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Gassama, Edrissa. "A Model of the Dye-Sensitized Solar Cell: Solution Via Matched Asymptotic Expansion." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1408058509.
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Rahman, Mohammed. "A performance and energy evaluation of a dye drawn forward osmosis (FO) system for the textile industry." Thesis, Cape Peninsula University of Technology, 2020. http://hdl.handle.net/20.500.11838/3068.
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Thesis (MEng (Chemical Engineering))--Cape Peninsula University of Technology, 2020Continuous growth in the world population has raised significant fears with regards to the sustainability of energy and water resources. Globally, water is an indispensable resource as it is essential for the sustenance of human, animal and plant life. Water is essential for all forms of life and plays a pivotal role in economic growth. The textile industry is one of the greatest consumers of water, it is, therefore, necessary to effectively treat the large amounts of wastewater before discharge to the environment. It is estimated that annually, more than 700,000-tonnes of textile wastewater is produced by the dyeing industry. Textile wastewater is generally characterised by electrolytes, suspended solids, mineral oils and multiple textile dyes, and has therefore been classified as one of the most polluting wastewaters. These dyes are toxic and, in most cases, are not biodegradable. The presence of very small amounts (i.e. < 1 ppm) of dyes in water has aesthetic impacts and is thus undesirable. It is, therefore, necessary to treat textile wastewater before discharging. Currently, membrane technology is widely used for wastewater treatment, as well as water purification. Forward osmosis (FO) is a promising technology for both these applications. FO is characterised by the flow of water through a semipermeable membrane from a feed solution (FS) characterised by the low solute concentration or low osmotic pressure (OP) to a draw solution (DS) characterised by the high solute concentration or high OP, due to the OP gradient across the membrane. The FO process eliminates the need for high hydraulic pressure, as required in traditional membrane technologies, and also has low fouling tendencies. Furthermore, FO has the advantage of lower energy requirements and membrane replacement costs. However, there are still many disadvantages such as reverse solute flux (RSF), membrane fouling, and concentration polarisation (CP) amongst others that still need to be addressed. Therefore, more research needs to be done in light of these limitations to better understand and mitigate these limitations to increase the effectiveness and efficiency of the FO process. This study aimed to evaluate a dye-driven FO system for the reclamation of water from textile wastewater and synthetic brackish water (BW5) by investigating the effects of membrane orientation, system flowrate, change in DS, and membrane fouling on the FO systems performance and energy consumption. The FS used was BW5 with sodium chloride (NaCl) content of 5 g/L whereas Reactive Black 5 (i.e. a reactive dye) and Maxilon Blue GRL (i.e. a basic dye) dyes were used as a DS, respectively. The membrane utilised was a cellulose triacetate (CTA) membrane and was tested in FO mode and pressure retarded osmosis (PRO) mode whilst the system flowrate was adjusted to 400, 500 and 600 mL/min, respectively. Experiments were performed using a bench-scale FO setup which comprised of an FO membrane cell, a double-head variable speed peristaltic pump, a digital scale, two reservoirs for the FS and DS, respectively, a digital multiparameter meter and a digital electrical multimeter to measure system energy consumption. Each experiment comprised of six steps: baseline 1 (membrane control), main experiment (dye-driven FO experiment), baseline 2 (membrane control repeat), membrane cleaning, membrane integrity (membrane damage dye identification) and membrane cleaning (preparation for next experiment). The baseline 1 and baseline 2 experiments operated for 3 h whilst each membrane cleaning procedure operated for 30 min. The main experiments operated for 5 h in the FO mode and 4 h in PRO mode whilst the membrane integrity experiments operated until a minimum of 10 mL water was recovered. Results showed that the PRO mode achieved both higher forward flux (𝐽𝑤) (i.e. 8.87, 8.71 and 9.13 L/m2.h for flowrates of 400, 500 and 600 ml/min) and water recovery (𝑅𝑒) rates compared to FO mode (i.e. 6.60, 6.88 and 7.58 L/m2.h for flowrates of 400, 500 and 600 ml/min). The variation of flowrates had little to no influence on the 𝐽𝑤, 𝐽𝑠 and 𝑅𝑒 of the system. The system consumed less energy in PRO mode (i.e. 381 kWh/m3 average consumption for all three flowrates) than FO mode (i.e. 417 kWh/m3 average consumption for all three flowrates). It was also observed that at a higher DS 𝑂𝑃, the system consumed less energy. Therefore, selecting an optimum initial 𝑂𝑃 is essential for a FO process to minimise the pumping energy. Furthermore, a change in DS from Reactive Black 5 dye to Maxilon Blue GRL dye had no significant impact on the system performance and energy consumption. In this study, no significant membrane fouling was observed, however, minute traces of fouling in the form of foreign functional groups could be observed in the attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) spectrums of the used membranes. Additionally, the observation of negligible changes in baseline 2 (membrane control) Re and Jw results suggested the possible occurrence of membrane fouling during the main experiment (dye-driven FO system).
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Yousef, Narin. "Solution-based and flame spray pyrolysis synthesis of cupric oxide nanostructures and their potential application in dye-sensitized solar cells." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119329.
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The dye sensitized solar cell (DSSC) is a promising low-cost technology alternative to conventional solar cell in certain applications. A DSSC is a photo-electrochemical photovoltaic device, mainly composed of a working electrode, a dye sensitized semiconductor layer, an electrolyte and a counter electrode. Sunlight excites the dye, producing electrons and holes that can be transported by the semiconductor and electrolyte to the external circuit, converting the sunlight into an electrical current. A material that could be useful for DSSCs is the nanoscale cupric oxide, which can act as a p-type semiconductor and has interesting properties such as low thermal emittance and relatively good electrical properties. The goal of this project was to synthesize and characterize CuO nanoparticles using three different methods and look into each products potential use and efficiency in DSSCs. The particles were synthesized using two different solution based chemical precipitation methods and a flame spray pyrolysis method, yielding nanostructures with different compositions, structures and sizes ranging from ~20 to 1000 nm. The nanoparticle powder synthesized by the flame spray pyrolysis route was tested as semiconductor layer in the working electrode of the DSSC. Current-voltage measurements presented low solar conversion efficiencies with a reversed current, meaning that the cupric oxide cells did not work in a desirable way. Further studies of the cupric oxide synthesis and its suitability in DSSCs are needed to increases the future possibilities for gaining well working p-type DSSCs with higher efficiencies.
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Petersson, Jonas. "Ultrafast, Non-Equilibrium Electron Transfer Reactions of Molecular Complexes in Solution." Doctoral thesis, Uppsala universitet, Fysikalisk kemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-235461.
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Photoinduced electron transfer is a fundamentally interesting process; it occurs everywhere in the natural world. Studies on electron transfer shed light on questions about the interaction between molecules and how the dynamics of these can be utilized to steer the electron transfer processes to achieve a desired goal. The goal may be to get electrons to the electrode of a solar cell, or to make the electrons form an energy rich fuel such as hydrogen, and it may also be an input or output for molecular switches. The importance of electron transfer reactions will be highlighted in this thesis, however, the main motivation is to gain a better understanding of the fundamental processes that affect the rate and direction of the electron transfer. A study of photoinduced electron transfer (ET) in a series of metallophorphyrin/bipyridinium complexes in aqueous solution provided fresh insight concerning the intimate relationship between vibrational relaxation and electron transfer. The forward electron transfer from porphyrin to bipyridinium as well as the following back electron transfer to the ground state could be observed by femtosecond transient absorption spectroscopy. Both the reactant and the product states of the ET processes were vibrationally unrelaxed, in contrary to what is assumed for most expressions of the ET rates. This could be understood from the observation of unrelaxed ground states. The excess energy given by the initial excitation of the porphyrin does not relax completely during the two steps of electron transfer. This is an unusual observation, not reported in the literature prior the studies presented in this thesis. This study also gave the first clear evidence of electronically excited radical pairs formed as products of intramolecular electron transfer. Signs of electronically excited radical pairs were seen in transient spectra, and were further verified by the observation that the rates followed a Marcus normal region behavior for all excitation wavelengths, despite the relatively large excess energy of the second excited state. This thesis also concerns electron transfer in solar cell dyes and mixed valence complexes. In the ruthenium polypyridyl complex Ru(dcb)2(NCS)2, where dcb = 4,4’-dicarboxy-2,2’-bipyridine, inter-ligand electron transfer (ILET) in the 3MLCT state was followed by means of femtosecond transient absorption anisotropy that was probed in the mid-IR region. Unexpectedly, ILET was not observed because electron density was localized on the same bpy during the time-window allowed by the rotational lifetime.
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Josefsson, Ida. "Simulations of a Ruthenium Complex and the Iodide/Triiodide Redox Couple in Aqueous Solution: Solvation and Electronic Structure." Thesis, Uppsala University, Department of Physics and Astronomy, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-126677.
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In dye-sensitized solar cells, the functions of light absorption and charge transport are separated. A photosensitive ruthenium-polypyridine dye in the cell absorbs light, injects an electron to a semiconductor and is then regenerated by a redox couple, typically iodide/triiodide. Quantum chemical calculations of the electronic structure of triiodide have been carried out with the restricted active space SCF method, including spin-orbit coupling, and with density functional theory. It was shown that the difference in charge density between the terminal and central atoms results in a splitting of the core levels. The calculations gave a value of the splitting of 0.8 - 1.0 eV for the 3d and 4d levels. Experimentally, the electronic structure has been investigated with photoelectronspectroscopy. The measured terminal/center splitting is 1.1 eV.The spin-orbit interaction of the 4d levels of triiodide has also been calculated. The splitting was determined to be 1.6 eV. The experimental value is 1.7 eV. An assignment of the peaks in the computed spectrum of triiodide was made and the features of the experimental spectrum have beenidentied.The theoretical valence spectrum of triiodide has been computed and assigned. The results can be used in the analysis of photoelectron spectra of the molecule. Information about the electronic structure of the redox couple can help in the understanding of the electron transfer processes and forfurther development of the solar cells. Furthermore, the solvation structure of the prototype dye, the tris(bipyridine)ruthenium(II) complex, in water and its interaction with iodide and chloride has been studied by means of molecular dynamics simulations. The trajectory analysis showed that the water molecules in the first solvation shell form a chain in between the bipyridine ligands. It was found that the iodide ions are more likely than chloride to enter between the ligands, which can be important for the electron transfer processin the solar cell.
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Charbonneau, Cecile. "Aqueous solution synthesis of nanocrystalline TiO2 powders: kinetics, characterization and application to fabrication of dye-sensitized solar cell photoanodes." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103625.
