Fenoglio, Rosa
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- 2008
- Full Text
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15. Pretreatment Effect on Pt/CeO2 Catalyst in the Selective Hydrodechlorination of Trichloroethylene
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Barrabés, Noelia, primary, Föttinger, Karin, additional, Llorca, Jordi, additional, Dafinov, Anton, additional, Medina, Francesc, additional, Sá, Jacinto, additional, Hardacre, Christopher, additional, and Rupprechter, Günther, additional
- Published
- 2010
- Full Text
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16. Modification of ceramic membranes by alcohol adsorption
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Dafinov, Anton, primary, Garcia-Valls, Ricard, additional, and Font, Josep, additional
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- 2002
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17. Pretreatment Effect on Pt/CeO2Catalyst in the Selective Hydrodechlorination of Trichloroethylene
- Author
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Barrabés, Noelia, Föttinger, Karin, Llorca, Jordi, Dafinov, Anton, Medina, Francesc, Sá, Jacinto, Hardacre, Christopher, and Rupprechter, Günther
- Abstract
Pt−ceria catalysts present different surface chemistries depending on the preparation method and the pretreatment. The catalytic behavior of Pt/CeO2catalysts in the hydrodechlorination of trichloroethylene (TCE) to ethylene was examined as a function of the pretreatment conditions and the noble metal precursor salts. Using FTIR and X-ray photoelectron spectroscopy, significant differences were observed in the surface properties of Pt/CeO2prepared from the H2PtCl6precursor after different pretreatment procedures (i.e., reduction or oxidation−reduction). These surface changes are related to chloride residues from the synthesis. Strong changes were observed in the selectivity of the catalysts to ethylene depending on the pretreatment conditions. The 0.5%Pt/CeO2catalyst showed a 13% selectivity toward ethylene after reduction, whereas after oxidation, followed by reduction, the selectivity increased up to 85% at the same conversion level. This effect was only observed when a chloride-containing precursor was used in the preparation. In this way, it is demonstrated that the use of a Cl-containing Pt precursor and an air treatment prior to reduction strongly improves the ethylene selectivity of Pt−CeO2dechlorination catalysts. This can be explained by formation of a CeOCl phase during the synthesis that decomposes upon air tempering, producing oxygen vacancies on the ceria support. We propose that these oxygen vacancies are active for cleaving off Cl from the TCE. Pt then supplies H to clean-off Cl as HCl. Reaction of TCE on Pt produces rather ethane, so Pt may be partly Cl-poisoned for the hydrodechlorination reaction but not for H2dissociation or CO adsorption.
- Published
- 2010
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18. Development and optimization of catalytic membrane reactors for wastewater treatments
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Pinos Vélez, Verónica Patricia, Dafinov, Anton, Medina Cabello, Francisco, Departament d'Enginyeria Química, Universitat Rovira i Virgili., and Universitat Rovira i Virgili. Departament d'Enginyeria Química
- Subjects
Ciències ,Química orgánica ,Catalysis ,Química inorgánica ,547 - Química orgànica ,Ingeniería Química ,Paladio ,RCM ,Catálisis ,Tesis de Doctor en el Programa en Ingeniería Química Ambiental y de Procesos ,62 - Enginyeria. Tecnologia ,Palladium ,546 - Química inorgànica ,54 - Química - Abstract
Es van obtenir diferents reactors catalítics de membrana (RCM) de membrana de fibra buida de Corindó i nanopartícules de Pd obtingudes per diferents metodologies: humitat incipients impregnació, polvorització catòdica, microemulsió i aliatge amb coure pel mètode de Poliol. RCMs es van provar en medi aquós, pressió ambiental i temperatura o 60 c en generació in situ de peròxid d'hidrogen, l'oxidació i hidrogenació de fenol i ibuprofè i reducció de Cr (VI). La RCM ha actuat com interfície catalítica per tal d'activar l'hidrogen i que reaccione amb oxigen o compost orgànic o inorgànic. La RCM impregnada amb Pd és l'única que van mostrar activitat i tests d'estabilitat. Aquest comportament es va deure a la presència d'àtoms i grups de Pd. La manca activitat de la resta