Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Iron-Carbon.
Rozprawy doktorskie na temat „Iron-Carbon”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Iron-Carbon”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
1
Long, Christopher Allen. "Kinetics and morphological study of interdiffusion in iron-carbon/iron-vanadium or iron-molybdenum couples /". The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu148759680782343.
Pełny tekst źródła
2
Dustman, John M. "Carbon sequestration by Iron seeding of phytoplankton /". May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Pełny tekst źródła
3
Minett, Daniel. "Conversion of carbon dioxide to hydrocarbons using iron nanoparticle-carbon nanotube catalysts". Thesis, University of Bath, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636515.
Pełny tekst źródłaStreszczenie:
Dealing with carbon dioxide waste is an on-going societal and technological challenge. One attractive proposition is to chemically convert waste carbon dioxide into useful chemical products. One possible route is to combine two well-known chemical processes, reverse water gas shift and Fischer-Tropsch synthesis, to make a catalyst capable of converting carbon dioxide directly into hydrocarbons. Iron nanoparticles supported on carbon nanotubes (CNT) have shown promise in the Fischer-Tropsch process. In this thesis, iron nanoparticles supported on carbon nanotubes (Fe@CNT) are shown to be effective catalysts for the coupled reverse water gas shift and Fischer-Tropsch reactions. Controlled oxidation of synthesised CNT can remove the graphitic shell from residual iron nanoparticles, activating them for catalysis. This process removes the need for expensive purification of CNT prior to use. Carbon nanotube powders generated in this way are difficult to handle, and could be difficult to scale-up. A method has been developed to grow long, aligned carbon nanotubes on a commercial cordierite monolith support, which has potential for scale up. The developed method does not require pre-treatment of the monolith prior to CNT synthesis. Using the same oxidation method these Fe@CNTs-monoliths have been demonstrated to act as catalysts for carbon dioxide conversion. The monolithic catalysts demonstrate improved mass transfer capabilities, leading to higher activities for the monolithic catalyst over a similar powder catalyst.
4
Barati, Sedeh Mansoor Coley Kenneth S. "Kinetics of carbon monoxide-carbon dioxide reaction with iron oxide containing slags". *McMaster only, 2005.
Znajdź pełny tekst źródła
5
Lin, Che-Hung [Verfasser], i Bernd [Akademischer Betreuer] Plietker. "Iron-catalyzed carbon-carbon bond activation / Che-Hung Lin ; Betreuer: Bernd Plietker". Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2018. http://d-nb.info/120618387X/34.
Pełny tekst źródła
6
Tapasa, Kanit. "Computer simulation of solute effects in model iron-copper and iron-carbon alloys". Thesis, University of Liverpool, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426141.
Pełny tekst źródła
7
Hudziak, Stephen. "Iron-filled carbon nanotubes : Synthesis, characterisation and applications". Thesis, Queen Mary, University of London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.528419.
Pełny tekst źródła
8
Clarke, Howard W. J. "Reinforcing wrought iron with carbon fibre reinforced polymers". Thesis, University of Southampton, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438037.
Pełny tekst źródła
9
Bok-Badura, J., A. Jakóbik-Kolon, M. Turek, S. Boncel, K. Karoń, J. Laskowski i P. Ceglarski. "Differences in Iron Removal from Carbon Nanoonions and Multiwall Carbon Nanotubes for Analytical Purpose". Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42517.
Pełny tekst źródłaStreszczenie:
The paper describes the differences between wet iron removal from carbon nanoonions and from multiwall carbon nanotubes for analytical purpose. Nowadays, both carbon nanoonions and multiwall carbon nanotubes are one of the most interesting materials with applicability in electronics, medicine and biotechnology. Medical applications of those nanomaterials require not only recognition of their structure but also measurement of metal impurities concentration. Inductively coupled plasma optical emission spectrometry as a method for Fe-determination requires liquid samples. Hence, we propose various protocols for leaching of iron from studied materials. Our results proved that structure of nanomaterials have an impact on the efficiency of iron removal.
10
Alenezi, Khalaf. "Electrochemical transformation of alkanes, carbon dioxide and protons at iron-porphyrins and iron-sulfur clusters". Thesis, University of East Anglia, 2013. https://ueaeprints.uea.ac.uk/47965/.
Pełny tekst źródłaStreszczenie:
The work contained in this thesis focuses on (i) chemical and electrochemical alkane oxidation using Fe-porphyrin complexes as catalysts (ii) electrochemical and photoelectrochemical CO2 reduction using Fe-porphyrin complexes (iii) electrochemical and photoelectrochemical generation of hydrogen using iron-sulfur cluster. Chapter 1 gives a general overview of the electrochemical techniques which underpin the work presenedt in this thesis. Chapter 2 reports the chemical and electrocatalytic oxidation of hydrocarbons to alcohols and epoxides by using iron (III) porphyrins as catalysts. A series of new basket-handle thiolate Fe (III) porphyrins have been used to mediate anodic oxidation of hydrocarbons, specifically adamantane hydroxylation and cyclooctene epoxidation. The electrocatalytic and chemical catalytic activity oxidation of the thiolate porphyrins are benchmarked against Fe (III) tetraphenyl porphyrin chloride and its tetrapentafluorophenyl analogue. Chapter 3 describes the electrochemical and photoelectrochemical reduction of carbon dioxide to carbon monoxide. This chapter shows that iron (III) porphyrin complexes are capable of carrying out electrocatalytic reduction of carbon dioxide at both vitreous carbon and illuminated p-type silicon surfaces, with reasonable current efficiencies. At illuminated p-type silicon photovoltages of ca 500mV are obtained. 7 Chapter 4 describes the electrochemical and photoelectrochemical reduction of proton to H2 using [Fe4S4 (SPh)4]2- as an electrocatalyst at both vitreous carbon and at illuminated p-type Si electrodes.
11
Zou, YuKai. "Iron-catalyzed growth of carbon fibers from hydrocarbon procursors". Ohio : Ohio University, 2002. http://www.ohiolink.edu/etd/view.cgi?ohiou1175014254.
Pełny tekst źródła
12
Weißker, Uhland. "Synthesis and mechanical properties of iron-filled carbon nanotubes". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-135707.
Pełny tekst źródłaStreszczenie:
Carbon forms the basis of a variety of compounds. The allotropic forms of carbon include graphene, fullerenes, graphite, carbon nanotubes and diamond. All these structures possess unique physical and chemical properties. This work focusses on the usage of carbon nanotubes (CNT), especially iron-filled CNT.
An industrial application of CNT requires the understanding of the growth mechanism and the control of the synthesis process parameters. Regarding iron-filled CNT the shell formation as well as the filling process has to be understood in order to control the CNT morphology and distribution and dimension of the iron filling. The thesis involves two topics - synthesis of CNT and characterization of their mechanical properties. Chapter 2 of the present work deals with the synthesis of iron-filled CNT. In this thesis all experiments and the discussion about the growth process were conducted with respect to the demands of magnetic force microscopy probes.
The experimental work was focused on the temperature profile of the furnace, the aluminum layer of the substrate, the precursor mass flow and their impact on the morphology of in-situ iron-filled CNT. By selecting appropriate process parameters for the temperature, sample position, gas flow and by controlling the precursor mass flow, CNT with a continuous filling of several microns in length were created.