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The scope of this thesis is the aqueous synthesis and characterization of titanium dioxide nanostructured powders for the fabrication of thin film photoanodes used in DSC devices. The development and study of this novel process is approached from the standpoint of determining the relationship between the hydrolytic behaviour of isothermally treated titanium tetrachloride aqueous solutions (speciation and kinetics of conversion of Ti(IV) into TiO2(s)) and the properties of the resultant TiO2 products. From an application standpoint, the aqueous synthesized nanocrystalline TiO2 material is studied for the formulation of screen-printing pastes used in the fabrication of mesoporous photoanodes and resultant dye-sensitized solar cell (DSC) performance. The synthesis of TiO2 nanostructured powders by forced hydrolysis of aqueous Ti(IV) chloride solutions is described in terms of precipitation kinetics and nucleation and growth mechanism over the temperature range 70-90 °C and Ti(IV) concentration 0.2-1.5 M. Several techniques are used to characterize the resultant solid products, among which are XRD, FEG-SEM/FEG-TEM, BET surface area, TGA, FT-IR, and EDS analyses. Via appropriate selection of conditions, the aqueous synthesis process is shown that can lead to the preferential production of nanostructured rutile powder with unique self-assembled nanofibre (100 nm – 3 µm) spheroidal particles or colloids made of well dispersed 4-8 nm crystallites with anatase as the major crystalline phase (85 wt.%). These results are explained and discussed based on the effect of various process parameters (T, agitation), but most importantly based on the pronounced effect of the initial concentration of the TiCl4 aqueous solution on the speciation of the solution and related kinetics of the hydrolysis reaction. When compared to benchmark products such as the P25 TiO2 from Degussa (50 m2/g, 30 nm average crystallite size, very little to no surface -OH/-OH2, and 3.15 eV band gap), the two types of aqueous-synthesized materials are found to possess a high specific surface area, with 80-120 m2/g for the rutile powders and 250-350 m2/g for the anatase powders, enhanced surface hydroxylation, and larger band gap (3.37 eV) in the case of the anatase nanopowder. These materials are shown that can be used for the fabrication of thin film photoanodes prepared by the screen-printing method either separately (i.e. anatase) or as hybrid (anatase-rutile) with the latter being superior in terms of photovoltaic performance. Finally, the direct preparation of paste without drying of the nanocolloids is demonstrated.Cette étude porte sur la synthèse en milieu aqueux de particules nano-structurées de dioxide de titane utilisées pour la fabrication de photoanodes, une composante des cellules photovoltaïques à pigments colorés (DSCs). Le développement et l'étude de ce nouveau procédé de synthèse est abordé de façon à déterminer la relation existante entre le comportement hydrolytique de solutions aqueuses de tetrachlorure de titane traitées de manière isothermique (spéciation et cinétique de conversion de Ti(IV) en TiO2(s)) et les propriétés des produits de TiO2 résultant. D'un point de vue pratique, le produit de TiO2 nanocristallin synthétisé en milieu aqueux est examiné pour la formulation de pâtes à imprimer utilisées dans le procédé de fabrication de photoanodes mésoporeuses; l'impact de ce matériau sur l'efficacité des cellules photovoltaïques à colorant est également considéré. La synthèse de poudres de TiO2 nano-structurées, effectuée par hydrolyse de solutions aqueuses de TiCl4, est décrite d'un point de vue de la cinétique de précipitation et des mécanismes de nucléation et de croissance des particules de TiO2, sur des intervalles de température et de concentration variant respectivement de 70 à 90 °C et de 0.2 à 1.5 M. Plusieurs techniques sont utilisées afin de caractériser les produits solides, parmi lesquels la DRX, le MEB et le MET, les spectroscopies FT-IR et EDS, et des mesures d'aire de surface BET et de thermogravimétrie. Il est montré qu'en choisissant les conditions expérimentales de manière appropriée, le procédé de synthèse en milieu aqueux mène à la production de poudres nano-structurées de rutile composées de particules sphéroïdales dont la forme résulte de la croissance radiale de nanofibres (de 100 nm à 3 µm) ou bien de colloïdes contenant des nano-cristaux de 4 à 8 nm dont la principale phase cristalline est l'anatase (85 % m/m). Ces résultats sont expliqués et commentés sur la base des effets induits par les paramètres expérimentaux (T, agitation) et plus particulièrement l'effet prononcé de la concentration de la solution aqueuse de TiCl4 sur la nature des espèces en solution et la cinétique associée à la réaction d'hydrolyse. Si l'on compare les matériaux synthétisés en milieu aqueux avec des produits standards commerciaux tels que la poudre de TiO2 P25 de Degussa (50 m2/g, 30 nm de taille moyenne de particules, présence faible voire nulle de groupes de surface -OH/-OH2 et un band gap de 3.15 eV), ceux-ci sont caractérisés avec une aire de surface plus importante, 80-120 m2/g pour les poudres de rutile et 250-350 m2/g pour les poudres d'anatase, un taux d'hydroxylation de surface plus élevé et un band gap plus large dans le cas de l'anatase (3.37 eV). Il est montré que ces matériaux, plus précisément la poudre d'anatase seule ou bien une poudre hybride d'anatase et de rutile, peuvent être utilisés afin de fabriquer des photoanodes préparées par méthode d'impression, la deuxième poudre ayant montré une qualité supérieure en termes de performance photovoltaïque. Enfin, la préparation de pâtes à imprimer directement à partir de nanocolloides de TiO2, sans avoir à recourir à l'extraction et au séchage des poudres, est décrite.
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Fan, Jiandong. "Solution Growth and Functional Properties of Vertically Aligned ZnO Nanowires." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/120578.
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This dissertation has focused on three main topics: (1) Synthesis and characterization of ZnO:Cl NWs; (2) Hetero and homo nanostructures based on ZnO:Cl NWs for efficient PEC cells; (3) Photovoltaic performance of DSCs based on ZnO NWs.
(1) Vertically aligned single-crystal and chlorine-doped ZnO NWs can be grown by a low-cost, high-yield and seed-free electrochemical route with controlled morphology, structural and optoelectronic properties. The carrier concentration of such ZnO:Cl NWs could be tuned in the range between 5× 1017 and 4×1020 cm-3 by varying the Cl doping concentration. Besides, intrinsic ZnO NWs with various lengths of 6-12 μm and diameters of 40-120 nm can also be obtained by hydrothermal deposition for the application in DSCs.
(2) Vertically aligned core@shell ZnO:Cl@ZnO homostructures and ZnO:Cl@ZnS and ZnO:Cl@TiO2 heterostructures NWs can be obtained by electrodeposition and/or SILAR two-step process. The PEC properties of these NWs can be highly enhanced up to a factor 5 with the presence of these shell layers. The enhancement factor depends on the shell thickness. These performances are associated with the improvement of the photogenerated charge carrier separation and surface to neutral inner part transfer capability achieved when increasing the space charge area within the NWs with a built-in electric field introduced by the doping profile.
(3) We have employed [Co(bpy)3]2+/3+ redox couple as electrolyte in ZnO NWs-based DSCs. A direct comparison of the performance of [Co(bpy)3]2+/3+ and I−/I3− redox couples demonstrated the higher suitability of the cobalt complex, both in terms of a significantly improved Voc (Delta/Voc~200 mV) and a increased photocurrent (Delta/Jsc ~10%). The post-annealing of the NWs in argon allowed further improving the power conversion efficiency with a value of 30% compared to air. The improved efficiency was dominated by significantly higher photocurrents (Delta/Jsc~50%) measured from Ar-DSCs when compared with Air-DSCs.Esta tesis se ha centrado en tres temas principales: (1) Síntesis y caracterización de NHs de ZnO:Cl; (2) Celdas PEC basadas en hetero y homo nanoestructuras obtenidas a partir de NHs de ZnO:Cl ; (3) DSCs basadas en NHs de ZnO. (1) NHs monocristalinos de ZnO, alineados verticalmente y dopados con cloro fueron sintetizados mediante un método electroquímico de baje coste, alto rendimiento y sin necesidad de semillas. Los resultados demuestran que la concentración de portadores de carga en estos NHs de ZnO:Cl puede ser controlada en un rango entre 5×1017 y 4×1020 cm-3. Además, NHs de ZnO intrínsecos de varias longitudes, entre 6 μm y 12 μm, pueden ser obtenidos por deposición hidrotérmica para aplicación en celdas solares sensibilizadas por colorante (DSCs). (2) Homoestructuras ZnO:Cl@ZnO y heteroestructuras ZnO:Cl@ZnS y ZnO:Cl@TiO2 verticalmente alineadas pueden ser obtenidas mediante electrodeposición y/o un proceso SILAR de dos pasos. Las propiedades PEC de estos NHs pueden ser altamente mejoradas hasta un factor 5 con la presencia de estas capas. El factor de mejora depende del grosor de la capa. La mejora en los rendimientos está asociada con la mayor generación de portadores de carga y la optimización de su transferencia a partir del incremento en el área de carga espacial debido al perfil dopante. (3) Hemos empleado la pareja redox [Co(bpy)3]2+/3+ como electrolito en DSCs basadas en NHs de ZnO. Una comparación directa del rendimiento de las parejas redox [Co(bpy)3]2+/3+ y I−/I3– demostró que el complejo de cobalto es más adecuado, tanto en términos de una significativa mejora en el Voc (Delta/Voc~200 mV) como en un mayor fotocorriente (Delta/Jsc~10%). El posterior sinterizado de los NHs en argón permitió una mejora del 30% en la eficiencia de conversión de luz en energía eléctrica. La mejora del rendimiento fotovoltaico fue atribuído a la incorporación de vacantes de oxígeno durante el sinterizado de los NHs en argón.
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Choi, Kit-hing. "The bleaching and dyeing industry in Hong Kong : environmental problems and some solutions /." Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B18735988.
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MAGADALENA, CARINA P. "Síntese de zeólitas de cinzas de carvão modificada por surfactante e aplicação na remoção de ácido laranja 8 de solução aquosa: estudo em leito móvel, coluna de leito fixo e avaliação ecotoxicológica." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23651.
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Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Abouamer, Karima Massaud. "Application of natural dyes in textile industry and the treatment of dye solutions using electrolytic techniques." Thesis, Brunel University, 2008. http://bura.brunel.ac.uk/handle/2438/5088.
