(Metallo-)Dendrimers in Catalysis, Nanoparticle Stabilization and Biological Application Technische Universität Chemnitz, Fakultät für Naturwissenschaften Dissertation 2011, 165 Seiten Die vorliegende Dissertationsschrift befasst sich mit der Darstellung, Charakterisierung und Anwendung neuartiger (Metallo-)Dendrimere. Den Schwerpunkt der Arbeit bildet dabei die terminale Funktionalisierung (Poly)amidoamin-basierender Dendrimere kleiner Generationen. Durch Standardpeptid-Knüpfungsreaktionen von 1,1´-(Diphenylphosphino)ferrocen-carbonsäure an dendritische (Poly)amidoamine ist eine Serie entsprechend funktionalisierter Metallodendrimere zugänglich. Die metallorganischen, Dendrimer-immobilisierten Engruppen können durch Zugabe von [Pd(3-C3H5)Cl]2 in heterobimetallische Übergangsmetallkomplexe umgewandelt werden und finden Einsatz als katalytisch aktive Systeme in C,C-Kreuzkupplungsreaktionen nach Heck. Ein weiterer Gegenstand der Arbeit ist die terminale Modifikation von (dendritischen) Ami-nen mit (Sp)-2-(Diphenylphosphino)ferrocen-1-carbonsäure. Nach erfolgter Umsetzung mit [Pd(3-C3H5)Cl]2 werden die erhaltenen planar-chiralen Verbindungen als Katalysatoren in asymmetrischen allylischen Substitutionsreaktionen eingesetzt. Ferner ist die Darstellung (Oligo)ethylenglykolether-terminierter (Poly)amidoamin-Dendrimere beschrieben. Diese werden als Stabilisatoren zur in-situ Generierung von Gold- sowie Magnetit-Nanopartikeln eingesetzt. Der Einfluss der dendritischen Template auf die Kolloidgrößen und Morphologien sowie die Eigenschaften der gebildeten Hybridmaterialien werden aufgezeigt. Darüber hinaus befasst sich die Arbeit mit der Verwendung biokompatibler (Oligo)ethylenglykolether-Dendrimere als Wirkstoffträger für Zytostatika bei der Krebsthera-pie. Die im Rahmen von in vitro Untersuchungen erhaltenen Ergebnisse werden präsentiert.

SILVA, André Leandro. Nanobiocompósitos superparamagnéticos para aplicação como antenas ressoadoras dielétricas. 2014. 126 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Departamento de Quimica Orgânica e Inorgânica, Programa de Pós-Graduação e Biotecnologia, Renorbio - Rede Nordeste de Biotecnologia, Fortaleza-CE, 2014. / Submitted by demia Maia (demiamlm@gmail.com) on 2016-05-20T13:09:52Z No. of bitstreams: 1 2014_tese_alsilva.pdf: 6480806 bytes, checksum: 946e32810e24c5137dfbba52bfd30bb8 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-05-20T13:10:43Z (GMT) No. of bitstreams: 1 2014_tese_alsilva.pdf: 6480806 bytes, checksum: 946e32810e24c5137dfbba52bfd30bb8 (MD5) / Made available in DSpace on 2016-05-20T13:10:43Z (GMT). No. of bitstreams: 1 2014_tese_alsilva.pdf: 6480806 bytes, checksum: 946e32810e24c5137dfbba52bfd30bb8 (MD5) Previous issue date: 2014 / There is a growing global interest for the development of green technologies that allow the use of products with less damage to environment, as well as for maximum and sustainable use of natural resources. The main aim of this study was to develop superparamagnetic nanobiocomposites for application as dielectric resonator antennas. For this purpose, a biobased thermoset plastic was prepared by using cardanol as an alternative to petrochemical phenol. This thermoset plastic was used as a polymer matrix and biocomposites were prepared by using 15 wt% of untreated and modified sponge gourd fibers by chemical treatment (NaOH 5, 10, and 15 wt% and NaClO 1 wt%) as dispersed phase. For the nanobiocomposites preparation, besides the sponge gourd fibers insertion, the thermoset plastic were also impregnated with magnetite nanoparticles in different contents (1, 5, and 10 wt%). Techniques of Thermogravimetry (TG), Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), Optical Microscopy, Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Mössbauer Spectroscopy, Tensile testing, Dielectric measurements, Vibrating Sample Magnetometry (VSM) and Biodegradation in simulated soil were performed for characterization. The results showed that alkaline treatment improved the thermal stability and the crystallinity index of the sponge gourd fiber. The crosslinking agent used (Diethylenetriamine) was efficient and enabled complete cure for all materials. The biocomposites reinforced by treated fiber showed better thermal stability, superior performance in Tensile testing and greater biodegradation rates, when compared to the biocomposite reinforced by raw fiber. The magnetite particles exhibited nanometric size, high purity and crystallinity, and superparamagnetic character. All nanobiocomposites showed superparamagnetic behavior, excellent thermal stability, good biodegradation rates, and better mechanical strength for the material with magnetite 10 wt%. All dielectric resonators antennas exhibited satisfactory return loss and suitability for commercial and technological applications, especially for performance in broadband. / É crescente o interesse mundial pelo desenvolvimento de tecnologias chamadas “verdes” que possibilitem o uso de produtos com menor impacto ao meio ambiente, assim como também se fortalecem as políticas de incentivo ao aproveitamento máximo e sustentável dos recursos naturais. O principal objetivo desse estudo foi desenvolver nanobiocompósitos superparamagnéticos para aplicação como antenas ressoadoras dielétricas. Para tal, um plástico termorrígido biobaseado foi preparado utilizando o cardanol em alternativa aos fenóis petroquímicos. Esse plástico termorrígido foi utilizado como matriz para o preparo de biocompósitos, utilizando 15% em massa de fibra de bucha bruta e também modificada por tratamento químico (NaOH 5, 10 e 15% e NaClO 1%) como fase dispersa. Para o preparo dos nanobiocompósitos, além da fibra de bucha, nanopartículas de magnetita, sintetizadas pelo método da coprecipitação, foram impregnadas no plástico termorrígido em diferentes teores de 1, 5 e 10% em massa. Técnicas de Termogravimetria (TG), Calorimetria exploratória diferencial (DSC), Análise dinâmico-mecânica (DMA), Microscopia eletrônica de varredura (MEV), Microscopia óptica, Microscopia eletrônica de transmissão (MET), Difração de raios X (DRX), Espectroscopia no infravermelho com transformada de Fourier (FTIR), Espectroscopia Mössbauer, Ensaios de resistência à tração, Medidas dielétricas, Magnetometria de amostra vibrante (VSM) e Biodegradação em solo simulado foram utilizadas para caracterização. Os resultados mostraram que o tratamento alcalino melhorou a estabilidade térmica e o índice de cristalinidade da fibra de bucha. O agente reticulador utilizado (DETA) mostrou-se eficiente, possibilitando a cura completa dos materiais. Os biocompósitos com fibra tratada apresentaram maior estabilidade térmica, resistência à tração superior e melhor índice de biodegradação em relação ao biocompósito com fibra natural. A magnetita sintetizada exibiu tamanho nanométrico, além de alta pureza, alta cristalinidade e caráter superparamagnético. Todos os nanobiocompósitos exibiram superparamagnetismo e mostraram excelente estabilidade térmica, boas taxas de biodegradação e melhor resistência mecânica para o material com 10% de magnetita. Todas as antenas ressoadoras dielétricas preparadas apresentaram perda de retorno satisfatória e, portanto, adequação para fins comerciais e tecnológicos, com maior potencial para atuação em banda larga.

