No description available.

No description available.

In this master thesis, the feasibility of Fenton-oxidation for the decolorization of reactive dyed cotton is investigated as a potentially environmental-friendly preparatory treatment for mechanical/chemical recycling. Raw, knitted cotton is dyed with a black and a blue dye, whereafter preliminary tests are performed to investigate the influence of increasing Fenton- solution concentrations and different iron-sources on the efficiency of the discoloration, without carrying out complete optimization of the process-parameters. Based on the preliminary test-results, Fenton-treatments of the reactive-dyed cotton are upscaled, with discoloration efficiencies of 62 and 73% (for the black- and blue-dyed cotton respectively). Thermal analysis (TGA, DSC and FTIR) and mechanical analysis (tensile tests and shredding of the fabric) of the upscaled treated samples are performed, and the results indicate no major alterations of the main cellulosic structure of the cotton fibers. However, besides the degradation of the dye-molecules, also some oxidation (and therefore damage) of the cellulose-chains of the cotton fibers occurs, leading to reduced mechanical properties. Although this facilitates the mechanical recycling process, it possibly also reduces the quality of the re-spun yarns. Nevertheless, the Fenton-oxidation in the context of decolorization of reactive-dyed cotton forms an interesting future research-topic with many opportunities and prospects for increasing the efficiency and sustainability of the recycling process, and therefor increasing the sustainability of the textile industry in general.

This study investigates nutrient and contaminant transport within the Oakohay Creek watershed in order to (1) demonstrate the effects of land use on water quality, (2) model and predict the trophic state of the proposed reservoir given current nutrient loads, and (3) understand potential groundwater flow paths within the reservoir footprint. This study demonstrates that the current, large-scale poultry industry, though not statistically significant with a confidence of 95%, does have a negative impact on the surface water quality. The study also shows evidence for a eutrophic reservoir (TSI-P of 59.4 area-weighted mean) with an increased potential for nuisance algal growth in the northeast segment (TSI-P of 66.0). Dye tracing studies suggest the potential for groundwater flow out of the reservoir as a result of potential paleo-channels within the Glendon Limestone. This study concludes that the location on the Oakohay Creek is not suitable for the construction of a reservoir.

Magister Scientiae - MSc (Chemistry) / Drinking water with high concentrations of inorganic and organic contaminants can cause adverse health defects. Specifically methyl orange dye is an organic water contaminant that has been known (along with others like methyl blue etc.) to have an increase in our water systems over the past few years due to increasing demand in industrial processes. It is therefore of utmost importance to remediate organic contaminants and ultimately enable prevention. The contaminants can be removed by photocatalysis. Anatase TiO2 is known for its photocatalytic degradation of environmental pollutants and photoelectro-chemical conversion of solar energy. However its application is limited since it is a wide band gap semiconductor, (Eg = 3.2 eV). The following study deals with the enhancement of the photocatalytic properties of TiO2 for remediation of organic water contaminants.

No description available.

The problem of investigating the possibilities of direct design transfer from plant to fabric and paper was divided into two parts. The first part is concerned with the exploration of the mechanics of the transfer. Invloved in this process are the technique of manipulating tools, of selecting suitable fabrics and paper, of determining chemicals that would facilitate the printing process and of experimenting with ways to preserve the finished design. The evaluation of the usability and durability of the finished print was based on a series of color fastness tests. The second part of this problem is concerned with the exploration of the design possibilities of the medium. The plants were tested and rated according to their visual attributes relative to the elements of design. Combinations of the successful plant prints were used to produce variations of pattern and texture. The results of the investigation were evaluated to determine the versatility of the medium as a design tool and the usefulness of the technique as a practical printing method

In this report we studied the properties of the dye IR806 and possible mechanisms of the dye sensitization effect on ytterbium-erbium co-doped upconversion nanoparticles. We found that the dye IR806 has two primary emission peaks in the NIR spectral range at around 850 nm and at around 950 nm. The intensity of these peaks were observed to be affected by the concentration of the dye and the addition of Gadolinium(III) chloride and Yttrium(III) chloride. Specifically increases in the intensity of the 950 nm peak relative to the 850 nm were of interest since ytterbium readily absorbs 950 nm and transfers this energy in the upconversion process. Our hypothesis is that the change in the intensity of the 850 nm and the 950 nm peak is associated with aggregation of the dye IR806 and the amount of monomers and dimers. Results from adding ytterbium-erbium co-doped upconversion nanoparticles in IR806-ethanol solution points to the picture of dimers being formed on the surface on the nanoparticles. This analysis is however based on the assumption that the 850 nm emission peak of IR806 is associated with monomers and that the 950 peak is associated with dimers, which is yet to be confirmed and further studies are therefore needed.

