Página 1 dos resultados de 518 itens digitais encontrados em 0.007 segundos

Covalent attachment of 3,4,9,10-perylenediimides onto the walls of mesoporous molecular sieves MCM-41 and SBA-15

TRINDADE, Fabiane J.; FERNANDES, Glauber J. T.; ARAUJO, Antonio S.; FERNANDES JR., Valter J.; SILVA, Barbara P. G.; NAGAYASU, Rafael Y.; POLITI, Mario J.; CASTRO, Francisco L.; BROCHSZTAIN, Sergio
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.7%
This work describes the covalent grafting of 3,4,9,10-perylenediimides (PDI), which are fluorescent dyes with very interesting optical properties, onto the walls of mesoporous molecular sieves MCM-41 and SBA-15. The mesoporous materials were first treated with 3-aminopropyltriethoxysilane (APTES) in anhydrous toluene, generating amine-containing surfaces. The amine-containing materials were then reacted with 3,4,9,10-perylenetetracarboxylic dianhydride (PTCA), generating surface-grafted PDI. Infrared spectra of the materials showed that the reaction with amino groups took place at both anhydride ends of the PTCA molecule, resulting in surface attached diimides. No sign of unreacted anhydride groups were found. The new materials, designated as MCMN2PDI and SBAN(2)PDI, presented absorption and emission spectra corresponding to weakly coupled PDI chromophores, in contrast to the strongly coupled rings usually found in solid PDI samples. The materials showed a red fluorescence, which could be observed by the naked eye under UV irradiation or with a fluorescence microscope. The PDI-modified mesoporous materials showed electrical conductivity when pressed into a pellet. The results presented here show that the new materials are potentially useful in the design of nanowires. (C) 2007 Elsevier Inc. All rights reserved.

Síntese e caracterização de catalisadores de níquel suportados em sílica mesoporosa altamente ordenada para hidrogenação de óleos vegetais; Synthesis and characterization of highly ordered mesoporous silica supported nickel catalysts for the hydrogenation of vegetable oils

Oliveira, Nara Andréa de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 14/04/2008 PT
Relevância na Pesquisa
46.62%
Este trabalho teve como objetivo a síntese e caracterização de sílicas mesoporosas suportadas com níquel para atuarem como catalisadores na hidrogenação de óleos vegetais. Foram escolhidas as sílicas mesoporosas ordenadas do tipo SBA-15 e FDU-1, sintetizadas a partir de TEOS como fonte de sílica e copolímeros triblocos como agentes direcionadores de estrutura em meio HCl. O Ni(NO3)2.6H2O foi utilizado como fonte de metal, cuja solução aquosa com a concentração de níquel desejada foi adicionada à sílica antes da remoção do molde polimérico, originando os precursores dos catalisadores. Após a impregnação, as amostras foram submetidas à calcinação sob atmosfera de ar, gerando o precursor na forma de óxido que ao ser tratado com H2 é reduzido Nio , forma ativa do catalisador. As técnicas de termogravimetria, termogravimetria derivada, difração de raios X a alto e baixo ângulo, isotermas de adsorção de nitrogênio e absorção atômica foram empregadas para a caracterização destes materiais. A TG/DTG foi utilizada para a simulação das melhores condições de calcinação/redução. As amostras foram calcinadas em um forno tubular com controlador de temperatura. Os ensaios de DRX confirmaram a fase NiO após calcinação e a fase Nio na redução...