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Anodic oxidation of a commercial dye, methylene blue (MB), from aqueous solutions using an electrochemical cell is reported. Data are provided on the effects of eight different types of supporting electrolytes, concentration of electrolytes, initial dye concentration, current and electrolytic time on the percentage removal of methylene blue. Anodic oxidation was found to be effective in achieving the removal of methylene blue from aqueous solutions. The optimised electrolytic conditions, for the removal of methylene blue (MB), were applied to the removal of azure A (AA), azure B (AB), azure C (AC), toluidine blue 0 (TBO), new methylene blue (NMB), dimethyl methylene blue (DMMB), thionine (TH), methylene green (MG), methyl violet (MV), Nile blue (NB), neutral red (NR), acridine orange (AO) and resorufin (RS) from aqueous solutions containing sodium chloride. Results indicated that between 84 to 100% of each dye of phenothiazine was removed during 60 minutes of electrolysis. The percentage removals for the phenothiazine dyes followed the following decreasing order: (MG ≈ MV) > (DMMB ≈ AA) > (AB ≈ AC ≈ NMB) > TBO > TH. However, the azine, acridine and oxazine dyes showed between 98 to 99% colour removal and the following decreasing order: NB ≈ NR > AO ≈ RS. Strongly electron withdrawing substituents such as nitro group or carbonyl group increases the degradation of the phenothiazine chromophore, whereas the electron donating groups such as amino and alkyl amino groups decrease the degradation. Anodic oxidation studies were extended to the destruction of eight permitted food colours, with azo and triarylmethane chromophore, from aqueous solution containing either sodium chloride or sodium sulphate as a supporting electrolyte. Again, sodium chloride was found to be the best supporting electrolyte and between 97 to 100% colour removal was achieved after 60 minutes of electrolysis. The percentage removal for the single azo based colourants followed the following increasing order: carmoisine > sunset yellow FCF > amaranth > ponceau 411 > tartrazine. However, the binary and ternary mixtures of food colour showed the following increasing order: blue > green > yellow food colours. The extractions and applications of 54 different types of natural dyes (53 from plants and one from animal origin) are evaluated using simple techniques. The extracted natural dyes were applied in dyeing three types of textile fabrics viz: a) paj silk, b) brushed cotton twill and c) crystallized shimmering satin. The effects of two eco-friendly mordants (alum and iron) on the dyeing process were compared with the dyeing process without mordants. The colour fastness to wash and light (both natural and artificial sun light) of these natural dyes were also assessed. The results showed that out of the 54 dyestuffs studied, 32 plants are potentially able to produce marketable natural dyes. These dyes produced good colour and met minimal performance standards for colour fastness to light and washing. The addition of mordants generally increased the fastness properties. Silk gave the best performance of dyeing uptake and stability. Cotton gave the poorest fastness properties. The overall results showed that, considering molecular associations, the fastness properties were of the order: anthraquinones and tannins> indigoid > flavones> flavonols > flavanols> carotenoids> anthocyanins. Anodic oxidation studies were extended to the destruction of ten natural dyes from aqueous solutions containing either sodium chloride or sodium sulphate as a supporting electrolyte. Anodic oxidation was effective in achieving the removal of green tea (35%), spinach (69%), Langdale yellow and turmeric (95%), carmine, saffron, henna (97%), beetroot, karkade and sumac (98%). However, TOC measurements and the UV analyses indicated that some organic intermediate compounds were formed in the presence of sodium chloride.
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Mousa, Souad Abd. "Photochemistry of β-carbolines and azine dyes in solution and colloidal systems." Thesis, Swansea University, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678433.
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Murray, S. G. "Solution and polymer photochemistry of azo dyes." Thesis, University of Leeds, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371437.
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BRUNO, MARIZA. "Utilização de zeólitas sintetizadas a partir de cinzas de carvão na remoção de corante em água." reponame:Repositório Institucional do IPEN, 2008. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11509.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
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Longeras, Olympe. "Design et compréhension de nouveaux solvants eutectiques profonds." Thesis, Université Clermont Auvergne (2017-2020), 2020. http://www.theses.fr/2020CLFAC048.
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Les solvants eutectiques profonds (DES) forment une nouvelle famille de solvants qui a émergé ces dernières années. Les DES sont de plus en plus étudiés de par leur faible coût, leur faible toxicité et leurs propriétés qui devraient leur permettre de remplacer des solvants toxiques utilisés dans de nombreux domaines de la chimie. Lors de ma thèse, un premier travail a permis d’établir les diagrammes de phases solide-liquide de trois DES partiellement biosourcés. Par la suite, une comparaison entre ces DES et des mélanges idéaux a permis d’établir que ces systèmes peuvent être considérés comme solvants eutectiques « profonds ». Au cours de mes travaux, un premier solvant aqueux possédant une température de solution critique inférieure a été mis en évidence et l’origine de cette propriété remarquable a été élucidée. Au-delà des travaux sur la compréhension des DES, ces solvants ont été testés pour deux applications : le captage du dioxyde de carbone et l’extraction liquide-liquide de colorantsDeep Eutectics Solvents (DES) is a new class of solvent which has emerged during the last decades. DES have been increasingly studied because of their low cost and low toxicity. Because of these properties, DES could potentially replace toxic solvents used in large area of chemistry. To reach this goal, a broader knowledge of these new systems has to be acquired. Therefore, in the first work of this thesis, solid-liquid phase diagrams of three partially renewable DES have been established. The comparison of these diagrams to an ideal mixing model is showing a negative deviation that allows to considered them as “deep” eutectics solvents. Following this work on the binary mixture, water was added to these DES. A first aqueous - DES mixture with a lower critical solution temperature (LSCT) has been highlighted and the origin of this remarkable property has been elucidated. To complete the initial work aiming to get a deeper understanding of these new DES, these solvents have also been tested for two applications: carbon dioxide capture and liquid-liquid extractions of dyes
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Natali, Andrea. "Double Dyke System - Natural engineering solutions." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21243/.
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According to various studies, the effects of climate change will be a danger to ecosystems and the population, especially in coastal areas, increasing the risk of floods. Authorities are taking action to prevent future disasters using traditional engineering solutions. These solutions can have high environmental and economic costs, fixing the coastline, increasing the salinization of aquifers, and can be subject to failure mechanisms.
For this reason, studies were made to use natural engineering solutions for coastal protection, instead of traditional solutions, to achieve the UN SDGs. Coastal ecosystems have the natural ability to repair and restore themselves, increasing soil elevation, and attenuating waves. One of these solutions is the Double Dyke System, consisting of creating a salt marsh between the first dyke and a second inland. The goal is to protect the coasts and to restore ecosystems.
The purpose of this study is to compare the costs of natural engineering solutions with traditional ones. It is assumed that these solutions may be more effective and less expensive in the long run. For this evaluation, a suitability analysis of the polders in the Dutch Zeeland region to assess the costs and benefits under different SLR scenarios was made. A saline intrusion model was also created to analyze the effects of a salt marsh on the aquifers. From the analyzes conducted, the implementation of the DDS turns out to be the cheapest coastal defense system in all SLR scenarios. The presence of a salt marsh could also have a positive impact on the prevention of saline intrusion in the various scenarios considered.
The DDS could have a positive economic and environmental impact in the long term, reducing the investment costs for coastal defense and bringing important benefits for the protection of man and nature.
Despite the results, more studies are needed on the efficiency of this defense system and on the economic evaluation of non-marketable ecosystem services.
16
Khan, Christopher Joseph 1982. "Solution for a modular die-level anodic bonder." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32764.
Full textAbstract:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references.
Anodic bonding is a common way to package silicon with Pyrex. The anodic bonding process requires high temperature, voltage, and moderate pressure to occur. Often, there are also expectations of alignment of features for things such as power or material delivery. The following thesis proposes a design for a die-level anodic bonding apparatus. It consists of a separate module to meet each requirement; a module for heating, aligning, and applying force. The apparatus is capable of heating the MEMS device to over 400⁰C, applying more than 1000V across the device, applying greater than 4MPa of pressure, and aligning to within 0.5[micro]m in two directions to create an accurately aligned anodic bond. The apparatus met all of these functional requirements and is modular. enough to easily be configured for many other die-level anodic bonding situations.
by Christopher Joseph Khan.
S.B.
17
MAGDALENA, CARINA P. "Adsorcao de corante reativo remazol vermelho RB de solucao aquosa usando zeolita de cinzas de carvao e avaliacao da toxicidade aguda com Daphnia similis." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9565.
Full textAbstract:
Made available in DSpace on 2014-10-09T12:28:05Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:01:22Z (GMT). No. of bitstreams: 0
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
18
Bowman, Amy Catherine. "A selective encapsulation solution for packaging an optical micro electro mechanical system." Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-0108102-140953.
Full textAbstract:
Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: packaging; micro electro mechanical systems; MEMS; electronics; die warpage; die bow; encapsulant; encapsulate; electrochemical migration; corrosion; wirebonds. Includes bibliographical references (p. 94-99).
19
Pirgalioglu, Saltuk. "Catalytic Ozonation Of Dye Solutions In A Semi-batch Reactor." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610158/index.pdf.
Full textAbstract:
Treatment of textile wastewaters containing dye materials using the conventional methods based on biological treatment is not possible. In order to overcome this problem, ozonation based on the oxidation of organic pollutants with ozone gas dissolved in aqueous phase have been studied widely. Catalytic ozonation and advanced oxidation processes (AOP) are also used in order to increase the efficiency of sole ozonation
In this work, catalytic ozonation processes in the presence of Copper Sulfide (CuS) powder and a synthesized catalyst by the impregnation of iron on alumina (Fe/Al2O3) were studied separately in the treatment of dye solutions, namely Remazol Brilliant Blue-R (RBBR) and Reactive Black-5 (RB-5). Besides catalytic ozonation runs, ozonation parameters and ozonation mechanism were also studied and a model was developed for the semi-batch ozonation.
Both catalysts increased the oxidation of side products measured by the decrease in the amount of total organic carbon (TOC) in the treated dye solutions. Dye removal rates were also enhanced in the treatment of RB-5 dye solutions while no significant effect was observed on dye removal rates of RBBR solutions.
TOC removals above 90% were observed in the catalytic ozonation using CuS for both of the dye solutions at pH =10 having initial dye concentration of 100 mg/L. The most significant effect of the catalyst addition was observed at pH = 3 where the TOC removals of non-catalytic ozonation were the lowest. CuS addition increased percent TOC removal at the end of the reaction period of 80 min by 123% in the treatment of 100 mg/L RBBR solution, and by 65% in the treatment of 100 mg/L RB-5 solution at pH = 3. On the other hand, addition of Fe/Al2O3 catalyst increased TOC removal of 100 mg/L RB-5 solution by 52 % at pH = 3.
In addition, volumetric mass transfer coefficients (kLa) of ozone in the absence and in the presence of a chemical reaction between dye and ozone were estimated from modeling. A correlation for the enhancement factor of ozone absorbed into dye solutions in terms of initial dye concentration was obtained and reported.
20
Goswami, Nimai Chandra. "Treatment of leather effluents and dye solutions using electrolytic techniques." Thesis, Brunel University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270534.
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21
Acar, Ebru. "Oxidation Of Acid Red 151 Solutions By Peroxone (o3/h2o2) Process." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605527/index.pdf.
