Dissertations / Theses on the topic 'Titanian magnetite'
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Longbottom, Raymond James Materials Science & Engineering Faculty of Science UNSW. "The formation of cementite from hematite and titanomagnetite iron ore and its stability." Awarded by:University of New South Wales. Materials Science and Engineering, 2005. http://handle.unsw.edu.au/1959.4/22023.
Full textBeydoun, Donia Chemical Engineering & Industrial Chemistry UNSW. "Development of a novel magnetic photocatalyst : preparation, characterisation and implication for organic degradation in aqueous systems." Awarded by:University of New South Wales. Chemical Engineering and Industrial Chemistry, 2000. http://handle.unsw.edu.au/1959.4/20451.
Full textCavanough, Gary. "Measurement of magnetic susceptibility in titanium minerals processing /." St. Lucia, Qld, 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17774.pdf.
Full textVono, Lucas Lucchiari Ribeiro. "Design of nanocatalysts supported on magnetic nanocomposites containing silica, ceria and titania." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-17082016-082602/.
Full textA separação magnética tem recebido muita atenção como uma tecnologia robusta, altamente eficiente e rápida para recuperar catalisadores sólidos após uso em reações em fase líquida. Muitos estudos têm focado nas metodologias para a imobilização de espécies cataliticamente ativas, mas o desenvolvimento de suportes magnéticos tem se limitado a nanopartículas magnéticas revestidas com sílica, polímeros ou carbono. O desenvolvimento de nanocompósitos magnéticos com a incorporação de outros óxidos é muito desejável para ampliar a aplicação dessa tecnologia de separação em catálise. Nesse contexto, estudos da estabilidade térmica de magnetita revestida com sílica (Fe3O4@SiO2) foram realizados para avaliar a possibilidade de calcina-la sem perder as propriedades magnéticas do suporte. Uma etapa de calcinação é necessária para a deposição de diferentes óxidos na superfície da sílica, tais como céria e titânia. O Fe3O4@SiO2 calcinado preservou a morfologia \"core-shell\" e as propriedades magnéticas, porém apresentou um aumentou de seis vezes na área superficial. Novos suportes magnéticos foram desenvolvidos pela deposição de céria e titânia sobre magnetita previamente revestida com sílica. Nanocatalisadores magneticamente recuperáveis de Rh, Pd e Ru foram preparados. Os catalisadores foram utilizados na hidrogenação de ciclo-hexano, benzeno ou fenol e o principal objetivo dessa tese foi o estudo da influência de cada suporte na atividade catalítica. Os catalisadores foram preparados de duas formas diferentes: impregnação-redução e imobilização de nanopartículas (NPs) metálicas pré-formadas. As NPs coloidais foram preparadas pela redução de sais metálicos e, também, pela decomposição de complexos organometálicos. Catalisadores de ródio preparados pela impregnação de cloreto de ródio(III) e redução com H2 mostraram alguns problemas de reprodutibilidade, que foram superados utilizando NaBH4 ou hidrazina como agentes redutores. A preparação de catalisadores pela imobilização de NPs coloidais é uma alternativa interessante para obter catalisadores reprodutíveis e muito ativos. Nanopartículas de Pd, Rh e Ru foram preparadas a partir de organometálicos e imobilizadas em Fe3O4@SiO2 calcinada, Fe3O4@SiO2CeO2 e Fe3O4@SiO2TiO2. A eliminação do agente estabilizante torna os catalisadores mais ativos durante os reusos. O catalisador de Rh sobre o suporte de céria foi o catalisador mais ativo na hidrogenação de ciclohexeno (TOF 125000 h-1). O catalisador de Pd foi o catalisador mais seletivo para a hidrogenação de fenol em ciclo-hexanona, independente do suporte usado. A formação de ciclo-hexanol é favorecida pelo suporte de titânia e a hidrodesoxigenação para produzir ciclo-hexano ocorreu principalmente no suporte de sílica.
Church, Nathan Stewart. "Magnetic properties of iron-titanium oxides and their nanoscale intergrowths." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609524.
Full textNoganta, Siyasanga. "Photocatalytic degradation of organic pollutants using Ag-Fe₃O₄/SiO₂/TiO₂ nanocomposite." Thesis, University of the Western Cape, 2015. http://hdl.handle.net/11394/5208.
Full textThe global lack of clean water for human sanitation and other purposes has become an emerging dilemma for human beings. The presence of organic pollutants in wastewater produced by textile industries, leather manufacturing and chemical industries is an alarming matter for a safe environment and human health. For the last decades, conventional methods have been applied for the purification of water but due to industrialization these methods fall short. Advanced oxidation processes and their reliable application in degradation of many contaminants have been reported as a potential method to reduce and/or alleviate this problem. Lately, it has been assumed that incorporation of some metal nanoparticles such as magnetite nanoparticles as photocatalyst for Fenton reaction could improve the degradation efficiency of contaminants. Core/shell nanoparticles, are extensively studied because of their wide applications in the biomedical, drug delivery, electronics fields and water treatment. The current study is centred on the synthesis of silver-doped Fe₃O₄/SiO₂/TiO₂ photocatalyst. Magnetically separable Fe₃O₄/SiO₂/TiO₂ composite with core–shell structure were synthesized by the deposition of uniform anatase TiO₂ NPs on Fe₃O₄/SiO₂ by using titanium butoxide (TBOT) as titanium source. Then, the silver is doped on TiO₂ layer by hydrothermal method. Integration of magnetic nanoparticles was suggested to avoid the post separation difficulties associated with the powder form of the TiO₂ catalyst, increase of the surface area and adsorption properties. Lastly and most importantly magnetic nanoparticles upsurge the production of hydroxyl groups or reduced charge recombination. The a synthesized catalysts were characterized using Transmission Electron Microscopy, X-ray Diffraction; Infra-red Spectroscopy, Scanning Electron Microscope and Energy Dispersive Spectroscopy. Other characterization techniques includeVibrating Sample Magnetometry, Brunauer Emmett Teller analysis and Thermogravimetric analysis. The average size of the particles size is 72 nm. Furthermore the photocatalytic performances of the magnetic catalysts were assessed in comparison with that commercial titanium dioxide for the degradation of methylene blue using photochemical reactor under ultra violet light. The results showed that the photocatalytic activity was enhanced using Fe₃O₄/SiO₂/TiO₂ and Ag-Fe₃O₄/SiO₂/TiO₂ compared with that for Fe₃O₄, commercial titanium dioxide powder.
Rumaiz, Abdul K. "Cobalt doped titanium dioxide, a possible candidate for dilute magnetic semiconductor." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 149 p, 2008. http://proquest.umi.com/pqdweb?did=1459915881&sid=3&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Full textDaniel, Lisa Maree. "Laponite-supported titania photocatalysts." Queensland University of Technology, 2007. http://eprints.qut.edu.au/16669/.
Full textAli, Bakhtyar. "Study of titanium dioxide based dilute magnetic semiconductors the role of defects and dopants /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 85 p, 2008. http://proquest.umi.com/pqdweb?did=1597633311&sid=20&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Full textZhang, Shixiong. "Unusual electronic transport and magnetism in titanium oxide based semiconductors and Metals." College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7736.
Full textThesis research directed by: Dept. of Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Clarke, Simon James. "An experimental study of some two-dimensional antiferromagnets." Thesis, University of Oxford, 1994. http://ora.ox.ac.uk/objects/uuid:a559d173-edd3-4c9b-aa6e-a09a6d0fd37f.
