Nos últimos anos, o desenvolvimento e a aplicação de sondas contendo átomos de calcogênio, expandiu significativamente, devido principalmente à reatividade dos elementos dessa família que são facilmente oxidados aos seus correspondentes calcogenóxidos e calcogenonas, permitindo diversas aplicações, especialmente em sistemas biológicos. A inserção de átomos pesados como os calcogênios, ao núcleo fluorofórico, leva à supressão de fluorescência, processo conhecido por \"efeito do átomo pesado\" também atribuída por Transferência Eletrônica Fotoinduzida (Photoinduced Electron Transfer). A oxidação do calcogênio ao correspondente calcogenóxido ou calcogenona inibe esse processo reestabelecendo a fluorescência. Todavia, moléculas com núcleo fluorofórico contendo, principalmente, os átomos de selênio e telúrio tem suas propriedades fotofísicas pouco investigadas, se comparado com moléculas contendo o átomo de enxofre. Neste trabalho foi tratado do desenvolvimento de metodologias de preparação de sondas contendo os átomos de selênio (II) e telúrio (II), mais especificamente, através da funcionalização da 7-hidróxi-4-metil-cumarina. Foram preparadas 6 calcogeno-cumarinas inéditas em rendimentos que variaram de 27% a 69%. Esses compostos apresentaram comportamento fluorescente condizente com o que havia sido idealizado: suas propriedades fotofísicas foram determinadas em acetonitrila, a 298 K, observando-se máximos de absorção em 290 nm e em 320 nm e máximo de emissão de fluorescência em 380 nm. Demais propriedades fotofísicas como rendimento quântico e tempo de vida do estado excitado também foram obtidas. Também foram realizados estudos com os compostos sintetizados frente a espécies oxidantes endógenas (ClO- e H2O2) permitindo inicializar estudos em sistemas celulares, observando-se que as cumarinas contendo o átomo de telúrio (II) demonstraram resultados promissores para seu uso como sondas fluorescentes. / In the last years, the development and application of chalcogen-containing dyes has expanded significantly, mainly due to the chalcogen elements reactivity that are are easily oxidized to their correspondent chalcogenides and chalcogenones, allowing several applications, especially in biological systems. The insertion of heavy atoms such as chalcogens to the fluorophoric core of the molecule leads to a fluorescence suppression, process known as \"heavy atom effect\", also attributed as Photoinduced Electron Transfer (PeT). The chalcogen oxidation to its correspondent chalcogenoxide or chalcogenone inhibts this process reestablishing the fluorescence of the molecule. However, fluorophoric molecules containing selenium and tellurium are not very investigated towards its photophysical properties if compared to their sulfur analogues. It is discussed in this this work, the development of methodologies for the preparation of probes containing selenium (II) and tellurium (II), more specifically, through the functionalization of the 7-methyl-4-hydroxi-coumarin. Six novel chalcogen-coumarins were prepared presenting yields varying from 27% to 69%. These compounds presented consistent fluorescent behavior for what it was predicted: their photophysical properties were determined observing absorption maxima at 290 nm and 320 nm and fluorescence maxima at 380 nm. Other photophysical properties such as quantum yields and excited state lifetime were also obtained. Studies with the synthetized compounds related to their behavior against endogenous oxidant species (ClO- and H2O2) were also conducted, allowing initial studies in cell systems, which demonstrated that the tellurium (II) derived coumarins presented promising results as fluorescent probes