Nanostructured materials based on mesoporous silica and mesoporous silica/apatite as osteogenic growth peptide carriers

Mendes, L. S.; Saska, S.; Martines, M. A U; Marchetto, R.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 4427-4434
ENG
Relevância na Pesquisa
56.76%
The aim of this work was the preparation of inorganic mesoporous materials from silica, calcium phosphate and a nonionic surfactant and to evaluate the incorporation and release of different concentrations of osteogenic growth peptide (OGP) for application in bone regeneration. The adsorption and release of the labeled peptide with 5,6-carboxyfluorescein (OGP-CF) from the mesoporous matrix was monitored by fluorescence spectroscopy. The specific surface area was 880 and 484 m2 g- 1 for pure silica (SiO) and silica/apatite (SiCaP), respectively; the area influenced the percentage of incorporation of the peptide. The release of OGP-CF from the materials in simulated body fluid (SBF) was dependent on the composition of the particles, the amount of incorporated peptide and the degradation of the material. The release of 50% of the peptide content occurred at around 4 and 30 h for SiCaP and SiO, respectively. In conclusion, the materials based on SiO and SiCaP showed in vitro bioactivity and degradation; thus, these materials should be considered as alternative biomaterials for bone regeneration. © 2013 Elsevier B.V.

Materiais meso-estruturados luminescentes

Rocha, Lucas Alonso
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Tese de Doutorado Formato: 161 f. : il.
POR
Relevância na Pesquisa
46.65%
Pós-graduação em Química - IQ; Partículas esféricas de sílica mesoporosa foram obtidas a partir da síntese “template” pelo processo de pirólise de aerossol. O processo foi otimizado para a obtenção de materiais mesoporosos sem resíduos orgânicos e preparados em uma única etapa, eliminando assim, a longa etapa de remoção do surfactante na metodologia tradicional (tratamento térmico ou extração soxhlet, podendo durar dezenas de horas). A otimização do processo de pirólise de aerossol proposta nesta tese reduziu este tempo para apenas alguns minutos. Os materiais apresentaram uma área superficial (BET) de até 1028 m2 .g-1 , com volume de poros (BJH) de 0,58 cm3 .g-1 . Os difratogramas de raios-X indicaram um alto grau de organização com um arranjo hexagonal de poros, confirmado também pela microscopia eletrônica de transmissão. Além disto, bandas características de grupos orgânicos não foram observadas nos espectros de absorção na região do infra-vermelho para as amostras obtidas acima de 600ºC. Amostras dopadas com íons Eu3+ também foram preparadas durante a tese. A análise por espectroscopia de luminescência, para íons Eu3+ , indicou que o íon está encapsulado nos canais mesoporosos sem prévia modificação química da matriz. Posteriormente...

Structural properties of Ti-SBA-15 mesoporous materials synthesised by a new “hibrid” method up to high titanium content,

Galacho, Cristina; Velho, Filipe; Carrott, Peter; Ribeiro carrott, Manuela; Nabais, Joao
Fonte: VI International Materials Symposium, Universidade do Minho, Publicador: VI International Materials Symposium, Universidade do Minho,
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.33%
Structural properties of Ti-SBA-15 mesoporous materials synthesised by a new “hibrid” method up to high titanium content,

Structural Characterisation and Mechanical Stability of Titanium Substituted Mesoporous Materials

Galacho, Cristina; Carrott, Manuela; Valerio, Joana; Carrott, Peter; Valente Nabais, Joao
Fonte: Materials Science Forum Publicador: Materials Science Forum
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.59%
Mesoporous silica and titanium SBA-15 samples with different Si/Ti molar ratio were prepared by direct one-step synthesis under strongly acidic hydrothermal conditions. The materials were characterised by X-ray diffraction, nitrogen adsorption at 77K. The Si/Ti values of the final calcined materials were determined by ICP analysis. It was found that all samples presented 2-D hexagonal structures with high degree of ordering. However, the metal content incorporated in all titanium mesoporous materials was very low, i.e., the Si/Ti molar ratio values of the final calcined samples are significantly different from the initial Si/Ti molar ratio in the synthesis gel. A study of mechanical stability in air was performed by exposing the calcined samples to a unidirectional external pressure in the range 74-814MPa. X-ray diffraction and nitrogen adsorption at 77K, on selected compacted samples, were used in order to evaluate the changes in mesoporous structure. It was found that, for all freshly calcined pure silica and titanium containing samples tested, the high quality SBA-15 structure is still observed after the application 148-370MPa of a unidirectional external pressure and the collapse of the pore structure occurs at around 814MPa.