Full textKaspar, Tiffany C. "Materials and magnetic studies of cobalt-doped anatase titanium dioxide and perovskite strontium titanate as potential dilute magnetic semiconductors /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/9902.
Full textStadler, Daniel [Verfasser]. "Magnetic Field-assisted Chemical Vapor Deposition of Iron, Vanadium and Titanium Oxides / Daniel Stadler." München : Verlag Dr. Hut, 2021. http://d-nb.info/1233525573/34.
Full textGwatinetsa, Demand. "Distribution of iron-titanium oxides in the vanadiferous main magnetite seam of the upper zone : Northern limb, Bushveld complex." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013281.
Full textLiu, Yawen. "Development of a continuous process for direct amide synthesis over titania based magnetic catalysts under RF heating." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/90834/.
Full textLuo, Mingliang. "Heterogeneous catalytic oxidation of aqueous phenol using an iron-based catalyst and a magnetic titanium dioxide photocatalyst." Thesis, University of East Anglia, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445198.
Full textSpegni, Alessio. "Approccio colloidale per la preparazione di fotocatalizzatori nanostrutturati a base di TiO2." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amslaurea.unibo.it/2557/.
Full textJeong, Byoung-Seong. "Growth and ferromagnetic semiconducting properties of titanium dioxide thin films an oxide-diluted magnetic semiconductor (o-dms) for spintronics /." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0004240.
Full textSolný, Tomáš. "Příprava a aplikace fotokatalyticky aktivního oxidu titaničitého." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2016. http://www.nusl.cz/ntk/nusl-256553.
Full textEL, HARFAOUI MOHAMMED. "Etude de l'etat magnetique localement cante et de sa dynamique dans le ferrite de lithium-titane dilue." Paris 6, 1988. http://www.theses.fr/1988PA066650.
Full textJorgetto, Alexandre de Oliveira. "Síntese de híbridos de sílica-titânia e de sílica-titânia-magnetita e sua organofuncionalização e sensitização com íons Fe3+ para fotocatálise degradativa de 4-clorofenol sob UV e luz visível /." Araraquara, 2018. http://hdl.handle.net/11449/153458.
Full textBanca: Raquel Fernandes Pupo Nogueira
Banca: Marcelo Organachi Orlandi
Banca: Katia Jorge Ciuffi
Banca: Silvana Ruella de Oliveira
Resumo: A contaminação de corpos d'água e águas subterrâneas por substâncias tóxicas ocasiona a redução da qualidade da água e até mesmo sua inapropriação para consumo. Atualmente as técnicas convencionais de tratamento de águas e resíduos aquosos não são capazes de descontaminá-los totalmente, pois substâncias recalcitrantes e substâncias parcialmente removidas/degradadas - como alguns clorofenóis (CPs) e substâncias desreguladoras endócrinas (SDEs) - permanecem na água mesmo após submetida aos tratamentos convencionais, reforçando a necessidade do desenvolvimento de procedimentos mais completos, sustentáveis e que também sejam economicamente viáveis. A exemplo, a fotocatálise heterogênea utilizando materiais semicondutores ativados pela radiação UV para produção, principalmente, de radicais hidroxilos pode ser aplicada para se degradar contaminantes em meio aquoso, sendo o óxido de titânio o material mais empregado devido àelevada atividade, baixo custo, estabilidade, disponibilidade e propriedades químicas, físicas e biológicas adequadas. Apesar de diversas vantagens associadas ao seu uso em fotocatálise heterogênea, sua aplicação na forma de suspensões (a fim de fazer melhor proveito da área superficial das partículas) ainda é restrita devido principalmente a dificuldades de separação/remoção destas após o processo de degradação. Neste trabalho, fotocatalisadores híbridos a base de titânia foram produzidos para realizar fotocatálise heterogênea de compostos orgânicos em meio aquo... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The contamination of waters and groundwaters by toxic substances reduces the quality of water and can even make it inadequate for consumption. Currently, the conventional techniques for treatment of waters and wastewaters are not able to completely decontaminate them. This is attributed to the presence of partially removed/degraded andrecalcitrant substances such as chlorophenols (CPs) and endocrine-disrupting chemicals (EDCs), since they persist in water even after the conventional treatment. This emphasizes the need for the development of more complete and sustainable processes that are also economically viable. For instance, heterogeneous photocatalysis utilizing UV-activated semiconductors for the production, mainly, of hydroxyl radicals is applied in the degradation of contaminants in aqueous medium. In this aspect, titanium oxide is the most used material in virtue of its high activity, low cost, stability, availability and suitable chemical, physical and biological properties. Despite so many advantages for the application of titanium oxide in heterogeneous photocatalysis, its application as slurries (to make better use of the surface area of particles) is still restrained by drawbacks related to separation/extraction steps. In this work, titania-based photocatalist hybrids were produced to perform heterogeneous photocatalysis of organic compounds in aqueous medium.As an alternative to implement particle separation from slurries, titania and mesoporous silica were depo... (Complete abstract click electronic access below)
Doutor
Jorgetto, Alexandre de Oliveira [UNESP]. "Síntese de híbridos de sílica-titânia e de sílica-titânia-magnetita e sua organofuncionalização e sensitização com íons Fe3+ para fotocatálise degradativa de 4-clorofenol sob UV e luz visível." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153458.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A contaminação de corpos d’água e águas subterrâneas por substâncias tóxicas ocasiona a redução da qualidade da água e até mesmo sua inapropriação para consumo. Atualmente as técnicas convencionais de tratamento de águas e resíduos aquosos não são capazes de descontaminá-los totalmente, pois substâncias recalcitrantes e substâncias parcialmente removidas/degradadas – como alguns clorofenóis (CPs) e substâncias desreguladoras endócrinas (SDEs) – permanecem na água mesmo após submetida aos tratamentos convencionais, reforçando a necessidade do desenvolvimento de procedimentos mais completos, sustentáveis e que também sejam economicamente viáveis. A exemplo, a fotocatálise heterogênea utilizando materiais semicondutores ativados pela radiação UV para produção, principalmente, de radicais hidroxilos pode ser aplicada para se degradar contaminantes em meio aquoso, sendo o óxido de titânio o material mais empregado devido àelevada atividade, baixo custo, estabilidade, disponibilidade e propriedades químicas, físicas e biológicas adequadas. Apesar de diversas vantagens associadas ao seu uso em fotocatálise heterogênea, sua aplicação na forma de suspensões (a fim de fazer melhor proveito da área superficial das partículas) ainda é restrita devido principalmente a dificuldades de separação/remoção destas após o processo de degradação. Neste trabalho, fotocatalisadores híbridos a base de titânia foram produzidos para realizar fotocatálise heterogênea de compostos orgânicos em meio aquoso. Como abordagem alternativa para implementação da separação de suspensões, realizou-se a deposição de sílica mesoporosa e titânia sobre núcleos de magnetita, sendo a magnetita responsável por possibilitar a separação magnética do material híbridode suspensões, enquanto que a sílica mesoporosa incrementaria a atividade da titânia por meio do aumento de sua área superficial. No caso do recobrimento por titânia, uma nova rota por meio de ebulição de etanol foi desenvolvida. Análises de difração de raios X indicaram que o recobrimento de sílica preveniu a conversão dos núcleos de magnetita à hematita após calcinação. Foi notado também a formação da fase anatase de titânia nos materiais híbridos para composições de titânia iguais ou maiores que 43 % em massa. Análises de espectroscopia de infravermelho reforçaram a presença de titânia juntamente à sílica, e também