Existing growth models have been analyzed and controversially discussed in order to explain the formation of typical morphologies of in-situ filled CNT. In this work a modified growth model for the formation of in-situ filled CNT has been suggested. The combined-growth-mode model is capable to explain the experimental results. Experiments which were conducted with respect to the assumptions of this model, especially the role of the precursor mass flow, resulted in the formation of long and continuous iron nanowires encapsulated inside multi-walled CNT. The modified growth model and the synthesis results showed, that besides the complexity of the parameter interaction, a control of the morphology of in-situ iron-filled CNT is possible.
In chapter 3 the measurements of mechanical properties of in-situ iron-filled CNT are presented. Two different experimental methods and setups were established, whereby one enabled a static bending measurement inside a TEM and another a dynamical excitation of flexural vibration of CNT inside SEM.
For the first time mechanical properties and in particular the effective elastic modulus Eb of in-situ iron-filled CNT were determined based on the Euler-Bernoulli beam model (EBM). This continuum mechanic model can be applied to describe the mechanical properties of CNT and especially MWCNT in consideration of the restriction that CNT represent a macro molecular structure built of nested rolled-up graphene layers. For evaluation and determination of the elastic modulus the envelope of the resonant vibrating state was evaluated by fitting the EBM to the experimental data. The experiments also showed, that at the nanoscale the properties of sample attachment have to be taken into account.
Thus, instead of a rigid boundary condition a torsion spring like behavior possessing a finite stiffness was used to model an one side clamped CNT. The extended data evaluation considering the elastic boundary conditions resulted in an average elastic modulus of Eb = 0.41 ± 0.11 TPa. The low standard deviation gives evidence for the homogeneity of the grown material. To some extend a correlation between the formation process, the morphology and the mechanical properties has been discussed. The obtained results prove the usability of this material as free standing tips for raster scanning microscopy and especially magnetic force microscopy. The developed methods provide the basis for further investigations of the CNT and the understanding of mechanical behavior in greater detail.
13
Murphy, Riley Tomas. "Reactivity of Iron-Bearing Minerals Under Carbon Sequestration Conditions". Diss., Temple University Libraries, 2011. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/140596.
Pełny tekst źródłaStreszczenie:
ChemistryPh.D.
The rise in anthropogenic carbon dioxide in the atmosphere has caused the pursuit of adequate methods to alleviate the resulting strain on the world's ecosystem. A promising strategy is the geological sequestration of carbon dioxide, in which carbon dioxide emitted from large point sources is injected underground for storage. Under storage, carbon dioxide trapped as a carbonate mineral may be stable for geological time periods. Experiments were conducted to test the potential of ferric-bearing minerals to sequester carbon as a ferrous carbonate mineral (siderite). The formation of siderite requires the reduction of ferric ions which may be achieved by the co-injection of H2S or SO2 contaminants with CO2. Both ferrihydrite and hematite nanoparticles were exposed to an aqueous Na2S solution in the presence of supercritical CO2 (scCO2) and were analyzed in situ by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). In situ ATR-FTIR indicated that the formation of siderite occurred on the order of minutes for ferrihydrite and hematite nanoparticles. Particles were analyzed post-reaction with X-ray diffraction (XRD) and electron microscopy. XRD results indicated that ferrihydrite reacted completely to form siderite and elemental sulfur after 24 h at 100 °C, while hematite only partially reacted to form siderite and pyrite after 24 h at 70 °C. Additionally, hematite nanoparticles were exposed to H2S and scCO2 in a series of batch reactions, and the reaction products were determined by XRD as a function of CO2 and H2S partial pressures, alkalinity, salinity, time, and temperature.
Temple University--Theses
14
Sun, Yifei. "Decomposition of polychlorinated biphenyls with activated carbon-supported iron". 京都大学 (Kyoto University), 2006. http://hdl.handle.net/2433/136149.
Pełny tekst źródła
15
Elihn, Karine. "Synthesis of carbon-covered iron nanoparticles by photolysis of ferrocene". Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2002. http://publications.uu.se/theses/91-554-5302-3/.
Pełny tekst źródła
16
Venkateswaran, N. "Magnetic and microstructure properties of iron-rare earth-carbon magnets". Thesis, Kansas State University, 1988. http://hdl.handle.net/2097/16051.
Pełny tekst źródła
17
Morris, Paul James. "Carbon export from natural iron fertilisation in the Southern Ocean". Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/66262/.
Pełny tekst źródłaStreszczenie:
It has long been recognised that some oceanic regions have persistently low chlorophyll levels, even though inorganic nutrients are plentiful. Studies have shown that these high-nutrient, low-chlorophyll (HNLC) areas are depleted in iron, which is an essential micronutrient for phytoplankton growth. In HNLC regions biological production can be enhanced with artificial mesoscale iron fertilisation. However, the ability of artificially induced phytoplankton blooms to efficiently sequester carbon to mesopelagic depths is still an open question. SubAntarctic islands in the HNLC Southern Ocean are a natural source of iron and thus fuel the annual phytoplankton blooms observed in their proximity. One such bloom, tied to the Crozet Islands (52ºE, 46ºS), provided the opportunity to examine particulate organic carbon (POC) export during the austral summer of 2004/5. This work was imbedded into the multi-disciplinary CROZEX project thus providing a rich context for data interpretation. Based on satellite imagery, a high chlorophyll region (max = 4 µg l-1) north and downstream of the Crozet Islands was distinguished from a low chlorophyll region (typically 0.3 µg l-1) south and upstream of the islands. POC export estimates, obtained with the naturally occurring particle reactive radionuclide tracer, 234Th, were initially D15 mmol C m-2 d-1 in the high chlorophyll region, compared with D5 mmol C m-2 d-1 in the low chlorophyll region. After a moderately small increase in chlorophyll in the south (max = 0.7 µg l-1) the spatial variability in POC export was lost, resulting in equally high levels of POC export (ca. 20 mmol C m-2 d-1) throughout the study area. After comparing the daily rates of POC export with temporally integrated new production calculated from nitrate budgets, a different spatial pattern emerged. New production (NP) presented consistently higher values in the north, when compared to the south. Two hypotheses were formulated to explain this, 1) dissolved organic matter (DOM) and suspended particulate organic matter (sPOM) produced from NP was stored in the mixed layer with this effect relatively greater in the north, 2) the export event in the north was longer resulting in greater seasonal POC export. Investigation of the DOM pool revealed that DOM accounted for 46±7% of NP and was consistent across the whole study area. In contrast, sPOM accumulated at differential rates of 18±7% in the north and 0±7% in the south. This suggested that differential storage of sPOM was responsible for the lack of a latitudinal gradient in POC export after the relatively small increase in chlorophyll in the south. After investigating the second hypothesis, the daily rates of POC export were scaled to seasonal integrals using a silicon budget, which allowed the formulation of a seasonal carbon budget. This revealed that over the timescale of the study the magnitude of NP and POC export were not the same with this difference greatest within the northern high chlorophyll region. This was the result of relatively greater storage of sPOM in the north and had the effect of reducing the amount of easily exportable POC to mesopelagic depths. Thus both hypotheses contributed to better understanding carbon export in the Crozet region.
18
Lammers, Kristin D. "Carbon dioxide sequestration by mineral carbonation of iron-bearing minerals". Diss., Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/339925.
Pełny tekst źródłaStreszczenie:
ChemistryPh.D.