Full textAbstract:
Wastewaters from textile industry contain organic dyes, which cannot be easily treated by biological methods. Therefore, pretreatment by an advanced oxidation process (AOP) is needed in order to produce more readily biodegradable compounds and to remove color and chemical
oxygen demand (COD) simultaneously. In this research, ozone (O3) is combined with hydrogen peroxide (H2O2) for the advanced oxidation of an azo dye solution, namely aqueous solution of Acid Red 151, which is called as &ldquoPeroxone process&rdquo
. The aim of the study is to enhance the ozonation efficiency in treating the waste dye solution. The effects of pH, initial dye and initial ozone concentrations and the concentration ratio of initial H2O2 to initial O3 on color and COD removals were investigated. Also, the kinetics of O3-dye reaction in the presence of H2O2 was approximately determined. As a result of the experimental study, it was seen that an increase in the initial dye concentration at a constant pH and initial ozone concentration did not change the COD % removal significantly, from a statistical analysis of the data. The results obtained at pH values of 2.5 and 7 gave higher oxidation efficiencies in terms of color and COD removals compared to those at pH of 10. The best initial molar ratio of H2O2 to O3 was found to be 0.5, which yielded highest treatment efficiency for each pH value studied. The results of the excess dye experiments suggest that the ozonation of Acid Red 151 follows an average first order reaction with respect to ozone at pH=2.5 and pH=7 whereas it is around 0.56 at pH=10. By Initial Rate Method, the orders with respect to individual reactants of O3 and dye were determined as one, the total order of the reaction being two for all the studied pH. As a conclusion, a further study of the peroxone process at a pH of 10 can be recommended to determine the reaction kinetics and mechanism at this pH, where radicals play an important role.
22
Duygulu, Yusuf Bahadir. "Decolorization Of Synthetic Dye Solutions By Using Basaltic Tephra And Clinoptilolite." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605241/index.pdf.
Full textAbstract:
Discharge of colored effluents without decoloration originated from textile industries may cause serious problems in the receiving environments.
In this study, natural materials that are basaltic tephra and clinoptilolite were used to remove various dyestuffs used in the textile industry. Those materials are cheap and available in large quantities in Turkey. The investigation of adsorption of basic, acidic and reactive dyes on these materials is the objective of this study.
During preliminary experiments it was seen that adsorption equilibrium was reached in about 2 days. In adsorption experiments, in order to obtain adsorption isotherms, a fixed amount of adsorbent and 100 mL dye solutions of different concentrations were placed in glass bottles which were shaken at 200 rpm and 25±2oC for 2 days. Then, samples were filtered and the equilibrium concentrations of dyestuffs in the solutions were determined by using spectrophotometer at appropriate wavelength corresponding to the maximum absorbency. After equilibrium concentrations of the solutions were obtained, Langmuir and Freundlich adsorption isotherm constants were calculated for the adsorbents used in this study. The removal efficiencies for cationic basic dyes are higher than those for anionic acidic and reactive dyes with the natural materials. Therefore, modification of surface properties of natural materials with a cationic surfactant was considered to increase the removal efficiencies of those for anionic dyes. After modification of the surface properties, adsorption capacities of adsorbents for anionic dyes were higher than those of natural materials. Finally, the adsorption capacity of activated carbon for the same dyes was determined to compare with that of natural and modified materials. The results showed that the adsorption of dyes on adsorbents used in this study fitted nicely the Langmuir Isotherm Equations.
23
Shargaieva, Oleksandra. "Formation and stability of hybrid perovskites." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19530.
Full textAbstract:
Solarzellen auf Basis von hybriden Perowskiten, wie zum Beispiel Methylammoniumbleitriiodid (CH3NH3PbI3), stellen eine der vielversprechendsten Solarzellenkonzepte dar. Dabei wurden Wirkungsgrade über 20 % gezeigt. Perowskite werden durch verschiedene lösungsbasierte Techniken abgeschieden. Daher konzentriert sich der erste Teil dieser Dissertation auf die Bildung von hybriden Perowskiten in der Lösung, während der zweite Teil der Stabilität von hybriden Perowskiten gewidmet ist. Im ersten Teil, wird die Bildung von Polyiodidplumbaten aus PbI2 in Lösung nachgewiesen. Die Bildung dieser Polyiodidplumbate konnte unabhängig von dem gewählten Lösungsmittel sowie unabhängig von der Beigabe von Methylammoniumiodid (CH3NH3I) beobachtet werden. Die Polyiodidplumbate zeigten, ähnlich wie CH3NH3PbI3, ein Photolumineszenzmaximum bei einer Wellenlänge von 760 nm, was auf einen gemeinsamen Ursprung des angeregten Zustands in PbI2-Komplexen und CH3NH3PbI3 hindeutet. Im zweiten Teil wurden darüber hinaus die Lichtbeständigkeit sowie die thermische und kompositionelle Stabilität untersucht. Die Untersuchung der thermischen Stabilität hat gezeigt, dass Tempern bei T <190 °C zu einer Verbesserung der Morphologie und der optoelektronischen Eigenschaften führt. Oberhalb einer Temperatur von 190 °C kam es dabei zur Zersetzung des Materials. Die Stabilität der Komposition wurde anhand von CsPb(I[1-x]Br[x])3-Perowskiten untersucht. Die Herstellung von Perowskiten mit einer großen Bandlücke war zunächst nicht möglich, da es bei den dafür notwendigen Kompositionen (0,3
24
Ngema, Silindile Lucia. "Competitive biosorption of a mixture of cationic dyes from a multicomponent solution using modified pine cone powder." Thesis, Vaal University of Technology, 2012. http://hdl.handle.net/10352/394.
Full textAbstract:
The biosorption of methyl violet and methylene blue onto modified pine cone powder was studied. Single and binary component systems studies were carried out for the biosorption of methyl violet and methylene blue onto raw, Fenton treated and acrylic acid grafted pine cone powder. Various experimental parameters were studied including initial dye concentration (200-900 mg/dm3), contact time, solution pH (4-12), mass of adsorbent (0.05-0.30g) and temperature (25-45 °C). Pseudo-first order and pseudo-second order equations were used to analyze the kinetic data. It was found that the data follow the pseudo -second order kinetic model for all temperature studied. The experimental data were analyzed using Langmuir and Freudlich isotherm model. The biosorption of methyl violet and methylene blue showed a better fit to Langmuir isotherm which properly describes the experimental data and that the sample surfaces are homogeneous. Various thermodynamic parameters, such as Gibbs energy (ΔG*), enthalpy change (ΔH*) and entropy change (ΔS*), were calculated which indicated the present system was spontaneous and exothermic process for methyl violet and methylene blue. It was found that enthalpy and entropy of acrylic acid grafted pine cone was higher as compared to raw and Fenton‘s reagent for methyl violet and methylene blue.
Raw, Fenton treated and acrylic acid pine cone powder were characterized with Fourier transform infrared spectroscopy (FTIR), Ultraviolet-visible spectroscopy (UV-VIS), Thermogravimetic analysis (TGA/DTA), X-ray Diffraction (XRD) and Brauner, Emmett and Teller (BET). The following parameters were used to determine the surface properties of the grafted pine cone: change in H+ concentration and oxidation reduction potential (ORP), surface negative charge, bulk density and acid number measurements. The FTIR analysis confirmed the presence of the organic compounds on the raw, Fenton treated and acrylic acid grafted pine cone powder. The UV/VIS determined the percentage removal of dyes from aqueous solution in single and binary component systems by comparing the raw, Fenton treated and Acrylic acid grafted pine cone powder. Thermo gravimetric analysis confirmed the reactions which occur at the molecular level of the raw, Raw + KMnO4 and Fenton treated + KMnO4 pine cone powder materials.
vi | P a g e
The second order derivative spectroscopy (SODS) was a suitable method for the analysis of the study of cationic dyes in binary solution. To determine the unknown concentrations of methyl violet and methylene blue dyes in binary solution using SODS, maximum wavelengths 561.8 nm and 623.1 nm were obtained. It was found that the percentage removal was higher for acrylic acid grafted pine cone than Fenton‘s treated and raw pine cone and treated samples adsorbed more methyl violet that methylene blue.
25
Hunt, Paula. "Photoreactions of dyes involving radicals in solution and on cotton." Thesis, Loughborough University, 2001. https://dspace.lboro.ac.uk/2134/34665.
Full textAbstract:
Cellulose is a natural polymer, which is used in many applications, including as clothing fabric. Thermal and photochemical degradation of cellulose is known to involve the production and reaction of radicals, and the degradation of dyes on cellulose fabrics is also thought to occur partially as a result of radical reactions. The radicals produced following hydrogen abstraction from cellulose are likely to be of the α-hydroxy type. The reactions of simple α-hydroxy radicals, as models for cellulose radicals, have therefore been studied here.
26
FERREIRA, PATRICIA C. "Estudos sobre a adsorção do corante reativo preto 5 de solução aquosa usando zeólita de cinza de carvão." reponame:Repositório Institucional do IPEN, 2011. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9984.
Full textAbstract:
Made available in DSpace on 2014-10-09T12:33:31Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:04:36Z (GMT). No. of bitstreams: 0
Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
27
Choi, Kit-hing, and 蔡結馨. "The bleaching and dyeing industry in Hong Kong: environmental problems and some solutions." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31253726.
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28
Balci, Ayse Irem. "Catalytic Ozonation Of Synthetic Wastewaters Containing Three Different Dyes In A Fluidized Bed Reactor." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613794/index.pdf.
Full textAbstract:
Environmental regulations have imposed limitations on a wide variety of organic and
inorganic pollutants in industrial textile wastewaters. There are several degradation
methods used in literature studies. Among these methods ozonation is one of the
most considered way to degrade refractory chemicals in textile wastewaters. In
recent years, catalytic ozonation as being one of the advanced oxidation processes
(AOPs), is applied to reduce the ozone consumption and to increase the Chemical
Oxygen Demand (COD) and Total Organic Carbon (TOC) removals.
Ozonation and catalytic ozonation of single and mixed dye solutions have been
examined both in a semi-batch reactor and also in a three phase fluidized bed reactor.
The dyes that are used in this study are Basic Blue 41 (BB-41), Basic Yellow 28
(BY-28) and Basic Red 18.1 (BR-18.1), these dyes are obtained from AKSA A.S.