apontou para um limite de deposição para a titânia, que foi posteriormente verificado também por espectrofotometria de fluorescência de raios X. Através de microscopia eletrônica de varredura, observou-se a formação e crescimento da fase anatase sobre partículas de sílica e magnetita para composições de 53 % de titânia ou maiores, e análises de espectroscopia de energia dispersiva de raios X demonstraram os elementos Si e Ti se encontrarem bem-distribuídos ao redor das partículas de magnetita, sílica e titânia. O material híbrido produzido apresentou estrutura mesoporosa como o da sílica MCM-41, no entanto de área superficial específica menor, atingindo em torno de 248 m2 g-1. Análises de ressonância magnética nuclear de 29Si indicaram haver ligação química entre as fases sólidas de sílica e titânia. Experimentos de fotodegradação demonstraram que os híbridos de magnetita, sílica e titânia consistem de adsorventes ineficientes de 4-clorofenol. A atividade fotocatalítica destes materiais apresentou relação com o crescimento da textura de titânia, sendo os materiais fotoativos aqueles com composições de 53 % ou maiores. Cinéticas de degradação de ordem zero foram observadas para todos os materiais. Os materiais fotoativos também se demonstraram indiferentes ao pH do meio, com eficiências similares em pH 3,0 e 7,2. Ao se comparar as eficiências dos materiais híbridos, em termos de suas taxas iniciais de degradação, com as de materiais comerciais Hombikat 100 UV e Aeroxide® TiO2 P25 estabeleceu-se que a ordem decrescente de eficiência sob concentrações de catalisador otimizadas foi Aeroxide® TiO2 P25 > Hombikat 100 UV >híbrido de sílica e titânia >híbrido de magnetita, sílica e titânia. Concluiu-se dos experimentos de degradação que a incorporação de sílica e magnetita aos fotocatalisadores de titânia compromete a eficiência degradativa destes; em contrapartida, no caso dos materiais contendo núcleos de magnetita, sua recuperação magnética pode consistir de uma propriedade compensatória em termos de aplicação. A fim de se incrementar a atividade fotocatalítica dos materiais, estes foram sujeitos a etapas de modificação superficial por meio da incorporação de ácido rubeânico (AR) por silanização ou adsorção direta e/ou também por complexação de íons Fe3+ em meio aquoso, com a finalidade de se sensitizar os fotocatalisadores. A imobilização do AR por meio de silanização demonstrou-se mais eficiente, enquanto sua dessorção foi verificada para o material modificado por adsorção direta. No caso dos materiais modificados com Fe3+, constatou-se que a complexação destes íons sobre os materiais híbridos implicou na redução da fotoatividade destes, enquanto nenhum efeito foi notado em pH 6 para a fotoatividade de Hombikat 100 UV modificado. Mais experimentos seriam necessários para se determinar as taxas de degradação iniciais dos materiais estudados. Nos experimentos sob luz visível apenas Hombikat 100 UV e sua respectiva versão modificada apresentaram atividade. Ao se aplicar o material Hombikat 100 UV modificado com Fe3+ em pH 3,0, notou-se evidência de aumento de eficiência sob iluminação UV.
The contamination of waters and groundwaters by toxic substances reduces the quality of water and can even make it inadequate for consumption. Currently, the conventional techniques for treatment of waters and wastewaters are not able to completely decontaminate them. This is attributed to the presence of partially removed/degraded andrecalcitrant substances such as chlorophenols (CPs) and endocrine-disrupting chemicals (EDCs), since they persist in water even after the conventional treatment. This emphasizes the need for the development of more complete and sustainable processes that are also economically viable. For instance, heterogeneous photocatalysis utilizing UV-activated semiconductors for the production, mainly, of hydroxyl radicals is applied in the degradation of contaminants in aqueous medium. In this aspect, titanium oxide is the most used material in virtue of its high activity, low cost, stability, availability and suitable chemical, physical and biological properties. Despite so many advantages for the application of titanium oxide in heterogeneous photocatalysis, its application as slurries (to make better use of the surface area of particles) is still restrained by drawbacks related to separation/extraction steps. In this work, titania-based photocatalist hybrids were produced to perform heterogeneous photocatalysis of organic compounds in aqueous medium.As an alternative to implement particle separation from slurries, titania and mesoporous silica were deposited on the surface of magnetite cores. The incorporation of magnetite to the hybrid aimed to enable its magnetic separation from slurries whereas the incorporation of silica had the purpose of incrementing its activity by increasing the surface area of the hybrid material. A new route has been developed to perform the titania coating, which was based on the boiling of ethanolic medium. X-ray diffraction analyses indicated that the silica layer prevented phase conversion of magnetite cores to hematite after calcination. The formation of titania anatase phase was also observed for the hybrid materials for the mass composition of 43 % or greater. Infrared spectroscopy supported the presence of titania along with silica, and also pointed to a deposition limit for the titania layer that was also verified posteriorly through x-ray fluorescence spectrophotometry. Scanning electron microscopy enabled the observation of the formation and growth of anatase phase over magnetite-silica particles for compositions of 53 % or greater. Energy-dispersive x-ray spectroscopy demonstrated that Si and Ti were well- distributed over the magnetite-silica-titania particles. The hybrid material presented mesoporous structure likewise MCM-41, but with a smaller specific surface area of approximately 248 m2 g 1.29Si nuclear magnetic resonance provided evidence that silica and titania phases were chemically bonded. Photodegradation experiments demonstrated that magnetite-silica-titania hybrids are inefficient 4-chlorophenol adsorbents. The photocatalytic activity of the hybrids demonstrated to have relation with the growth of the titania texture, being the photoactive materials those with mass compositions of 53 % or greater. The kinetic behavior of the materials was found to have zero order and was pH-independent, having similar performances at pH 3.0 and 7.2. As the efficiencies of the hybrids are compared with those of commercial materials Hombikat 100 UV and Aeroxide® TiO2 P25, the decreasing order of efficiency could be obtained as Aeroxide® TiO2 P25 > Hombikat 100 UV >silica-titania hybrid > magnetite-silica-titania hybrid. Degradation experiments allowed to conclude that the incorporation of silica and magnetite to the titania photocatalists compromise their efficiencies; on the other hand, in the case of the materials containing magnetite cores, the possibility of magnetic retrieval may consist of a compensatory property with regard to practical application. To increment the photocatalytic activity of the materials, they underwent surface modification steps to have immobilized rubeanic acid (RA) either through sinalization or through direct adsorption. The complexation of Fe3+ to the surface of the hybrids was also tested in combination with rubeanic acid or without it to perform the sensitization of the photocatalysts. The immobilization of RA via silanization demonstrated to be more efficient, whereas its desorption could be verified for the material modified with RA by direct adsorption. In the case of hybrid materials modified with Fe3+ ions, the complexation of the ions led to a decay in their performance whereas no effect was observed at pH 6 for the material Hombikat 100 UV modified with Fe3+.More experiments are necessary to determine the initial degradation rates of the studied materials. In the experiments under visible light, only Hombikat 100 UV and its modified version presented photoactivity. When Fe3+-modified Hombikat 100 UV was tested at pH 3.0, evidence of increase in activity was noted under UV illumination.