Modern civilization highly depends on energy and finding alternative sources to fossil fuels becomes more and more necessary. The sun is the most abundant energy source available and exploiting it efficiently would result in a great environmental and economic breakthrough. Among the photovoltaic devices, dye-sensitized solar cells (DSCs) emerged for their tremendous commercial potential deriving from a combination of low-cost production and attractive features, such as flexibility and transparency, for indoor and outdoor applications. In the DSCs, a dye anchored to a semiconductor layer (typically TiO2) is responsible for capturing the sunlight and converting it into electricity. Nevertheless, many commercially available dyes for DSCs are based on a very rare metal, ruthenium, and its replacement with a cheaper, more abundant metal is desirable. A good alternative to ruthenium could be copper, which possesses similar photophysical properties in coordination with diimine ligands, but it is considerably cheaper and relatively earth-abundant. In this work, a particular “on-surface self-assembly” strategy was employed to form, on the surface of TiO2, heteroleptic copper (I) complexes with a “push-pull” design which facilitates the electron transfer from the copper (I) complex into the conduction band of TiO2 and enhances the performance of the photovoltaic devices.This thesis focuses on the investigation of the properties of five new heteroleptic copper (I) complexes bearing the same anchoring ligand but different ancillary ligands. Because of the method employed for their synthesis, a solid-state characterization of the optical and electrochemical properties on TiO2 was performed employing tools such as UV-Vis spectroscopy, cyclic voltammetry (CV), and differential pulse voltammetry (DPV). As internal benchmark through the entire characterization, the homoleptic copper (I) complex with the anchoring ligand was also studied. Some patterns between the heteroleptic complexes on TiO2 and their respective homoleptic complexes in solution were found, opening the possibility to predict the behaviour of unknown heteroleptic complexes starting from their corresponding homoleptic. Furthermore, the characterization was necessary to ensure that the complexes were fulfilling the requirements to be employed as dyes. The performances of the heteroleptic, and of the anchoring-ligand homoleptic, copper (I) complexes were then investigated as photosensitizers in DSC devices mainly by measuring the current density-voltage (J-V) characteristics at different light intensities and in the dark, the incident photon-to-current efficiency (IPCE), and electron lifetimes. As benchmark for the degree of effectiveness of the device, the state-of-the-art ruthenium (II) complex N719 was also studied. All the copper (I) complexes showed an overall similar behaviour. The J-V characteristics showed a power conversion efficiency up to 2,05% for the best performing device, which is 25% of the efficiency of DSCs based on N719. On the other hand, the least performing heteroleptic copper (I) complex studied showed an efficiency of 1,23%. From a general analysis combining all the results obtained, it may be concluded that a reason for the limited photocurrent measured through these devices can be due to incomplete dye coverage of TiO2. Despite the lower performance compared to the standard dye N719, the simplicity of the system is promising, and its considerable economic advantage could pave the way to the use of DSCs in everyday life applications. / Modernt samhälle är mycket beroende på energi och det blir allt mer akut att hitta alternativa källor till fossila bränslen. Solen är den mest riklig energikällan som finns och att utnyttja den effektivt skulle resultera i stora miljö- och ekonomiska genombrott. Färgämne sensibiliserade solceller (”dye-sensitized solar cells”; DSC) utvecklade i 90-talet för sin breda kommersiella potential som härrör från en kombination av låg kostnadsproduktion och attraktiva egenskaper, såsom möjligheter för flexibilitet och transparens. I DSC är ett färgämne förankrat till den ytan av en halvledare (vanligtvis TiO2). Färgämnet är ansvarigt för att fånga solljuset och överföra elektronerna till halvledaren för att producera el. Många kommersiella färgämnen för DSC är baserade på rutenium, en mycket sällsynt metall. Ersättning av rutenium med en billigare, rikligmetall är önskvärt mot mer hållbara DSC. En bra alternativmetall till rutenium är koppar. Komplexen av koppar(I) har liknande fotofysiska egenskaper till rutenium (II) men koppar är mer vanlig och mindre dyr än rutenium. Heteroleptiska koppar(I) komplexen med en "push-pull" design syntetiserades på ytan av TiO2 genom "ytan assisterade självmontering". "Push-pull" designen underlättar elektronöverföring från koppar(I)-komplexet till ledningsbandet av TiO2. Denna avhandling fokuseras på undersökning av egenskaperna av fem nya heteroleptiska koppar(I) komplex med den samma förankrings ligand men olika distala ligander. På grund av metoden som används i syntesen av heteroleptiska koppar(I) komplex, var karakterisering av komplexen vid optiska och elektrokemiska metoder utfördes på TiO2. Metoderna för karakterisering var UV-Vis-spektroskopi, cyklisk voltametri (CV) och differentialpuls voltametri (DPV). Som en intern standard genom hela karaktäriseringen studerades även