Made available in DSpace on 2014-10-09T12:42:11Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:08Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Nesta Dissertação, foram sintetizadas microesferas poliméricas com propriedades magnéticas à base de metacrilato de glicidila e divinilbenzeno pela técnica de polimerização em suspensão. O material utilizado para conferir as propriedades magnéticas ao copolímero foi magnetita sintetizada no laboratório. Foram estudados os efeitos da modificação da magnetita com ácido oleico, da velocidade de agitação, do teor de agente reticulante, do teor de material magnético adicionado e do teor de agente de suspensão sobre as características das partículas poliméricas obtidas. As microesferas foram caracterizadas quanto ao seu aspecto morfológico, à estabilidade térmica, à incorporação de material magnético e quanto às suas propriedades magnéticas. A quantidade de partículas de ferro incorporadas foi afetada pela velocidade de agitação durante a síntese, pelo teor de material magnético adicionado, pela fase de dispersão do material magnético e pelo teor de monômeros no copolímero. A estabilidade térmica dos copolímeros foi afetada, principalmente, pelo teor de material magnético incorporado e pelo teor de monômeros, levando em consideração resinas com a mesma quantidade de material magnético adicionado. A magnetização de saturação para as microesferas foi afetada pelo teor de material magnético incorporado. A modificação da superfície da magnetita com ácido oleico foi considerada importante para a incorporação do material magnético na matriz do copolímero.Partículas poliméricas magnéticas com comportamento superparamagnéticos foram obtidas com morfologia esférica e magnetização de saturação de 7,11 (emu/g), utilizando razão molar de monômeros de 50/50 %, 1 % de PVA, 20 % de magnetita modificada com ácido oleico adicionada à fase orgânica e velocidade de agitação mecânica de 500 rpm / In this dissertation, polymeric microspheres with magnetic properties based on glycidyl methacrylate and divinylbenzene were synthesized by suspension polymerization technique. In order to obtain magnetic properties, magnetite particles modified by oleic acid were synthesized in laboratory. The effects of stirring rate, concentration of crosslink, the concentration of magnetite added and the concentration of stabilizer on the particles properties were studied. The magnetic microspheres were characterized according their morphology, thermal stability, incorporation of magnetite and their magnetic properties. The incorporate of iron particles content was mainly affected by stirring rate during the synthesis, by the content of magnetic material added, by the dispersion phase of magnetic material and by the monomers content in the copolymer. The thermal stability of copolymers was mainly affected by the content of magnetic material incorporated and by the monomers content, taking in account the resins with the same content of magnetic material added. The saturation magnetization for the microspheres was effected by the content of magnetic material incorporated. The modification with oleic acid was considered important to the incorporation of the magnetic material in the copolymer matrix.Magnetic polymeric particles with superparamagnetic behavior have been obtained with spherical morphology and saturation magnetization of 7.11 (emu/g). It was used monomers molar ratio of 50/50 %, 1% PVA, 20 % magnetite particles modified by oleic acid dispersion on organic phase and stirring rate of 500 rpm during the synthesis

Laboratory magnetic measurements are used to develop a methodology to characterize the Kiruna-type Rare Earth Elements (REE) bearing apatite iron-oxide deposits at Blötberget in central Sweden. This high-grade ore deposit is known to have sharp boundaries between lens shaped main ore bodies of magnetite-rich ore, and a complex hematite-rich ore associated with pegmatites and skarn formation. The thesis covers laboratory magnetic measurements of 37 samples originating from eight drill cores and reference samples from previously mined area. It focuses on on-covering how the samples relate in terms of magnetic susceptibility, further its dependency on temperature, frequency, field and the orientation. The results are correlated with petrographic analysis previously performed on accompanying thin sections. The measurements show that magnetite with strong susceptibility contribution overshadow