Fapesp 2013/22955-2 e 2015/05224-0
GUILHERME, ENEIDA da G. "Preparacao de materiais magneticamente duros a base de ligas de terra rara-ferro nitrogenadas." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10786.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
Schell, Juliana. "Investigação de parâmetros hiperfinos dos óxidos semicondutores SnO2 e TiO2 puros e dopados com metais de transição 3d pela espectroscopia de correlação angular gama-gama perturbada." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-24032015-135507/.
Full textThis study aimed the use of nuclear technique Perturbed γ-γ Angular Correlation Spectroccopy (PAC) to measure the hyperfine interactions in thin films and powder samples of SnO2 and TiO2 pure and doped with transition metals to obtain a systematic investigation of defects and magnetism from an atomic point of view with the main motivation the application in spintronics. The work also focused on the preparation and characterization of samples by conventional techniques such as X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and magnetization measurements. Pure samples of the films were measured by the systematic variation of thermal treatment and applied magnetic field. These measurements were performed in HISKP at the University of Bonn (Rheinische Friedrich-Wilhelms-Universität Bonn) using 111In(111Cd) or 181Hf (181Ta); at IPEN, in turn, these measurements were performed after the diffusion of the same probe nuclei. Another part of PAC measurements were carried out using 111mCd(111Cd) and 117Cd (117In) in Isotope Mass Separator On-Line (ISOLDE) at Centre Européen Recherche Nucléaire (CERN). The measurements were performed from 8 K to 1173 K. After comparing results from macroscopic techniques with those from PAC, it was concluded that there is a correlation between the defects, magnetism and the mobility of charge carriers in semiconductors studied here. A step forward in the search for semiconductors, whose magnetic ordering allows its use in electronics based on spin. Some results have been published, including results obtained at the University of Bonn for the sandwich doctorate period [1-7].
Vono, Lucas Lucchiari Ribeiro. "Elaboration de catalyseurs supportés par dépôt de nanoparticules métalliques sur des composites magnétiques contenant de la silice, de l'oxyde de cérium et de l'oxyde de titane." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30026/document.
Full textMagnetic separation has received a lot of attention as a robust, highly efficient and rapid catalyst separation technology. Many studies have focused on the immobilization of catalytic active species, but the development of magnetic supports has been limited to silica, polymer or carbon-coated magnetic nanoparticles (NPs). The design of magnetic nanocomposites and the incorporation of other oxides are thus highly welcome to broaden the application of this separation technology in the field of catalysis. In this context, studies of the thermal stability of silica coated magnetite (Fe3O4@SiO2) were performed to evaluate the possibility of calcining it without losing the magnetic properties of the support. The calcination would permit the deposition of different oxides on the silica surface, such as ceria and titania. The calcined Fe3O4@SiO2 material preserved its core-shell morphology and magnetic properties, and increased its surface area six times. A post-coating process was developed for the deposition of ceria and titania on Fe3O4@SiO2. Magnetically recoverable Rh, Pd and Ru nanocatalysts were prepared on the surface of the magnetic supports. The obtained catalysts were employed in hydrogenation of cyclohexene, benzene or phenol and the study of the influence of each support on the catalytic activity was the main objective of this thesis. For the deposition of the metallic nanoparticles on the supports in order to obtain the active catalysts two different approaches were followed: the impregnation and the sol immobilization of pre-formed metal NPs. Concerning the synthesis of the colloidal metal NPs, they were prepared either by reduction of metal salts or by decomposition of organometallic complexes. Rhodium catalysts prepared by impregnation of rhodium(III) chloride and reduction with H2 showed some reproducibility issues that were surpassed by using NaBH4 or hydrazine as reducing agents. The preparation of catalysts by the immobilization of colloidal NPs is an interesting alternative to obtain reproducible and very active catalysts. Nanoparticles of Pd, Rh and Ru were prepared by an organometallic approach and immobilized on calcined Fe3O4@SiO2, Fe3O4@SiO2CeO2 and Fe3O4@SiO2TiO2. The elimination of Rh stabilizing agent over ceria support appears to be different than in other supports and was the most active catalyst in the hydrogenation of cyclohexene (TOF 125,000 h-1). The Rh, Pd and Ru catalysts were employed in the hydrogenation of phenol. Palladium was the most selective catalyst to cyclohexanone, no matter the support used. The formation of cyclohexanol is enhanced in the support with titania and the hydrodeoxygenation to produce cyclohexane occurred mainly in the support with silica
Fleurette-Delobbe, Valérie. "Variations du type structural reo::(3) dans des fluorures et oxyfluorures de niobium iv : etude des interactions magnetiques." Paris 6, 1987. http://www.theses.fr/1987PA066373.
Full textGrönefeld, Katharina [Verfasser], Anna-Kathrin [Akademischer Betreuer] Hell, Hans-Christoph [Gutachter] Ludwig, and Rainer [Gutachter] Mausberg. "Skoliose-Therapie bei Kindern und Jugendlichen mit dem MAGEC®(magnetic expansion control)-Spinalsystem in Kombination mit dem VEPTR (vertical expandable prosthetic titanium rib)-Instrumentarium / Katharina Grönefeld ; Gutachter: Hans-Christoph Ludwig, Rainer Mausberg ; Betreuer: Anna-Kathrin Hell." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://d-nb.info/1164031023/34.
Full textCavalcante, Geane Carolina Gonçalves. "Evolução tectônica e reologia de uma crosta orogênica quente: o caso do Anatexito Carlos Chagas, Faixa Araçuaí (Leste do Brasil)." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/44/44141/tde-11022014-143756/.
Full textThe Araçuaí belt was formed by the collision between South American and African protocontinents during the Neoproterozoic. Its eastern part consists of an extensive migmatitic area (~300 km long x 50-100 km wide) where crop out anatexites and leucogranites (Carlos Chagas unit), migmatitic kinzigites and granulites that probably are the record of a widespread partial melting of the middle to lower crust. Field observations associated with microstructural evidences indicate that the deformation occurred when the rocks were incompletely solidified. Synkinematic temperature estimates realized using the TitaniQ (titaniun-in-quartz) geotermomether suggest that the minimum temperature for the quartz crystallization is ~750°C. Such temperatures combined with bulk rock composition of leucosome in the anatexites suggest that the viscosity of crustal rocks was dropped to at least 108 Pa s. Low viscosity values associated with field and microstructural evidences are consistent with the generation of at least 30% volume of melt during the orogeny. The presence of large volumes of melt promotes a drastic weakening of the mechanical strength of rocks and suggests that the anatectic crust of the eastern Araçuaí belt represents an analogue of present day hot orogen such the Himalayas. Detailed mineralogy investigation permitted to characterize the paramagnetic behaviour of the anatexites and the ferromagnetic behaviour of the granulites. Crystallographic preferred orientation (CPO) measurements using the EBSD (Electron Backscatter Diffraction) technique reveal that the magnetic foliation results from the preferred orientation of the biotite [001] oriented normal to the flow plane. However, given the feeble linear anisotropy of this mineral, only a subsidiary contribution of its subfabric to the origin of the magnetic lineation (k1) was observed. Correspondence between [001] of feldspars and k1 is due to the CPO of small inclusions of ilmenite that mimic the CPO of their host minerals. Correlation between k1 of the Anisotropy of Anhysteretic Remanent Magnetization (AARM) and k1 of the Anisotropy of Magnetic Susceptibility (AMS) demonstrate that, at the specimen scale, the magnetic lineation has a contribution of the anisotropy of the ferromagnetic minerals. AMS measurements realized to recover the mineral fabric and investigate the migmatitic flow field revealed a complex strain pattern in which, considering the lineation trends, especially, it is possible to characterize three structural sectors. The north region (structural sector 1) with foliations dominantly sub-horizontal and lineation trending NW-SE is interpreted as a region of tectonic escape that may represent a horizontal channel flow. This oblique tectonic escape probably results from gravity forces (gravity-driven flow). The Southern region (structural sectors 2 and 3) with variable trending foliations (NE-SW, E-W and NW-SE) and lineation plunging to North and West, probably reflect a flow regime dominantly influenced by the E-W convergence of the African and South-American continents (collision-driven flow). Altogether, the characteristics of the various domains suggest that the deformation of the partially molten middle crust of the Araçuaí belt was the result of the combination of gravity forces due to the topographic load and tectonic forces due to the convergence between the African and South-American continents.