Carbon dioxide (CO2) is formed when fossil fuels such as oil, gas and coal are burned in power producing plants. CO2 is naturally found in the atmosphere as part of the carbon cycle, however it becomes a primary greenhouse gas when human activities disturb this natural balanced cycle by increasing levels in the atmosphere. In light of this fact, greenhouse gas mitigation strategies have garnered a lot of attention. Carbon capture, utilization and sequestration (CCUS) has emerged as a possible strategy to limit CO2 emissions into the atmosphere. The technology involves capturing CO2 at the point sources, using it for other markets or transporting to geological formations for safe storage. This thesis aims to understand and probe the chemistry of the reactions between CO2 and iron-bearing sediments to ensure secure storage for millennia. The dissertation work presented here focused on trapping CO2 as a carbonate mineral as a permanent and secure method of CO2 storage. The research also explored the use of iron-bearing minerals found in the geological subsurface as candidates for trapping CO2 and sulfide gas mixtures as siderite (FeCO3) and iron sulfides. Carbon dioxide sequestration via the use of sulfide reductants of the iron oxyhydroxide polymorphs lepidocrocite, goethite and akaganeite with supercritical CO2 (scCO2) was investigated using in situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The exposure of the different iron oxyhydroxides to aqueous sulfide in contact with scCO2 at ~70-100 ˚C resulted in the partial transformation of the minerals to siderite (FeCO3). The order of mineral reactivity with regard to siderite formation in the scCO2/sulfide environment was goethite < lepidocrocite ≤ akaganéite. Overall, the results suggested that the carbonation of lepidocrocite and akaganéite with a CO2 waste stream containing ~1-5% H2S would sequester both the carbon and sulfide efficiently. Hence, it might be possible to develop a process that could be associated with large CO2 point sources in locations without suitable sedimentary strata for subsurface sequestration. This thesis also investigates the effect of salinity on the reactions between a ferric-bearing oxide phase, aqueous sulfide, and scCO2. ATR-FTIR was again used as an in situ probe to follow product formation in the reaction environment. X-ray diffraction along with Rietveld refinement was used to determine the relative proportion of solid product phases. ATR-FTIR results showed the evolution of siderite (FeCO3) in solutions containing NaCl(aq) concentrations that varied from 0.10 to 4.0 M. The yield of siderite was greatest under solution ionic strength conditions associated with NaCl(aq) concentrations of 0.1-1 M (siderite yield 40% of solid product) and lowest at the highest ionic strength achieved with 4 M NaCl(aq) (20% of solid product). Based partly on thermochemical calculations, it is suggested that a decrease in the concentration of aqueous HCO3- and a corresponding increase in co-ion formation, (i.e., NaHCO3) with increasing NaCl(aq) concentration resulted in the decreasing yield of siderite product. At all the ionic strength conditions used in this study, the most abundant solid phase product present after reaction was hematite (Fe2O3) and pyrite (FeS2). The former product likely formed via dissolution/reprecipitation reactions, whereas the reductive dissolution of ferric iron by the aqueous sulfide likely preceded the formation of pyrite. These in situ experiments allowed the ability to follow the reaction chemistry between the iron oxyhr(oxide), aqueous sulfide and CO2 under conditions relevant to subsurface conditions. Furthermore, very important results from these small-scale experiments show this process can be a potentially superior and operable method for mitigating CO2 emissions.
Temple University--Theses
19
Oliver, Jacques L. "Iron and carbon limitation of prokaryotic growth in the ocean". W&M ScholarWorks, 2005. https://scholarworks.wm.edu/etd/1539616797.
Pełny tekst źródłaStreszczenie:
Studies were undertaken to examine the roles of iron and carbon in modulating prokaryotic growth in the ocean. The context of the first study was an open-open iron fertilization experiment in the high nutrient, low chlorophyll (HNLC) regime in the Southern Ocean. The context of the second study was the oligotrophic, iron-replete, and organic carbon-limited northwest Sargasso Sea. Experimental sea water cultures were amended with an iron chelator, desferrioxamine B (DFOB), and other nutrients to examine the effects of iron and carbon limitation on growth. In the first study prokaryotic abundance, carbon production, and growth rate increased in response to iron in two experimental locations north and south of the Antarctic Polar Front Zone (North Patch and South Patch, respectively). However, prokaryotes responded indirectly to iron-induced phytoplankton production. Prokaryotic production was highly correlated to particulate primary production (r2 = 0.80). Prokaryotes comprised a larger percentage of particulate organic carbon (POC) in the North versus the South Patch relative to non-fertilized waters. Analysis of prokaryotic community structure was also examined. Results showed unique prokaryotic communities existed in the North and South Patch for both iron-fertilized and non-fertilized waters. Additionally, community composition shifted over time in the South Patch and was distinct from non-fertilized waters. Measures of community diversity indicated an increase in taxonomic richness and diversity in iron-fertilized waters over time. Specific taxonomic groups monitored over time in the South Patch exhibited a differential response to the iron-induced phytoplankton bloom. at the domain level, the biomass response was greater for Eubacteria compared to Archaea. at the clade level, Cytophaga-Flavobacteria net biomass yields outpaced SAR11, although both exhibited significant increases (p < 0.05) in net growth rate over time in the South Patch. In the second study DFOB did not limit utilization of organic carbon (glucose). Conversely, DFOB stimulated prokaryotic growth in a dose-dependent manner. The trend of the response to DFOB was similar to glucose; however, the magnitude of the response (i.e. growth rate and biomass yield) at higher equivalent carbon doses was greater than that of glucose. Additionally, DFOB and glucose elicited a differential taxonomic response.
20
Al-Biatty, Hesham Jassim. "Aspects of carbon-sulphur-iron geochemistry and diagenesis in ancient sediments". Thesis, University of Leeds, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277352.
Pełny tekst źródła
21
Kalcioglu, Ali Ferdi 1960. "Distribution of antimony between carbon-saturated iron and blast furnace slags". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277129.
Pełny tekst źródłaStreszczenie:
Understanding the effects of the process parameters on the distribution behaviour of antimony between metal and slag in the iron blast furnace is critical to develop a universal method of controlling temper embrittlement in commercially pure low alloy steels.
22
Vaughan, Ronald L. "Modeling AS(V) removal in iron oxide impregnated activated carbon columns". free to MU campus, to others for purchase, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3060150.
Pełny tekst źródła
23
Xie, Li. "Factors and mechanisms controlling bromate removal by zerovalent iron /". View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202005%20XIE.
Pełny tekst źródła
24
Busch, Jan, Tobias Meißner, Annegret Potthoff i Sascha Oswald. "Plating of nano zero-valent iron (nZVI) on activated carbon : a fast delivery method of iron for source remediation?" Universität Potsdam, 2011. http://opus.kobv.de/ubp/volltexte/2011/5379/.
Pełny tekst źródłaStreszczenie:
The use of nano zerovalent iron (nZVI) for environmental remediation is a promising new technique for in situ remediation. Due to its high surface area and high reactivity, nZVI is able to dechlorinate organic contaminants and render them harmless. Limited mobility, due to fast aggregation and sedimentation of nZVI, limits the capability for source and plume remediation. Carbo-Iron is a newly developed material consisting of activated carbon particles (d50 = 0,8 µm) that are plated with nZVI particles. These particles combine the mobility of activated carbon and the reactivity of nZVI. This paper presents the rst results of the transport experiments.Der Einsatz von elementarem Nanoeisen ist eine vielversprechende Technik zur Sanierung von Altlastenschadensfällen. Aufgrund der hohen Oberäche und der hohen Reaktivität kannn ZVI chlororganische Schadstoffe dechlorieren und zu harmlosen Substanzen umwandeln. Der Einsatz von Nanoeisen zur Quellen- und Fahnensanierung wird jedoch durch mangelnde Mobilität im Boden im eingeschränkt. Carbo-Iron ist ein neu entwickeltes Material, das aus Aktivkohlepartikeln (d50 = 0,8 µm) und nZVI besteht. Diese Partikel kombinieren die Mobilit ät von Aktivkohle mit der Reaktivität von nZVI. Dieser Artikel beschreibt erste Ergebnisse von Transportuntersuchungen.