de catalitzadors amb Pd es va deure a la formació d'hidrur de Pd en les condicions de reacció., Se obtuvieron diferentes reactores catalíticos de membrana (RCM) desde membranas de fibra hueca de corindón y nanopartículas de paladio obtenidas por diferentes métodos: Impregnación a humedad incipiente, sputtering, microemulsion y aleación con cobre por el método del poliol. Los RCM fueron probados en medio acuoso, presión ambiental y temperatura ambiente o 60C en la generación in situ de peróxido de hidrógeno, oxidación e hidrogenación de fenol e ibuprofeno y reducción de Cr(VI). Los RCM actuaron como interfaz catalítica para que el hidrógeno se active y reaccione con el oxígeno o el compuesto orgánico o inorgánico. Los RCM con paladio por impregnación fueron los únicos que presentaron actividad y estabilidad en las pruebas. Este comportamiento se dio gracias a la presencia de átomos y clusters de paladio. La falta de actividad de los otros catalizadores de paladio se debió a la formación de hidruro de paladio en las condiciones de reacción., Different catalytic membrane reactors (CMRs) were obtained from hollow fiber membranes corundum and palladium nanoparticles obtained by different methods: Incipient wetness impregnation , sputtering , microemulsion and copper alloy by the method of the polyol. The CMRs were tested in aqueous medium, ambient pressure and ambient temperature or 60C for the in situ generation of hydrogen peroxide, oxidation and hydrogenation of phenol and ibuprofen and reduction of Cr(VI). The catalytic CMR acted as interface for the reactions between hydrogen with oxygen or organic or inorganic compound. Only the CMRs with palladium by impregnation were actives and stabilites during the tests. This behavior occurred thanks to the presence of clusters and single atoms of palladium. The lack of activity of the other kind of palladium catalysts were due to the formation of palladium hydride in the reaction conditions.
- Published
- 2016
19. Development of a novel catalytic membrane reactor: application in wastewater treatment
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Osegueda Chicas, Oscar Antonio, Departament d'Enginyeria Química, Universitat Rovira i Virgili., Medina Cabello, Francisco, Dafinov, Anton, Sueiras Romero, Jesús Eduardo, and Universitat Rovira i Virgili. Departament d'Enginyeria Química
- Subjects
66 - Enginyeria, tecnologia i indústria química. Metal·lúrgia ,62 - Enginyeria. Tecnologia - Abstract
Los procesos de oxidación químicos son una herramienta universal para el tratamiento de aguas subterráneas, efluentes industriales y aguas residuales. Una de estas técnicas se basa en la generación de radicales hidroxilos (•OH), y se le conoce con el nombre de proceso de oxidación avanzada (AOP). Aunque dicho proceso es considerado una poderosa herramienta para la degradación de contaminantes, este enfrenta varias limitación prácticas especialmente en función del sistema seleccionado para la generación de los •OH. El objetivo de este trabajo fue proponer y poner a prueba una estrategia novedosa con el fin de ampliar la aplicabilidad de la oxidación avazanda, integrando al sistema el uso de reactores de membrana catalítica (CMR). Los esfuerzos fueron enfocados en la aplicación de los CMRs para la oxidación de un compuesto orgánico modelo (fenol), utilizando peróxido de hidrogeno generado in situ como fuente de •OH. Las características de los CMRs permiten la síntesis directa de H2O2., Chemical oxidation processes are the most universal tool for treatment of contaminated groundwater, industrial effluents and wastewater. Oxidation at mild conditions and based on the generation of highly reactive hydroxyl radicals (•OH) is referred to as advanced oxidation process (AOP). Even though this technique is considered as powerful regarding contaminant degradation, it faces several practical limitations in a large scale due to the cost of the system selected for •OH generation. The aim was to propose and test a novel strategy in order to extend the applicability of AOP, whereby the integration of catalytic membrane reactors (CMRs) plays a key role. The efforts were focused on the application of the CMRs for direct oxidation of a model organic compound by the in-situ generated hydrogen peroxide. The inherent properties of the CMRs permit the direct synthesis of hydrogen peroxide starting from H2 and O2 using noble metal as an active phase.