GRANDIN, LEROY ANNICK. "Oxydes ternaires de niobium et de titane a structure lamellaire et a charpente tridimensionnelle." Caen, 1987. http://www.theses.fr/1987CAEN2004.
Full textKessler, Michel. "Contribution à l'étude des phases de laves ScxTi(1-x)Fe2 : structures magnétique et cristallographique." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10235.
Full textSCHELL, JULIANA. "Investigação de parâmetros hiperfinos dos óxidos semicondutores SnOsub(2) e TiOsub(2) puros e dopados com metais de transição 3d pela espectroscopia de correlação angular gama-gama perturbada." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23699.
Full textMade available in DSpace on 2015-06-09T18:22:49Z (GMT). No. of bitstreams: 0
Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Latroche, Michel. "Caracterisations physico-chimiques des bronzes de titane en relation avec leur stoechiometrie." Nantes, 1988. http://www.theses.fr/1988NANT2019.
Full textCourtois, Denis. "Contribution à l'étude des propriétés cristallographiques et magnétiques des composés R3(Fe,T')29 (R=terre rare, T'=Ti ou V)." Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10247.
Full textCho, Suyeon. "Synthesis and characterization of refractory oxides doped with transition metal ions." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00856580.
Full textGriffith, Kent Joseph. "Atomic and electronic structure of complex metal oxides during electrochemical reaction with lithium." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/271191.
Full textShen, Chia-Yu, and 沈佳俞. "Synthesis and characterization of magnetite/titanium dioxide composite nanoparticles." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/71783932011013602439.
Full text國立中央大學
環境工程研究所
97
Photocatalysts assist decomposition of pollutants more effectively. However, particle size of nano-photocatalyst is usually too small to be separated and recycled from the reaction system, especially for wastewater treatment. These disadvantages lead to loss of photocatalyst particles and application of photocatalysis in scale-up is thus limited. The main objective of this research is to preparing magnetic TiO2 composite nanoparticles, which can be recycled by using external magnetic field. Magnetite nanoparticles were synthesized by chemical co-precipitation and the size was controlled by adding surfactant. The magnetic TiO2 composite nanoparticles were synthesized by sol-gel method. The composite nanoparticles were characterized by XRD, TEM, SQUID, ICP-AES and ASAP to understand the effects of preparation conditions on the properties of composite nanoparticles. The results of SQUID confirmed that acid-wash dissolved Fe3O4 nanoparticles on the surface of composite nanoparticles and the magnetic susceptibility was thus decreased. Still, the magnetic property of the particles is acceptable for magnetic separation. Calcination did not affect magnetic susceptibility of magnetic TiO2 composite particles. Decomposition of methanol by TiO2 nanoparticles and magnetic TiO2 composite nanoparticles were carried out to compare their photocatalytic ability. HCHO concentration displayed linear increase with reaction time. The formation rate of HCHO when pure TiO2 nanoparticles were used was higher than that when magnetic TiO2 composite nanoparticles were used as catalysts.
Stiller, Markus. "Defect Induced Magnetism in Titanium Dioxide." 2020. https://ul.qucosa.de/id/qucosa%3A75180.
Full text宋昆燁. "Room temperature magnetism of oxidized titanium nitride thin films." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/87796252826001895042.
Full text國立交通大學
電子物理系所
100
In this thesis, we have prepared oxidized titanium nitride thin films which were grown on STO(100) substrates by pulsed laser deposition (PLD). The surface morphology of samples with various oxygen pressure was studied by means of atomic force microscopy(AFM). The crystal structures and electronic states were investigated by means of x-ray diffraction(XRD) and x-ray absorption spectroscopy(XAS). The ferromagnetic measurements by means of superconducting quantum interference device(SQUID). The results of SQUID measurements showed room temperature ferromagnetism obviously when oxygen pressure greater than 1x10-4 torr and then disappeared gradually. The results of XRD, XAS and SQUID measurements indicated that the room temperature ferromagnetism changed with structures. The structures change and disorder led oxygen vacancies . Finally, the BMPs overlapped would produce ferromagnetism .
"Structural and magnetic properties of cobalt doped titanium dioxide." Thesis, 2008. http://library.cuhk.edu.hk/record=b6074668.
Full textIn this work, we study the properties of cobalt-implanted titanium dioxide, a room temperature dilute ferromagnetic semiconductor discovered in 2001. The ferromagnetic interaction mechanism is however controversial. By using metal vapor vacuum arc (MEVVA) ion source, different doses of cobalt ions were implanted into anatase structures of titanium dioxide (TiO2) thin films. The TiO2 films which were sputtered on SiO2 (100nm)/Si (110) substrates and rutile structure of TiO2. The cobalt implanted TiO2 thin films were prepared with different atomic fraction and then thermally treated at different temperature after ion implantation. The structural properties of the anatase titanium dioxide were also studied as a comparison to rutile titanium dioxide.
Rutherford backscattering spectrometry (RBS) was performed to determine the composition of cobalt. The crystal structure of the thin films and rutile single crystal was mainly anatase as detected in XRD spectra. X-ray photoelectron spectrometry (XPS) and transmission electron microscopy (TEM) were also used in sample analysis. Vibrating sample magnetometer (VSM) was employed to study the magnetic properties of the cobalt implanted films. Ferromagnetic behaviors of these films were observed at room temperature.
Semiconductor spintronics is a promising new field of study in the ongoing quest to make electronic devices faster, cheaper, and more efficient. While current spintronics utilize the spin property of electrons to achieve greater functionally, the integration of spintronics into conventional semiconductor electronics will lead to advances optoelectronics, quantum computing, and other emerging fields of technology. This integration relies on effective generation; injection, transport, and detection of spin polarized electron current. To these end, mastering synthesis of room temperature ferromagnetic semiconductors is inevitable.
Luk, Wing Yan.
Adviser: H. P. Ho.
Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3730.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references.
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts in English and Chinese.
School code: 1307.
HUANG, WEI-CHIEH, and 黃偉傑. "Surface Treatment of Medical Titanium Assisted by Magnetic Field." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/04027529771520491355.