Adsorption properties of activated carbons and ordered mesoporous materials for organic pollutants in aqueous systems

Cansado, Isabel; Galacho, Cristina; Nunes, Angela; Carrott, Manuela; Carrott, Peter
Fonte: CIIEM - 2009 Publicador: CIIEM - 2009
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
56.4%
Adsorption properties of activated carbons and ordered mesoporous materials for organic pollutants in aqueous systems. livro de resumos do III Congresso Internacional de Engenharia e Gestão da Energia e Meio Ambiente

IN-SITU XRD STUDIES OF THERMAL STABILITY OF PURE SILICA AND Ti-MCM-41 MATERIALS

Franco, Nuno; Alves, Eduardo; Galacho, Cristina; Carrott, Manuela; Carrott, Peter
Fonte: SPM e FEUP Publicador: SPM e FEUP
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.33%
In this work we present a study on the thermal stability of siliceous and titanium containing ordered mesoporous materials with MCM-41 structure, prepared by direct synthesis at ambient temperature and pressure, as previously described [1]. Grades with different pore diameter and Si/Ti molar ratios were analyzed, in the form of compacted powder, to assess its influence on the order-disorder transition temperature.

Templated mesoporous materials: expectations, facts and challenges

Ribeiro Carrott, M.M.L.
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Aula
ENG
Relevância na Pesquisa
66.53%
This presentation included an overview of the main types of the mesoporous structures that can be generated via template processes, addressing the role of surface chemistry on their formation and implications in their properties and applications. Some aspects considered involved the introduction of catalytic functionalities, the important contributions that these model porous solids brought to the testing of fundamentals underlying gas adsorption, previously developed with common mesoporous materials having broad pore size distributions, and also their potential as molecular sieves for big molecules in the liquid phase. Together with the beautiful aspects, some challenges still to overcome, were also mentioned.

Use of rice husk ash as only source of silica in the formation of mesoporous materials

Schwanke,A. J.; Melo,D. M. A.; Silva,A. O.; Pergher,S. B. C.
Fonte: Associação Brasileira de Cerâmica Publicador: Associação Brasileira de Cerâmica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2013 EN
Relevância na Pesquisa
66.49%
This paper reports the synthesis of molecular sieves similar to MCM-41 using rice husk ash as only source of silica. For comparison purposes, a standard synthesis was performed using aerosil 200 commercial silica. The rice husk silica was obtained by heating treatment at 600 ºC and leaching for 2 h in reflux with HCl 1mol.L-1 and used in the synthesis. The samples prepared were characterized by N2 adsorption, X-ray diffraction (XRD), scanning electronic microscopy (SEM) and thermogravimetric analysis (TG). By type-IV adsorption isotherms, the formation of mesoporous materials was observed. XRD showed the formation of hexagonal unidirectional pore materials similar to MCM-41. By SEM, it could be observed that the rice husk has fibrous aspect and that synthesis using calcined and leached rice husk did not react entirely because silica was only partially dissolved.

Synthesis of mesoporous silica microsphere from dual surfactant

Narayanan,Venkatathri
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2008 EN
Relevância na Pesquisa
46.58%
A new procedure is reported to synthesis mesoporous silica micro sphere for the first time. In these method two surfactants namely Span 80 and Tween 80 were used. Small angle X ray diffraction and N2 adsorption analysis shows the synthesized material has mesoporous property. The material has spherical morphology with 1-10 µm particle size. Beside the material found to have microcapsule property as observed from the Transmission electron microscopy. The Fourier transform Infrared spectroscopic analysis reveals that the materials are similar to other mesoporous materials. We also encapsulated an UV-absorber Ibuprofen inside the microcapsule, by mixing it before the synthesis. This shows a possibility of the materials in cosmetic applications.