the hematite contribution in the samples. Transition changes in susceptibility are noticeable when crossing the Verwey temperature; -153°C, Curie temperature; 580°C and Néel temperature; 680°C. The Morin temperature appears at -60°C, or is missing. Linear relationships are identified between the magnitude difference in susceptibilities across transitions at high temperature and wt% magnetite and hematite have been identified. The Blötberget skarn and hematite-rich ore samples have a higher degree of susceptibility anisotropy than the other ore-types. Blötberget samples are dominated by multidomain characteristics in remanence, saturation and coercivity. High temperature measurements have shown that the magnetite is close to pure. The low temperature measurements suggest hematite is impure or bears a petrological footprint. The study also shows that rich iron ore samples sometimes can be at risk of being overlooked with standard methods of measuring susceptibility / Laboratorietekniska metoder kan användas som ett komplement till malmgeologi och geofysisk prospektering. I denna metodstudie karaktäriseras apatitjärnmalm från Blötberget, nära Grängesberg. En fyndighet bestående av linsformade malmkroppar rika på magnetit och ofta avskilda men komplexa hematitrika stråk. Studien är gjord 37 prover från totalt 8 borrkärnor, och lokaler som tillhörde produktion från gruvverksamhet under 1900-talet. Mätmetoderna fokuserar på att kartlägga malmens magnetiska egenskaper, och hur temperatur, frekvens, fältstyrka samt riktning påverkar dessa. Resultaten jämfördes med tidigare petrografisk studie av tillhörande tunnslip Resultaten visar att magnetit står för merparten av susceptibiliteten i proverna, men att även hematit kan urskiljas och kvantifieras. Temperaturberoende har påvisats vid övergångar för Verwey-temperatur; -153°C, Curie-temperatur; 580 °C, och Néeltemperatur; 680 °C. Den förväntade Morin-temperaturen vid -14°C, påträffades vid -60 °C eller saknas helt för flera av de hematitrika proverna. Magnetiskt anisotropa prover återfinns bland prover som identifierats som skarn eller hematitrika. Magnetisk granulometri visar karaktär av multidomäntyp med låg magnetisk coercivitet och hög satureringsförmåga. Högtemperaturmätningar av susceptibilitet visar på ren magnetit för prover från Blötberget. Samtidigt visar lågtemperaturemätningar att hematit sannolikt har inblandning av titanium eller bär på ett mer komplext förflutet. Studien visar också att det finns en risk i att enbart förlita sig på bulksusceptibilitet för prover rika på malm.

Made available in DSpace on 2014-10-09T12:42:11Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:08Z (GMT). No. of bitstreams: 0 / No presente estudo obteve-se com sucesso o compósito zeólita:magnetita usando-se como material de partida sulfato ferroso para síntese da magnetita e cinzas leves de carvão para síntese da fase zeolítica. A zeólita foi sintetizada por tratamento hidrotérmico alcalino e as nanopartículas de magnetita foram obtidas pela precipitação de íons Fe2+ em uma solução alcalina. Uma reprodutibilidade foi alcançada na preparação de diferentes amostras do nanocompósito zeolítico. O material foi caracterizado pelas técnicas de espectrometria de Infravermelho, difratometria de raios-X de pó, fluorescência de raios-X, microscopia eletrônica de varredura com a técnica de EDS, massa especifícia e área específica e por outras propriedades físico-químicas. O compósito era constituído pelas fases zeolíticas hidroxisodalita e NaP1, magnetita, quartzo e mulita das cinzas remanescentes do tratamento alcalino e magnetita incorporada na sua estrutura. A capacidade de remoção de U(VI) de soluções aquosas sobre o compósito zeólita:magnetita foi avaliada pela técnica descontínua. Os efeitos do tempo de contato e da concentração inicial do adsorbato sobre a adsorção foram avaliados. Determinou-se o tempo de equilíbrio do sistema e foram avaliados os modelos cinéticos de pseudo-primeira ordem, pseudo-segunda ordem e o modelo de difusão intrapartícula. Um tempo de contato de 120 min foi suficiente para a adsorção do íon uranilo alcançar o equilíbrio. A velocidade de adsorção seguiu o modelo cinético de pseudo-segunda-ordem, sendo que a difusão intrapartícula não era a etapa determinante do processo. Dois modelos de isotermas de adsorção, os modelos de Langmuir e de Freundlich, também foram avaliados. O modelo de Langmuir foi o que melhor se ajustou aos dados experimentais. A partir do modelo cinético e da isoterma que melhor descreveram o comportamento do sistema foi possível calcular os valores teóricos para a capacidade máxima de adsorção do U(VI) sobre o compósito zeólita:magnetita. As capacidades máximas de remoção calculadas foram de 20,7 mg.g-1 pela isoterma de Langmuir e de 23,4 mg.g-1 pelo modelo cinético de pseudo-segunda ordem. O valor experimental obtido foi 23,3 mg.g-1. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