(Yalova, Istanbul) textile plant. In order to measure the concentration of each dye in
the mixed dye solution, &ldquoabsorbance vs. concentration&rdquo
calibration correlations were developed. The effect of inlet dye concentration, inlet gas and liquid flow rates, pH, catalyst type [perflorooctyl alumina (PFOA) and alumina] and catalyst dosage were determined experimentally. Catalyst characterization analyses were done in order to determine the maximum number of times that the catalyst can be used and it was found to be 3 times. Gas washing bottle experiments are conducted to find the v amount of ozone required to oxidize one mole of each dye used in the study. Oxidation of BB-41, BR-18.1 and BY-28 dyes were investigated in a semi-batch reactor as single dye solutions by sole and catalytic ozonation with alumina and PFOA catalyst particles. The highest TOC and COD removals being 58.3% and 62.9%, respectively, were obtained at pH of 10 for BB-41 and 55.2% and 58.8%, respectively, for BR-18.1 with alumina catalyst. On the other hand, for BY-28 PFOA catalyst yielded highest TOC and COD reductions being 61.3% and 66.9%, respectively, at pH of 4. Minimum fluidization velocity (uL,min), the hold-up values of gas, liquid and solid phases, the dispersion coefficients (DL), and volumetric ozone-water mass transfer coefficients (kLa) were estimated at various gas and liquid flow rates in order to observe the effect of liquid mixing in the reactor on ozonation process. While PFOA catalyst was found to be effective in oxidizing BY-28 in acidic conditions (pH=4), BR-18.1 and BB-41 are degraded in alkaline medium (pH=10) with alumina catalyst better compared to acidic conditions. For catalytic ozonation reactions in fluidized bed reactor, the highest dye removals in mixed dye solution were observed for BY- 28 being 99.29% for gas flow rate (QG) of 340 L/h, liquid flow rate (QL) of 150 L/h and pH=4, initial dye concentration being 30 mg/L of each dye with PFOA catalyst, while for BR-18.1 and BB-41 being 95.39% and 97.95% respectively for QG = 340 L/h, QL = 150 L/h and pH=10, initial dye concentration being 30 mg/L of each dye with alumina catalyst. The highest TOC and COD reductions, 25.2% and 32.4%, respectively, were achieved in the catalytic ozonation of the mixed dye using PFOA as the catalyst at a pH of 4 and at a gas to liquid flow rate ratio of 2.26 (QG = 340 L/h, QL = 150 L/h). Highest dye removals were obtained at the same gas and liquid flow rates as those of the highest TOC and COD reductions in the experiments. Empirical TOC removal equations were obtained as a function of inlet TOC concentration, solution pH, gas and liquid flow rates.
29
Bunhu, Tavengwa. "Preparation and evaluation of Lignocellulose-Montmorillonite nanocomposites for the adsorption of some heavy metals and organic dyes from aqueous solution." Thesis, University of Fort Hare, 2011. http://hdl.handle.net/10353/535.
Full textAbstract:
The need to reduce the cost of adsorption technology has led scientists to explore the use of many low cost adsorbents especially those from renewable resources. Lignocellulose and montmorillonite clay have been identified as potentially low cost and efficient adsorbent materials for the removal of toxic heavy metals and organic substances from contaminated water. Montmorillonite clay has good adsorption properties and the potential for ion exchange. Lignocellulose possesses many hydroxyl, carbonyl and phenyl groups and therefore, both montmorillonite and lignocellulose are good candidates for the development of effective and low cost adsorbents in water treatment and purification. The aim of this study was to prepare composite materials based on lignocellulose and montmorillonite clay and subsequently evaluate their efficacy as adsorbents for heavy metal species and organic pollutants in aqueous solution. It was also important to assess the adsorption properties of the modified individual (uncombined) lignocellulose and montmorillonite. Lignocellulose and sodium-exchanged montmorillonite (NaMMT) clay were each separately modified with methyl methacrylate (MMA), methacrylic acid (MAA) and methacryloxypropyl trimethoxysilane (MPS) and used as adsorbents for the removal of heavy metals and dyes from aqueous solution. The lignocellulose and NaMMT were modified with MMA, MAA and MPS through free radical graft polymerisation and/or condensation reactions. NaMMT was also modified through Al-pillaring to give AlpMMT. The materials were characterised by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and small angle X-ray scattering (SAXS) and characterisation results showed that the modification of the montmorillonite with MAA, MMA and MPS was successful. The modified lignocellulose and montmorillonite materials were evaluated for the adsorption of heavy metal ions (Cd2+ and Pb2+) from aqueous solution by the batch method. The adsorption isotherms and kinetics of both Cd2+ and Pb2+ onto the NaMMT clay, AlpMMT and lignocellulose materials are presented. The Langmuir isotherm was found to be the best fit for the adsorption of both heavy metals onto all the adsorbents. AlpMMT showed very poor uptake for heavy metals (both Cd2+ and Pb2+). PMMAgMMT, PMAAgMMT, PMAAgLig and PMPSgLig showed improved adsorption for both heavy metals. The mechanism of heavy metal adsorption onto the adsorbents was best represented by the pseudo second-order kinetic model. PMPSgLig, NaMMT and AlpMMT showed relatively high adsorption capacities for methyl orange, while the adsorption of neutral red was comparable for almost all the adsorbents. Neither the Langmuir model nor the Freundlich model was found to v adequately describe the adsorption process of dyes onto all the adsorbents. The pseudo second-order model was found to be the best fit to describe the adsorption mechanism of both dyes onto all the adsorbents. The modification of lignocellulose and montmorillonite with suitable organic groups can potentially produce highly effective and efficient adsorbents for the removal of both heavy metals and dyes from contaminated water. Novel adsorbent composite materials based on lignocellulose and montmorillonite clay (NaMMT) were also prepared and evaluated for the removal of pollutants (dyes and heavy metals) from aqueous solution. The lignocellulose-montmorillonite composites were prepared by in situ intercalative polymerisation, using methyl methacrylate, methacrylic acid and methacryloxypropyl trimethoxysilane (MPS) as coupling agents. The composite materials were characterised by FTIR, TGA, TEM and SAXS. SAXS diffractograms showed intercalated nanocomposites of PMMAgLig-NaMMT and PMAAgLig-NaMMT, whereas PMPSgLig-NaMMT showed a phase-separated composite and the same results were confirmed by TEM. The lignocellulose-montmorillonite composites were assessed for their adsorption properties for heavy metal ions (Cd2+ and Pb2+) and dyes (methyl orange and neutral red) from aqueous solution. Among these composite materials, only PMAAgLig-NaMMT showed a marked increase in the uptake of both Cd2+ and Pb2+ relative to lignocellulose and montmorillonite when used independently. The adsorption data were fitted to the Langmuir and Freundlich isotherms, as well as to the pseudo first-order and pseudo second-order kinetic models. The data were best described by the Langmuir isotherm and the pseudo second-order kinetic model. On the adsorption of dyes, only PMPSgLig-NaMMT showed enhanced adsorption of methyl orange (MetO) compared with lignocellulose and montmorillonite separately. The enhanced adsorption was attributed to the synergistic adsorption due to the presence of MPS, lignocellulose and NaMMT. Competitive adsorption studies were carried out from binary mixtures of MetO and Cd2+ or Pb2+ in aqueous solution. The adsorption process of MetO onto the composite material was found to follow the Freundlich adsorption model, while the mechanism of adsorption followed both the pseudo first-order and pseudo second-order models. This particular composite can be used for the simultaneous adsorption of both heavy metals and organic dyes from contaminated water. The adsorption of neutral red to the composite materials was comparable and the pseudo second-order kinetic model best described the adsorption mechanism.
30
Al-Degs, Yahya Salim. "Adsorption of anionic reactive dyes on activated carbon from aqueous solution." Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394600.
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31
Schmitt, Christophe. "Etude de la coacervation complexe entre la beta-lactoglobuline et la gomme d'acacia en solution aqueuse." Phd thesis, Institut National Polytechnique de Lorraine - INPL, 2000. http://tel.archives-ouvertes.fr/tel-00007723.
Full textAbstract:
L'influence de la concentration totale en biopolymères et de la polydispersité de la protéine sur la formation et la stabilité de coacervats a été étudiée dans un mélange b-lactoglobuline/gomme d'acacia/eau. Les mélanges de b-lactoglobuline (b-lg) native ou agrégée (56% d'agrégats insolubles à pH 4,75) et de gomme d'acacia à des pH compris entre 3,6 et 5,0 sont caractérisés par une séparation de phase par coacervation complexe. Une concentration totale élevée en biopolymères limite l'influence du pH et du ratio de mélange protéine : polysaccharide sur la formation des coacervats dans les deux systèmes. En revanche, une forte polydispersité de la b-lg permet d'étendre l'aire de la zone biphasique des diagrammes de phases ternaires obtenus à pH 4,2. Des coacervats et des précipités sont obtenus en présence d'agrégats de b-lg. Seuls des coacervats sont visibles avec la b-lg native. Leur taille est contrôlée par les agrégats protéiques qui interagissent spécifiquement avec une fraction de la gomme d'acacia. La structure des coacervats est caractérisée par une vacuolisation issue d'une coalescence partielle des plus petits coacervats. Après interaction avec la gomme d'acacia, des mesures de dichroïsme circulaire indiquent une modification de la structure en hélice a de la b-lg, caractérisée par une densité de charge positive. La stabilité et la structuration des coacervats formés résultent d'un équilibre entre des phénomènes de floculation, coalescence et sédimentation des coacervats comme indiqué par des mesure de diffusion de la lumière en milieu turbide et microscopie confocale à balayage laser. Enfin, l'étude de la cinétique de structuration des mélanges b-lg/gomme d'acacia/eau par diffusion de la lumière aux petits angles, révèle des phénomènes de diffusionnels et hydrodynamiques responsables de la croissance des domaines structuraux. Dans certains cas, la cinétique de coacervation complexe peut être décrite par le modèle théorique de décomposition spinodale.
32
Bhamidipati, Kanthi Latha. "Detection and elimination of defects during manufacture of high-temperature polymer electrolyte membranes." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43616.
Full textAbstract:
Defect generation and propagation in thin films, such as separation membranes, can lead to premature or catastrophic failure of devices such as polymer electrolyte membrane fuel cells (PEMFC). It is hypothesized that defects (e.g., air bubbles, pin-holes, and holes) originate during the manufacturing stage, if precise control is not maintained over the coating process, and they propagate during system operation. Experimental and numerical studies were performed to detect and eliminate defects that were induced during slot die coating of high-viscosity (1 to 40 Pa-s), shear-thinning solutions. The effects of fluid properties, geometric parameters and processing conditions on air entrainment and coating windows (limited set of processing conditions for which defect-free coating exists) were studied. When smaller slot gaps and coating gaps were used, relatively small bubbles were entrained in the coated film. The air bubble sizes increased as the viscosity of the coating solution decreased. A semi-empirical model correlating the maximum coating speed to a solution's material properties, geometric parameters and processing conditions was developed. Such a predictive model will enable engineers to determine the maximum coating boundary for shear-thinning and Newtonian solutions within certain constraints. Smaller coating gaps and low-viscosity solutions produced higher coating speeds. The surface tension property of the coating solution provided stability to the coating bead. Therefore, solutions with higher surface tension could be processed at higher coating speeds.