Full text明志科技大學
化學工程系生化工程碩士班
105
This study explored the effect of electrochemical polishing of biological titanium in a time varied magnetic field. In the experiment, two-electrode electrochemical cell a potentiostat and a magnetic field generator were used. The applied magnetic field changes over time with a sine wave or square wave to assist the electrochemical polishing. The experimental variables include magnetic field strength, magnetic field waveform, magnetic field direction, magnetic field oscillation frequency and applied voltage. In the electrochemical reaction, the dynamic potential method, chronoamperometry method and AC imped AC impedance method were used. Then the atomic force microscopy (AFM) was employed to detect the changes in the surface roughness after the samples were treated by sine wave and square wave magnetic field.
Chuang, Fu-Chun, and 莊富鈞. "Synthesis and Characterization of Visible-Light-Active Titania Photocatalysts of Magnetic Core-shell Type." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/43148861411352708078.
Full text東海大學
環境科學與工程學系
98
Abstract Photocatalysts of high surface area (SA) possess superiority for photocatalytic reaction. Therefore, nano-size materials of high SA have been attracting extensive attention for decades due to the novel characteristics and high activity. Nano-sized photocatalysts are mostly used in slurry or immobilized systems, in which the latter does need the further separation equipments. Although the slurry system demands special separation process, the high photocatalytic ability makes it popularly adapted. However, the simple separation of nano-particles from liquid phases is still a difficult task up to now. Another task for traditional photocatalysts is to broaden the application of photocatalysts and make them effective under the visible-light irradiation. In order to overcome these two tasks, this study, therefore, investigated the synthesis of magnetically visible-light-active photocatalysts and their applications on the degradation of the endocrine disrupting chemical of dimethy phthalate (DMP). A series of magnetic S-doped (sulfide doped) TiO2 photocatalysts were synthesized by means of TTIP and thiourea with sol-gel routes. The synthetic parameters (e.g., water concentration of admixture and calcination temperature) were designed with response surface methodology (RSM). Prior to synthesis of S-TiO2, the magnetic carrier (SiO2/Fe3O4, M) was firstly prepared by precipitation (Fe3O4) and sol-gel (SiO2) routes. Sequentially, S-doped TiO2 was coated on magnetic carrier to obtain magnetic visible-light-active photocatalysts (SM-TiO2). The obtained photocatalysts have been characterized by TEM, SQUID, ESCA, FTIR, XRD, PL, UV-VIS-NIR spectrometer and Electrophoresis. The results showed that the optimal condition for SM-TiO2 synthesis is at sulfide loading ratio of 1.3-1.88 at.% and calcination temperature of 514-550oC, judged by the photocatalytic degradation of DMP. The obtained SM-TiO2 was at an average diameter smaller than 20 nm. The UV-VIS-NIR spectrometry showed that the red shift existed in the samples of SM-TiO2. The PL indicated that recombination rates of electron–hole pairs were the slowest for the SM-TiO2 synthesized at the optimal condition. The peaks at around 529.6, 530.4 and 531.6 eV of XPS spectra can be attributed to the oxygen in Ti–O–Ti, Ti–O–S and S–O–S linkages, respectively. The peaks corresponding to 1050 and 1131 cm-1 of FITR spectra confirmed the existence of SO42-. XRD spectra showed that the main crystal of SM-TiO2 was anatase phase. However, as the calcination temperature was as high as 750oC, the rutile phase occurred and was inhibited by the existence of sulfide. With respect to the adsorption and photodegradation of DMP with SM-TiO2, Langmuir and Freundlich isotherms and Langmuir-Hinshelwood model can well describe adsorption and photocatalytic behavior, respectively. In addition, the SM-TiO2 of 6.88 emu g-1 can be easily recovered from the heterogeneous system. After 6 run experiments (e.g., photo-degradation and then recovery for one run), the reaction rate of k was between 0.0185 to 0.0147 mg L-1 min-1 g-1, indicating that the stable physicochemical property. This study demonstrated that novel visible-light-active titania photocatalysts of magnetic core-shell type were successfully synthesized and applied on the degradation of DMP. Keywords: magnetic, photodegradation, visible-light-active, sulfide, Langmuir-Hishelwood model, Dimethy phthalate, Titania
Leal, Cátia Daniela Jordão. "Removal of AOX from pulp mill industry effluents by heterogeneous photocatalysis." Master's thesis, 2018. http://hdl.handle.net/10773/24480.
Full textNos últimos anos, as fábricas da pasta de papel têm enfrentado desafios na gestão do tratamento de efluentes, devido ao aumento da produção dos mesmos e às preocupações ambientais, relacionadas com a necessidade de cumprir limites de descarga que são cada vez mais rigorosos e impostos por nova legislação. Os efluentes gerados na etapa de branqueamento contêm, entre outros poluentes orgânicos, compostos halogenados adsorvíveis (AOX) que podem ser foto-oxidados com radiação ultravioleta. Existem fortes evidências que confirmam a eficiência das nanopartículas de dióxido de titânio (TiO2) como fotocatalisador na degradação de compostos AOX. No entanto, há a necessidade de desenvolver suportes para o nano-TiO2, de modo a permitir a sua recuperação e reutilização em ensaios fotocatalíticos consecutivos, sendo este o principal objetivo desta tese. Assim, neste trabalho investigaram-se duas estratégias independentes: (1) a preparação de nano-TiO2 com propriedades magnéticas com vista a uma recuperação fácil e rápida por separação magnética e (2) o uso de esferas geopoliméricas contendo TiO2, que foram produzidas com uma percentagem de cinzas de resíduos da produção da pasta e papel. Todos os materiais preparados foram caracterizados por difração de raio X, espectroscopia (FTIR e UV-vis) e microscopia eletrónica (SEM e TEM). As nanopartículas de TiO2 com propriedades magnéticas foram preparadas por co-precipitação in situ de magnetite (Fe3O4) na presença de TiO2. Os materiais Fe3O4/TiO2 foram preparados com teores variáveis de TiO2 (entre 14.0 e 43.5%m/m), sendo compostos por nanopartículas de magnetite e TiO2, numa configuração irregular e não homogénea. O teor mais elevado de TiO2 foi obtido para a amostra Fe3O4/TiO2 (1:3) após centrifugação (43.5%). As esferas geopoliméricas contendo TiO2 tinham cerca de 3 mm de diâmetro médio e uma superfície porosa. Em termos de composição química, os compostos maioritários são TiO2 (24%), quartzo (22%) e muscovita (20%). Numa etapa seguinte, todos os materiais foram testados na degradação fotocatalítica de AOX em amostras reais provenientes do caudal de branqueamento. Os ensaios decorreram durante 1 hora, num fotoreator laboratorial, com adição de H2O2 e utilizando luz UV como fonte de radiação. A percentagem de remoção de AOX foi semelhante, independentemente do tipo de suporte utilizado. Os melhores resultados foram obtidos com Fe3O4/TiO2 (1:3) centrifugadas (remoção de 73.3% de AOX) e com as esferas (remoção de 68.9% de AOX). Comparando estes resultados com os de TiO2 não suportado (76.6%), a eficiência de remoção nos fotocatalisadores suportados foi ligeiramente menor. Além disso, também se observou que o uso de luz UV aumenta o desempenho dos fotocatalisadores, enquanto o tipo de agitação (agitação magnética vs. injeção de ar comprimido) não influenciou de forma significativa os resultados. A percentagem de catalisador recuperado magneticamente diminuiu com o aumento do teor de TiO2 e com a exposição à luz UV, sugerindo que estes materiais sejam sensíveis à radiação UV e que percam alguma da sua força magnética durante os ensaios de fotocatálise. Reutilizando os fotocatalisadores recuperados numa segunda série, a remoção de AOX foi relativamente similar às anteriores, com o melhor resultado a pertencer a Fe3O4/TiO2 (1:1), 75.8%, o que provou a sua capacidade de ser eficientemente reutilizado para remover AOX. As esferas geopoliméricas tiveram a sua superfície e poros degradados após os vários testes de fotocatálise, mas a sua composição química não se alterou significativamente. Estas também foram submetidas a uma segunda série de ensaios que permitiram remover cerca de 65.5% de AOX
Mestrado em Engenharia Química
Lu, Jun-xian, and 呂俊賢. "The production of magnetic titanium dioxide particles and the degradation of dye." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/39250706755944031551.
