" A series of symmetric and asymmetric 2-arylidene and 2,5-diarylidene cyclopentanone dyes have been synthesized. Their electronic absorption and fluorescence spectra have been measured in a wide variety of nonpolar and polar, aprotic and protic solvents. Absorption and fluorescence spectral maxima have been correlated with the ET(30) empirical solvent polarity scale. Lippert-Mataga analysis (in aprotic solvents) demonstrates the increase in the electronic dipole moment from the ground singlet to excited singlet states, consistent with the internal charge transfer (ICT) nature of the S0 --> S1 excitation. TD-DFT spectral calculations support the ICT natures of these compounds. Photophysical properties of these compounds involved measuring both fluorescence quantum yields and lifetimes in various solvents. Investigation of the deactivation kinetics involved determining the first-order radiative and nonradiative rates of decay upon knowledge of the quantum yield and lifetime data. Fluorescence quantum yields and lifetimes of the compounds studied varied depending on the nature of the solvent environments. Excited state protonation in acetic acid was observed for several 2,5-diarylidene cyclopentanones and deltapKa’s have been determined via the Forster Cycle. Thorough work on the photochemistry of (2E,5E)-2,5-bis(p-dimethylaminobenzylidene)-cyclopentanone (bis-dmab) was carried out, consisting of testing bis-dmab as a singlet oxygen photosensitizer, and examination of both the chemical reactivity of bis-dmab with singlet state oxygen (self-sensitized photooxidation) and (E,E) --> (E,Z) photoisomerization. "

Ormosils (Organically Modified Silicates) have been used in the past as hosts for various organic molecules. In this work, seven different photochromic dyes most of which belong to the spirooxazine / merocyanine family were doped into thin films that were prepared using several increasingly inorganic Ormosil formulations. These dyes were either physically incorporated into the pores of the film or covalently bound to the matrix via a siloxane substituent. The dyes, which undergo a reversible color change upon irradiation, are relatively stable, although they will ultimately degrade after prolonged exposure to ultraviolet irradiation. This work focuses on identifying the variables that influence the rate of dye degradation, including rigidity of the Ormosil matrix, wavelength of irradiation, and the presence of oxygen. The silylated dyes, which are generally regarded as having reduced mobility within the pores of the Ormosil, degraded more slowly, suggesting a link between stability and rotational and translational freedom. Irradiation wavelength also affected dye stability in that limiting exposure to wavelengths in the near UV (and eliminating visible light) causes the least degradation. This is attributed to the photostability of the photomerocyanine isomer. Finally, the presence of oxygen was shown to cause dramatic enhancement in degradation. The mechanisms of each of these effects are discussed.

Textile industries are the major users of dyes in the world. A huge fraction of dyes are discharged out from the textile industries, causing serious damage to the environment. Bioremediation based technologies has been proved to be the most desirable and cost- effective method to counter textile dye pollution. The ability of the microorganisms to decolorize and metabolize dyes can be employed to treat the environment polluted by textile dyes. In this work, a total of 84 bacterial strains were isolated from Kelambakkam Solar Salt Crystallizer ponds (or salterns) and screened for their ability to produce extracellular tannase and laccase enzymes and eventually to decolorize three widely used textile dyes- Reactive Blue 81, Reactive Red 111 and Reactive Yellow 44. Of these 84 strains, 18 strains exhibited tannase activity and 36 strains showed positive laccase enzyme activity. The 11 bacterial strains that displayed both tannase and laccase enzyme activity were screened for their ability to decolorize the three textile azo dyes (100 mg/L). Out of 11 strains only 2 strains i.e., AMETH72 and AMETH77 showed best decolorization (%) in all the three dyes under static condition at room temperature. Repeated- batch immobilization study used to select the most efficient bacterial strain revealed that, isolate AMETH72 was efficient than AMETH77 in decolorizing the dyes. The 16S rRNA sequencing of AMETH72 showed 99% phylogenetic similarity to Halomonas elongata. The dye degradation products analyzed by FTIR and UV-Vis techniques displayed complete disruption of azo linkages and biodegradation of dyes to simpler compounds. The treated dyes also improved growth and total chlorophyll content in Wheat and Green gram seedlings, as compared to the untreated dyes. This indicated the non- toxicity of the biologically degraded dye products. Thus the entire study concluded that halotolerant marine bacteria from the salterns can be effectively used to bioremediate the textile dyes. / Program: MSc in Resource Recovery - Industrial Biotechnology