33
Chevallier, Christophe. "Écoulements élongationnels de solutions diluées de polymères." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2009. http://tel.archives-ouvertes.fr/tel-00529305.
Full textAbstract:
La présence de polymères flexibles de grande masse molaire modifie de manière spectaculaire les écoulements de solution même en régime dilué. Il y a un couplage fortement non linéaire entre le champ de vitesse de la solution et la conformation microscopique des chaînes de polymères. Ce couplage est le plus efficace en écoulement élongationnel. Cette thèse porte sur l'étude de ce couplage, et sur les moyens de corréler les contraintes élongationnelles macroscopiques avec l'observation de la microstructure. Le détachement d'une goutte de solutions d'ADN (un biopolymère pouvant être visualisé) en solvant visqueux est ralenti par la formation d'un filament. La dynamique d'amincissement du filament, observée avec une caméra rapide, se déroule à taux d'élongation constant. Cela permet la mesure de la viscosité élongationnelle très élevée de ces solutions. Cette mesure a lieu dans l'air et dans un fluide d'immersion suffisamment peu visqueux. Il est possible de visualiser l'ADN par microscopie de fluorescence, mais pas au sein d'un filament cylindrique entouré d'air. On immerge l'échantillon pour adapter l'indice et faire disparaitre l'interface courbe. Plusieurs méthodes de correction (notamment la réalisation d'un objectif de microscope spécifique) sont étudiées pour pallier aux très fortes aberrations optiques qui empêchent l'observation de l'ADN. De plus, les effets de la transition de déroulement et de la viscosité élongationnelle sont aussi étudiés au sein d'écoulements microfluidiques à dominante élongationnelle.
34
Santos, Willy Glen. "Estudo de transferência de energia eletrônica entre poli(p-fenilenovinileno) e corantes iônicos em solução." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/75/75131/tde-07042008-140839/.
Full textAbstract:
Neste trabalho estudou-se a síntese fotoquímica do Poli(pfenilenovinileno) (PPV) e a transferência de energia deste polímero para corantes iônicos tais como Basic Blue 3 (BB), Safranina-O (Sf), Eosina-Y (Eoy) e Resazurina (Rz). Na síntese do precursor do PPV, observou-se que o prolongamento do tempo de adição de NaOH no processo de polimerização resultou na inibição do mecanismo SN1, evitando a propagação dos polímeros hidrolisados. Medidas de FTIR e emissão de fluorescência mostraram que o processo de conversão do PTHT em PPV por via fotoquímica também gera polímeros oxidados, assim como na conversão térmica. Espectros de absorção eletrônica do polímero-corante aniônico mostraram que as bandas do corante estão deslocadas para regiões de menor energia, sugerindo a formação de um complexo no estado fundamental. No caso do polímero-corante catiônico, nenhuma mudança espectral é observada, indicando que o efeito de supressão pode estar ocorrendo no estado excitado. Os espectros de fluorescência estacionária e resolvida no tempo indicaram que a transferência de energia ocorre do estado excitado do polímero para o estado fundamental do corante via mecanismo de Förster. No caso do sistema polímero-corante aniônico, a transferência de energia ocorre no estado fundamental das espécies. A constante de supressão dinâmica do sistema PPV-BB foi determinada e comparada com a constante de supressão estática, demonstrando que a supressão do PPV pelo corante não ocorre apenas pelo mecanismo do tipo Förster, mas também pela supressão estática.The aim of this work was to study the photochemical synthesis of poly(pphenylene vinylene) (PPV) and the energy transfer process evolving PPV and ionic dyes, such as Basic Blue-3, Resazurin, Eosin-Y, Safranin. It was observed that, in the synthesis of PPV precursor, the addition of NaOH in lager time intervals resulted in the inhibition of SN1 mechanism, avoiding the propagation of hydrolyzed polymers. FTIR and fluorescence emission measurements showed that the photochemical conversion from PTHT to PPV also generated oxidized polymers, as in thermal conversion. Electronic absorption of the system polymer-anionic dye revealed a red shift, suggesting the presence of complex species in the ground state. No structural changes or shifts were observed in the system polymer-cationic dye. Steady-state and time resolved fluorescence revealed that energy transfer occurs from the polymer excited-state to dye ground state, by Förster mechanism. For polymeranionic dye system, energy transfer occurs in ground state of both species. Dynamic quenching constant of PPV-Basic Blue-3 was determinated and compared with the static quenching constant. In this case, the quenching of fluorescence occurs by Förster energy transfer and also static quenching.
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Ratcliff, J. "Reactive dyes for cellulose : selectivities in alcohol/water solutions." Thesis, Swansea University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638619.
Full textAbstract:
This project is concerned with reactive dyes for dyeing cellulose (cotton) where reactive groups in the dye molecule form a covalent bond with hydroxyl groups in the cellulose chain by nucleophilic substitution or addition mechanisms. A fundamental problem is that the undesirable hydrolysis of the dye is a competing reaction under dyeing conditions and the hydrolysed dye is then no longer available for reaction with the fibre. The particular feature of interest is the chemical selectivity of the reactions of these dyes towards the fibre in preference to reaction with water and the factors which can influence these selectivities. In order to study the selectivities alone, without complications from the diffusion characteristics and substantivities of individual dyes, a homogeneous system was preferable for the investigations. So, a range of compounds were chosen as models to represent cellulose in these reactions. They covered simple alcohols, diols, polyols, and carbohydrate and sugar molecules - methanol, n-propanol, isopropanol, ethane-1,2-diol, α- and β-methylglucopyranoside, tetrahydropyran-2-methanol, mannitol, sorbitol, glucose and maltose. Using methanol as a cellulose model, the effects on rates and selectivities of varying the temperature between 0 and 60°C and additives to the dye bath such as acetonitrile, tetrabutylammonium bromide, urea, sodium chloride, sodium carbonate and dimethylformamide in a concentration of 100g/l have been investigated. Finally a survey of dyes with a wide range of reactive systems was carried out to determine whether selectivities are related to the reactive group that is used in the dyeing process. Reactive groups covered were : dichlorotriazine, monochlorotriazine, monofluorotriazine, chlorodifluoropyrimidine, dichloroquinoxaline, masked vinyl sulphones and acrylamides.
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Atkinson, David. "Structure and Reactivity of 2-Arylazonaphthol Dyes in Solution and in Cellophane." Thesis, University of York, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485333.
Full textAbstract:
The structure and reactivity of four 2-arylazo-l ,8-dihydroxynaphthalene (monoazo) dyes and their 2,7-bisarylazo- (bisazo) analogues in water, DMSO, and cellophane were studied using various techniques. NMR and UV-visible absorption spectroscopic studies ' suggested that the azo tautomer content (::;12 %), intramolecular hydrogen-bonding strength, and pKa (ca. 9.9-10.7), of each monoazo dye in water, increased with the increasing electron-donating ability of substituents on the phenyl ring. Contributions from the four tautomers of each bisazo dye to the overall composition were also found to depend on the electron-donating ability ofphenyl substituents. The intramolecular hydrogen-bonding strength and pKa (ca. 10.4-11.1) of the bisazo dyes were greater than for their monoazo ~ounterparts. None of the dyes aggregated significantly in water at ::;1 x 10-3 mol dm·3 , consistent with their extensive sulfonation. Dye reduction by a.-hydroxyalkyl radicals waS studied using time-resolved UV-visible absorption spectroscopy. The rate constant for electron transfer from radical to dye was similar for each dye (ca. 2-4 x 109 dm3 morl S·l). The radical anions formed by electron transfer disproportionated with rate constants of ca. 2-7 x 107 dm3 morl S·l for the monoazo dyes and one of the bisazo dyes, and ca. 6 x 108 dm3 morl S·l for the remaining bisazo dyes. The hydrazo compound formed by disproportionation ofthe bisazo dyes was observed to decay by two independent first-order processes. Product analysis studies using lH NMR spectroscopy, HPLC, and LC-MS suggested that dye reduction cleaves the N-N bond. Electrochemical studies ofthe dyes were consistent with the four-electron reduction of each hydrazone or azo group to yield aminated products. Product analysis studies suggested that electrochemical reduction of the azo group on one side of a bisazo dye occurred more readily than at the hydrazone group on the other, consistent with the products generated by reaction with photoinitiator radicals.
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Edwards, Douglas James. "Solution and solid-state studies of some bleachable semi-conducting photographic dyes." Thesis, Royal Holloway, University of London, 1987. http://repository.royalholloway.ac.uk/items/cdaa5aae-1c33-47cd-a361-1fdd4ad0ae33/1/.
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A number of monomeric and oligomeric hydroxypyridone mono- and poly-methine bridged oxonol and merocyanine dyes have been prepared and their solution and solid-state properties have been investigated. One particular and commercially important feature of the solution chemistry of the oxonol dyes is the reaction with sulphite ion leading to bleaching of the dye. The mechanism of this process has not previously been investigated. A detailed kinetic and spectroscopic study supports the previously proposed mechanism in which the nucleophile adds to the methane bridge in a Michael-type fashion. The reaction intermediates have been detected spectroscopically for several nucleophiles but in general are too unstable to be isolated. Oxonol and merocyanine dyes readily undergo molecular aggregation in both solution and the solid-state. One previous X-ray diffraction analysis of an oxonol dye has been carried out which revealed that the anions formed planar molecular stacks. Such an arrangement is well suited to intermolecular charge transfer and hence electronic conduction. The main objective of the current work has been to investigate how this stacking might be influenced by variation of substituents and counter-ions with a view to modifying the conduction properties. X-ray structure studies reveal that variation of the cation leads to three different types of solid-state structure: herringbone; uniform; and dimeric. The electrical properties have been investigated in detail by d.c. conductivity and a.c. dielectric spectroscopy measurements. They suggest that in general, the simple hydroxypyridone trimethine oxonols are semi-insulating (10⁻⁸ < δ < 10⁻¹² Ω⁻¹ cm⁻¹) though some exceptions have been found. Any observable d.c. conduction is essentially ionic in nature. The merocyanines and pentamethine oxonols are semi-conducting (10⁻⁴ < δ < 10⁻⁸ Ω⁻¹ cm⁻¹) as a consequence of added electronic contributions to the conduction mechanism. The most highly conducting oxonol salt, containing the tetrathiafulvalene (TTF) radical cation has a d.c. conductivity, δ ≃ 10⁻³ Ω⁻¹ cm⁻¹ (compacted powder, room temperature). In this case electronic conduction dominates.
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Rasilingwani, Tshimangadzo Edward. "Removal of Congo red dye from aqueous solution using a clay based nanocomposite." Diss., 2018. http://hdl.handle.net/11602/1216.