Orientador: Elson Longo / Banca: Sonia Maria Zanetti / Banca: Elaine Cristina Paris / Banca: Fenelon Martinho Lima Pontes / Banca: Ademir Geraldo Cavallari Costalonga / Resumo: Neste trabalho propôs-se sintetizar partículas fotocatalisadoras de óxido de titânio (TiO2), beta molibdato de prata (β-Ag2MoO4) e a heteroestrutura TiO2/Ag2MoO4 para principal aplicação em fotocatálise. As partículas de TiO2 e a heteroestrutura foram sintetizadas utilizando o método solvotérmico assistido por micro-ondas (SAMO), enquanto que as partículas de β-Ag2MoO4 foram sintetizadas pelo método de co- precipitação. As sínteses foram realizadas a partir das soluções diluídas dos sais de partida, em diferentes solventes, tempos de reação e temperaturas para o controle do tamanho e forma dos cristais. A atividade fotocatalítica destes materiais foi analisada para a degradação dos corantes orgânicos alaranjado de metila e rodamina 6G sob irradiação com lâmpada ultravioleta (UV) de 254 nm. Foram realizadas caracterizações por difração de raios X (DRX), espectroscopia vibracional na região do infravermelho, fotoluminescência (FL) e medida de área de superfície específica (método BET). As morfologias dos cristais foram analisadas por intermédio de microscopia eletrônica de varredura de alta resolução e feixe de íon focalizado (FIB). As propriedades ópticas foram investigadas por espectroscopia na região do ultravioleta-visível (UV-vis). Os resultados de DRX mostram uma estrutura tetragonal para os pós de TiO2 e uma estrutura cúbica do tipo espinélio para as partículas de β-Ag2MoO4. Os espectros de infravermelho apresentaram bandas de absorção caraterísticas para cada material. ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This research proposed to synthesize photocatalytic particles of titanium dioxide (TiO2), beta silver molybdate (β-Ag2MoO4), and TiO2/Ag2MoO4 heterostructures for application in photocatalytic processes mainly. TiO2 particles and heterostructures were synthesized using microwave-assisted solvothermal (SAMO) method, while β- Ag2MoO4 particles were synthesized via co-precipitation method. All syntheses were made from the starting dilute salt solutions in different solvents, temperatures, and reaction times in order to control the size and the shape of the crystals. Photocatalytic activity of these materials was analyzed for degradation of the organic dyes methyl orange and rhodamine 6G under ultraviolet light (UV) irradiation at 254 nm. Characterizations were performed using X-ray diffraction (XRD), infrared vibrational spectroscopy, photoluminescence (PL) and specific surface area determination (BET method). The morphologies of the crystals were examined by high resolution scanning electron microscopy (HRSEM) and focused ion beam (FIB). The optical properties were investigated by UV-Vis spectroscopy. XRD results showed a tetragonal structure for the powders of TiO2, and a cubic spinel structure for β-Ag2MoO4 particles. Infrared spectra presented characteristic absorption bands for each material. PL bands indicated a broad emission with a maximum at wavelength of 605 nm, which corresponds to the emission in the yellow region for TiO2 powder. Regarding the β-Ag2MoO4 powders emis... (Complete abstract click electronic access below) / Doutor

Includes errata attached to first leaf. Includes bibliographical references. The complexation of a range of monovalent and divalent metal ions by the bibracchial lariat ethers has been investigated. Also investigates the complexation of metal ions and the anionic azo dye Brilliant Yellow by the diazacrown linked cyclodextrin dimers.

Near-infrared (NIR) fluorescence imaging has emerged as an attractive non-invasive approach for direct visualization of diseases which depends on the development of stable, highly specific and sensitive optical probes. The NIR region of the electronic spectrum offers a reduction in the background autofluorescence and an increase in the tissue penetration depth. Cyanine dyes have often been considered promising contrast optic agents owing to their photophysical properties. Herein the synthesis of various penta- and heptamethine benzothiazole cyanine dyes has been described and their in vivo imaging efficacy was determined. Varying functionalities on the benzothiazole aromatic ring and changing substituents on the benzothiazolium nitrogen atom reflected subsequent changes in the imaging pattern and have resulted in the development of promising brain targeting agents.