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Este trabalho visa o estudo de processos de degradação fotocatalítica e fotoeletrocatalítica de corantes sobre dióxido de titânio. O enfoque está voltado ao uso de técnicas espectroscópicas, com especial destaque para o desenvolvimento de metodologias de espectroscopia vibracional Raman intensificada. Nesse sentido, tem-se em vista a investigação dos mecanismos envolvidos nos processos de fotodegradação e fotoeletrodegradação de corantes, através da identificação de intermediários e produtos de processos de degradação por técnicas de espectroscopia eletrônica e Raman. Os estudos de fotocatálise são também expandidos para ambientes eletroquímicos. Nos chamados processos fotoeletrocatalíticos, a combinação de processos eletroquímicos e fotoquímicos mostra-se bastante promissora para a degradação de poluentes orgânicos. O primeiro desafio no desenvolvimento desse trabalho foi construir o fotorreator adequado que permitisse a obtenção de amostras para serem analisadas por espectroscopia Raman, e apresentasse boa eficiência nos processos de fotocatálise e também fotoeletrocatálise. Encontrado o fotorreator adequado, investigamos o comportamento cinético dos processos foto(eletro)degradação de corantes, buscando verificar a dependência com o potencial eletroquímico aplicado, o efeito do eletrólito suporte, e a identificação de intermediários formados durante o processo de degradação. Analisamos também aspectos relacionados aos mecanismos de adsorção de corantes sobre a superfície do dióxido de titânio. Tais aspectos podem ser de significativa relevância no desenvolvimento de técnicas eficazes para o tratamento de poluentes orgânicos. Nossos estudos estiveram principalmente centrados em dois corantes: o azocorante verde de Janus e o corante antraquinônico alizarina vermelha S. Os resultados obtidos nos estudos da cinética dos processos fotoeletrocatalíticos sugerem que o efeito do potencial aplicado depende de maneira significativa da natureza química do corante. Observou-se uma tendência dos processos fotoeletrocatalíticos serem mais eficientes na remoção da coloração da solução corante do verde de Janus quando comparados aos fotocatalíticos. Tal tendência não foi observada para o corante alizarina vermelha S. Essa diferença de comportamento pôde ser relacionada à natureza das interações específicas de entre cada corante e a superfície do catalisador. Nossos estudos a respeito dos mecanismos envolvidos nos processos de degradação do verde de Janus revelaram que as primeiras etapas dos processos de fotodegradação e fotoeletrodegradação seguem mecanismos diferentes. Os resultados obtidos mostram que a degradação do verde de Janus em suspensão de TiO2 envolve entre suas etapas modificações na ligação azo desse corante (N=N), resultando na formação de um composto intermediário derivado da fenossafranina. No processo fotoeletrocatalítico, por outro lado, observa-se um mecanismo diferenciado o qual não envolve em suas etapas iniciais a quebra da ligação azo do corante / This work focuses on the study of photocatalytic and photoelectrocatalytic degradation processes of dyes over titanium dioxide. The main approach is based on the use of spectroscopic techniques, with special emphasis to methodologies based on surface-enhanced Raman spectroscopy. Within this context, the mechanisms involved in the photodegradation and photoelectrodegradation of dyes are investigated by the identification of degradation intermediates through vibrational and electronic spectroscopies. In the so-called photoelectrocatalytic processes, the combination of electrochemical and photochemical processes is an interesting and promising approach for the degradation of a wide variety of organic pollutants. The first step in the development of the present work was to build a photo reactor that allowed the analysis of samples through Raman spectroscopy and presented a good efficiency for both photocatalytic and photoelectrocatalytic processes. We then investigated the kinetic behavior of the photo(electro)degradation of dyes in order to verify the dependence upon the electrochemical applied potential, the effect of the supporting electrolyte, and the identification of intermediate products formed during the degradation process. We also analyzed aspects related to the adsorption mechanisms of the dyes on the titanium dioxide surface. Such aspects can be relevant to the understanding and to the development of efficient techniques for the remediation of organic pollutants. Our studies focused mainly on two dyes: the azo dye Janus green and the anthraquinonic dye alizarin red S. The results obtained in the kinetic study of the photoelectrocatalytic processes suggest that the effect of the applied electrochemical potential strongly depends on the chemical nature of the investigated dye. We have observed that the decolorization of Janus green is favored for photoelectrocatalytic process as compared to the photocatalytic degradation. Such behavior was not observed for the anthraquinonic dye alizarin red S. This difference was related to the nature of the specific interactions between each dye and the catalyst surface. Our studies regarding the mechanisms of degradation revealed that the first steps of the photocatalytic and photoelectrocatalytic processes of Janus green followed different routes. The obtained results indicate that the degradation of Janus green in aqueous TiO2 suspension involves changes in the azo bond (N=N), resulting in the formation of an intermediate compound a derived from the phenosafranine structure, whereas for the photoelectrocatalytic process there are evidences of a different mechanism that does not involve the cleavage of the azo bond.

No description available.

