Literatura académica sobre el tema "Nanoparticules colorantes"
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Artículos de revistas sobre el tema "Nanoparticules colorantes"
Suárez Heredia, Martha Azucena, Yery Mateo Morillo Reinoso, José Augusto Rosero, Gabriela Johana Haro Morales y Marlon Agustín Ichau Espinoza. "EFICIENCIA DE ENCAPSULACION DE CAROTENOIDES EXTRAIDOS DE Capsicum annuum EN NANOPARTICULAS DE ZEINA". FIGEMPA: Investigación y Desarrollo 1, n.º 1 (28 de junio de 2019): 47–52. http://dx.doi.org/10.29166/revfig.v1i1.1017.
Texto completoPineda Mejía, Martha Elena, Liliana Ángela Terán Casafranca, Waldo Ernesto Gloria Zevallos y Luis Alberto Cuadrao Zavaleta. "Sellado marginal de obturaciones de resina compuesta fotoactivadas con luz L.E.D. y luz halógena". Odontología Sanmarquina 15, n.º 1 (14 de mayo de 2014): 19. http://dx.doi.org/10.15381/os.v15i1.2825.
Texto completoSuárez H., Martha y Carlos Brito D. "EFICIENCIA DE ENCAPSULACION Y CAPACIDAD DE CARGA DE ANTOCIANINAS DE Vaccinium floribundim Kunt EN NANOPARTICULAS DE ZEINA". infoANALÍTICA 8, n.º 1 (17 de enero de 2020): 83–97. http://dx.doi.org/10.26807/ia.v8i1.98.
Texto completoTesis sobre el tema "Nanoparticules colorantes"
Biswas, Deep Sekhar. "Light-harvesting nanomaterials for single molecule detection and energy transport". Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAF013.
Texto completoThis study explores the light-harvesting in ionic dye-loaded polymericnanomaterials, revealing fundamental features related to their brightness,blinking behavior and energy transfer. Tuning chemistry of loaded ion saltsimproves their fluorescence quantum yield and light-harvesting performancewith an antenna effect reaching 4800, the highest reported to date. Long-distance energy transfer between nanoparticles beyond the Forster law isuncovered, yielding a DNA nanosensor. The research is extended toelectrospun dye-loaded nanofibers, also revealing unique long-distanceenergy transfer. This interdisciplinary study deepens our understanding oflight-harvesting and paves the way for various applications
PINEDO, HERNANDEZ SAMANTHA YADIRA 554061 y HERNANDEZ SAMANTHA YADIRA PINEDO. "Obtención de un material funcional de clinoptilolita con nanopartículas de Fe-Cu y su aplicación para la remoción del colorante azul 1 en solución acuosa". Tesis de doctorado, Universidad Autónoma del Estado de México, 2019. http://hdl.handle.net/20.500.11799/105491.
Texto completoUna roca zeolítica modificada con hierro (Ze-Fe) y un composito de esa zeolita modificada y nanopartículas de Fe-Cu (Ze-Fe (Fe-Cu)) se investigaron para la eliminación de azul 1. El compuesto se sintetizó por reducción in situ de sales de Fe y Cu usando borohidruro de sodio. Ambos materiales se caracterizaron por espectroscopía IR, BET, XRD, SEM y TEM. El análisis de TEM demostró que las nanoestructuras de Fe-Cu, con un tamaño promedio entre 11 y 15 nm, se dispersaron exitosamente en el material zeolítico. Se realizó la caracterización fisicoquímica, se analizó la morfología de las muestras obtenidas con microscopia electrónica de barrido (SEM), se pudo apreciar la presencia de los cristales típicos de la clinoptilolita. El análisis de composición química elemental realizado por espectroscopia de dispersión de energía de rayos X (EDS); se registró el aumento del hierro después de ser acondicionada la zeolita. Además se observó que el área específica de la zeolita aumentó después de los tratamientos de 37.61 (m2/g) en la zeolita natural a 220.34 (m2/g) la zeolita férrica. En los experimentos de cinética de adsorción para los materiales se observó que al inicio, la velocidad de adsorción es alta, esto es de 0 a 7 h de contacto; el equilibrio de adsorción se alcanzó a las 72 h de contacto. Los experimentos por lotes mostraron que la adsorción del colorante es más favorable para Ze-Fe (Fe-Cu) que para Ze-Fe, los datos de adsorción cinética siguieron el modelo cinético de segundo orden. Los resultados también mostraron que la eliminación del colorante fue mayor para ambos materiales a un pH entre 3 y 5. La eliminación del azul 1(azul brillante) fue de 87.02% para Ze-Fe (Fe-Cu) y de 75.29% para Ze-Fe. Los valores de ΔH ° de 52.60 kJ / mol para Ze-Fe y 126.29 kJ / mol para Ze-Fe (Fe-Cu) indicaron que los procesos de adsorción son endotérmicos para ambos materiales. La segunda etapa fue evaluar la remoción de azul 1 de una solución acuosa mediante un el composito de la clinoptilolita modificado con nanopartículas de Fe-Cu, mediante los procesos de oxidación avanzada (proceso Fenton con y sin radiación UV). Se preparó un composito en dos etapas, la primera fue la obtención del material zeolitíco acondicionado con FeCl3, en condiciones de reflujo, y la segunda fue la obtención del composito de la clinoptilolita con nanopartículas de Fe-Cu, mediante la técnica de reducción in situ de sales metálicas en presencia del material zeolítico. Algunos factores como el pH de la solución, la cantidad de adsorbente, el tiempo de contacto, la concentración inicial de la solución y la temperatura tuvieron un impacto en la