This thesis consists of two parts. The first part deals with the magnetic properties of Fe3O4 nanocrystals and their possible application in water remediation. The second part is on the delamination of layered materials and the preparation of new layered hybrids from the delaminated sheets. In recent years, nanoscale magnetic particles have attracted considerable attention because of their potential applications in industry, medicine and environmental remediation. The most commonly studied magnetic nanoparticles are metals, bimetals and metal oxides. Of these, magnetite, Fe3O4, nanoparticles have been the most intensively investigated as they are, non-toxic, stable and easy to synthesize. Magnetic properties of nanoparticles such as the saturation magnetization, coercivity and blocking temperature are influenced both by size and shape. Below a critical size magnetic particles can become single domain and above a critical temperature (T B , the blocking temperature) thermal fluctuations can induce random flipping of magnetic moments resulting in loss of magnetic order. At temperatures above the blocking temperature the particles are superparamagnetic. Magnetic nanocrystals of similar dimensions but with different shapes show variation in magnetic properties especially in the value of the blocking temperature, because of differences in the surface anisotropy contribution. The properties of magnetic nanoparticles are briefly reviewed in Chapter 1. The objective of the present study was to synthesize Fe3O4 nanocrystals of different morphologies, to understand the difference in magnetic properties associated with shape and to explore the possibility of using Fe3O4 nanocrystals in water remediation. In the present study, oleate capped magnetite (Fe3O4) nanocrystals of spherical and cubic morphologies of comparable dimensions (∼10nm) have been synthesized by thermal decomposition of FeOOH in high-boiling octadecene solvent (Chapter 2). The nanocrystals were characterized by XRD, TEM and XPS spectroscopy. The nanoparticles of different morphologies exhibit very different blocking temperatures. Cubic nanocrystals have a higher blocking temperature (T B = 190 K) as compared to spheres (T B = 142 K). From the shift in the hysteresis loop it is demonstrated that the higher blocking temperature is a consequence of exchange bias or exchange anisotropy that manifests when a ferromagnetic material is in physical contact with an antiferromagnetic material. In nanoparticles, the presence of an exchange bias field leads to higher blocking temperatures T B because of the magnetic exchange coupling induced at the interface between the ferromagnet and antiferromagnet. It is shown that in these iron oxide nanocrystals the exchange bias field originates from trace amounts of the antiferromagnet wustite, FeO, present along with the ferrimagnetic Fe3O4 phase. It is also shown that the higher FeO content in nanocrystals of cubic morphology is responsible for the larger exchange bias fields that in turn lead to a higher blocking temperature. Magnetic nanoparticles with moderate magnetization can be easily separated from dispersions by applying low intensity magnetic fields. Oleate capped spherical and cubic iron oxide nanocrystals have considerable magnetic moment and hence have the potential as host-carriers for magnetic separation in environmental remediation. These nanocrystals are, however, dispersible only in non-polar solvents like chloroform, toluene, etc. Environmental remediation requires that the nanocrystals be water dispersible. This was achieved by functionalizing the surface of the iron oxide nanocrystals by coordinating carboxymethyl-β-cyclodextrin (CMCD) cavities (Chapter 3). The hydroxyl groups located at the rim of the anchored cyclodextrin cavity renders the surface of the functionalized nanocrystal hydrophilic. The integrity of the anchored CMCD molecules are preserved on capping and their hydrophobic cavities available for host-guest chemistry. The CMCD capped iron oxide