homoleptiska koppar(I) komplex med förankringsliganden. Egenskaperna på heteroleptiska koppar(I) komplexen på TiO2 ytan kunde förutsägas från mätning av egenskaperna på homoleptiska koppar(I) komplexen. Koppar(I) komplexen är undersöktes som fotosensibiliserare i färg-sensibiliserade solceller. Effektiviteten av solcellerna med koppar(I) komplexen eller rutenium (II) komplex (N719) utvärderades genom att mäta fotokurrentdensitetsspänningen (J-V) vid olika ljusintensiteter, incidentfoton-till-ström effektiviteten (”incident photon-to-current efficiency”; IPCE) och laddningsrekombinationen (elektronlivstiden). Koppar(I) komplexen hade övergripande liknande egenskaper i solceller. En kraft omvandlingseffektivitet av 2,05% nås för den bästa solcellen med ett koppar(I) komplex. Medan den bästa effektiviteten med N719 färgämnet var 7,57%. En svaghet i självmonteringen av koppar(I) komplexen på ytan av TiO2 är den ofullständiga bindningen till ytan men självmonteringen metoden var enkel och kunde skapa många, olika färgämnen i kort tid. Trots den lägre prestandan jämfört med standardfärgen N719 är systemets enkelhet lovande, och dess stora ekonomiska fördel kan bana vägen till användningen av DSC i vardagsläget. / La civiltà moderna è fondata sull’uso dell’energia e trovare fonti alternative ai combustibili fossili è diventato sempre più necessario. La radiazione proveniente dal sole è la risorsa energetica più abbondante e disponibile sul nostro pianeta e sfruttarla al massimo comporterebbe una svolta decisiva per l’ambiente e l’economia. Tra i dispositivi fotovoltaici, le celle di Grätzel, conosciute anche come DSC dall’acronimo inglese (dye-sensitized solar cell), sono emerse per il loro enorme potenziale commerciale, dovuto alla combinazione tra basso costo di produzione e interessanti caratteristiche, come la loro flessibilità e trasparenza, che gli conferiscono la possibilità di integrazione negli edifici e l’uso in applicazioni “indoor”. Nelle DSC, un foto-sensibilizzatore, detto anche dye, ancorato ad uno strato di un materiale semiconduttore (tipicamente TiO2), è responsabile della cattura della luce solare e della sua conversione in elettricità. Tra i dye commercialmente disponibili per le DSC vi sono per lo più complessi di coordinazione basati su un metallo molto raro, il rutenio; la sua sostituzione con un metallo più abbondante ed economico è auspicabile per la diffusione di questa tecnologia. Una buona alternativa al rutenio potrebbe essere fornita dal rame, che possiede proprietà foto-fisiche molto simili al primo quando in coordinazione con diimmine; in più è abbastanza economico e relativamente abbondante sulla Terra. Una particolare strategia di "autoassemblaggio sulla superficie" è stata impiegata per formare, sullo strato di TiO2, complessi eterolettici di rame (I) con un design “push-pull” che facilita il trasferimento di elettroni dal complesso di rame (I) alla banda di conduzione di TiO2, migliorando così le prestazioni dei dispositivi fotovoltaici. Questa tesi si concentra sullo studio delle proprietà di cinque nuovi complessi eterolettici di rame (I) che possiedono lo stesso legante di ancoraggio ma diverso legante secondario. A causa del metodo impiegato per la loro sintesi, è stato necessario eseguire la caratterizzazione delle loro proprietà ottiche ed elettrochimiche direttamente sulla superficie del TiO2, utilizzando strumenti come la spettroscopia UV-Visibile, la voltammetria ciclica (CV) e la voltammetria ad impulsi differenziali (DPV). Come riferimento interno durante l'intera caratterizzazione, è stato studiato anche il complesso di rame (I) omolettico con il legante di ancoraggio. Tra i complessi eterolettici su TiO2 e i loro rispettivi complessi omolettici in soluzione, è stato individuato un trend con la possibilità di prevedere il comportamento dei primi a partire dal loro corrispondente omolettico. Inoltre, la caratterizzazione ottica ed elettrochimica è necessaria per garantire l’adeguatezza dei complessi come dye. Le prestazioni dei complessi eterolettici e del complesso omolettico con il legante di ancoraggio, sono state quindi studiate come foto-sensibilizzatori nei dispositivi DSC; in particolare è stata misurata la curva di densità di corrente – voltaggio (J-V) a diverse intensità di luce e al buio, l’efficienza quantica esterna (EQE o dall’acronimo inglese incident photon-to-current efficiency, IPCE) e infine il tempo di vita dell’elettrone nella banda di conduzione del semiconduttore. Come standard interno, per verificare l’efficacia del dispositivo, è stato anche studiato il ben noto complesso di rutenio (II), N719. Generalmente, tutti i complessi di rame (I) hanno mostrato un comportamento simile. Le curve caratteristiche J-V hanno presentato un'efficienza pari fino al 2,05% per il complesso di rame che ha dato le prestazioni migliori (25% dell'efficienza di N719). Da un'analisi generale che combina tutti i risultati ottenuti, si può concludere che una ragione per cui la foto-corrente risulta limitata potrebbe essere data dall’incompleta copertura del TiO2 da parte del complesso di rame (I) e quindi dallo scarso adsorbimento del dye. Nonostante le prestazioni inferiori rispetto allo standard N719, la semplicità del sistema è promettente e il suo notevole vantaggio economico potrebbe aprire la strada all'utilizzo delle DSC nelle applicazioni della vita quotidiana.