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Modern manufacturing processes assume efficient utilization and recycling of natural resources whenever possible. Over the past decade paper recycling has progressed from 33.5% in 1990 to just above 48% in 2002.1 Indeed, for certain select grades, (newspaper and old corrugated containers) greater than 70% is currently being recycled. In contrast, mixed office waste and colored directory papers are often underutilized. A major difficulty in recycling these grades of paper is the problems associated with decolorizing the dyes present in the paper.2 Of the commonly used paper dyes, the stilbene dye Direct Yellow 113 and methine dye Basazol 46L are notorious4 for poor bleachability with the commonly used chemical bleaching agents including chlorine dioxide, oxygen, hydrogen peroxide and sodium dithionite. The ability of white-rot fungi to decolorize colored effluents containing textile dyes is currently the subject of intensive research efforts. The secreted enzymes involved in dye decolorization include manganese peroxidase, lignin peroxidase and laccase. Laccase, a lignolytic enzyme, has also been studied for many years for the biobleaching of wood pulps. The ability of laccase to delignify pulp is greatly enhanced by the addition of small molecule mediators such as 2-2´ azinobis (3-ethylbenzthiazoline-6-sulfonate) (ABTS) and 1-hydroxybenzotriazole (HBT). This research project focused on applying laccase combined with a mediator to decolorize C.I. Direct Yellow 11 and Basazol 46L. Three mediators were tested: ABTS, HBT and violuric acid. Laccase/ABTS was most effective with 60% of the color being removed. The level of color removal was maintained at 60% even when ABTS concentration was lowered from 5 mM to 0.01 mM. When laccase/1 mM ABTS was applied to Direct Yellow 11 in solution, the majority of color loss occurred within 60 minutes. The ability of soybean (SBP) and horseradish (HRP) peroxidases and laccase to decolorize Direct Yellow 11 and Basazol 46L in solution was also examined. The results demonstrated that these two recalcitrant dyes could be effectively decolorized by enzymatic treatments by horseradish peroxidase, soybean peroxidase, and laccase with ABTS as mediator. SBP is effective from pH 4.5 to 8.5. The stilbene dye Direct Yellow 11 responded to both SBP and laccase/ABTS. For the methine dye Basazol 46L, SBP was a more effective treatment than HRP or laccase/ABTS. Basazol 46L responded quickly to SBP treatment with 74% reduction in signal intensity within 5 minutes. To evaluate the effectiveness of laccase/ABTS treatment, pulp dyed with Direct Yellow 11 and three commercial colored pulps were subjected to seven different bleaching treatments. These treatments consisted of 1)laccase/ABTS; 2)laccase/ABTS followed by alkaline extraction; 3)laccase/ABTS followed by bleaching with sodium dithionite; 4)oxygen bleaching; 5)oxygen bleaching followed by dithionite treatment; 6)alkaline hydrogen peroxide bleaching; and 7)alkaline peroxide bleaching followed by dithionite treatment. The best results were obtained by including reductive bleaching with sodium dithionite. For Direct Yellow 11 dyed pulp, laccase/ABTS followed by dithionite yield comparable reduction in color to oxygen or peroxide followed by dithionite.