particles are water dispersible and separable in modest magnetic fields (<0.5 T). Small molecules like naphthalene and naphthol can be removed from aqueous media by forming inclusion complexes with the anchored cavities of the CMCD-Fe3O4 nanocrystals followed by separation of the nanocrystals by application of a magnetic field. The adsorption properties of the iron oxide surface towards arsenic ions are unaffected by the CMCD capping so it too can be simultaneously removed in the separation process. To extend the application of the iron oxide nanocrystals so that they can both capture and destroy organic contaminants present in water, cyclodextrin functionalized water dispersible core-shell Fe3O4@TiO2 (CMCD-Fe3O4@TiO2) nanocrystals have been synthesized (Chapter 4). The application of these particles for the photocatalytic degradation of endocrine disrupting chemicals (EDC), bisphenol A and dibutyl phthalate, in water is demonstrated. EDC molecules that may be present in water are captured by the CMCD-Fe3O4@TiO2 nanoparticles by inclusion within the anchored cavities. Once included they are photocatalytically destroyed by the TiO2 shell on UV light illumination. The magnetism associated with the crystalline Fe3O4 core allows for the magnetic separation of the particles from the aqueous dispersion once photocatalytic degradation is complete. An attractive feature of these ‘capture and destroy’ nanomaterials is that they may be completely removed from the dispersion and reused with little or no loss of catalytic activity. The second part of the thesis deals with the intercalation of surfactants in inorganic layered solids and their subsequent delamination of the functionalized solid in non-polar solvents. The solids investigated were - the anionic layered double hydroxides (LDH), the 2:1 smectite clay, montmorillonite (MMT), layered metal thiophosphates (CdPS3) and graphite oxide (GO). Layered Double Hydroxides (LDH) are lamellar solids of the general chemical formula [M0(1−x)Mx(OH)2], where M0 is a divalent metal ion and M a trivalent ion. The structure of the Mg-Al layered double hydroxide (Mg-Al LDH) may be derived from that of brucite, Mg(OH)2, by isomorphous substitution of a part of the Mg2+ by trivalent Al3+ ions with electrical neutrality maintained by interlamellar exchangeable ions like nitrate or carbonate. The ion exchange intercalation of the anionic surfactant dodecyl sulfate (DDS) in an Mg-Al LDH and the subsequent delamination of the surfactant intercalated LDH in non-polar solvent is reviewed in Chapter 5. Delamination results in a clear dispersion of neutral nanosheets. The delaminated sheets are neutral as the surfactant chains remain anchored to the inorganic sheet. On solvent evaporation, the sheets re-stack to give back the original surfactant intercalated solid. This strategy for delamination of layered solids by intercalation of an appropriate surfactant followed by dispersing in a non-polar solvent has been extended to montmorillonite (MMT) and cadmium thiophosphates (CdPS3) by ion-exchange intercalation of the cationic surfactant dioctadecyldimethylammonium bromide (DODMA) followed by sonication in non-polar solvents e.g. toluene or chloroform as in the case of the LDH (Chapter 6). The nanosheets of the MMT and CdPS3 are electrically neutral as the surfactant chains remain anchored to the inorganic sheet even after exfoliation. Graphite oxide (GO) too can be delaminated by functionalizing the sheets by covalently linking oleylamine chains to the GO sheets via an amide bond. The oleylamine functionalized GO is easily delaminated in non-polar solvents to give electrically neutral GO nanosheets. It is shown in Chapter 7 that the 1:1 mixtures of dispersions of montmorillonite-DODMA with Mg-Al LDH-DDS nanosheets can self assemble, on solvent evaporation, to give a new layered solid with periodically alternating montmorillonite and LDH layers. In this method attractive forces between the neutral exfoliated nanosheets of cationic and anionic ensures self-assembly of a perfectly periodic alternating layered structure. The method has been extended to synthesize new layered solids in which surfactant tethered cationic and anionic inorganic sheets alternate. The hybrid solids synthesized are CdPS3—MgAl-LDH, CdPS3—CoAl-LDH, GO—MgAl-LDH, GO—CoAl-LDH. The procedure outlined in Chapter 7 allows for a simple, but versatile, method for generating new periodically ordered layered hybrid solids by self-assembly.