Full textAbstract:
MENVSCDepartment of Ecology and Resource Management
In this study, the efficacy of bentonite clay, pre-treated magnesite and their nanocomposite on the removal of Congo red dye from aqueous solution was explored. Batch experimental approach was a technique used to fulfil the goals of this study. A number of operational parameters were optimised, and they include effects of shaking time, adsorbent dosage, initial CR dye concentration, initial solution pH and temperature. Findings of the study revealed that the optimum conditions that are suitable for the removal of CR dye are 20 minutes, 0.5 g of dosage, 120 mg/L, 250 rpm, and pH = 7. This has achieved > 99% removal efficacy of CR dye for the nanocomposite and reduced it to below the South African National Standard (SANS) 241 water quality specifications. Furthermore, kinetic studies revealed that bentonite clay, pre-treated magnesite, and their nanocomposite fitted very well to pseudo-second-order kinetics than pseudo-first-order kinetics. The regression analysis was observed to be 1, 0.9, and 0.9 for bentonite clay, pre-treated magnesite, and their nanocomposite respectively. Adsorption isotherms indicated that CR removal by bentonite clay, pre-treated magnesite, and their nanocomposite fitted well to Langmuir adsorption isotherm than the Freundlich adsorption isotherm hence indicating mono-layer adsorption. Thermodynamic values for CR removal were observed to be: ΔH0 (kJ mol-1) = 43.86, 30.67, and 24.88 for bentonite clay, pre-treated magnesite, and their nanocomposite respectively. This indicates that the reaction is endothermic. The positive ΔS0 (kJ mol-1 K-1) values for bentonite clay and 25 °C for pre-treated magnesite confirms that there is an increase in the degree of randomness at solid/solution interface during the removal of CR ions from aqueous solution. The negative values of ΔG0 (kJ mol-1) for 40 – 70 °C on bentonite and the entire range for the nanocomposite suggest the spontaneity and feasibility of CR adsorption whereas the positive ΔG0 (kJ mol-1) for bentonite clay suggest a non-spontaneous nature of adsorption. As such, pre-treated magnesite/bentonite clay nanocomposite demonstrated superior adsorption capacity in relation to individual materials and other materials reported in literature.
NRF
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Lee, Pei-Lin, and 李佩玲. "Treatment of Dye-containing Solution by Nanofiltration." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/49951838786708121152.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
91
Experiments were run with three acid dyes (Acid red 4, Acid orange 10 and Acid red 27) and a Desal DK type nanofiltration. The effects of pressure, cross flow velocity, temperature, feed concentration and pH on flux and rejection were studied. Experimental results indicated that the separation of NaCl and NaNO3 was mainly due to the Donnan exclusion. The separation of dye solution was due to the sieving effect primarily and less important to the Donnan exclusion. The separation of dye solution was also significantly affected by the molecular size, charge and adsorption ability on the membrane of dye. The effects of operational factors showed that permeate flux increased with increasing pressure and temperature. The increasing concentration and the membrane carries the opposite charge as the dye reduced the permeate flux but enhanced permeate concentration. However, the rejections of dyes were more than 97% in all cases whatever the conditions.
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FanChiang, Jen-Mao, and 范姜仁茂. "Degradation of anthraquinone dye in aqueous solution by ozonation." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/51505856573489673534.
Full textAbstract:
博士國立中央大學
環境工程研究所
98
The objective of this study was to investigate the degradation of anthraquinone dyes in aqueous solution by ozonation using a semi-batch reactor. The effects of various operating parameters, such as initial dye concentrations, ozone feed rates and initial pH, on performance of color, dye, and TOC removal were evaluated. Also, possible dye degradation products were identified to investigate degradation pathways. Finally, the biodegradability enhancement of dye solution by ozonation was assessed. The experimental results showed that Reactive Blue 19 (RB-19) could be degraded by ozonation. The color and dye removal were more rapid and complete than TOC removal in all ozonation tests. However, increasing the initial RB-19 concentration had significant effect on decreasing the elimination of RB-19. In addition, increasing ozone feed rates had all positive effects on color, dye and TOC removal, particularly on TOC diminution. Also, the rate constant and efficiency of color removal were highest at initial acidic pH condition, but dye and TOC removal were more effective at the basic pH value likely due to more powerful and non-selective hydroxyl radical oxidation. The results of UV/VIS and FTIR spectra showed that the anthraquinone structures, nitrogen linkages and amino groups of RB-19 were destroyed under direct ozone reaction. The identification by LC-MS and GC-MS analyses indicated that some organic acids (e.g., phthalic acids) and 1,3-indanone could be the primary degradation products, respectively. Thus, the possible degradation pathways, which count on the initial destruction of either amino groups or C–N–Aromatic linkages, were proposed Basically, ozonation was confirmed to have potential to increase BOD5/COD ratio of RB-19 solution. On the other hand, ozonation also decreased Microtox toxicity and increased SOUR of RB-19 solution. The enhanced biodegradability was validated by screen tests, which revealed an improved DOC removal by biodegradation.
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Hsu, Guo-cheng, and 徐國城. "Control and Observation of Solution Phase Dye Molecules Aggregation Effects." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/3u4mh6.
Full textAbstract:
碩士國立中山大學
光電工程研究所
96
Luminescent properties of the dye molecules can be influenced by the environments as well as intermolecular interactions. Suitable control the aggregation can be useful for optoelectronic device applications. In this thesis, we investigate the spectroscopic properties of dye molecule, DiI_C18, in solutions. Solvents and concentrations are used to control the degree of aggregation. Absorption and emission are used to probe the properties. We use water, methanol, and ethylene glycol as key solvents to control the aggregation effects, especially the methanol solution mixing with water. As the concentration increased, the change of the absorption spectra are observed, which is caused by the aggregation between molecules. Two types of aggregations: head-to-tail structure and parallel structure, are proposed. Head-to-tail structure behaves red-shifted spectrum, and a corresponding shorter decay lifetime. On the contrary, parallel structure aggregation exhibits blue-shifted absorption spectrum and a longer fluorescence lifetime. Both structures are observed at different period after mixing. Only monomer exists in the methanol solution, even at high concentration. However, after missing with water, parallel structure aggregates are formed. Head-to-tail structure aggregates are formed after a much longer period, usually several hours after the mixing. These aggregates not only have different photo-physical properties. After high light intensity illumination, parallel structures are easier to turn into non-fluorescent structures, while head-to-tail structures last a longer period. Monomer structures exhibit the longest period. This provides additional evidence for the formation of different structures in the mixing solutions.
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Chiou, Wen Chang, and 邱紋昌. "Study on electrical treatment of dye solution by Iron electrode." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/90787887777225092945.
Full textAbstract:
碩士國立中央大學
化學工程研究所
81
Researching the reactions of electrodes and mechanism of color-removing through 山 type groove which contains the anode and cathode chambers , anode produces ferrous ions dissolving in the acid solution and pH rise upward according to cathode reaction. When the contents of the anode and the cathode chambers were mixiing , producing ferrous hydroxide in solution which chemically reacts with dye and coprecipitates to remove more than 88 % of color and organics. Reduction in voltage and increase in electrolysis time in the same electric quantity would rise efficiency. The solution , after electrolysis , controlled in the weak acid also rise decoloring efficiency. Three different types of dye were treated . The best efficiency of electrolysis is BWS direct dye , then is RS/HC acid dye and the worst is H-E3B reactive dye. The electrolysis of potassium chloride solution using山 type groove would produce little hypochlorous acid to oxidize dye. Application of streaming current technique to determine the best dose is done. The three different concentration ,100、200、300 ppm,dye solution were treated at pH 3. The streaming current readings controlled between -0.12 and -0.18 gains the best cogulation result. If the solution contains electrolyte streaming current readings will be interferenced and refer no relation to decoloring.
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Chen, Shin Chung, and 陳溪泉. "Study on electrical treatment of dye solution by Aluminum electrode." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/29144483580806075359.
Full textAbstract:
碩士國立中央大學
化學工程研究所
81
Electrolysis dyestuff solution, plate that is coated by polystyrene(inclusive Pd) can reduce sediment. Dyestuff solu- tion in electrobath flows from cathode to anode, plate arran- gement is cathode in bottom and anode in top. Then let bubble accures from bottom, it can help dyestuff floating. For three reactive dyes ( Evercion Navy Blue H-ER blue dye, Evercion Orange H-ER yellow dye, Evercion H-E3B red dye) ,the percent of decoloring in electrolysis Evercion H-E3B red dye is better. For three red dye ( RS H/C acid dye, Evercion H-E3B reactive dye, BWS direct dye), the percent of decoloring in electrolysis RS H/C acid dye is better. Evercion H-E3B dye is influence in PH value.When PH value more than 10, color can be changed from red to yellow. The bi- ggest absorption wavelength can be changed from 512 nm to 473 nm. The absorbility is also reduced. A dyestuff solution can be decolored by strong base. But dyestuff solution includes coag- ulation, then PH value must less than 7 and near 7, the effect of coagulation is better. That the sediment of coagulation solved in water,then it delivers dyestuff in full. But the sediment of electrolysis solved in water, then it delivers dyestuff only 76.36% . THe meaning is that some dyestuff is broken or associated by Alum- inum.
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Nguyen, Chin. "Research portfolio: a new in-vitro methodology for the study of microleakage of low volume shrinkage composite resin." Thesis, 2011. http://hdl.handle.net/2440/71849.