- Published
- 2013
20. Selective Hydrogenation Catalysts For Environmental Processes: Nitrate And Chlorocompounds Removal
- Author
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Barrabés Rabanal, Noelia, Departament d'Enginyeria Química, Universitat Rovira i Virgili., Medina Cabello, Francisco, Dafinov, Anton, and Universitat Rovira i Virgili. Departament d'Enginyeria Química
- Subjects
environmental catalysis ,nitrates ,trichloroethylene ,bimetallic ,504 - Ciències del medi ambient ,nanoparticles ,ceria ,hydrotalcites ,54 - Química - Abstract
En el presente trabajo se han diseñado, sintetizado y caracterizado catalizadores heterogéneos. Se ha estudiado la actividad y selectividad, de estos materiales, en el tratamiento de compuestos que comportan problemas medioambientales. Para la preparación de los catalizadores se han utilizado diferentes técnicas tales como impregnación, proceso redox y combustión. A su vez, se han sintetizado nanopartículas metálicas, depositándolas en diferentes materiales y testado su actividad catalítica. La actividad de estos catalizadores se ha comparado con catalizadores comunes en diferentes procesos. Por otro lado, se han utilizado diferentes materiales, alumina, carbón activo, ceria e hidrotalcitas, con el propósito de estudiar el efecto del soporte.La contaminación por nitratos en las aguas subterráneas es un problema importante en determinadas regiones. Esta problemática ha impulsado el estudio de la eliminación catalítica de los nitratos, en la que se enfoca la primera parte de la tesis. Este estudio se realizó en un reactor en continuo de lecho fijo. Se sintetizaron, caracterizaron y ensayaron, varios catalizadores monometálicos, bimetálicos y de nanopartículas soportadas. Una vez determinada la actividad y la estabilidad de los catalizadores se procedió a optimizar los materiales con el fin de mejorar la selectividad de éstos hacia nitrógeno. El presente trabajo ha sido el punto de partida para la puesta en marcha de una planta piloto para el tratamiento de aguas subterráneas reales contaminadas con nitratos. Próximamente será inaugurada una planta de eliminación catalítica de nitratos de aguas subterráneas con capacidad 500m3/día en las proximidades de El Morell (Tarragona).La segunda parte de la tesis se enfoca en el proceso de hidrodecloración catalítica de compuestos orgánicos clorados como el tricloroetileno. Los experimentos se llevaron a cabo en fase gas utilizando diferentes tipos de catalizadores, los cuales fueron sintetizados y caracterizados. Se emplearon diferentes catalizadores, mono y bimetálicos, para la transformación del tricloroetileno a un producto de valor añadido, como es el etileno.El presente trabajo, además de aportar conocimientos fundamentales en la catálisis heterogénea, contribuye a forjar soluciones a problemas medioambientales reales que afectan a la salud humana., In the present study have been designed, synthesised and characterised heterogeneous catalysts. Their activities and selectivity have been studied in the treatment of compounds that present environmental problems. For the catalysts preparation different protocols such as incipient-wetness impregnation, co-impregnation, redox and combustion have been followed. In addition, metal nanoparticles were synthesized and deposited on several materials as well as tested their catalytic behaviour. The activity and the selectivity of nanoparticle catalysts with that of other catalysts in different processes were compared. On the other hand, different materials such as alumina, active carbon, ceria and hydrotalcites were used to study the role of them as catalyst supports.In the light of the current demand for drinking water, the first part of this thesis studies the catalytic hydrogenation of nitrates. The study is carried out in a fixed bed continuous reactor. Several bimetallic, monometallic and supported nanoparticle catalysts have been synthesised, characterized and tested in order to improve their activity and stability and to optimise their selectivity to nitrogen. The present study was further extended and some of the catalysts have been used as a starting point for a Pilot Plant investigation into eliminating nitrate in real ground water. At this moment, a plant is being constructed in the vicinity of El Morell, Tarragona, which can use catalysis to reduce nitrates in 500 m3/day of groundwater.The second part of the thesis deals with the catalytic hydrodechlorination of chlorinated organic compounds such as TCE. The experiments were done in gas phase. Different types of catalysts have been synthesised, characterized and tested and the final objective is to obtain an active and stable catalyst that is selective toward valuable products such as ethylene. This research aims to use catalytic technologies to contribute to solving real environmental problems that affect human life.
- Published
- 2009
Catalog
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