Ordered mesoporous silica carrier system applied in nanobiothecnology

Sousa,Andreza de; Sousa,Edésia Martins Barros de
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2005 EN
Relevância na Pesquisa
56.46%
Ordered mesoporous materials like SBA15 possess a network of channels and pores of well-defined size in the nanoscale range (2-50 nm). This particular pore architecture makes them suitable candidates for hosting and delivery under appropriate conditions of a variety of molecules of pharmaceutical interest, including radiopharmaceuticals. The characteristics of SBA-15 prepared in different temperatures and the behavior of this system regarding microencapsulation of a model drug were investigated. The calcined samples were formed in 0.2 g disks and were soaked in a solution of atenolol used as a model drug. The modification of the aging temperature provoked changes in the structure of the pores, indicating the presence of microporosity and connections between mesopores. Aging the materials at a higher temperature resulted in no microporosity and this fact influenced the control of the release of the model drug.

Synthesis and catalytic applications of combined zeolitic/mesoporous materials

Vernimmen, Jarian; Meynen, Vera; Cool, Pegie
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 30/11/2011 EN
Relevância na Pesquisa
46.74%
In the last decade, research concerning nanoporous siliceous materials has been focused on mesoporous materials with intrinsic zeolitic features. These materials are thought to be superior, because they are able to combine (i) the enhanced diffusion and accessibility for larger molecules and viscous fluids typical of mesoporous materials with (ii) the remarkable stability, catalytic activity and selectivity of zeolites. This review gives an overview of the state of the art concerning combined zeolitic/mesoporous materials. Focus is put on the synthesis and the applications of the combined zeolitic/mesoporous materials. The different synthesis approaches and formation mechanisms leading to these materials are comprehensively discussed and compared. Moreover, Ti-containing nanoporous materials as redox catalysts are discussed to illustrate a potential implementation of combined zeolitic/mesoporous materials.

Evaluation of the zinox and zeolite materials as adsorbents to remove H2S from natural gas

Melo, Dulce Maria de Araújo; Souza, José Roberto de; Melo, Marcus Antonio de Freitas; Martinelli, Antonio Eduardo; Cachima, Gustavo Henrique Bezerra; Cunha, Jardel Dantas da
Fonte: Colloids and Surfaces Publicador: Colloids and Surfaces
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
56.41%
MELO, Dulce Maria de Araújo et al. Evaluation of the Zinox and Zeolite materials as adsorbents to remove H2S from natural gas. Colloids and Surfaces. A, Physicochemical and Engineering Aspects, Estados Unidos, v. 272, p. 32-36, 2006.; Mesoporous materials can be generally used as adsorbents to remove impurities from gases. During the past few years, H2 S has been removed from natural gas using materials such as dolomite, zeolites, and industrial compounds, which can be widely used by oil and natural gas companies. The present study focused on the use of Zeolite 13X and Zinox 380 as H2 S adsorbent at 25 ◦ C. They were characterized by chemical analyses (X-ray fluorescence and atomic absorption), X-ray diffraction, particle size distribution analyses and FT Infrared spectroscopy. Adsorption reactions were carried out using proposed models. The results revealed that both materials studied could be used as H2 S adsorbents in natural gas exceeding the capabilities of industrial compounds

Mesoestruturas porosas a partir de materiais naturais; Porous mesostructures from natural materials

Schwanke, Anderson Joel
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Ciência e Engenharia de Materiais; Processamento de Materiais a partir do Pó; Polímeros e Compósitos; Processamento de Materiais a part Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Ciência e Engenharia de Materiais; Processamento de Materiais a partir do Pó; Polímeros e Compósitos; Processamento de Materiais a part
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
56.7%
The MCM-41 mesoporous synthesis was done using rice hulls ash and chrysotile as natural alternative silica sources. For the using of these sources, chemical and thermic treatments were done in both materials. After chemical and thermic treatments, these materials were employed on the MCM-41 mesoctructures synthesis. The natural materials treated and employed in the synthesis were characterized by several techniques such as X-ray diffraction, N2 adsorption and desorption, scanning electronic microscopy and thermogravimetric analysis. MCM-41 standart samples synthetized with aerosil 200 commercial sílica were used to evaluation. The formed material from rice hulls ash showed values from BET specific area about 468 m².g-1, N2 adsorption and desorption isotherms and loss mass similar to reference materials. The silica from chrysotile calcined and leached was employed to mesoporous materials synthesis. The BET specific area showed values about 700 m².g-1, N2 adsorption and desorption isotherms type IV and loss mass similar to mesoporous materials. The formed material from calcined and leached chrysotile, without calcination, applied to phenol remotion carried high performance liquid chromatography and evaluated with organophilic clays with different treatments. By the characterization techniques were proved that mesoporous materials with lesser order that reference samples. The material formed from rice hulls ash without the calcination step achieved better adsorption results than organophilic clays; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior; A síntese dos mesoporosos do tipo MCM-41 foram realizadas empregando materiais naturais como cinza da casca de arroz e crisotila como fontes alternativas de sílica. Para a utilização destas fontes...