by Cheung Kit Hing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 175-199). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstracts --- p.ii / Table of Contents --- p.vi / List of Figures --- p.xviii / List of Plates --- p.xxii / List of Tables --- p.xxiii / Abbreviations --- p.xxv / Equations --- p.xxviii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- The chemistry of azo dyes --- p.1 / Chapter 1.2 --- Azo dyes classification --- p.2 / Chapter 1.3 --- Environmental concerns and toxicity --- p.4 / Chapter 1.3.1 --- Toxicity of azo dyes --- p.5 / Chapter 1.3.2 --- Carcinogenicity --- p.5 / Chapter 1.3.3 --- Ecotoxicity --- p.11 / Chapter 1.3.3.1 --- Toxicity to microorganisms --- p.12 / Chapter 1.3.3.2 --- Toxicity towards vertebrates --- p.13 / Chapter 1.4 --- Treatment of azo dyes --- p.13 / Chapter 1.4.1 --- Physical treatment --- p.14 / Chapter 1.4.1.1 --- Adsorption --- p.14 / Chapter 1.4.1.2 --- Membrane technology --- p.15 / Chapter 1.4.2 --- Chemical treatments --- p.15 / Chapter 1.4.2.1 --- Chlorination --- p.16 / Chapter 1.4.2.2 --- Fenton's reaction --- p.16 / Chapter 1.4.2.3 --- Ozonation --- p.16 / Chapter 1.4.2.4 --- Coagulation --- p.17 / Chapter 1.4.3 --- Biological treatments --- p.17 / Chapter 1.4.3.1 --- Activated sludge process --- p.18 / Chapter 1.4.3.2 --- Biodegradation --- p.18 / Chapter 1.4.3.3 --- Biosorption --- p.21 / Chapter 1.4.3.3.1 --- Modeling of sorption --- p.24 / Chapter 1.4.3.3.1.1 --- Langmuir sorption model --- p.24 / Chapter 1.4.3.3.1.2 --- Freundlich sorption model --- p.25 / Chapter 1.4.4 --- Advanced oxidation processes --- p.25 / Chapter 1.4.4.1 --- Photocatalytic oxidation --- p.26 / Chapter 1.4.4.2 --- Titanium dioxide (TiO2) --- p.26 / Chapter 1.4.4.3 --- Mechanism of photocatalytic oxidation using photocatalyst TiO2 --- p.28 / Chapter 1.4.4.4 --- Photocatalytic oxidation of s-triazine containing compounds --- p.30 / Chapter 1.4.4.5 --- Photocatalytic oxidation of Procion Red MX-5B --- p.31 / Chapter 1.4.4.6 --- Cyanuric acid --- p.32 / Chapter 1.4.4.6.1 --- Application --- p.32 / Chapter 1.4.4.6.2 --- Toxicity --- p.32 / Chapter 1.4.4.6.3 --- Photocatalytic oxidation resistance --- p.34 / Chapter 1.4.4.6.4 --- Biodegradation --- p.35 / Chapter 1.4.4.7 --- Enhancement of photocatalytic oxidation by using sorbent immobilized with TiO2 --- p.35 / Chapter 1.4.4.7.1 --- Sorption --- p.35 / Chapter 1.4.4.7.2 --- Immobilization of TiO2 --- p.37 / Chapter 1.4.8 --- Integration of treatment methods --- p.39 / Chapter 2. --- Objectives --- p.41 / Chapter 3. --- Materials and methods --- p.42 / Chapter 3.1. --- Sorption --- p.42 / Chapter 3.1.1 --- Chemical reagents --- p.42 / Chapter 3.1.2 --- Determination of Procion Red MX-5B --- p.42 / Chapter 3.1.3 --- Sampling --- p.44 / Chapter 3.1.4 --- Isolation of Procion Red MX-5B-sorbing bacteria --- p.44 / Chapter 3.1.5 --- Screening of Procion Red MX-5B sorption ability --- p.44 / Chapter 3.1.6 --- Identification of isolated bacterium --- p.46 / Chapter 3.1.7 --- Optimization of cell yield and sorption capacity --- p.47 / Chapter 3.1.7.1 --- Preparation of cell culture of Vibrio sp. --- p.47 / Chapter 3.1.7.2 --- Growth phase --- p.47 / Chapter 3.1.7.2.1 --- Growth curve --- p.47 / Chapter 3.1.7.2.2 --- Dye sorption capacity --- p.47 / Chapter 3.1.7.3 --- Initial pH --- p.48 / Chapter 3.1.7.3.1 --- Growth curve --- p.48 / Chapter 3.1.7.3.2 --- Dye sorption capacity --- p.48 / Chapter 3.1.7.4 --- Temperature --- p.49 / Chapter 3.1.7.4.1 --- Growth curve --- p.49 / Chapter 3.1.7.4.2 --- Dye sorption capacity --- p.49 / Chapter 3.1.7.5 --- Glucose concentrations --- p.49 / Chapter 3.1.7.5.1 --- Growth curve --- p.49 / Chapter 3.1.7.5.2 --- Dye sorption capacity --- p.50 / Chapter 3.1.8 --- Optimization of sorption process --- p.50 / Chapter 3.1.8.1 --- Preparation of sorbent --- p.50 / Chapter 3.1.8.2 --- Dry weight of sorbent --- p.50 / Chapter 3.1.8.3 --- Temperature --- p.50 / Chapter 3.1.8.4 --- Agitation rate --- p.50 / Chapter 3.1.8.5 --- Salinity --- p.51 / Chapter 3.1.8.6 --- Initial pH --- p.51 / Chapter 3.1.8.7 --- Concentration of Procion Red MX-5B --- p.51 / Chapter 3.1.8.8 --- Combination study of salinity and initial pH --- p.51 / Chapter 3.2. --- Photocatalytic oxidation reaction --- p.52 / Chapter 3.2.1 --- Chemical reagents --- p.52 / Chapter 3.2.2 --- Photocatalytic reactor --- p.52 / Chapter 3.2.3 --- Optimization of sorption and photocatalytic oxidation reactions using biomass of Vibrio sp.immobilized in calcium alginate beads --- p.54 / Chapter 3.2.3.1 --- Effect of dry weight of immobilized cells of Vibrio sp. --- p.54 / Chapter 3.2.3.1.1 --- Sorption --- p.55 / Chapter 3.2.3.1.2 --- Photocatalytic oxidation --- p.56 / Chapter 3.2.3.2 --- Effect of UV intensities --- p.57 / Chapter 3.2.3.3 --- Effect of TiO2 concentrations --- p.57 / Chapter 3.2.3.3.1 --- Sorption --- p.57 / Chapter 3.2.3.3.2 --- Photocatalytic oxidation --- p.57 / Chapter 3.2.3.4 --- Effect of H202 concentrations --- p.57 / Chapter 3.2.3.5 --- Effect of the number of beads --- p.58 / Chapter 3.2.3.5.1 --- Sorption --- p.58 / Chapter 3.2.3.5.2 --- Photocatalytic oxidation --- p.58 / Chapter 3.2.3.6 --- Effect of initial pH with and without the addition of H2O2 --- p.58 / Chapter 3.2.3.7 --- Control experiments for photocatalytic oxidation of Procion Red MX-5B --- p.59 / Chapter 3.2.3.8 --- Combinational study of UV intensities and H2O2 concentrations --- p.59 / Chapter 3.2.3.9 --- Photocatalytic oxidation of Procion Red MX-5B under optimal conditions --- p.59 / Chapter 3.2.3.10 --- "Sorption isotherms of calcium alginate beads immobilized with 70 mg Vibrio sp. and 5,000 mg/L TiO2" --- p.59 / Chapter 3.3 --- Biodegradation --- p.60 / Chapter 3.3.1 --- Chemical reagents --- p.60 / Chapter 3.3.2 --- Sampling --- p.60 / Chapter 3.3.3 --- Enrichment --- p.60 / Chapter 3.3.4 --- Isolation of cyanuric acid-utilizing bacteria --- p.61 / Chapter 3.3.5 --- Determination of cyanuric acid --- p.61 / Chapter 3.3.6 --- Screening of Procion Red MX-5B sorption ability --- p.61 / Chapter 3.3.7 --- Screening of cyanuric acid-utilizing ability --- p.61 / Chapter 3.3.8 --- Bacterial identification --- p.63 / Chapter 3.3.9 --- Growth and cyanuric acid removal efficiency of the selected bacterium --- p.63 / Chapter 3.3.10 --- Optimization of reaction conditions --- p.64 / Chapter 3.3.10.1 --- Effect of salinity --- p.64 / Chapter 3.3.10.2 --- Effect of cyanuric acid concentrations --- p.65 / Chapter 3.3.10.3 --- Effect of temperature --- p.65 / Chapter 3.3.10.4 --- Effect of agitation rate --- p.65 / Chapter 3.3.10.5 --- Effect of initial pH --- p.66 / Chapter 3.3.10.6 --- Effect of initial glucose concentration --- p.66 / Chapter 3.3.10.7 --- Combinational study of glucose and cyanuric acid concentrations --- p.66 / Chapter 3.4 --- Detection of cyanuric acid formed in photocatalytic oxidation reaction --- p.66 / Chapter 3.5 --- "Integration of sorption, photocatalytic oxidation and biodegradation" --- p.67 / Chapter 4. --- Results --- p.68 / Chapter 4.1. --- Sorption --- p.68 / Chapter 4.1.1 --- Determination of Procion Red MX-5B --- p.68 / Chapter 4.1.2 --- Isolation of Procion Red MX-5B-sorbing bacteria --- p.68 / Chapter 4.1.3 --- Screening of Procion Red MX-5B sorption ability --- p.68 / Chapter 4.1.4 --- Identification of isolated bacterium --- p.72 / Chapter 4.1.5 --- Optimization of cell yield and sorption capacity --- p.72 / Chapter 4.1.5.1 --- Growth phase --- p.72 / Chapter 4.1.5.1.1 --- Growth curve --- p.72 / Chapter 4.1.5.1.2 --- Dye sorption capacity --- p.72 / Chapter 4.1.5.2 --- Initial pH --- p.75 / Chapter 4.1.5.2.1 --- Growth curve --- p.75 / Chapter 4.1.5.2.2 --- Dye sorption capacity --- p.75 / Chapter 4.1.5.3 --- Temperature --- p.75 / Chapter 4.1.5.3.1 --- Growth curve --- p.75 / Chapter 4.1.5.3.2 --- Dye sorption capacity --- p.79 / Chapter 4.1.5.4 --- Glucose concentrations --- p.79 / Chapter 4.1.5.4.1 --- Growth curve --- p.79 / Chapter 4.1.5.4.2 --- Dye sorption capacity --- p.79 / Chapter 4.1.6 --- Optimization of sorption process --- p.82 / Chapter 4.1.6.1 --- Dry weight of sorbent --- p.82 / Chapter 4.1.6.2 --- Temperature --- p.82 / Chapter 4.1.6.3 --- Agitation rate --- p.86 / Chapter 4.1.6.4 --- Salinity --- p.86 / Chapter 4.1.6.5 --- Initial pH --- p.86 / Chapter 4.1.6.6 --- Concentration of Procion Red MX-5B --- p.90 / Chapter 4.1.6.7 --- Combination study of salinity and initial pH --- p.90 / Chapter 4.2. --- Photocatalytic oxidation reaction --- p.94 / Chapter 4.2.1 --- Effect of dry weight of immobilized cells of Vibrio sp. --- p.94 / Chapter 4.2.1.1 --- Sorption --- p.94 / Chapter 4.2.1.2 --- Photocatalytic oxidation --- p.96 / Chapter 4.2.2 --- Effect of UV intensities --- p.96 / Chapter 4.2.3 --- Effect of TiO2 concentrations --- p.96 / Chapter 4.2.3.1 --- Sorption --- p.96 / Chapter 4.2.3.2 --- Photocatalytic oxidation --- p.101 / Chapter 4.2.4 --- Effect of H2O2 concentrations --- p.101 / Chapter 4.2.5 --- Effect of the number of beads --- p.101 / Chapter 4.2.5.1 --- Sorption --- p.105 / Chapter 4.2.5.2 --- Photocatalytic oxidation --- p.105 / Chapter 4.2.6 --- Effect of initial pH with and without the addition of --- p.105 / Chapter 4.2.7 --- Control experiments for photocatalytic oxidation of Procion Red MX-5B --- p.109 / Chapter 4.2.8 --- Combinational study of UV intensities and H202 concentrations --- p.112 / Chapter 4.2.9 --- Photocatalytic oxidation of Procion Red MX-5B under optimal conditions --- p.112 / Chapter 4.2.10 --- "Sorption isotherms of calcium alginate beads immobilized with 70 mg Vibrio sp. and 5,000 mg/L Ti02" --- p.112 / Chapter 4.3 --- Biodegradation --- p.116 / Chapter 4.3.1 --- Isolation of cyanuric acid-utilizing bacteria --- p.116 / Chapter 4.3.2 --- Determination of cyanuric acid --- p.116 / Chapter 4.3.3 --- Screening of Procion Red MX-5B sorption ability --- p.116 / Chapter 4.3.4 --- Screening of cyanuric acid-utilizing ability --- p.116 / Chapter 4.3.5 --- Bacterial identification --- p.118 / Chapter 4.3.6 --- Growth and cyanuric acid removal efficiency of the selected bacterium --- p.118 / Chapter 4.3.7 --- Optimization of reaction conditions --- p.122 / Chapter 4.3.7.1 --- Effect of salinity --- p.122 / Chapter 4.3.7.2 --- Effect of cyanuric acid concentrations --- p.122 / Chapter 4.3.7.3 --- Effect of temperature --- p.126 / Chapter 4.3.7.4 --- Effect of agitation rate --- p.126 / Chapter 4.3.7.5 --- Effect of initial pH --- p.132 / Chapter 4.3.7.6 --- Effect of initial glucose concentration --- p.132 / Chapter 4.3.7.7 --- Combinational study of glucose and cyanuric acid concentrations --- p.132 / Chapter 4.4 --- Detection of cyanuric acid formed in photocatalytic oxidation reaction --- p.137 / Chapter 4.5 --- "Integration of sorption, photocatalytic oxidation and biodegradation" --- p.137 / Chapter 5. --- Discussion --- p.141 / Chapter 5.1 --- Sorption --- p.141 / Chapter 5.1.1 --- Isolation of Procion Red MX-5B-sorbing bacteria --- p.141 / Chapter 5.1.2 --- Screening of Procion Red MX-5B sorption ability --- p.141 / Chapter 5.1.3 --- Identification of isolated bacterium --- p.141 / Chapter 5.1.4 --- Optimization of cell yield and sorption capacity --- p.142 / Chapter 5.1.4.1 --- Growth phase --- p.142 / Chapter 5.1.4.1.1 --- Growth curve --- p.142 / Chapter 5.1.4.1.2 --- Dye sorption capacity --- p.143 / Chapter 5.1.4.2 --- Initial pH --- p.146 / Chapter 5.1.4.2.1 --- Growth curve --- p.146 / Chapter 5.1.4.2.2 --- Dye sorption capacity --- p.146 / Chapter 5.1.4.3 --- Temperature --- p.146 / Chapter 5.1.4.3.1 --- Growth curve --- p.146 / Chapter 