Currently in Taiwan¡¦s textile-dying industry, sodium hypochlorite (NaOCl) is popularly used as a decolorization oxidant. In order to surely meet the effluent color regulation of 550 ADMI (American Dye Manufactures Institute), excessive dosage of sodium hyperchlorite is commonly used, which results in the increase of residual chloride and the accumulation of toxic chlorinated compound in the environment. This study probes into the characteristics of substitute oxidant for sodium hypochlorite to avoid the production of toxic products. The study includes decolorization efficiency evaluation, economical analysis and feasibility of commercial application. This study adopts ozone as an oxidant and ultraviolet light as the oxidant enhancer for the purpose of preventing the occurrence of secondary pollution products like trihalomethane from the sodium hyperchlorite application. Literature review indicates that there are several studies for reaction mechanisms of oxidation and disinfection of ozone and ultraviolet light for decolorization and the conclusions reveal much promising results. There are three topics in this study, which are: Topic 1: Feasibility study. This study focuses on whether the effluent color concentration of the treatment process meets the color effluent standard or not. A 3.5 L volume reactor was used in this section. Topic 2: Influencing factor analysis. A 14 L volume reactor was adopted for analyzing the influencing factors for decolorization and for comparing the differences in treatment efficiencies between a dye finishing plant effluent and two commercial dyestuff samples. Topic 3: Economic analysis. The analysis focuses on economic comparison between NaOCl and UV/Ozone processes for effluent decolorization. Analysis results of the investment cost, operation/maintenance expense, and investment return duration are presented in this section. A 50 L volume reactor was used to achieve the evaluation for this part. First topic of this study examined some operating parameters for treating effluent from the biological and chemical coagulation units of a dye-finishing wastewater treatment plant using the UV/Ozone technique to meet an effluent regulation of 550 ADMI values could be reduced from approximately 4,000 to 200 ADMI in an hour using the UV/Ozone technique. The results show that higher color removal efficiency could be achieved at pH values around 3 as compared with higher pH values of around 7 and 10. This might be due to the fact that the predominant ozone molecules at lower pH values are more selective to certain chromophore molecules in wastewater, despite the fact that hydroxyl radicals are predominant at higher pH values and have a stronger oxidation capability than ozone. The UV light used in this study emitted from the experimental lamp can excite oxygen and water molecules to produce ozone molecules and hydroxyl radicals that can then increase decolorization rate. The findings of this investigation reveal that the proposed UV/Ozone treatment scheme has potential for development into an environmentally friendly decolorization approach for dye finishing wastewater treatment. The second topic is to investigate the feasibility of applying UV/Ozone techniques to reduce color content caused by two commercial reactive dyes (Orange-13 and Blue-19). Bench experiments were performed using a 14-L reactor. Controlling factors including pH value, dosage of ozone, reaction time, and UV intensity were evaluated to obtain the optimal operating parameters. Results from this study show that the ozone dosage and pH value dominated the effects on the decolorization process. However, UV intensity shows relatively insignificant effects. Results also indicate that the color content could be reduced from 2,000 to 200 ADMI within a reaction time of 30 minutes with a total ozone dosage of 100 mg/L. This study shows that pH values of approximately 3 and 10 favored the decolorization of the studied Dye Blue-19 and Orange-13, respectively. This was due to the effects that molecular ozone and hydroxyl radicals had significant oxidative power at low and high pH, respectively. Moreover, molecular ozone was more selective to certain dye structures during its oxidation process. This also caused the effect that pH value played an important role on color removal. Kinetic analyses show that the decolorization reactions of Dye Orange-13 and Blue-19 followed a first-order decolorization model. Experimental results also indicate that the degree of decolorization was primarily proportional to the ozone dosage. Results from this study provide us an insight into the characteristics and mechanisms of decolorization by UV/ozone technique. Results will also aid in designing a system for field application of dye finishing plants. According to the results from the third topic, for a dye finishing plant of wastewater flow rate of 800CMD (m3/day), the capital cost of equipment and related establishment as well as amendment is about US$ 116,300, and the monthly operation and maintenance cost is US$ 4,030. In this study, ozone was used as a substitute decolorizing oxidant to treat the effluent from the secondary biological and physical/chemical treatment plant. Because the current cost for the decolorization oxidant (NaOCl) is approximately US$ 5,700 per month, the monthly saving, adopting the decolorization system using UZ/Ozone, will be US$ 1,670. The investment return period will be over 7 years and is not attractive to the plant owners. However, to prevent the accumulated toxicity of chloride compounds in the environment and to promote the desires of investment on the advanced decolorization technique, a favorable tax deduction policy needs to be applied.

<p>Decolorization of Azo dyes in synthetic wastewater composition which is similar to real textile wastewater was carried out by microbial process. Experiments were performed in two continuous systems. Experiments were performed under anaerobic conditions in order to break the nitrogen bond of the azo group (-N=N-). A synthetic dye solution which contained 200 mg/L Reactive Black 5, 200 mg/L Procion Red MX-5B and 1 g/L yeast extract was prepared. In this study, living microorganisms were used to degrade the dyes in wastewater. Rice husks which contain bacteria and fungi were used in the reactors of continuous systems. The parameters tested on continuous system were wastewater composition, the number of reactors, the amount of yeast extract in wastewater composition, the wastewater flowrate, washing the system with wood chips solution, addition of yeast extract solution.  Results have shown that increasing the number of reactors, the retention time, the amount of yeast extract and washing the system with wood chips solution had positive effects for degradation of the dyes from wastewater. When the flowrate was increased the retention time has decreased so degradation of dyes has decreased but although the flowrate increased twice, % degradation hasn’t decreased as the same ratio. Therefore this result showed that this process can be worked for faster flowrates. Microbial process is a promising technology which might be used to treat wastewater containing azo dyes with good performance.</p><p> </p>

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