25
Johnson, Timothy Van. "The kinetics of reduction of iron from silicate melts by carbon monoxide--carbon dioxide gas mixtures at 1300CÌ¥". Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14840.
Pełny tekst źródłaStreszczenie:
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1987.M.I.T. copy lacks leaf 40. Vita.
Bibliography: leaves 202-206.
by Timothy Van Johnson.
Sc.D.
26
Randall, G. P. "Organoiron routes towards compactin analogues". Thesis, University of East Anglia, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380987.
Pełny tekst źródła
27
Aguiló, Aguayo Noemí. "Production and characterisation of carbon-encapsulated iron nanoparticles by arc-discharge plasma". Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/96477.
Pełny tekst źródłaStreszczenie:
Carbon-encapsulated iron nanoparticles have being researched heavily, since they present advantageous properties over other protective coatings such as polymer or silica. The carbon coating protects the iron core from oxidation, chemical and thermal degradation and hence, magnetic cores present stable magnetic properties when nanoparticles are exhibited in air or other environments. Several studies about carbon-encapsulated magnetic nanoparticles were already reported. However, nanoparticles are obtained rather polydisperse and not very uniform in composition, making very difficult their use for several applications. The aim of this thesis is the production and characterisation of carbon-encapsulated iron nanoparticles showing very narrow size distributions with well-characterised magnetic properties for several applications, in particular, those related to the biomedical field (hyperthermia, drug delivery or as agents contrast in MRI). However, the systematic study of these applications was not the framework of this thesis.
The content of this dissertation comprises the design of two arc-discharge plasma (ADP) reactors (a conventional and a modified one); the experimental study of the different reactor parameters involved; the morphological, structural and magnetic characterisation of the obtained nanoparticles; the comprehension of the mechanisms involve in the formation of this kind of nanoparticles in comparison with nanoparticles obtained by other methods; and finally, a first approach to the functionalisation of the nanoparticles for the biomedical applications.
This thesis is structured in four parts: Backgrounds (Chapter 1), Nanotools (Chapter 2 and Chapter 3), Results (from Chapter 4 to Chapter 8) and finally, the Conclusions.
Chapter 1 - Basis of carbon-encapsulated iron nanoparticles:
A general introduction of the nanoparticle properties derived from their nanometric dimensions is presented in this chapter. The state of the art about the formation mechanisms and techniques used for the generation of carbon-encapsulated iron nanoparticles is described. Several applications of this kind of nanoparticles in fields such as biomedicine, electronics or food and environmental, are also presented.
Chapter 2 - Characterisation methods:
The most common characterisation techniques used to investigate the morphological, composition, structural and magnetic properties are described within this chapter. Details about the equipments and conditions used during this thesis for the characterisation of the nanoparticles are also reported.
Chapter 3 - Experimental set-up:
In this chapter, the description of two different arc-discharge reactors used during this thesis is presented. A first reactor (the conventional ADP) was developed by following similar experimental setups described in the literature. Second reactor (a modified ADP) was designed to overcome the disadvantages from the first reactor and to obtain high quality nanoparticles (narrower size distribution, uniform composition).
Chapter 4 - Preliminary studies from conventional ADP reactor:
This chapter presents a design of experiments (DOE) based on the Plackett-Burman design in order to evaluate the reactor parameters that influence the most the final characteristics of the nanoparticles. The study was performed using the conventional ADP reactor and the preliminary results were very useful for the development of next generation of experiments using the second reactor, the modified ADP.
Chapter 5 - Generation of nanoparticles by a modified ADP reactor:
Morphological and structural properties of the nanoparticles obtained by the modified ADP reactor are presented. The discussion of the effect of the most relevant parameters on the formation of the nanoparticles was reported. Iron core diameters with corresponding size distribution as well as the carbon shell formation obtained under different parameter conditions were investigated.
Chapter 6 - Magnetic properties of the nanoparticles:
A systematic study of the magnetic properties of the nanoparticles obtained in Chapter 5 is performed. Size-dependent variables such as magnetic moments, coercivity values, blocking temperature and anisotropy energies were presented. Magnetic properties were in agreement with the morphological characteristics of the nanoparticles.
Chapter 7 – Thermally induced structural evolution of the nanoparticles:
The comparison of annealed nanoparticles obtained by mADP and chemical vapour deposition (CVD) method is presented in this chapter. Differences on the morphological, structural and magnetic properties were studied. Structural evolution of nanoparticles during annealing under in-situ TEM observations was investigated.
Chapter 8 - First approach to biomedical applications:
As a first approach to biomedical applications, the stabilisation of the nanoparticles in aqueous solution by using polyvinyl-alcohol was investigated. Results of the internalisation of the nanoparticles into HeLa cells are presented.Les nanopartícules magnètiques de ferro recobertes de carboni s’estan investigant en gran mesura, ja que presenten avantatjoses propietats sobre d’altres recobriments protectors del nucli magnètic com els polímers o la sílice. El recobriment de carboni protegeix el nucli de ferro de l’oxidació, la degració química i tèrmica, d’aquesta manera els nuclis presenten propietats magnètiques estables quan les nanopartícules s’exhibeixen en aire o en un altre medi. S’han realitzat diversos estudis sobre aquest tipus de nanopartícules, però aquest tipus de nanopartícules s’obtenen amb gran dispersió de grandàries i poca uniformitat en les seves característiques. És encara un repte en aquest camp la producció de nanopartícules de ferro recobertes de carbon amb propietats morfològiques i estructurals, així com l’estudi sistemàtic de les seves propietats magnètiques. Per aquest motiu, l’objectiu d’aquesta tesi es centra en la producció i caracterització de nanopartícules superparamagnètiques de ferro recobertes de carboni amb estreta distribució de mides i amb propietats magnètiques ben caracteritzades per diverses aplicacions, en particular, les relacionades amb el camp de la biomedicina. No obstant això, l’estudi sistemàtic d’aquestes aplicacions es troba fora del marc d’aquesta tesi. El contingut s’estructura en quatre parts: • La primera part d’introducció conté els aspectos bàsics sobre aquest tipus de nanopartícules, així com les propietats derivades de la seva mida nanomètrica, les tecnologies que s’utilitzen per generar aquest tipus de nanopartícules, una explicació sobre els possibles mecanismes responsables de la seva formació i les principals aplicacions d’aquestes nanopartícules. • La segona part descriu les tècniques utilitzades per la seva caracterització que engloben tècniques de microscopia, de difracció de raigs-X, d’espectroscòpia Raman, per la caracterització col•loidal de les nanopartícules fins la seva caracterització magnètica. També inclou la descripció detallada dels equips basats en la descàrrega d’arc utilitzats per la seva producció. El primer equip es va dissenyar seguint les característiques d’un reactor convencional (conventional ADP reactor). El segon equip basat en la mateixa tecnologia de descàrrega d’arc, però modificat (mADP reactor) i dissenyat especialment amb l’objectiu de millorar les característiques del producte final. • La tercera part exposa els resultats obtinguts durant aquesta tesi. L’estudi previ del reactor convencional basat en un disseny d’experiments de Plackett-Burman per avaluar l’efecte dels diferents paràmetres del reactor en la grandària dels nuclis de ferro. A partir d’aquest estudi, es va realitzar un estudi més específic en el nou reactor modificat on es van estudiar l’efecte del corrent d’arc utilizat, la velocitat del flux d’heli i el contigut de ferrocè com a matèria prima del ferro. Després es va realitzar l’estudi sistemàtic de les seves propietats magnètiques observant la dependència d’aquestes propietats amb la grandària dels nuclis de ferro. A continuació, es va presentar la comparació d’aquestes nanopartícules amb d’altres obtingudes mitjantçant el mètode de dipòsit químic en fase vapor (CVD). A partir d’aquesta comparació es va estudiar l’evolució estructural d’aquestes nanopartícules sotmetes a un tractament tèrmic en observació in-situ d’un microscopi de transmissió electrònica. Finalment, es va presentar un primer estudi de les propietats col•loidals en suspensió d’aquestes nanopartícules recobertes amb un polímer d’alcohol de polivinil (PVA). Es presenta un primer estudi de l’internalització d’aquestes nanopartícules en cèl•lules tumorals HeLa. • Per acabar es presenten les conclusions i l’apèndix que conté informació sobre les mostres produïdes i un llistat de publicacions, congressos, patents resultants d’aquest treball.