Síntese, caracterização e aplicação do MCM-41 e A1-MCM-41 na pirólise do resíduo atmosférico de petróleo

Castro, Kesia Kelly Vieira de
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Química; Físico-Química; Química Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Química; Físico-Química; Química
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
46.61%
In present work, mesoporous materials of the M41S family were synthesized, which were discovered in the early 90s by researchers from Mobil Oil Corporation, thus allowing new perspectives in the field of catalysis. One of the most important members of this family is the MCM-41, which has a hexagonal array of mesopores with pore diameters ranging from 2 to 10 nm and a high surface area, enabling it to become very promising for the use as a catalyst in the refining of oil in the catalytic cracking process, since the mesopores facilitate the access of large hydrocarbon molecules, thereby increasing the production of light products, that are in high demand in the market. The addition of aluminum in the structure of MCM-41 increases the acidity of the material, making it more beneficial for application in the petrochemical industry. The mesoporous materials MCM-41 and Al-MCM-41 (ratio Si / Al = 50) were synthesized through the hydrothermal method, starting with silica gel, NaOH and distilled water. CTMABr was used as template, for structural guiding. In Al-MCM-41 the same reactants were used, with the adding of pseudoboehmite (as a source of aluminum) in the synthesis gel. The syntheses were carried out over a period of four days with a daily adjustment of pH. The optimum conditions of calcination for the removal of the organic template (CTMABr) were discovered through TG / DTG and also through analysis by XRD...

Magnetic nanocomposites with mesoporous structures: synthesis and applications

Liu, J.; Qiao, S.; Hu, Q.; Lu, G.
Fonte: Wiley - VCH Verlag GmbH & Co KGaA Publicador: Wiley - VCH Verlag GmbH & Co KGaA
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
56.69%
Magnetic nanocomposites with well-defined mesoporous structures, shapes, and tailored properties are of immense scientific and technological interest. This review article is devoted to the progress in the synthesis and applications of magnetic mesoporous materials. The first part briefly reviews various general methods developed for producing magnetic nanoparticles (NPs). The second presents and categorizes the synthesis of magnetic nanocomposites with mesoporous structures. These nanocomposites are broadly categorized into four types: monodisperse magnetic nanocrystals embedded in mesoporous nanospheres, microspheres encapsulating magnetic cores into perpendicularly aligned mesoporous shells, ordered mesoporous materials loaded with magnetic NPs inside the porous channels or cages, and rattle-type magnetic nanocomposites. The third section reviews the potential applications of the magnetic nanocomposites with mesoporous structures in the areas of heath care, catalysis, and environmental separation. The final section offers a summary and future perspectives on the state-of-the art in this area.; Jian Liu, Shi Zhang Qiao, Qiu Hong Hu, and Gao Qing (Max) Lu

Study of the performances of innovative materials for the treatment of contaminated water