Full text東南科技大學
防災科技研究所
99
Taiwan used for various kinds of industrial dyes, a large proportion of the dyes was discharged into the sewage; most of the compounds are difficult to decomposition by microbial. TiO2 photocatalyst powders used to degradation of dyes, there are also having recovery problems. In this study, TiOSO4 and C12H28O4Ti are used as the basic compounds of photocatalyst. The sol-gel method was used, and FeCl3 and FeCl2 was use to modified the characteristic of TiO2. Iron particles coated by TiO2 was dehydration at 125 ℃, then to calcined to 300 ℃ at furnace and, to production of magnetic TiO2. Finally, dye degradations of TiO2 photocatalytic reaction were conducted by the ultraviolet light. After the photocatalytic reaction, the recycling of TiO2 magnetism particles was assessment by magnets. The results showed the TiOSO4 coated particles with the benefit photocatalytic efficiency of dyes and the more sustained photodegradation abilities. The recycling of TiO2 magnetism particles was only 65 % ~ 75%. While the C12H28O4Ti coated particles with the less photocatalytic efficiency of dyes and the recycling of TiO2 magnetism particles was more than 95%.
Chen, Wei-Jen, and 陳韋任. "Study of Functional Titania Magnetic Nanoparticles in the Detection and Photo-Killing of Pathogenic Bacteria." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/46584956624382733739.
Full text國立交通大學
應用化學系所
97
Bacterial infections may cause fatal damages if proper treatment is not conducted in time. Antibiotics are effective medicines against pathogenic bacteria. However, the emergence of antibiotic-resistant strains of bacteria results in the difficulties in the treatment of bacterial infections. Thus, it is urgent to develop rapid diagnostic methods and alternative therapy. A rapid detection method and two photo-killing approaches for pathogenic bacteria were proposed in this work. In the first part of this thesis, magnetic Fe3O4/TiO2 core/shell nanoparticles (Fe3O4@TiO2 NPs) consisting of anatase structure titania self-assembled with dopamine molecules was covalently with immunoglobulin G (IgG). The NPs were employed as affinity probes and photokilling agents for pathogenic bacteria such as Staphylococcus aureus and Streptococcus pyogenes, whose surfaces contain the binding proteins of IgG, i.e., protein A and M protein, respectively. Once bacteria were targeted by the NPs, the NP-bacteria were isolated and resuspended in medium solution followed by illumination of UV-B light (λmax~306nm, 0.412 mM/cm2). The results demonstrated that the survival ratio of the bacteria targeted by the NPs under UV light illumination was decreased to <20% within 20 min. An alternative photo-killing approach by using unmodified magnetic Fe3O4/TiO2 core/shell (Fe3O4@TiO2) NPs as affinity probes and photo-killing agents was also proposed in this work. It has been demonstrated that titania shell on the NPs is capable of interacting with lipopolysaccharides (LPS), which contains a number of phosphate functional groups, on the surfaces of Gram-negative bacteria. Thus, Fe3O4@TiO2 NPs are capable of interacting with these bacteria. Similarly, once the NPs targeted the bacteria, the cell growth of the bacteria targeted by the NPs can be effectively inhibited under illumination of UVB light. The results show that the survival ratio of the bacteria targeted by the NPs under UV light illumination within 5 min is decreased to <10 %. In this thesis, a rapid detection methods based on the combination of Fe3O4@TiO2 NPs with proteomics strategies was developed. On the basis of the interactions between the LPS of Gram-negative and the NPs, the bacteria can be effectively concentrated by the NPs within 1.5 min under microwave-heating. The bacteria-NP conjugates were then subjected into a microwave oven for further enzymatic digestion for 1 min. Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) and MS/MS were then employed for further characterization. Bacteria species can be identified by combining the resultant mass spectra with protein database searches. The potential biomarker ions for Gram-negative bacteria including E. coli O157:H7 、E. coli UTI 、P. aeruginosa 、S. sonnei、K. pneumoniae were discovered through the study. It was also demonstrated that this approach can be used to directly identify trace of bacteria from clinical urine samples (10 μL) within 15 min. The detection limit of this approach for bacteria is as low as several hundred or thousand cells.
彭程豪. "The Preparation of Magnetic-Titanium-Dioxide Photocatalysts and its Application in Dye Wastewater Treatment." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/55699300943408717961.
Full text明新科技大學
化學工程研究所
98
Experimental treatment by using photocatalyst-TiO2 alone for dye wastewater is very efficient, especially for decolorization. Besides, the secondary pollution by the application of TiO2 can be eliminated. But, the difficulty of solids (TiO2 ) and liquid (wastewater) separation problems exists and hard to solve.Therefore this project will focus on the preparation of magnetic photocatalysts, which has the characters and advantages for solving separation problems. The magnetic field can be applied in recycling and solid-liquid separation. Chemical co-precipitation process was used for the preparation of magnetic Ni-Cu-Zn ferrite. It was then mixed and treated with titanium sulfate, NH4OH or urea to form Ni-Cu-Zn ferrite/TiO2. The prepared magnetic TiO2 was used as photocatalysts to treat dye wastewater by solar irradiation. Langmuir-Hinshelwood kinetic model was also studied. In the result, magnetic photocatalysts was examined by XRD. It was found that TiO2 is anatase structure. In FBL dye wastewater, the treatment by TiO2(Ferrite:TiO2=1:1) by ammonia method is the most effective. When COD of FBL dye is 100ppm, the removal of TOC is 92.66% and the removal of ADMI is 99.42%. When COD of FBL dye is 400ppm, the removal of TOC is 86.58% and the removal of ADMI is 97.05%. It is evident that the prepared NiZnCu Ferrite/TiO2 photocatalysts exist both magnetic and photocatalytic properties. Langmuir adsorption isotherm and Langmuir-Hinshelwood kinetic model can all be applied to the dye wastewater treatment.
Yao, Chih-Chung, and 姚志忠. "Process And Characterization Of Titanium Dioxide Coatings By Dynamic Magnetic Cylindrical Cathodic Arc DepositionAbstract." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/84538867831336437108.