28
Ghane, Ghanad Iman. "Atmospheric leaching of enargite in iron sulfate solutions catalyzed by activated carbon". Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/39280.
Pełny tekst źródłaStreszczenie:
Traditionally, smelting has been the primary method of treatment for copper sulfide concentrates. In modern smelters the environmental problem of sulfur dioxide emission has been addressed effectively, but pyrometallurgical treatment of concentrates containing elevated levels of arsenic is still difficult and costly. Therefore, arsenic is considered a penalty element for smelters. However, the depletion of “clean” (non-arsenical) copper deposits and the increasing demand for copper will make the treatment of copper-arsenic sulfides such as enargite and tennantite unavoidable. Thereby a viable processing method is required. Hydrometallurgical treatment of enargite using atmospheric leaching promises a comparatively simple method for managing arsenic by co-precipitating it with iron in the form of scorodite. The major challenge involved with this option is the slow rate of enargite leaching.
A novel treatment for enargite-rich copper concentrates through atmospheric ferric leaching catalyzed by activated carbon is presented in this study. Enargite concentrates from three different sources in Chile and Peru and one enargite mineral sample from the United States were used in the leaching experiments. Batch leaching tests were conducted in sealed, jacketed, glass stirred-tank reactors. The results showed that enargite leaching was up to 6 times faster in the presence of activated carbon, making it possible to achieve virtually complete copper extraction within 24 hours. SEM studies revealed changes in the morphology of the passive layer on enargite particles which is formed as a product of leaching. The laboratory-scale tests indicated that desirable leaching kinetics could be maintained after recycling activated carbon particles multiple times to new leaching tests and also at a carbon:enargite concentrate mass ratio as low as 0.25. Activated carbon loss was reduced from 26 % to 5 % of the initial carbon mass by decreasing the impeller speed from 1200 rpm to 800 rpm, while the leaching performance remained similar. The effects of concentrate grind size, solution redox potential and initial total iron concentration on copper extraction have also been studied. The presented method promises a commercially attractive route to treat enargite concentrates.
29
Jonker-Brash, Robina Ann. "Erosion of refractories : mechanisms for dissolution of graphite by iron-carbon melts". Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297215.
Pełny tekst źródła
30
Rasheed, Senan. "Photocatalytic Carbon Dioxide Reduction with Zinc(II) Dipyrrin Photosensitizers and Iron Catalyst". Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/etd/3730.
Pełny tekst źródłaStreszczenie:
Much of the energy used in the United States and around the globe is obtained from petroleum, natural gas, and coal. Photocatalytic CO2 reduction can be used to transform CO2 to useful fuels and making fossil fuels more renewable. Input of energy is required, and the sun can provide the required energy for this transformation. Photosensitizer, catalyst, and electron donor are required for photocatalytic CO2 reduction.
Due to lack of earth-abundant sensitizers, zinc dipyrrin complexes were synthesized by previous group members and have been used as photosensitizers in this research. The ground and excited state electrochemical properties of two zinc dipyrrin complexes were determined in polar and nonpolar solvents and the measured potentials were used to match the zinc sensitizers with an energetically appropriate iron porphyrin catalyst and a benzylthiol sacrificial electron donor. Lastly, pure CO2 gas was used as the source of carbon for the reduction of CO2 by photocatalysis with the zinc photosensitizers, iron catalyst and sacrificial electron donor. The products formed in headspace were analyzed by GC
31
Hyde, Brian. "Effects of Carbon on Fracture Mechanisms in Nanocrystalline BCC Iron - Atomistic Simulations". Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/27315.
Pełny tekst źródłaStreszczenie:
Atomistic computer simulations were performed using embedded atom method interatomic potentials in α-Fe with impurities and defects. The effects of intergranular carbon on fracture toughness and the mechanisms of fracture were investigated. It was found that as the average grain size changes the dominant energy release mechanism also changes. Because of this the role of the intergranular carbon changes and these mechanisms compete affecting the fracture toughness differently with changing grain size.
Grain boundary accommodation mechanisms are seen to be dominant in the fracture of nanocrystalline α-Fe. To supplement this work we investigate grain boundary sliding using the Σ = 5,(310)[001] symmetrical tilt grain boundary. We observe that in this special boundary sliding is governed by grain boundary dislocation activity with Burgers vectors belonging to the DSC lattice. The sliding process was found to occur through the nucleation and glide of partial grain boundary dislocations, with a secondary grain boundary structure playing an important role in the sliding process. Interstitial impurities and vacancies were introduced in the grain boundary to study their role as nucleation sites for the grain boundary dislocations. While vacancies and H interstitials act as preferred nucleation sites, C interstitials do not.Ph. D.
32
Deslandes, Maria. "SYNTHESIS OF ALL-CARBON SPIROCYCLES BY INTRAMOLECULAR IRON-MEDIATED DIENE/OLEFIN CYCLOCOUPLING". Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1354141980.
Pełny tekst źródła
33
Khalfallah, Ibrahim Youniss A. "The Effect of Milling Time on the Structure and the Properties of Mechanically Alloyed High Carbon Iron-Carbon Alloys". Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/80479.
Pełny tekst źródłaStreszczenie:
The effects of mechanical alloying milling time and carbon concentration on microstructural evolution and hardness of high-carbon Fe-C alloys were investigated. Mechanical alloying and powder metallurgy methods were used to prepare the samples. Mixtures of elemental powders of iron and 1.4, 3, and 6.67 wt.% pre-milled graphite were milled in a SPEX mill with tungsten milling media for up to 100h. The milled powders were then cold-compacted and pressure-less sintered between 900°C and 1200°C for 1h and 5h followed by furnace cooling. Milled powders and sintered samples were characterized using X-ray diffraction, differential scanning calorimetry, Mossbauer spectroscopy, scanning and transmission electron microscopes. Density and micro-hardness were measured. The milled powders and sintered samples were studied as follows:
In the milled powders, the formation of Fe_3 C was observed through Mossbauer spectroscopy after 5h of milling and its presence increased with milling time and carbon concentration. The particle size of the milled powders decreased and tended to become more equi-axed after 100h of milling. Micro-hardness of the milled powders drastically increased with milling time as well as carbon concentration. A DSC endothermic peak around 600°C was detected in all milled powders, and its transformation temperature decreased with milling time. In the literature, no explanation was found. In this work, this peak was found to be due to the formation of Fe_3 C phase. A DSC exothermic peak around 300°C was observed in powders milled for 5h and longer; its transformation temperature decreased with milling time. This peak was due to the recrystallization and/or recovery α-Fe and growth of Fe_3 C .