This dissertation contains the synthesis and characterization of squaraine based new functional materials. In the first part of this thesis work, a water soluble benzothiazolium squaraine dye was synthesized with pyridium pendents, and controlled aggregation properties were achieved. After formation of partially reversible J-aggregation on a polyelectrolyte (poly(acryl acid) sodium salt) template, the nonlinear, two-photon absorption cross section per repeat unit was found to be above 30-fold enhanced compared with nonaggregate and/or low aggregates. Using a similar strategy, sulfonate anions were introduced into the squaraine structure, and the resulting compounds exhibited good water solubilities. A ‘turn on’ fluorescence was discovered when these squaraine dyes interacted with bovine serum albumin (BSA), titration studies by BSA site selective reagents show these squaraine dyes can bind to both site I and II of BSA, with a preference of site II. Introduction of these squaraine dyes to BSA nanoparticles generated near-IR protein nano fabricates, and cell images were collected. Metal sensing properties were also studied using the sulfonates containing a benzoindolium squaraine dye, and the linear response of the absorption of the squaraine dye to the concentration of Hg2+ makes it a good heavy metal-selective sensing material that can be carried out in aqueous solution. Later, a squaraine scaffold was attached to deoxyribonucleosides by Sonogashira coupling reactions, in which the reaction conditions were modified. Iodo-deoxyuridine and bromo-deoxyadenosine were used as the deoxyribonucleosides building blocks, and the resulting squaraine dye-modified deoxyribonucleosides exhibited near-IR absorption and emission properties due to the squaraine chromophore. Interestingly, these non-natural deoxyribonucleosdies showed viscosity dependent photophysical properties, which make them nice candidates for fluorescence viscosity sensors at the cellular level. After incubation with cells, these iv viscosity sensors were readily uptaken by cell, and images were obtained showing regions of high viscosity in cells.