Vanadium extraction methods were developed for iron-vanadium-phosphorus (Fe-V-P) melts derived from processing of V-bearing titanomagnetites and steel slags. Studies on phase relationships of V slags were carried out to provide important understanding of the extraction processes. Phase relationship in vanadiferous slag was investigated experimentally at 1573K, 1673K and 1773K, for the compositional range of 0-6mass% Al2O3, 1-5mass% CaO, 10-17mass% SiO2, with MnO and V2O3 fixed at 5.5mass% and 30mass%, balanced with FeO. The slags were found to be solid-liquid mixtures, of liquid, spinel and in some cases free silica. Alumina was identified as the preferred additive to prohibit precipitation of free silica. A method for V extraction to vanadiferous slag was developed based on Fe-V(2mass%)-P(0.1mass%) melts at 1677K using a semi-industrial scale BOF. Oxidation was carried out with an oxygen enriched air jet and iron ore pellets. The complete dissolution of pellets was achieved by deliberately creating good stirring conditions utilising high momentary decarburisation rates. The P distribution to the slag was low when good stirring conditions was obtained. Phase relationship in Al2O3-CaO(25-35mass%)-SiO2-VOx slag was investigated experimentally at an oxygen partial pressure of 9.37•10-11atm and 1873K. The maximum solubility of V-oxide in the slag was 9-10mass% V2O3. Two solid phases were found, a solid solution of Al2O3 in V2O3 (karelianite) and hibonite with fractionation of V into the crystal structure. V extraction experiments to Al2O3-CaO-SiO2 based slags were carried out in 150kg scale by blowing CO2 gas into the metal bath consisting mainly of 1-10mass% V and 1mass% P. At these conditions, oxidation of V was favoured over Fe. Up to 10-13mass% V2O3 could be dissolved in the slag before a viscous slag saturated in V-oxide was observed. The phosphate capacity in the slag was low and as a result this slag could at once be subjected to a final reduction step for production of ferrovanadium with 40-50mass% V. / Metoder för att utvinna vanadin till högvärdiga vanadinslagger från metallsmältor innehållande främst järn (Fe), vanadin (V) och fosfor (P) utvecklades. Metallsmältorna framställs genom att processa primära V råvaror, såsom titanomagnetit, och sekundära råvaror av i huvudsak vanadinrik stålslagg. Fasstudier av högvärdiga vanadinslagger genomfördes som grund för utvecklingsarbetet. Experimentella fasstudier av vanadinspinellslagg med 30vikt% V2O3 och 5.5vikt% MnO genomfördes vid en temperatur av 1573K, 1673K och 1773K. Övriga komponenter i slaggen varierades inom ett intervall av 0-6vikt% Al2O3, 1-5vikt% CaO och 10-17vikt% SiO2, viktad med järnoxid. Samtliga slagger var sammansatt av både flytande- och fastfas. Den fasta fasen utgjordes främst av en vanadin- och järnrik spinellfas och i vissa fall även av fri SiO2. Genom försök i en stålkonverter i semi-industriell skala utvecklades och validerades en metod för vanadinutvinning från råjärnsmältor innehållande 2vikt% V och 0.1vikt% P, vid en temperatur av 1677K. Oxidationen utfördes med syreanrikad luft via en vattenkyld topplans och genom tillsats av hematit pellets. Omsättningen av pellets säkerhetsställdes genom god omrörning som erhölls under korta perioder med höga gasvolymer som en effekt av hög avkolningstakt. Råjärnet efter behandlingen innehöll cirka 3vikt% C och 0.1vikt% V. Producerad vanadinspinellslagg bestod av upp till 30vikt% V2O3. Fosforfördelningen till slaggen var låg under processbetingelser med god omrörning. Experimentella fasstudier av Al2O3-CaO(25-35vikt%)-SiO2-VOx slagg genomfördes vid en temperatur av 1873K och ett syrepartialtryck av 9.37·10-10atm. Den