In the sintered samples, almost 100% of pearlitic structure was observed in sintered samples prepared from powders milled for 0.5h. The amount of the pearlite decreased with milling time, contrary to what was found in the literature. The decrease in pearlite occurred at the same time as an increase in graphite-rich areas. With milling, carbon tended to form graphite instead of Fe_3 C. Longer milling time facilitated the nucleation of graphite during sintering. High mount of graphite-rich areas were observed in sintered samples prepared from powders milled for 40h and 100h. Nanoparticles of Fe_3 C were observed in a ferrite matrix and the graphite-rich areas in samples prepared from powders milled for 40h and 100h. Micro-hardness of the sintered samples decreased with milling time as Fe_3 C decreased. The green density of compacted milled powders decreased with milling time and the carbon concentration that affected the density of sintered samples.Ph. D.
34
Gu, Zhimang. "Development and evaluation of innovative iron-containing porous carbon adsorbents for arsenic removal". Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/5864.
Pełny tekst źródłaStreszczenie:
Thesis (Ph. D.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 10, 2007) Vita. Includes bibliographical references.
35
Göhring, HOLGER [Verfasser], i Eric Jan [Akademischer Betreuer] Mittemeijer. "Interaction of carbon and nitrogen in iron / Holger Göhring ; Betreuer: Eric Jan Mittemeijer". Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2016. http://d-nb.info/1124841334/34.
Pełny tekst źródła
36
Fookes, B. G. "Factors influencing the sub-critical decomposition of austenite in iron-silicon-carbon alloys". Thesis, Brunel University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.351912.
Pełny tekst źródła
37
BYSTRÖM, MARCUS. "Anchoring a Molecular Iron Based Water Oxidation Catalyst onto a Carbon Paste Electrode". Thesis, KTH, Skolan för kemivetenskap (CHE), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-172212.
Pełny tekst źródłaStreszczenie:
This thesis concerns the development and the study of Iron-based water oxidation catalysts (WOCs) and how to immobilize them onto the hydrophobic surface of a carbon paste electrode. In the introductory chapter a general background of the field of water splitting and this thesis is given. In the second chapter, experimental performance is described from synthesis to measurements of a complete complex-doped electrode. The third chapter deals with the results and the discussion of the performed experiments. In chapter four, a descriptive conclusion of the obtained data is held.Det här arbetet berör studien och utvecklingen utav järnbaserade katalysatorer, speciellt framtagna för för delning utav vatten. Utöver detta undersöks även om dessa katalysatorer (WOCs) kan immobiliseras på den hydrofoba ytan hos elektroder gjorda på kol-pasta. I det inledande kapitlet ges en generell bakgrund till området som berör delning utav vatten. I det andra kapitlet presenteras det experimentella utförandet utav synteser samt elektrokemiska mätningar som berörts under arbetets gång i jakten på en komplexdopad elektrod. I det tredje kapitlet diskuteras resultaten från mätningarna samt möjliga framtidsutsikter. I det fjärde kapitlet presenteras slutsatserna utav studien.
38
Hu, Di. "Surface modification and electronic structure characterisation of carbon-based and iron-based materials". Thesis, Aberystwyth University, 2017. http://hdl.handle.net/2160/04016083-f5c2-4542-a75a-74ee93b36100.
Pełny tekst źródłaStreszczenie:
This thesis provides an important basis for understanding the surface modulation mechanism and electronic structure variation on semiconducting surfaces and metallic thin films. The use of real-time photoelectron spectroscopy (REES) makes it possible to monitor the solid surfaces during in situ processing. The surfaces that have been investigated were (100) facet boron-doped diamond surfaces and iron thin films. The surface processing treatments include annealing, thin film coating and exposure to oxygen and hydrogen microwave plasma sources. The oxygen-terminated (100) facet diamond was annealed up to 1000°C while monitoring with REES. The oxygen desorption process on the surface can be divided into four distinct stages according the oxygen concentration on the diamond (100) surface during the heating cycle. The ratio of ketone/ether groups has been investigated. Moreover, the true band bending on O-terminated (100) has been investigated with real-time characterization, which has a maximum difference of +1.0 eV comparing with the room temperature XPS spectra data. Fluorouracil (5-FU), as a drug widely used in leukaemia and bowel cancer treatment, which is demonstrated to degrade on silver coated catheter surfaces, producing hydrofluoric acid and therefor leading to adverse effects on patients. In order to compare diamond as coating material, the adsorption of 5-FU on the oxygen and hydrogen terminated diamond (100) surfaces has been studied with x-ray photoelectron spectroscopy (XPS), showing extremely different behaviours. Utilising the shape memory alloy (SMA) substrate, the continuously mediated strain was transferred from the substrate to Fe films through a thermally controlled shape memory effect. The pure strain modulated electronic structure in the Fe thin films was studied using in situ XPS and first-principle calculations. The result demonstrates that the compressive strain increases the overlap of outer orbits and enhances the shielding effect to core electrons, resulting in significant tunability on the binding energy of core electrons and related magnetic anisotropy.
39
Göhring, Holger [Verfasser], i Eric Jan [Akademischer Betreuer] Mittemeijer. "Interaction of carbon and nitrogen in iron / Holger Göhring ; Betreuer: Eric Jan Mittemeijer". Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2016. http://d-nb.info/1124841334/34.
Pełny tekst źródła
40
Della, Monica Francesco. "Development of iron-based catalysts for the coupling of carbon dioxide with epoxides". Doctoral thesis, Universita degli studi di Salerno, 2018. http://hdl.handle.net/10556/3087.
Pełny tekst źródłaStreszczenie:
2016 - 2017Beside the environmental and energetic issues, carbon dioxide can be considered as a resource. Many chemical transformations based on CO2 as C-1 building block have been developed. The coupling reaction of epoxides with CO2 is one of the most attractive. An overview on the state of the art for metal-mediated process is provided. Particular enphasis is given to the iron-based systems, because it is an ideal candidate for the development of environmental and economic sustainable catalytic systems. It is the aim of this thesis to investigate the application of sulphur containing ligand based iron complexes, starting from the encouraging results reported by the research group of Capacchione in the case of the bis-thioether-tri-phenolate ligand based bimetallic Fe(III) complex.3 The synthesis and the complete characterization of five new thioether triphenolate ligands (L2-6), and of the corresponding bimetallic iron(III) complexes (2-6) is reported... [edited by author]
XVI n.s.
41
NAKAMURA, Toshio, Hiroki KONDO, 俊夫 中村 i 宏樹 近藤. "加速器質量分析計を用いた鉄製遺物の14C年代測定に関する基礎研究". 名古屋大学年代測定資料研究センター, 2012. http://hdl.handle.net/2237/18163.
Pełny tekst źródła
42
Huggins, Gonzalez Angeire Sugey. "Galvanic Interactions in Sweet and Sour Environments". The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1557002644383622.
Pełny tekst źródła
43
Alharthi, Abdulrahman. "Hydrogen and carbon nanostructure formation from methane cracking over iron and zeolite based catalysts". Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/5309/.