5.1.4.3.2 --- Dye sorption capacity --- p.147 / Chapter 5.1.4.4 --- Glucose concentrations --- p.147 / Chapter 5.1.4.4.1 --- Growth curve --- p.147 / Chapter 5.1.4.4.2 --- Dye sorption capacity --- p.147 / Chapter 5.1.5 --- Optimization of sorption process --- p.148 / Chapter 5.1.5.1 --- Dry weight of sorbent --- p.148 / Chapter 5.1.5.2 --- Temperature --- p.148 / Chapter 5.1.5.3 --- Agitation rate --- p.149 / Chapter 5.1.5.4 --- Salinity --- p.149 / Chapter 5.1.5.5 --- Initial pH --- p.150 / Chapter 5.1.5.6 --- Concentration of Procion Red MX-5B (MX-5B) --- p.152 / Chapter 5.1.5.7 --- Combination study of salinity and initial pH --- p.153 / Chapter 5.2. --- Photocatalytic oxidation reaction --- p.153 / Chapter 5.2.1 --- Effect of immobilized cells of Vibrio sp. --- p.153 / Chapter 5.2.1.1 --- Sorption --- p.153 / Chapter 5.2.1.2 --- Photocatalytic oxidation --- p.154 / Chapter 5.2.2 --- Effect of UV intensities --- p.155 / Chapter 5.2.3 --- Effect of TiO2 concentrations --- p.155 / Chapter 5.2.3.1 --- Sorption --- p.155 / Chapter 5.2.3.2 --- Photocatalytic oxidation --- p.156 / Chapter 5.2.4 --- Effect of H2O2 concentrations --- p.156 / Chapter 5.2.5 --- Effect of the number of beads --- p.157 / Chapter 5.2.5.1 --- Sorption --- p.157 / Chapter 5.2.5.2 --- Photocatalytic oxidation --- p.158 / Chapter 5.2.6 --- Effect of initial pH with and without the addition of --- p.158 / Chapter 5.2.7 --- Control experiments for photocatalytic oxidation of Procion Red MX-5B --- p.160 / Chapter 5.2.8 --- Combinational study of UV intensities and H202 concentrations --- p.161 / Chapter 5.2.9 --- Photocatalytic oxidation of Procion Red MX-5B under optimal conditions --- p.161 / Chapter 5.2.10 --- "Sorption isotherms of calcium alginate beads immobilized with 70 mg Vibrio sp. and 5,000 mg/L Ti02" --- p.161 / Chapter 5.3 --- Biodegradation --- p.162 / Chapter 5.3.1 --- Isolation of cyanuric acid-utilizing bacteria --- p.162 / Chapter 5.3.2 --- Determination of cyanuric acid --- p.163 / Chapter 5.3.3 --- Screening of Procion Red MX-5B sorption ability --- p.163 / Chapter 5.3.4 --- Screening of cyanuric acid-utilizing ability --- p.163 / Chapter 5.3.5 --- Bacterial identification --- p.163 / Chapter 5.3.6 --- Growth and cyanuric acid removal efficiency of the selected bacterium --- p.164 / Chapter 5.3.7 --- Optimization of reaction conditions --- p.165 / Chapter 5.3.7.1 --- Effect of salinity --- p.165 / Chapter 5.3.7.2 --- Effect of cyanuric acid concentration --- p.165 / Chapter 5.3.7.3 --- Effect of temperature --- p.166 / Chapter 5.3.7.4 --- Effect of agitation rate --- p.167 / Chapter 5.3.7.5 --- Effect of initial pH --- p.167 / Chapter 5.3.7.6 --- Effect of initial glucose concentration --- p.167 / Chapter 5.3.7.7 --- Combinational study of glucose and cyanuric acid concentrations --- p.168 / Chapter 5.4 --- Detection of cyanuric acid formed in photocatalytic oxidation reaction --- p.170 / Chapter 5.5 --- "Integration of sorption, photocatalytic oxidation and biodegradation" --- p.171 / Chapter 5.6 --- Recommendations --- p.171 / Chapter 6. --- Conclusions --- p.173 / Chapter 7. --- References --- p.175 / Appendix --- p.200

O trabalho buscou identificar se o intemperismo acelerado Xênon, utilizando a norma ASTM D4452-12, em corantes naturais encapsulados em matriz de sílica pelo processo sol gel com o uso de alcóxidos, conforme descrito pela patente INPI BR 10 2013 0219835, e injetadas em matriz de policloreto de polivinila (PVC) preservam as características de cor original dos corantes. Utilizou-se comparação dos mesmos corantes naturais – carmim, curcuma, índigo e urucum – sem encapsulamento e com encapsulamento, e injetados na mesma matriz de PVC. Executou-se a determinação da variação da cor antes do ensaio de intemperismo e após 126 h, 252 h, 378 h e 504 h em câmara de intemperismo Xênon utilizando-se a norma ASTM D4459-12. Utilizou-se o corante Tartrazina (INS 102) um azo corante sem encapsulamento como comparação do comportamento dos corantes naturais com um corante sintético. Os resultados indicam que não houve proteção da perda da coloração para os corantes naturais encapsulados, sendo a perda de coloração mais acentuada que os não encapsulados. Concluiu-se que é necessário executar alguns cuidados nas fases de encapsulamento dos corantes naturais como: uma dispersão cuidadosa dos corantes naturais e inclusão de um processo de repetição do encapsulamento do xerogel. / The study aimed to identify the Xenon accelerated weathering, using ASTM D4452-12 standards, of natural dyes encapsulated in the silica matrix by the sol-gel process with the use of alkoxides as described by the patent INPI BR 10 2013 0219835, and injected into matrix of polyvinyl chloride (PVC) preserve characteristics of original color of the dye. We used to compare the same natural colors - carmine, turmeric, indigo and annatto - without encapsulation and with encapsulation, and injected into the same matrix of PVC. Performed to determine the change in color before the weathering test after 126 h, 252 h, 378 h and 504 h in Xenon weathering chamber using ASTM D4459- 12 standards. We used the dye Tartrazine (INS 102) an azo dye without encapsulation as a comparison of the behavior of natural dyes with a synthetic dye. The results indicate that there was no protection of natural dyes encapsulated, with the loss of saturation more severe than the non-encapsulated natural dyes. It follows that some care needs to perform the encapsulation stages of natural dyes as a careful dispersion of natural colorants includes a process of repeat the encapsulation of the xerogel.