eficiencia de la 12 adsorción. Los resultados muestran que la degradación del colorante fue similar de 97 a 99% y casi 100% a un pH de 3, es importante mencionar que la acidez es un factor crucial para los procesos de oxidación de Fenton. Los datos cinéticos se ajustaron mejor al modelo de segundo orden para ambos materiales bajo procesos Fenton y foto-Fenton. Hubo ligeras diferencias en las eficiencias de eliminación del colorante entre los dos materiales: 98.8% de degradación para ZeFe.PF y 95.94% para el composito Ze-Fe(Fe-Cu). Sin embargo, el composito Ze-Fe(Fe-Cu) muestra una mayor tasa de degradación, ya que el equilibrio se alcanzó en aproximadamente 20 horas y para la zeolita (Ze-Fe) en aproximadamente 50 horas. Ambos materiales muestran una adsorción similar en el equilibrio de 0,99 y 0,96 mg / g para Ze-Fe y Ze-Fe (Fe-Cu), respectivamente. Por lo tanto, la activación heterogénea de H2O2 fue el principal responsable del proceso de degradación del colorante. De acuerdo con los parámetros obtenidos de los diferentes modelos de isotermas, el mejor modelo que se ajusta a la adsorción del azul 1 por los materiales fue el modelo de Freundlich, que indica que la adsorción se realiza en superficies heterogéneas.
Dorier, Marie. "Impact du colorant alimentaire E171 et de nanoparticules de dioxyde de titane sur des modèles cellulaires, in vitro, d'épithélium intestinal". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAV082/document.
Texto completoMicro-sized titanium dioxide (TiO2) particles are used for years by industrials for their attractive physical and chemical properties. The use of TiO2 nanoparticles (NPs) is also constantly increasing, because the nanometric size gives new interesting properties to particles which industrials are looking for. In some daily-life products including paints, plastics, paper, medicines and food, micro-sized TiO2 particles are used as a pigment for their opacifying and whitening capacities. The use of TiO2 as a food additive, i.e. E171 in the EU, has been authorized in most countries since the 60ies, without any established acceptable daily intake, because of their low toxicity and intestinal absorption. However, it was recently shown that E171 can contain up to 43% of particles with diameter ranging from 1 to 100 nm, i.e. NPs. Still, E171 is not a nanomaterial as described in the European recommendation of definition because it contains less than 50% of NPs (in number). Food grade TiO2 is present in a wide range of food products while little is known about its toxicological impact to human health. The toxicity of ingested TiO2, either nano- or micro-sized, is increasingly documented, still E171 itself is rarely used in these studies.According to in vivo and in vitro studies, TiO2 particles were proven relatively safe for intestinal cells, no cytotoxicity neither genotoxicity were reported. Nevertheless, particles were often reported to increase reactive oxygen species (ROS) cell content, to impair autophagic processes and modulate gene expression and the content of proteins involved in oxidative stress, endoplasmic reticulum stress and inflammatory response regulation. Interestingly, their reported impact on intestinal cells suggests alteration of almost all the components of the intestinal barrier function, i.e. microbiota, mucus, cell junctions and transporters. This intestinal barrier function is altered in patients suffering from intestinal bowel diseases, these persons are thus possibly more sensitive to mineral particulate in food.The present study aimed at improving knowledge on the toxicity of food-grade TiO2. To this purpose, the impact of E171 was evaluated on in vitro cell models representative of the human intestinal epithelium, i.e. a model of differentiated Caco-2 enterocytes, a model of mucus-secreting epithelium obtained by coculture of Caco-2 and HT29-MTX mucus-secreting cells and a model of the follicle-associated epithelium, which lines Peyer patches, obtained by coculture of Caco-2(C1) and RajiB cells. These cell models were either acutely exposed for 6 h, 24 h and 48 h or chronically exposed for 21 days to E171. In parallel, they were exposed to two model TiO2-NPs, A12 which has the same crystalline structure as E171 and P25, a well-documented TiO2-NPs. Our results show that E171 and TiO2-NPs induced no overt cell mortality but significant oxidative stress, and that they oxidatively damage DNA. They modulate the expression of genes involved in oxidative stress and endoplasmic reticulum stress regulation. They also modulate the expression of genes, as well as the content of proteins from mucus, ABC transporters and inflammatory markers, which are the main players of the intestinal barrier function and presumably increase epithelium sensitivity to xenobiotics. These data suggest that they may be implicated in the development or aggravation of inflammatory bowel diseases
Chavillon, Benoît. "Synthèse et caractérisation d'oxydes transparents conducteurs de type p pour application en cellules solaires à colorant". Nantes, 2011. http://www.theses.fr/2011NANT2024.