Pełny tekst źródłaStreszczenie:
The production of hydrogen by the catalytic cracking of methane was investigated. An extensive study was undertaken on two categories of materials, namely iron-containing wastes and prepared catalysts, which include palladium-based catalysts, nickel-based catalysts and a copper-based catalyst. Three types of iron-containing waste materials were examined as pre-catalysts. The iron waste samples comprised a biogenic sample from a local Landfill site; waste residue sample from an old local nail works site and Red Mud. The resulting waste iron catalysts are environmentally benign and may be “thrown away” following use. The biogenic sample presented an unusual tubular morphology resulting from its biogenesis. All these materials possessed significant peak activity for hydrogen production at 800 °C. Significant carbon deposition occurred on these samples. Calcination of biogenic and waste residue samples at 900 °C enhanced performance. Carbon was deposited in the form of carbon filaments on the waste residue sample. The addition of Pd promoted the biogenic sample’s activity but poisoned the waste residue sample. Cracking of methane over palladium-containing zeolite catalysts has also been studied. Pd/H-ZSM-5 exhibited the highest peak hydrogen formation rate at 750 °C and the highest amount of carbon was produced at 900 °C. The addition of Ni, Co, Cu and Fe dopants did not improve performance. The effect of support type (H-ZSM-5, -Al2O3 and SiO2) on the Pd catalyst performance was also investigated, with -Al2O3 producing the best activity. All post-reaction Pd catalysts showed the formation of carbon filaments. On comparing the catalytic activity of Pd/H-ZSM-5, Ni/H-ZSM-5 and Cu/H-ZSM-5, it was found that Pd/H-ZSM-5 catalyst possessed the highest activity, while Ni/H-ZSM-5 and Cu/H-ZSM-5 catalysts showed lower activity and similarity to each other in behaviour. Carbon filaments were formed over Pd/H-ZSM-5 and Cu/H-ZSM-5 but did not form over Ni/H-ZSM-5. It was observed that the carbon filaments only grow at higher Ni-loading on the zeolite. The catalytic activities of Ni on different supports were evaluated and SiO2 was found to be the most effective support.
44
Al-Attas, Omar. "Competitive Adsorption of Iron and Natural Organic Matter in Groundwater Using Granular Activated Carbon". Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23349.
Pełny tekst źródłaStreszczenie:
The treatment of potable water in Vars, ON is accomplished by filtering the colored, iron-laden groundwater through granular activated carbon (GAC) filters. When first installed, these filters unexpectedly experienced chromatographic displacements of iron into the produced water which resulted in orange-brown water at consumers’ taps. The treatment plant was later modified by adding potassium permanganate oxidation and a greensand filter prior to the GAC adsorption columns. Consequently, iron was almost completely removed and no longer caused operational problems. The main objective of this dissertation is to study the interactions between natural organic matter (NOM) and iron that caused the observed chromatographic effect. This study was divided into three main stages: a) characterization study on Vars groundwater and its treatment system; b) study of the competitive adsorption of iron with NOM in Vars groundwater; and c) evaluation of the rapid small-scale column test (RSSCT) for predicting the full-scale GAC column breakthroughs. The characterization of Vars groundwater showed that ferrous iron was found to be the dominant iron species, representing 90% of the total iron, and that 15 - 35% of the iron was complexed with NOM. It was hypothesized that the chromatographic displacement of iron from the GAC columns was caused by NOM-iron complexes; however, field mini-column experiments showed this was not the case. Thus, competitive adsorption between iron and NOM was seen as the more likely cause of the chromatographic effect. The adsorption capacity of ferrous iron in Vars raw water was less than that in organic-free water by a factor of 7 due to the competition with NOM over the GAC adsorbing sites. However, the NOM adsorption capacity was not reduced due to the presence of ferrous iron. It was hypothesized that ideal adsorption solution theory (IAST) models, which have been successful in describing competitive adsorption between target organic compounds and NOM, could model the competition between an inorganic compound such as ferrous iron and NOM. The hypothesis was proved to be correct, and the adsorption isotherm of iron in competition with NOM in Vars groundwater was simulated very well by several versions of the IAST model. However, none of the models were capable of simulating the competitive adsorption of NOM and ferrous iron simultaneously. Since the presence of iron did not significantly reduce the adsorption capacity of NOM, a simplified approach of using the single-solute NOM isotherm to represent the competitive NOM isotherm was recommended. The performance of the rapid small-scale column test (RSSCT) was evaluated in order to simulate the iron chromatographic effect observed at Vars’ full-scale GAC column. The RSSCT was not capable of predicting the iron phenomenon and the test proved to be problematic due to the oxidation and precipitation of iron within the small voids between the small-scale column’s GAC particles. The RSSCT, using constant and linear diffusivities, were applied to simulate the NOM adsorption after greensand treatment. Integrating both diffusivities, the tests predicted the onset and slope of the NOM breakthrough up to 10-L water treated/g GAC, which is equivalent to 250 days of operation time for the full-scale column. However, the NOM breakthroughs deviated beyond that point and the RSSCT using constant diffusivity underestimated the column performance greatly. On the other hand, the linear diffusivity RSSCT underestimated the performance to a lesser degree and its NOM breakthrough was quite parallel to the full-scale performance with lower NOM removals of 15%. The higher long-term NOM removal in the full-scale system may be explained by biodegradation, a phenomenon that was not considered by the short duration of RSSCT.
45
Anyakwo, C. N. "The kinetics of Cr2̲O3̲ reduction from slags by carbon dissolved in molten iron". Thesis, University of Strathclyde, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382250.
Pełny tekst źródła
46
Tarhuni, Sarah. "Mixed valency in redox-active, all-carbon bridged bimetallic complexes of iron and molybdenum". Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/mixed-valency-in-redoxactive-allcarbon-bridged-bimetallic-complexes-of-iron-and-molybdenum(8e081a41-817f-4e98-bc89-c2e1a44e10fe).html.
Pełny tekst źródłaStreszczenie:
This thesis describes the development of new procedures for the synthesis of homo- and hetero-bimetallic complexes [M-(C≡C-C≡C)-M*] linked by a butadiyndiyl (-C≡C-C≡C-) bridge (where M, M* = Mo(dppe)(η-C7H7) and Fe(dppe)Cp) and also of the diethynyl-anthracenyl bridged complex [{Mo(dppe)(-C7H7)}2(μ-C≡CC14H8C≡C)] in which an anthracenyl group is inserted into the butadiyndiyl bridge. The redox chemistry and mixed valence character of these systems are investigated by a range of synthetic, electrochemical and spectroscopic techniques. Chapter 1: (Introduction) presents a literature review related to all-carbon bridged bimetallics including their synthesis, redox chemistry and mixed valence properties. Chapter 2: describes the synthesis of the key precursor [FeI(dppe)Cp] in multi-gram quantities. A new synthetic protocol has been developed to vinylidene [Fe(C=CH2)(dppe)Cp][PF6] and acetylide [Fe(C≡CH)(dppe)Cp] complexes starting from the iodo precursor [FeI(dppe)Cp] which can be conveniently used in place of the chloro precursor [FeCl(dppe)Cp]. We also identified the carbene species [Fe{C(OMe)Me}(dppe)Cp][PF6], which is formed as a by-product from the reaction of the vinylidene with a molecule of methanol solvent. Chapter 3: describes the synthesis and characterisation of butadiyndiyl bridged [{Fe(dppe)Cp}2(-CCCC)]n+ (n = 0, 1, 2). The electronic structure of [{Fe(dppe)Cp}2(-CCCC)]n+ has been investigated in all thermally accessible oxidation states (0, 1, 2, 3) and compared directly with the closely related ruthenium analogue [{Ru(dppe)Cp}2(-CCCC)]n+. Particular focus was given to the formally 'mixed valent' radical cations [{Fe(dppe)Cp}2(-CCCC)]+ and [{Ru(dppe)Cp}2(-CCCC)]+, where the spectroscopic data highlight significant differences between the iron and ruthenium complexes. Furthermore, in this chapter the heterobimetallic complex [{Fe(dppe)Cp}(µ-C≡C-C≡C){Mo(dppe)(C7H7)}] was successfully synthesised and characterised by microanalysis, IR, mass spectrometry and cyclic voltammetry. Chapter 4: discusses the synthesis of the diethynyl-anthracene bridged complexes [{Mo(dppe)(-C7H7)}2(μ-C≡CC14H8C≡C)]n+ (n = 0, 1, 2). The focus of the investigation is to determine the effect of a diethynyl-benzene vs. diethynyl-anthracene bridge in bimetallics supported by the Mo(dppe)(C7H7) end cap. In the mixed valence (n = +1) state, the odd electron should be more localised on the ligand bridge of the anthracene derivative and this principle was investigated by EPR spectroscopy.