Ng, Tsz Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 86-98). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / Table of Contents --- p.vii / List of Figures --- p.xiii / List of Plates --- p.XV / List of Tables --- p.xxi / Abbreviations --- p.xxii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- "Pollution, toxicity and environmental impact of azo dye" --- p.1 / Chapter 1.2 --- Common treatment methods for dyeing effluent --- p.2 / Chapter 1.2.1 --- Physicochemical methods --- p.2 / Chapter 1.2.1.1 --- Coagulation/ flocculation --- p.2 / Chapter 1.2.1.2 --- Adsorption --- p.3 / Chapter 1.2.1.3 --- Membrane filtration --- p.4 / Chapter 1.2.1.4 --- Fenton reaction --- p.4 / Chapter 1.2.1.5 --- Ozonation --- p.5 / Chapter 1.2.1.6 --- Photocatalytic oxidation --- p.6 / Chapter 1.2.2 --- Biological treatments --- p.7 / Chapter 1.2.2.1 --- Degradation of azo dyes by bacteria --- p.8 / Chapter 1.2.2.1.1 --- Anaerobic conditions --- p.8 / Chapter 1.2.2.1.2 --- Aerobic conditions --- p.9 / Chapter 1.2.2.1.3 --- Combined anaerobic and aerobic conditions --- p.10 / Chapter 1.2.2.2 --- Decolourization of azo dyes by fungi --- p.11 / Chapter 1.2.2.3 --- Mechanisms of azo dye reduction by microorganisms --- p.12 / Chapter 1.3 --- "Chromium species, toxicity and their impacts on environment" --- p.14 / Chapter 1.4 --- Common treatment methods for chromium --- p.16 / Chapter 1.4.1 --- Chemical and physical methods --- p.16 / Chapter 1.4.2 --- Biological methods --- p.17 / Chapter 1.4.2.1 --- Chromium reduction by aerobic bacteria --- p.17 / Chapter 1.4.2.2 --- Chromium reduction by anaerobic bacteria --- p.18 / Chapter 1.5 --- Studies concerning azo dye and Cr(VI) co-treatment --- p.19 / Chapter 1.6 --- Response surface methodology --- p.21 / Chapter 1.6.1 --- Response surface methodology against one-factor-at-a-time design --- p.22 / Chapter 1.6.2 --- Phases of response surface methodology --- p.25 / Chapter 1.6.3 --- 2 - level factorial design --- p.26 / Chapter 1.6.4 --- Path of steepest ascent --- p.27 / Chapter 1.6.5 --- Central composite design --- p.28 / Chapter 2. --- Objectives --- p.30 / Chapter 3. --- Materials and Methods --- p.31 / Chapter 3.1 --- Isolation of bacterial strains --- p.31 / Chapter 3.1.2 --- Azo dye decolourization --- p.33 / Chapter 3.1.3 --- Chromate reduction --- p.34 / Chapter 3.2 --- Identification of selected bacterial strains --- p.35 / Chapter 3.2.1 --- Gram stain --- p.35 / Chapter 3.2.2 --- Sherlock® Microbial Identification System --- p.35 / Chapter 3.2.3 --- 16S ribosomal RNA sequencing --- p.37 / Chapter 3.3 --- Optimization of dye decolourization and chromate reduction efficiency with response surface methodology --- p.38 / Chapter 3.3.1 --- Minimal-run resolution V design --- p.38 / Chapter 3.3.2 --- Path of steepest ascent --- p.40 / Chapter 3.3.3 --- Central composite design --- p.41 / Chapter 3.3.4 --- Statistical analysis --- p.43 / Chapter 3.3.5 --- Experimental validation of the optimized conditions --- p.43 / Chapter 3.4 --- Determination of the performance of the selected bacterium in different conditions --- p.43 / Chapter 3.5 --- Determination of azoreductase and chromate reductase activities --- p.44 / Chapter 3.5.1 --- Preparation of cell free extract --- p.44 / Chapter 3.5.2 --- Azoreductase and chromate reductase assay --- p.45 / Chapter 3.6 --- Determination and characterization of degradation intermediates --- p.45 / Chapter 3.6.1 --- Isolation and concentration of the purple colour degradation intermediate --- p.45 / Chapter 3.6.2 --- Mass spectrometry analysis --- p.47 / Chapter 3.6.3 --- Atomic absorption spectrometry analysis --- p.48 / Chapter 4. --- Results --- p.49 / Chapter 4.1 --- Azo dye decolourizing and chromate reducing ability of the isolated bacterial strain --- p.49 / Chapter 4.2 --- Identification of selected bacterium --- p.50 / Chapter 4.3 --- Optimization of dye decolourization and chromate reduction efficiency with response surface methodology --- p.50 / Chapter 4.3.1 --- Minimal-run resolution V design --- p.50 / Chapter 4.3.2 --- Path of the steepest ascend --- p.54 / Chapter 4.3.3 --- Central composite design --- p.55 / Chapter 4.3.4 --- Validation of the predicted model --- p.62 / Chapter 4.4 --- Performance of the selected bacterium in different conditions --- p.62 / Chapter 4.4.1 --- Chromate and dichromate --- p.62 / Chapter 4.4.2 --- Initial pH --- p.63 / Chapter 4.4.3 --- Low and high salt concentration --- p.63 / Chapter 4.4.4 --- Initial K2CrO4 concentration --- p.63 / Chapter 4.4.5 --- Initial Acid Orange 7 concentration --- p.63 / Chapter 4.4.6 --- Nutrients limitation --- p.64 / Chapter 4.5 --- Chromate reductase and azoreductase activities --- p.67 / Chapter 4.6 --- Determination of degradation intermediates --- p.67 / Chapter 4.6.1 --- Mass spectrum of the degradation intermediate --- p.68 / Chapter 4.6.2 --- Chromium content of the degradation intermediate --- p.70 / Chapter 5. --- Discussion --- p.71 / Chapter 5.1 --- Characteristic of Brevibacterium linens --- p.71 / Chapter 5.2 --- Optimization of dye decolourization and chromate reduction with response surface methodology --- p.72 / Chapter 5.3 --- Performance of Brevibacterium linens under different culture conditions --- p.75 / Chapter 5.4 --- Postulation of mechanisms --- p.76 / Chapter 5.4.1 --- Possible reasons of unexpected results of the effect of initial Acid Orange 7 and K2CrO4 concentration --- p.76 / Chapter 5.4.2 --- Properties of the purple colour degradation intermediate --- p.78 / Chapter 5.4.3 --- Mechanisms likely responsible for the chromate reduction --- p.80 / Chapter 5.4.4 --- Explanation of the unexpected results --- p.80 / Chapter 6. --- Conclusions --- p.83 / Chapter 7. --- References --- p.86 / Chapter 8. --- Appendices --- p.99 / Chapter 8.1 --- Definition and calculation of different terms in 2-level factorial design --- p.99 / Chapter 8.2 --- Definition and calculation of different terms in ANOVA table --- p.100 / Chapter 8.3 --- Aliases of terms and resolution --- p.103 / Chapter 8.4 --- Moving of factors in path of steepest ascent --- p.105 / Chapter 8.5 --- Estimation of the parameters in linear regression models --- p.106 / Chapter 8.6 --- Definition and calculation of different terms in test of fitness --- p.109

Cai, Qinhong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 142-166). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / Table of contents --- p.viii / List of figures --- p.xv / List of plates --- p.xix / List of tables --- p.xxi / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Pollution generated from dyeing industry --- p.1 / Chapter 1.2 --- Occurrence and pollution of chromium azo dyes --- p.2 / Chapter 1.3 --- Common treatment methods for dyeing effluents --- p.7 / Chapter 1.3.1 --- Physicochemical methods --- p.7 / Chapter 1.3.2 --- Chemical methods --- p.9 / Chapter 1.3.2.1 --- Ozonation --- p.10 / Chapter 1.3.2.2 --- Fenton reaction --- p.11 / Chapter 1.3.2.3 --- Sodium hypochlorite (NaOCl) --- p.12 / Chapter 1.3.2.4 --- Photocatalytic oxidation (PCO) --- p.13 / Chapter 1.3.3 --- Physical methods --- p.14 / Chapter 1.3.3.1 --- Adsorption --- p.14 / Chapter 1.3.3.2 --- Membrane filtration --- p.15 / Chapter 1.3.4 --- Biological treatments --- p.16 / Chapter 1.3.4.1 --- Decolorization of azo dyes by bacteria --- p.16 / Chapter 1.3.4.1.1 --- Under anaerobic conditions --- p.18 / Chapter 1.3.4.1.2 --- Under anoxic conditions --- p.19 / Chapter 1.3.4.1.3 --- Under aerobic conditions --- p.21 / Chapter 1.3.4.2 --- Mechanisms of azo dye reduction by bacteria --- p.23 / Chapter 1.3.4.3 --- Decolorization of azo dyes by fungi and algae --- p.27 / Chapter 1.4 --- Chromium species and their impacts on environment --- p.27 / Chapter 1.4.1 --- Chromium toxicology and speciation --- p.28 / Chapter 1.4.2 --- Common treatment methods for chromium --- p.31 / Chapter 1.5 --- Studies concerning treatment of chromium azo dyes --- p.32 / Chapter 1.6 --- Response surface methodology (RSM) --- p.33 / Chapter 1.6.1 --- RSM vs. one factor-at-a-time (OFAT) design --- p.36 / Chapter 1.6.2 --- Phases of RSM --- p.39 / Chapter 1.6.3 --- Two level factorial design --- p.40 / Chapter 1.6.4 --- Path of steepest ascent (PSA) --- p.43 / Chapter 1.6.5 --- Central composite design (CCD) --- p.44 / Chapter 1.6.6 --- Estimation of the parameters in linear regression models --- p.45 / Chapter 1.6.7 --- Test of fitness --- p.47 / Chapter 2. --- Objectives and significance of the project --- p.49 / Chapter 3. --- Materials and methods --- p.50 / Chapter 3.1 --- Chemicals --- p.50 / Chapter 3.1.1 --- Chemicals for preparation of bacterial culture media --- p.50 / Chapter 3.1.2 --- Chemicals for identification of bacteria --- p.50 / Chapter 3.1.3 --- Chemicals for chromium speciation --- p.51 / Chapter 3.1.4 --- Chemicals for immobilization of bacterial cells --- p.52 / Chapter 3.2 --- Sludge samples --- p.53 / Chapter 3.3 --- Characterization of Acid Yellow 99 --- p.54 / Chapter 3.4 --- Monitor of azo dye decolorization --- p.55 / Chapter 3.5 --- "Isolation of bacterial strains, which can degrade Acid Yellow 99" --- p.55 / Chapter 3.6 --- Identification of selected bacterial strains --- p.58 / Chapter 3.6.1 --- Gram stain --- p.58 / Chapter 3.6.2 --- Sherlock® microbial identification system --- p.58 / Chapter 3.6.3 --- Biolog® microstation system --- p.59 / Chapter 3.6.4 --- Selection of the most effective bacterial strains --- p.59 / Chapter 3.6.5 --- 16S ribosomal RNA sequencing --- p.60 / Chapter 3.7 --- Chromium speciation with interferences of chromium organic complexes --- p.60 / Chapter 3.7.1 --- Instrumentation --- p.60 / Chapter 3.7.2 --- Column preparation --- p.61 / Chapter 3.7.3 --- Determination