Texto completoThe objective of the thesis was clearly identified as the synthesis of nanostructured p-type semi-conductors for the fabrication of p-Dye Sensitized Solar Cells (p-DSSCs). In that framework, our studies concerned first the preparation of crack free homogeneous films of NiO with control of their thickness by an hydrothermal method. Then, a low fraction of metallic nickel was systematically detected which could explain in part the good photovoltaic performances of solar cell with NiO as photocathode. However, to achieve higher yield, NiO must be replaced by an other p-type semiconductor to deliver higher Voc. In that context, the synthesis of CuGaO2 nanoparticles by an hydrothermal method was undertaken with ethylene glycol as reducing agent. P-DSSC was set up with this material and exhibits interesting photovoltaic performance. In parallel, synthesis of nanoparticles of LaOCuS was carried out. Unfortunately, this compound has not been tested in dye sensitized solar cell because of a lack of an appropriate redox mediator. Finally, the stabilization of p-type ZnO:N was performed by nitridation of zinc peroxide ZnO2. This compound crystallizes with a wurtzite structure which accommodates the presence of peroxide groups, nitride anions and zinc vacancies
Renaud, Adèle. "Semi-conducteurs de type p pour une application en cellules solaires à colorant". Nantes, 2013. https://archive.bu.univ-nantes.fr/pollux/show/show?id=bc5d055e-878e-4b2d-af7c-44949293c4df.
Texto completoThese thesis works focused on the realization of p-type dye sensitized solar cells (DSSCp) with a photocathode using an alternative to NiO. The objective was to replace the p-type semiconductor by more transparent and conductive materials and displaying a lower valence band energy to enable the generation of higher open circuit voltages (Voc). In this context, CuGaO2, LaOCuS and ZnO:N compounds were synthesized in nanoparticles form, characterized by X-ray diffraction and their flat band potentials (Vfb) were determined by complex impedance spectroscopy. As a result CuGaO2, LaOCuS and ZnO:N have Vfb significantly higher (0. 49 V/SCE), similar (0. 36 V/SCE) and lower (0. 20 V/SCE) than that of NiO (0. 33 V/SCE). Thus, dye sensitized solar cells based on the delafossite material were made and tested with the PMI-NDI dyad as dye and a cobalt complex as redox mediator. A greater VOC than that observed for NiO under the same conditions is highlighted. This result is unfortunately altered by a lower short circuit current (Jsc). To try to overcome this drawback, CuGaO2:Mg materials with a higher specific surface area than that of CuGaO2 have been prepared and tested. Simultaneously, we have focused on the achievement of cells based on LaOCuS, more conductive material than NiO. In addition, the p-type conductivity of ZnO:N was further characterized
Chavillon, Benoit. "Synthèse et caractérisation d'oxydes transparents conducteurs de type p pour application en cellules solaires à colorant". Phd thesis, Université de Nantes, 2011. http://tel.archives-ouvertes.fr/tel-00674543.
Texto completoWang, Jin. "Nanoparticules à base d'oxyde de titane par pyrolyse laser : synthèse, proprietés et application au photovotaïque". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112222/document.