maximala lösligheten av vanadinoxid i slaggen var 9-10vikt% V2O3. Två fasta faser identifierades, V2O3 (Karelianit) med fast löslighet av Al2O3 och Hibonit med vanadinoxid inlöst i kristallstrukturen. Experimentella försök för att utvinna vanadin från en stålsmälta bestående av 1-10vikt% V och 1vikt% P till en slagg med en initial sammansättning av 7-40vikt% Al2O3, 25-35vikt% CaO och 27-64vikt% SiO2 utfördes i en skala av 150kg. Oxidation av vanadin åstadkoms genom att blåsa in CO2 gas i stålsmältan via en spolsten. Under dessa processförhållanden var oxidationen av vanadin gynnsam framför järn och fosfor. Lösligheten av vanadinoxid i slaggen var upp till 10-13vikt% V2O3. Slagg mättad med vanadinoxid var viskös som en konsekvens av utfällning av V2O3 med inlöst Al2O3. Slaggens gynnsamma vanadin och järn- samt vanadin och fosfor förhållande möjliggör att genom slutreduktion producera ferrovanadin med en vanadinhalt av 40-50vikt% och låg fosforhalt. / <p>QC 20170912</p>

This thesis deals with the combined ultra-high vacuum (UHV) and electrochemical (EC) studies of selected iron oxide surfaces, namely Fe3O4(001) and -Fe2O3(012). The state-of- the-art knowledge regarding these surfaces is briefly reviewed, and importance of understanding these materials in the electrochemical environment is discussed. The design of the transfer system between UHV and EC environment is presented; individual features of the system are thoroughly discussed and the system is used for testing the stability of the Fe3O4(001) (2×2)R45° surface reconstruction in ambient conditions. The experimental results presented in this thesis show that the Fe3O4(001) (2×2)R45° reconstruction, utilized as an adatom array for single atom catalysis studies, survives both exposure to air and to liquid water, if the exposure is achieved in well-controlled fashion. Further, this thesis presents the first-ever atomic scale scanning tunneling microscopy (STM) study of the -Fe2O3(012) surface, which is important for photoelectrochemical water splitting. STM images of two surface reconstructions of the -Fe2O3(012) surface known to date are presented. A bulk terminated model of the (1×1) reconstruction is confirmed and a novel surface structure model for the (2×1) reconstructed surface is proposed. Adsorption studies of H2O and O2 on the (2×1) reconstructed surface are documented by timelapse STM.

V práci je zkoumán vliv podmínek na průběh hydrolýzy alkoxidů titanu a vlastností připravovaných nanočástic oxidu titaničitého s důrazem na teplotu a množství vody přítomné v systému. Připravované hydrolyzáty alkoxidů titanu a nanočástice oxidu titaničitého připravené z hydrolyzátů jsou studovány metodami XRD, DTA – TGA, SEM – EDS, BET a PCCS. Nanočástice magnetitu byly syntetizovány pomocí precipitační reakce z roztoku Mohrovy soli a jejich krystalová struktura, velikost a povrchové vlastnosti byly sledovány s vyhodnocením vlivu teploty a při modifikaci povrchu polykarboxyletherovým superplastifikátorem. Pro upevnění TiO2 na povrch magnetitu byla použita kombinovaná metoda aplikace vybraných nanočástic TiO2 s hydrolýzou TiO2 pomocí alkoxidů titanu za účelem přípravy fotokatalyticky aktivního core-shell práškového katalyzátoru s vylepšenými vlastnostmi adsorpce na povrchu. Studovány byly možnosti aplikace TiO2 na povrch Mn-Zn feritu, kdy byl studován vliv depozice tenkých vrstev C a Au na morfologii povrchu. Fotokatalytická aktivita vybraných připravených materiálů byla studována pomocí dekompozice methylenové modři v roztoku a par isopropanolu a ethanolu rozkládaných pomocí Mn-Zn feritu v experimentálním chemickém reaktoru s magnetickým polem stabilizovaným ložem nosiče katalyzátoru.