Full textAbstract:
Microleakage has been defined as the passage of bacteria, fluids, molecules or ions along the tooth-restoration interface (Kidd, 1976). This leakage may be clinically undetectable, but is a major factor influencing the longevity of dental restorations as it causes many severe biological effects on the restored tooth including the recurrence of caries, pulp pathology, hypersensitivity and marginal breakdown (Hersek, 2002). The investigation of microleakage is, therefore, important in the assessment of restorative materials. A variety of in vitro methods have been introduced into the study of microleakage including compressed air, neutron activation, electrochemical, fluid filtration, bacteria and the use of dyes (Karagenς, 2006; Kidd, 1976;Taylor, 1992). In addition, various techniques such as scanning electron microscopy, transmission electron microscopy and electron probe microscopic analysis have been used to image and measure leakage. However, the above specimen preparation techniques are two-dimensional in nature and do not take the whole tooth-restoration interface into account, as some sections obtained randomly are taken to measure microleakage. Over the past few years there have been efforts to investigate microleakage of restorative materials three dimensionally (Gale, 1994; Iwami, 2005; Lyroudia, 2000; Youngson, 1992). However, this methodology was also destructive as images were reconstructed from serial cross-sections of continuously ground surfaces. One of the most advanced techniques in medical imaging in recent years has been the advent of micro-computed tomography (MCT) that can achieve a spatial resolution at the micron level. Recently, the MCT Skyscan 1072 (MCT 1072) has been introduced into dentistry for the study of many subjects including dental materials, dental morphology and dental implants (Bergmans, 2001; Park, 2005; De Santis, 2005). De Santis et al (2005) first used MCT to study microleakage and although these workers introduced a non-destructive method, the model they chose had some weaknesses. From the clinical perspective only flat dentine surfaces were studied rather than definite cavities, as in the clinical situation. Furthermore, no three-dimensional quantitative and qualitative analyses were undertaken. In considering various methods that have been used to study microleakage, the technology of MCT would appear to offer significant advantages over two-dimensional methods involving sectioning of specimens. In order to image microleakage using MCT, an x-ray contrast dye solution is needed. It has been reported that a silver nitrate solution has been the only metal solution that is able to express the microleakage of restorative materials (Besnault, 2003; Taylor, 1992; Taylor, 1993; Tsatsas, 2005). Filtek Silorane (3M ESPE) has been recently introduced into the market and is considered as a low volume shrinkage composite resin. Very little microleakage research has been done for this new material. It is from this fundamental basis that the project evolved, with firstly, the need to explore the potential of using MCT scanning of composite resin restorations and secondly, to develop a suitable study model that can be used effectively with the MCT 1072. Thirdly, qualitative and quantitative microleakage patterns of Filtek Silorane are studied non-destructively and three-dimensionally. As an introduction to this investigation it is necessary to review the adverse effects of microleakage on the restored teeth. In addition, aetiologies and dynamic processes of microleakage will be considered. Furthermore, the current methodologies with their main advantages and disadvantages will be discussed. Having discussed the current thinking on microleakage, there will be a further discussion of x-ray contrast dye solutions and MCT 1072. There will be also an overview of the new version of composite resin namely, Silorane. Finally, the factors that can influence the results of microleakage studies will be reviewed.Thesis (D.Clin.Dent.) -- University of Adelaide, School of Dentistry, 2011
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Chen, Zhao-Ting, and 陳炤廷. "Application of modified magnetite to adsorb organic dye in aqueous solution." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/6tx4c5.
Full textAbstract:
碩士國立宜蘭大學
環境工程學系碩士班
103
In this research, the surface of magnetite modified with silicate and phenyl polymers(Ph/ SiO2/ Fe3O4).It was used to adsorb organic dye-Rhodamine B in aqueous solution in a batch system. Thus, although the dye was confirmed toxic , it in Asia is still widely used. The magnetic adsorbent use Fe3O4 as core, after the sodium silicate coating as a magnetic carrier (SiO2/ Fe3O4). Utilize phenyltrimethoxysilane after modification of the polymer was dissolved in toluene phenyl connect magnetic adsorbent surface (Ph/ SiO2/ Fe3O4). And use this phenyl compound to absorb Rhodamine B, magnetic particles can overcome the aqueous solution of the problem of tiny particles recovered. The experiment utilizing FTIR, XRD and TGA analysis and other methods of material properties, can know phenyltrimethoxysilane successful polymerization of the magnetic carrier (Fe3O4). The pH of the reaction adsorption can understand that the magnetic adsorbent will not affect the adsorption capacity. The experimental adsorption isotherm data into the model can be understood, Ph / SiO2 / Fe3O4 on the adsorption behavior of Rhoda mine B is more in line with the Langmuir model can be estimated by the formula, the maximum adsorption capacity (Qm) and the free energy was 142.18 mg g 1 and -48.48kJ / mol. A pseudo-first-order model cold best describe the adsorption kinetics, the reaction rate constants can be substituted into the Arrhenius equation to calculate the activation energy of the reaction was 14.023 kJ / mol. The optimum condition to desorb Rhodamine B by Ph / SiO2 / Fe3O4 is provided by a solution with 100% ethanol.
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Din, Jang-Jong, and 丁建中. "Study on An Electrolysis oxidation of Dye Solution by Carbon Fiber Electrode." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/71601869447369104339.
Full textAbstract:
碩士國立中央大學
化學工程研究所
82
When use electrochemical treatment in the decolorization dyeing effluent, it was always operated with metal as a cathode. The metal cathode would react and dissolve in dyeing effluent. The metal ion which was contained in effluent is another pollution and increases the amount of sludge. The research use carbon fiber and stainless steel as a cathode and an anode. The equipment can be successful in remov- ing the color of dye from aqueous solution and don`t increase any sacond pollution. But this methode remove organic carbon very slowly. Following experiment, organic carbon were removed 16% during 90 minutes, but the dye was decomposed during 30 minutes. In order to research the reaction of electrolysis and mechanism of color- removing, choose Ｈ-type tube to treat dye solution. Then cell was operated in batch mode to understand the variables of operation (example：concentration of electro- lyte, concentraion of dye solution, voltage and pH value of initial dye solution, etc. ) and the effect of electrochemical treatment. Applying the above result operate cell of flowing cyclization mode. Cell of flowing cyclization mode can treat large amount of dye solution but the flow rate of dye solution must fit other operated condition. Following experiment, when the flow rate of dye solution were 30 and 50 ml/min, the decolor amount of per coulomb were 0.3 and 0.05mg.
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Wang, Ling-Chi, and 王鈴祺. "Treatment of Dye and Isopropanol in Aqueous Solution by UV/La2Ti2O7 process." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/66aex8.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
94
A highly donor-doped (110) layered perovskite, La2Ti2O7, was found to be an efficient photocatalyst under UV irradiation. The activity depended on the crystalline phase and the surface area of perovskite oxide. The grinding methods of the mixed oxide precursors before sintering as well as the sintering temperature affected the crystalline phase and the surface area of the formed perovskite. La2Ti2O7 in this study was prepared by solid state reaction (SSR) and the obtained powders were characterized by XRD, SEM, UV-DRS, XPS and zeta potential. Photocatalytic degradation of dye and IPA in aqueous solution by UV/ La2Ti2O7 process was studied. The experiments were carried out under solution pH, initial concentration of RR22 and IPA, UV light intensity and catalyst loading. Photocatalytic degradation of RR22 and IPA in aqueous solution by UV/ La2Ti2O7 process was increased with increasing UV light intensity and catalyst loading. Photocatalytic degradation of RR22 and IPA in aqueous solution by UV/ La2Ti2O7 process was decreased with increasing initial concentration. Photocatalyst degradation was better in acid than in alkaline solution for IPA in aqueous solution by UV/ La2Ti2O7 process but the experimental trend of RR22 was different from IPA. The reaction rate of photocatalytic degradation was faster at pH=3.0, the slowest at pH=7.0 and that suddenly increased at solution pH 8.0~11.0. Reaction rate of RR22 photocatalytic degradation was faster than that of photolysis in acidic solution but reaction rate of RR22 photocatalytic degradation was slower than that of photolysis at pH=10.0~pH=11.0.
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Hsu, Chun-Chih, and 許純芝. "Ultrafast photoisomerization dynamics of azo dye in solution and a polymer film." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/19137824936481896647.
Full textAbstract:
碩士國立交通大學
電子物理系所
97
The photoisomerization of 4’-[(N,N-Dihydroxyethyl)amino]-nitroazobenzene (Disperse Red 19) in solution and in polymer film are investigated by femtosecond time-resolved absorption spectroscopy. Using broadband sub-10 fs visible pulses, the dynamics of electronic relaxation and molecular vibrations are observed in both samples. The motion of a wavepacket in the excited state out of the Franck-Condon state occurs on the time scale of ~100 fs. The excited state relaxation occurs with time constant of 0.63 ps in solution and 0.84 ps in polymer films. For a solution and a polymer film, the vibrational cooling in the ground state proceeds are 2.55 ps and 4.43 ps, respectively, suggesting that the isomerization dynamics are sensitive to the molecular environments. To the best of our knowledge, this work is the first experimental observation for the ultrafast processes of DR19 in different molecular environments.
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chen, Sin-Hong, and 陳信宏. "Photocatalytic Destruction of Dye in Aqueous Solution by TiO2-Based Composite Materials." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/55596571845026197309.
Full textAbstract:
碩士大葉大學
環境工程學系碩士班
95
The objectives of this work are to prepare various TiO2-based composite materials using the photodeposition method, and to decompose different dyestuffs in aqueous solutions under UV irradiation. Several kinds of photocatalysts were synthesized, including TiO2/Al2O3, TiO2/GAC, Fe/TiO2/Al2O3, Ba/TiO2/Al2O3, and Sr/TiO2/Al2O3. Their physico-chemical characteristics were also analyzed by ICP-AES, BET, SEM/EDX, and XRD. Additionally, the optimum experimental conditions (including pH value, TiO2 loading, and initial dye concentration) were studied. The experimental results showed that the BET specific surface areas for the various photocatalysts are about 103~105 m2/g. As for the decay of dye concentration,rate equation of the pseudo-first-order reaction can be used to fit the data. It also revealed that the photocatalysts doped with metals (that is, Fe/ TiO2/Al2O3, Ba/TiO2/Al2O3,andSr/TiO2/Al2O3) had greater reaction rates and could remove dyestuffs more effectively. In addition, For both dye solutions (AR27 and RR141), the optimum pH value and photocatalyst loading were found to be 3 and 0.05g, respectively.
50
Hu, Bing-Chuen, and 胡秉淳. "All-solution process for manufacturing dye-sensitized solar cells photoelectrodes using inkjet printing." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/4nezx3.
Full textAbstract:
碩士國立高雄應用科技大學
機械與精密工程研究所
104
In this study, the titanium dioxide (TiO2) solution was printed on a conductive fluorine-doped tin oxide (FTO) coated glass by inkjet printing to be used as a dye-sensitized solar cell (DSSC) photoelectrode. The TiO2 electrode was yielded with porosity after sintering at 450 ° C. The counter electrode (CE) was yielded and compared with nano silver, graphene, platinum, and carbon. Using inkjet printing, the layer-stacked photoelectrode was obtained, while it was difficult using a doctor blade method. As compared to screen printing, inkjet printing easily generated the TiO2 photoelectrode with a mesh and grid pattern. The 3D micro structure of the photoelectrode pattern was obtained. At the same time, scanning electron microscopy (SEM) was used to observe its surface morphology and cross section. Using inkjet printing, its thickness was simply controlled with 10.25µm for printing of 4 layers. Then using platinum as a CE, the DSSC was found with a power conversion efficiency of 4.4%. These experiments result show that it is possible using inkjet printing for fabricating DSSC. This way of producing the photoelectrode still requires improvement in the method. In the future, the printing parameters and materials configuration can be further studied to increase the power conversion efficiency, and to be developed in flexible applications. Keyword：inkjet printing, TiO2, dye-sensitized solar cells, photoelectrode