Texto completoThis work is related to the development of new TiO2 porous photo-electrodes based on nanopowders synthesized by laser pyrolysis for application in solid-state dye-sensitized solar cells. Two different types of TiO2 powders were synthesized: TiO2 nanoparticles doped with different levels of nitrogen, and TiO2/MWNTC (Multi Wall Carbon Nanotubes) nanocomposites. In the first case, the efficiency of the solar cells is dependent on the nitrogen amount in the powder, in relation with the localization of the dopants in the TiO2 structure. High nitrogen contents are associated with high defect densities at the TiO2 nanoparticle surface, leading to intense charge recombination. Although this effect limits the performance of the cells, it can be counterbalanced by an increased electrical conductivity due to the presence of N atoms. Finally, for moderate doping levels, the incorporation of nitrogen can improve the efficiency of the cells, compared to reference devices. Regarding the use of TiO2/MWNTC nanocomposites, the one step synthesis by laser pyrolysis from a precursor mixture including MWNTC leads to nanopowders where nanotubes appear very homogeneous dispersed of. The nanotubes are also highly coated with TiO2 particles, improving their electrical interactions with the TiO2 particles. The efficiencies of the solar cells made from such composites are found to be 20% larger than that of reference cells. This improvement is mainly attributed to faster charge collection and reduced charge recombination rates
Mesguich, Frederic. "Stratégie innovante pour la mise en forme de nanostructures TiO2/Au à propriétés synergétiques pour le photovoltaïque". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2014. http://tel.archives-ouvertes.fr/tel-00978847.
Texto completoZehani, Mongia. "Optimisation du procédé polyol pour la synthèse de nanoparticules d'oxyde de zinc : mise à l'échelle du procédé et applications photovoltaïques". Thesis, Paris 13, 2014. http://www.theses.fr/2014PA132044/document.
Texto completoThanks to developments in synthesis methods and characterization techniques, nanomaterials research field is increasingly active and attractive. This thesis aims to investigate the polyol process for zinc oxide nanoparticles synthesis. Indeed, this method has the advantage of providing a wide variety of particle morphology with a good crystalline quality. In this thesis, we show that by varying the synthesis conditions we can adjust the size, the size distribution and the morphology of nanoparticles to obtain either shaped nanospheres as small as 6 nm or nanowires as long as 600 nm. Our systemic study focused on a set of parameters that control the forced hydrolysis reaction including stoichiometry, temperature, nature of the polyol but also mixing, injection of reagents and ultrasound activation. We show that the shape of the nanoparticles is determined by the competition between growth rates of different zinc oxide crystal facets. Our study also compared different mixing devices such as laboratory reactor, T- mixer and impinging jets. More over, to mass produce zinc oxide nanoparticles, we developed an original strategy to understand the effect of mixing on nanoparticle size. In our approach, we correlate the turbulent energy dissipated as obtained from Computation Fluid Dynamics with theme asured nanoparticle size. The application to the specific case of zinc oxide has allowed us to produce sample aliquots of ~50 g per Batch. These nanoparticles were subsequently incorporated into dye-sensitized solar cells as semi conducting material at the École Nationale Supérieure de Chimie de Paris. Indeed, the morphological richness of the zinc oxide produced via polyol process suggests good adsorption of the dye on their surfaces. Our results show that the photoconversion efficiencies depend both on the morphology and the size. Our best photoconversion efficiency approaches 5.3%
Cojocaru, Ludmila. "Films d’oxydes semi-conducteurs nanoporeux et nanocristallins pour dispositifs photovoltaïques hybrides". Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14630/document.
Texto completoIn the context of the development of efficient, low-cost and environmentally friendly photovoltaic devices, the synthesis of metal-oxide semiconductors such as SnO2, Zn2SnO4 and WO3 with various textures and morphologies have been developed in order to achieve nanoporous photoanodes for dye-sensitized solar cells. According to studies carried out by different characterization methods (SEM, TEM, XRD and BET), the resulting materials show interesting features for the expected application. Dye solar cells were then fabricated from photoanodes processed with these oxides and several parameters influencing their performance were optimized to improve the overall conversion efficiency. In particular, the beneficial effect of different treatments of the photoanodes (ie aqueous TiCl4 or water treatment) on the power conversion efficiency and the stability of the devices has been evidenced. Thus, state-of-the art or, even, record efficiencies were reached in the case of SnO2-based systems. These performances were then rationalized by determining the electronic and ionic processes occurring in these devices by various physical methods (threshold voltage and open-circuit photovoltage decay measurements, electrochemical impedance spectroscopy). Finally, electrodes based on WO3 and deposited on flexible substrates have shown very promising electrochromic properties, which opens up new prospects in the field of smart displays