of percentage retained and recovery --- p.62 / Chapter 3.7.4 --- "Speciation of Cr(VI), ionic Cr(III) and chromium azo dye" --- p.63 / Chapter 3.7.4 --- Preparation of Cr(III)-organic complexes --- p.65 / Chapter 3.7.5 --- Preparation of a microbial degraded chromium azo dye sample --- p.65 / Chapter 3.8 --- Chromium distribution in a treated solution --- p.66 / Chapter 3.9 --- Distribution of AY99 in a treated solution --- p.68 / Chapter 3.10 --- Optimization of decolorization process with response surface methodology (RSM) --- p.70 / Chapter 3.10.1 --- Correlation of cell mass and cell density of selected bacteria --- p.70 / Chapter 3.10.2 --- Preliminary investigation of the optimum conditions --- p.70 / Chapter 3.10.3 --- Minimal run resolution V (MR5) design --- p.71 / Chapter 3.10.4 --- Path of steepest ascent (PSA) --- p.74 / Chapter 3.10.5 --- Central composite design (CCD) and RSM --- p.75 / Chapter 3.10.6 --- Statistical analysis --- p.76 / Chapter 3.10.7 --- Experimental validation of the optimized conditions --- p.77 / Chapter 3.11 --- Immobilization of bacterial cells --- p.77 / Chapter 3.11.1 --- Immobilization by polyvinyl alcohol (PVA) gels --- p.77 / Chapter 3.11.2 --- Immobilization by polyacrylamide gels --- p.78 / Chapter 3.11.3 --- Performance of immobilized cells and free cells --- p.79 / Chapter 3.11.5 --- Storage stabilities of immobilized cells and free cells --- p.80 / Chapter 3.12 --- Performance of a laboratory scale bioreactor --- p.80 / Chapter 3.12.1 --- Chromium distribution in the bioreactor --- p.82 / Chapter 3.12.2 --- Distribution of AY99 in the bioreactor --- p.82 / Chapter 3.12.3 --- Fourier transform infrared spectroscopy (FT-IR) analysis of suspended particles in the treated solution --- p.84 / Chapter 4. --- Results --- p.85 / Chapter 4.1 --- Characterization of AY99 --- p.85 / Chapter 4.2 --- Identification of isolated bacterial strains --- p.86 / Chapter 4.3 --- Selection of the most effective bacterial strains --- p.89 / Chapter 4.4 --- Chromium speciation with interferences of chromium organic complexes --- p.91 / Chapter 4.4.1 --- Effect of pH --- p.91 / Chapter 4.4.2 --- Speciation of Cr(VI)，ionic Cr(III) and chromium azo dye --- p.92 / Chapter 4.4.3 --- Effect of other Cr(III)-organic complexes --- p.93 / Chapter 4.4.4 --- Limit of detection --- p.94 / Chapter 4.4.5 --- Capacity of Amberlite XAD-4 resin --- p.94 / Chapter 4.4.6 --- Determination of Cr(VI) in a microbial degraded chromium azo dye solution --- p.95 / Chapter 4.5 --- Chromium distribution in a free cells treated solution --- p.95 / Chapter 4.6 --- Distribution of AY99 in free cells treated solution --- p.96 / Chapter 4.7 --- Optimization of decolorization process with RSM --- p.98 / Chapter 4.7.1 --- Correlation of cell mass and cell density of selected bacteria --- p.98 / Chapter 4.7.2 --- MR5 design --- p.100 / Chapter 4.7.3 --- Path of steepest ascent (PSA) --- p.102 / Chapter 4.7.4 --- Central composite design (CCD) and RSM --- p.103 / Chapter 4.8 --- Immobilization of bacterial cells --- p.106 / Chapter 4.8.1 --- Performance of immobilized cells and free cells --- p.106 / Chapter 4.8.2 --- Storage stabilities of immobilized cells and free cells --- p.108 / Chapter 4.9 --- Performance of the laboratory scale bioreactor --- p.108 / Chapter 4.9.1 --- Treatment efficiencies of the bioreactor --- p.108 / Chapter 4.9.2 --- Performance stability of the bioreactor in 5 consecutive runs --- p.111 / Chapter 4.9.3 --- Chromium distribution in the bioreactor --- p.114 / Chapter 4.9.4 --- Distribution of AY99 in the bioreactor --- p.115 / Chapter 4.9.5 --- FT-IR analysis of suspended particles in the treated solution --- p.115 / Chapter 5. --- Discussion --- p.117 / Chapter 5.1 --- Chromium speciation with interferences of chromium organic complexes --- p.117 / Chapter 5.2 --- Chromium distribution --- p.117 / Chapter 5.3 --- Distribution of AY99 --- p.122 / Chapter 5.4 --- Optimization of decolorization process with RSM --- p.124 / Chapter 5.4.1 --- MR5 design --- p.124 / Chapter 5.4.2 --- Path of steepest ascent (PSA) --- p.125 / Chapter 5.4.3 --- Central composite design (CCD) and RSM --- p.126 / Chapter 5.5 --- Immobilization of bacterial cells --- p.126 / Chapter 5.5.1 --- Performance of immobilized cells and free cells --- p.126 / Chapter 5.5.2 --- Storage stability of immobilized cells and free cells --- p.128 / Chapter 5.6 --- Performance of the laboratory scale bioreactor --- p.130 / Chapter 5.6.1 --- Treatment efficiencies of the bioreactor --- p.130 / Chapter 5.6.2 --- Performance stability of the bioreactor in 5 consecutive runs --- p.131 / Chapter 5.6.3 --- FT-IR analysis of suspended particles in the treated solution --- p.132 / Chapter 5.6.4 --- Post treatments of bioreactor treated effluents / Chapter 6. --- Conclusions --- p.136 / Chapter 7. --- References --- p.142