47
Yazzie, Kyle E. "Block copolymer-templated iron oxide nanoparticles for bimodal growth of multi-walled carbon nanotubes". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43205.
Pełny tekst źródłaStreszczenie:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008.Includes bibliographical references (leaves 65-66).
Since their discovery carbon nanotubes (CNTs) have sparked great interest due to their exceptional mechanical, electrical, and thermal properties. These properties make carbon nanotubes desirable for numerous applications including: nanoelectronics, high-strength composites, energy storage, superhydrophobic surfaces, sensors, and biomaterial interfaces. Bulk synthesis of carbon nanotubes with controlled physical features, i.e. length, diameter, multiwalled vs. single walled, carbon nanotube chirality, etc. is necessary to make full use of carbon nanotubes exceptional properties in commercial aspects. Typical carbon nanotube synthesis processes use chemical vapor deposition (CVD), arc-discharge, and laser ablation. Synthesizing carbon nanotubes via CVD typically involves depositing a thin metal film on a silicon substrate, and heating the substrate so that the thin metal film dewets and forms metallic nanoparticles. A hydrocarbon gas is then flowed over the nanoparticles to initiate carbon nanotube growth. Though these thin metal film catalysts are easy to prepare, they offer poor control over nanoparticle diameters and areal density. It has been shown that physical properties of carbon nanotubes, such as diameter and uniformity of growth, are directly related to the diameter of the catalyst nanoparticle, and that chirality of the carbon nanotube is inversely related to the catalyst nanoparticle diameter. Therefore, fully exploiting the unique properties of carbon nanotubes requires an understanding of how to control catalyst nanoparticle diameters, and thereby carbon nanotube physical characteristics. Bennett et al demonstrated that controllability of nanoparticle diameters is possible using a simple poly(styrene-b-acrylic acid) (PS-b-PAA) amphiphilic block copolymer. The amphiphilic PS-b-PAA block copolymer forms micelles, when dissolved in toluene, with anionic carboxylic acid groups available from the PAA.
(cont.) The anionic PAA carboxylic acid groups can be used to sequester metal cations, so that metal is effectively loaded into the micelles. The size of nanoparticles can be controlled by the size of the PAA portion of the block copolymer. When spin cast onto a substrate, the metal-loaded PS-b-PAA micelles form a quasi-ordered block copolymer thin film. Maximizing the amount of metal-loaded micelles in solution can maximize the resulting areal density of nanoparticles, thereby forming a monodisperse, quasi-hexagonal nanoparticle array. The deposited micellular thin film and substrate can then be etched with oxygen plasma, removing the organic polymer so that only the nanoparticle array is left, and the substrate is ready for carbon nanotube growth.
by Kyle E. Yazzie.
S.B.
48
Indelicato, Bina M. (Bina Mukund) 1973. "Comparision of zero-valent iron and activated carbon for treating chlorinated contaminants in groundwater". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50018.
Pełny tekst źródła
49
Hsieh, Cheng-En, i 謝承恩. "Hydrogen adsorption of iron/carbon nanocomposite". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/46010177843747959288.
Pełny tekst źródłaStreszczenie:
碩士國立清華大學
材料科學工程學系
97
Carbon nanopowder intrinsically has the characteristics of high specific surface area and micropores, which are favorable for hydrogen adsorption. In this study, we obtained Fe/CNP nanocomposite materials by modifying the surface of the carbon nanopowder (CNP) with different iron oxides. To measure hydrogen storage behaviors of Fe/CNP nanocomposite, we used PCT apparatus at hydrogen pressure of 37atm and 300K. The specific surface areas and pore diameter were analyzed by N2/77K BET, and the surface morphologies were studied by SEM. Further, XRD analysis clearly indicated the presence of different iron oxides in these composite materials. From the experimental result, the hydrogen adsorption capacity of γ-Fe2O3 / CNP composite increased with different iron contents (7wt%、28wt%、56wt%). Especially, γ-Fe2O3 / CNP composite with 14 wt% of iron-spiked showed maximum hydrogen adsorption of 0.48wt%, which is 1.9 times of the original CNP(0.256wt%). For one reason, massive micropores appeared when iron oxide formed on the surface of CNP. For another, it was postulated that γ-Fe2O3 crystals promoted the access of hydrogen molecules by polarizing the surface, which benefited the migration of hydrogen molecules to the carbon nanopowder (CNP) surface. In this case, γ-Fe2O3 played as a promoter to attract hydrogen molecules whereas CNP skeleton performed as the principal absorbent for hydrogen storage. The hydrogen adsorption capacity of the other composite α-Fe2O3 / CNP decreased with all iron contents compared to original CNP. It was result from the decrease of micopores on surface. In order to investigate the contribution to hydrogen adsorption capacity between two different iron oxides, we transformed α-Fe2O3/CNP composite to γ-Fe2O3 / CNP composite under hydrogen atmosphere of 20atm and 633K. We found out that the hydrogen adsorption increased after phase transformation. This phenomenon proved that the presence of γ-Fe2O3 made the surface of composite more attractable for hydrogen than α-Fe2O3. Based upon our experimental results, a high hydrogen uptake could be achieved by appropriately adjusting the surface polarity of CNP with well dispersed iron oxides crystals and more micropores on surface.
50
宋隆裕. "Removal of Residual Carbon in Iron Powder by Carbon Dioxide". Thesis, 1990. http://ndltd.ncl.edu.tw/handle/11628155279764226246.
Pełny tekst źródłaStreszczenie:
碩士國立臺灣科技大學
工程技術研究所
78
The purpose of this research was to study the decarburization of residual carbon in iron powder using CO2-Ar mixing gas. The iron powder was obtained by a direct reduction of mill scale with coke. After the reduction, residual carbon was left in the produced iron powder. The carbon existed in forms of iron carbide Fe3C or coke. The decarburization was studied in a quartz tube reactor. Iron powder with particle sizes of 40-45, 45-60, 60-85 and 120-200. meshes were employed. The experimental reaction temperatures were ranged between 893-923 K and 002 partial pressures were ranged between O.I and 0.4 atm. The effluent gas from the decarburization was analyzed by a G. C. equipped with a thermal conductivity detector. The experimental results show that particle size affects the decarburization rate very little. The rate of decarburization and iron oxidation both increase with a increase of reaction temperature and CO2 partial pressure. Experimental data have shown the decarburization take place before the oxidation of the iron powder. The decarburization could be divided into two stages. The first stage , with a carbon conversion on between 0-30 %, is called a nucleation stage and is represented by The decarburization is rapid in this stage. The second stage, with a carbon conversion greater than 50 %, is called a shrinking core stage. In this stage the decarburization is slower than the frist stage.