Full text明道大學
材料科學與工程學系碩士班
100
In this study, a method of changing magnetic field and structure applied in dynamic magnetic cylindrical cathodic arc can control the field magnetron, and also can make the arc melt uniformly on the target to improve some disadvantages resulted from traditional arc source. The novel cylindrical structure can be used in big area process. In this study were divided into two parts, first, the traditional four-inch target and the cylindrical target to compare their mechanical properties, including: Hardness, Deposition rate, Adhesion and Surface roughness. The second part of the depositing TiO2 for further fabricating dye-sensitized solar cells (DSSC). The main process is to vary the partial pressure and friction of oxygen for depositing TiO2 films on different substrates of SS304 stainless and silicon wafer, finally improve the crystallization, microstructure and light-catalysis to fabricate the DSSC. In this experiment Field Emission Scanning Electron Microscope (FESEM) is used to observe the morphology on the surface and cross-section and X-ray Diffraction (XRD) is used to observe the change of crystallization phases. And the X-ray photoelectron spectroscopy (XPS) measurements film elements.
Chen, Hsiang-ting, and 陳湘婷. "Magnetic properties of titanium dioxide dissolved light on the influence of the photocatalytic reaction." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/13512879513100783064.
Full text國立中央大學
環境工程研究所
97
Magnetic titanium dioxide particles were synthesized. The effects of preparation parameters, such as Fe/Ti weight ratio, period of acid wash, and calcinations temperature on photodissolution of magnetite nanoparticles were studied. The influences of photodissolution of the magnetite nanoparticles on the photon-assisted catalysis were also investigated. Photocatalysis of methanol to formaldehyde was conducted. Photocatalysis by pure TiO2 with addition of Fe3+ ions in the methanol solution was performed to examine the effects of photo-dissolved iron on the photocatalytic ability magnetic titanium dioxide. The results showed that severe acid wash would destroy the matrix of TiO2 and increase the surface area of magnetic TiO2 particles. Thus, when the acid wash time was too long, more Fe3O4 were washed out. Also, as the calcinations temperature increased, the photodissolution of magnetite decreased, which maybe because the crystalline of TiO2 shifted from anatase to rutile, in which the binding between rutile and magnetite were stronger. As the iron concentration in the solution increased, the photocatalysis of methanol decreased. Our preliminary tests also showed that the magnetic TiO2 synthesized in this work has weak photocatalytic ability by visible light.
Tseng, I. Peng, and 曾義鵬. "Synthesis of Magnetic Core-shell Titanium Dioxides and their Application on Photocatalytic Degradation of Phenol." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/61209344372185149392.
Full text東海大學
環境科學與工程學系
97
Photocatalytic degradation of phenol with P-25 TiO2 was proceed to investigating the optimal experimental parameters of this study. The experimental parameters are included intensity of irradiation, atmospheric conditions, different air flow-rates, pH of solution and dose of TiO2. The main by-products such as o-DHB, p-DHB and 1,4-BQ were detected by HPLC and the mineralization of phenol and by products were detected by TOC analyzer. The core-shell magnetic Titanium dioxide (TiO2/SiO2/Fe3O4, M-TiO2) was synthesized by chemical coprecipitation method and sol-gel process. The M-TiO2 was calcined at 450℃ with various retention time. The identification of surface characteristic of various M-TiO2 were performed by SEM-EDS, XRD, SQUID, UV-vis NIR spectrophotometer. The crystalloid phase of superparamagnetic M-TiO2 was anatase, rutile and magnetite and the point of zero charge (pHpzc) of M-TiO2 is 5.5. The activity of various M-TiO2 was performed by photocatalytic degradation with phenol. As the result, the M-TiO2 calcnied with 450 with 120 min showed optimal performance with stable mineralization after three times experiment in this study.
Peng, Yen-Po, and 彭彥博. "Development of gadolinium titanium oxide sensing membrane using magnetic beads as enzyme immobilization carrier for bio-sensor application." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/64265983458503984470.
Full text長庚大學
電子工程學系
99
Since Bergveld reported on ion sensitive field effect transistors (ISFETs) for measuring ion concentrations in solutions, recently the ISFET structure has become more important in medical and environmental measurement applications because it has many advantages such as: small size, high-speed response, easy to operate and having the compatible fabrication technology as CMOS devices. Recently, high-k dielectric materials, such as Al2O3, Ta2O5, TiO2, WO3, and ZrO2 were proposed as hydrogen ion sensing membrane for pH-ISFET to replace Si3N4 membrane because of their high sensitivity performance. In this thesis, GdTixOy dielectric grown using reactive RF sputtering was investigated as sensing membrane of pH-EIS structure. We found the optimum condition was that the annealing temperature was 900°С. It exhibited a larger sensitivity, lower drift rate, and smaller hysteresis width. Additionally, in order to avoid the generation of hydration layer of the gate insulator and reduce the formation of Gd-silicate, we deposited Ti on GdxOy sensing membranes and all samples were rapid thermal annealed (RTA) in O2. We found that Ti-doping exhibits better sensing characteristics. We use the sensor for the detection of glucose enzyme, and we use magnetic beads as novel enzyme immobilization to compare with the alginate immobilization. Because the small size of magnet beads, the effective enzyme contact area will be increaseed. We expect that increase of the sensing characteristics and the prevention of the protein adsorption.
FENG, WU CHIA, and 巫嘉峰. "Preparation、Characterization and Application of Mn–Zn Ferrite Powders and Magnetic Titanium Dioxide from Used Dry Batteries and Spent Steel Pickling Liquids." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/88286996033570710616.
Full text明新科技大學
化學工程與材料科技研究所
100
Spent dry batteries and spent pickling liquids are harmful pollutants. The former contains manganese dioxide(oxidant), zinc and the latter contain ferrous ion(reducing agent). Owing to oxidation-reduction reaction, manganese dioxide in the batteries is soluble in the spent acidic liquids. Subsequently the liquids after reactions contain iron, manganese, and zinc ions, which are the essential composition for making Mn-Zn ferrite. The spent dry batteries were put into the spent pickling liquid solutions.Then analyze the composition of the solution.By using zinc as the basis,adjust the calculated composition by making up the deficiency of manganese and iron.Then by adding alkali into the solutions and heating the solutions to weak alkali, iron, manganese, and zinc ions were precipitated out from the solution as amorphous hydroxides and slowly transform to crystalline spinel Mn-Zn ferrite powders.The powders were filtered、washed and dried to obtain Mn-Zn ferrite powders. Experimental treatment by using photocatalyst-TiO2 alone for dye wastewater is proven to be very efficient. Besides, the secondary pollution by the application of other advanced treatment methods can be eliminated. But, the difficulty of solids (TiO2 ) and liquid (wastewater) separation problems exists and hard to solve. Therefore, this study will use titanium sulfate、urea and Mn-Zn ferrite powder to produce modified titanium dioxide photocatalyst.Finally by filtration , drying , grinding and calcination to obtain magnetic photocatalyst powder which can be recovered by the application of the magnetic field. The characterization of the prepared Mn-Zn ferrite power and modified magnetic photocatalysts with their application in the dye wastewater treatment under solar irradiation was investigated by using AA﹐XRF﹐XRD﹐SEM﹐DLS﹐SQUID﹐BET﹐TOC and colorimeter.The Langmuir adsorption isotherm and Langmuir-Hinshelwood kinetic model were proven to be applicable to the FBL dye wastewater treatment by using these photo magnetic Mn-Zn ferrite/TiO2 catalysts under soler irradiation. Key words : Magnetic photocatalyst﹐Mn-Zn ferrite powder﹐Waste batteries﹐Waste pickling solution﹐Chemical co-precipitation method﹐Advanced oxidation process (AOP)﹐Solar/magnetic-TiO2 treatment﹐Langmuir-Hinshelwood kinetic model