DE FOLLY D'AURIS, ALESSANDRA
Fonte: La Sapienza Universidade de Roma Publicador: La Sapienza Universidade de Roma
Tipo: Tese de Doutorado
EN
Relevância na Pesquisa
46.68%
In this thesis were evaluated the performances of various type of “zeolite like” adsorbents used for wastewater treatment in P&T or PRB installations. This was made up by characterizing the equilibrium behavior, through the construction of isotherms and how they behave in a flow system through the study and evaluation of breakthrough curve. In particular, we take into account water contaminated by emulsified and dissolved oil, high concentrations of organic contaminants (> 100 ppm), inorganic ions, cations as Cd2+, Pb2+, Mn2+ and anions of As. This is a typical situation of produced water or groundwater underlying refineries, depots and petrol stations. It will also evaluate the effect of the presence of salts in solution, because the sites are often located in coastal areas where there are often significant phenomena of saline intrusion. To solve such complex situations of contamination, it was imagined an intervention strategy based on the coupling in series of different adsorption processes, agents selectively on different fractions of contaminants and based on the use of different adsorbent materials. In particular it has been suggested to use: - amorphous mesoporous materials (MSA) for the removal of dispersed and emulsified oil. Mesoporous materials with appropriate open channels have been found effective in removing dissolved and emulsified oil...

MESOPOROUS SILICA MATERIALS IN ASYMMETRIC CATALYSIS AND SELECTIVE FUNCTIONALIZATION

Seki, Tomohiro
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
46.62%
This thesis describes the synthesis and application of three types of selectively functionalized mesoporous materials. In the first section, periodically ordered mesoporous organosilicas (PMOs) are prepared that have the axially chiral bidentate phosphine ligand 2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl (BINAP) embedded in the wall structure. Asymmetric hydrogenation of β-ketoesters under high-pressure hydrogen gas and hydrogen transfer reduction were carried out using Ru catalysts resulting from these materials. In the next chapter, our new methodology to selectively functionalize the internal/external surface of SBA-15, a mesoporous silica whose pore diameter is ~8 nm, by blocking the pore surface with reloaded Pluronic P123® micelles is presented. Multiple tests were attempted to validate the efficiency of the methodology including nitrogen adsorption, quantitative analysis by solid state NMRs, fluorescence measurements, elemental analysis and XPS. Eventually SS NMR proved to be the most appropriate. Finally, chapter four describes ordered organic materials in catalysis, namely star-shaped polymers containing chiral core-gels synthesized from chiral 1,1’- binaphthalene-2,2’-diol (BINOL) and 1,1’-binaphthalene-2,2’-diamine (BINAM). The kinetic resolution of 1-phenyl ethanol was carried out expecting to see differential affinity of the chiral core-gel to one enantiomer of the substrate in hydrogen transfer oxidation reaction.; Thesis (Ph.D...

Valoración no cromatográfica de especies elementales basada en sistemas automáticos de extracción en fase sólida; Non chromatographic determination of elemental species based in solid phase extraction systems

Kim, Manuela Leticia
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2009 SPA
Relevância na Pesquisa
46.59%
En el presente trabajo se han estudiado sistemas en flujo contínuo para la valoración de especies elementales de cromo, vanadio y metales del grupo IB (Cobre, Plata y Oro) mediante su aislamiento de la matriz y preconcentración sobre sustratos ad-hoc sin utilizar la migración diferencial de especies como alternativa analítica. Se han estudiado sistemas en flujo utilizando extracción en fase sólida mediante la incorporación de microcolumnas empaquetadas con sólidos híbridos mesoporosos basados en sílica, los que han sido sintetizados en el laboratorio y caracterizados en ocasión del presente trabajo. El sistema en flujo así diseñado se ha acoplado en línea a distintos detectores espectroscópicos, dando lugar a diferentes aplicaciones en las que los sólidos híbridos mesoporosos son utilizados por primera vez con un objetivo analítico. Dentro de los alcances del presente trabajo se encuentran: · El diseño de los sistemas en flujo idóneos para los estudios de especiación y preconcentración de los analitos en estudio: Sistemas de extracción en fase sólida en línea (FI-SPE) acoplados con sistemas de detección contínua (espectrofotometría Uv-Vis) y discretas (espectrometría de absorción atómica con atomización electrotérmica...