Agrotóxicos são frequentemente relatados na literatura em contaminações de ambientes aquáticos, sendo provenientes do lixiviamento de solos, do descarte inadequado de embalagens agrícolas, dentre outros. Nesse contexto, os processos oxidativos avançados (POA) têm sido estudados como alternativa para o tratamento desses compostos em meio aquoso. Os POA consistem na oxidação de compostos orgânicos pela formação de radicais livres com alto poder oxidante. Diante desses aspectos, o presente trabalho teve como proposta o estudo da degradação dos herbicidas hexazinona e diuron, aliada ao planejamento experimental do tipo composto central, a fim de otimizar o processo de degradação. Para tanto, realizaram-se as degradações através dos processos H2O2/UV e foto-Fenton em concentrações iniciais próximas a 7 e 20 mg L-1 para a hexazinona e diuron, respectivamente. Os experimentos foram conduzidos em um reator fotoquímico (200 mL a 25 °C) com aplicação de irradiação UV, proveniente de uma lâmpada de Hg (degradação H2O2/UV) e de luz negra (degradação foto-Fenton). No processo via H2O2/UV foram avaliadas a concentração de H2O2 (0,65 a 13,34 mmol L-1) e pH (2,77 a 11,23), e para o processo foto-Feton avaliou-se a concentração de H2O2 (0,09 a 29,1 mmol L-1) e Fe (II) (0,01 a 0,92 mmol L-1). Como variável independente, utilizou-se a remoção de Carbono Orgânico Total (COT) nos dois casos. A eficiência na degradação dos herbicidas foi determinada através das técnicas de Espectroscopia UV-Vis, Cromatografia Líquida de Alta Eficiência (HPLC/UV), remoção de Carbono Orgânico Total e Cromatografia de Íons. A análise dos modelos matemáticos, obtidos a partir dos planejamentos, possibilitou a avaliação da influência das variáveis, determinando as melhores condições. No processo H2O2/UV observou-se que a influência da variável H2O2 é maior comparada ao pH. A melhor condição de degradação apresentou concentrações de H2O2 iguais a 7 mmol L-1 e valores de pH de 2,8. Como resultado, obteve-se 96 % de remoção do COT e a não detecção de ambos os herbicidas após 2 minutos de reação. No processo foto-Fenton, a realização de três planejamentos foi necessária para a otimização do sistema. Primeiro e segundo planejamentos indicaram a melhor condição, enquanto que o terceiro planejamento revelou que concentrações elevadas de H2O2 e Fe2+ não garantem maior eficiência. As condições ideais encontradas foram iguais a 0,291 mmol L-1 para o Fe2+ e 2,91 mmol L-1 para o H2O2, obtendo-se 76 % de remoção do COT e não detecção dos herbicidas nos primeiros minutos de degradação. Em ambas as degradações não foi possível observar diferenças em relação a cinética de degradação para os herbicidas. A degradação via H2O2/UV mostrou melhor desempenho, pois apresentou maior taxa de mineralização além de não necessitar o emprego do íon Fe(II). / Pesticides are often reported in the literature on aquatic environments contamination, being a result of soil leaching, improper disposal of agricultural packages, among others. In this context, advanced oxidation processes (AOP) have been studied as an alternative to treat these compounds in aqueous medium. The AOP consist in the oxidation of organic compounds through the formation of free radicals with a high oxidizing power. Considering these aspects, the present work aimed to study degradation of the herbicides diuron and hexazinone, coupled with an experimental setup as central compost, in order to optimize the degradation process. For this purpose, the degradation was carried out by H2O2/UV and photo-Fenton processes at initial concentrations close to 7 and 20 mg L-1 to hexazinone and diuron, respectively. The experiments were conducted in a photochemical reactor (200 mL at 25 ° C) with application of UV irradiation from Hg lamp (H2O2/UV degradation) and black-light (photo-Fenton degradation). In the H2O2/UV process, the concentrations of H2O2 (0.65 to 13.34 mmol L-1) and pH (2.77 to 11.23) were evaluated, and in the photo-Fenton process, the concentrations of H2O2 (0.09 to 29.1 mmol L-1) and Fe (II) (0.01 to 0.92 mmol L-1) were analyzed. In both processes, the removal of Total Organic Carbon (TOC) was used as an independent variable. The efficiency of the herbicide degradation was determined by UV/Vis spectroscopy, high performance liquid chromatography (HPLC/UV), removal of the Total Organic Carbon and ion chromatography. The analysis of the mathematical models obtained from the experimental setup allowed the evaluation of the variables influence ,determining the best conditions. The H2O2/UV process showed that the influence of the H2O2 is higher compared to that of the pH. The best degradation condition presented H2O2 concentrations of 7 mmol L-1 and a pH value of 2.8. As a result, 96% TOC removal was observed, and none of the herbicides were detected after 2 minutes of reaction. In the photo-Fenton process, the conduction of three setups was necessary to confirm the best condition. The first and second setups indicated the best condition, while the third one showed that high concentrations of H2O2 and Fe2+ do not guarantee a greater degradation efficiency. Ideal conditions were equal to 0.291 mmol L-1 for Fe2+ and 2.91 mmol L-1 for H2O2, where 76% of TOC removal was obtained and also no herbicides detection was seen in the early minutes of degradation. In both processes, it was not possible to observe differences in the degradation kinetics of the herbicides. The H2O2/UV degradation showed better performance because of a greater mineralization rate besides not requiring the ion Fe (II) use.

Agrotóxicos são frequentemente relatados na literatura em contaminações de ambientes aquáticos, sendo provenientes do lixiviamento de solos, do descarte inadequado de embalagens agrícolas, dentre outros. Nesse contexto, os processos oxidativos avançados (POA) têm sido estudados como alternativa para o tratamento desses compostos em meio aquoso. Os POA consistem na oxidação de compostos orgânicos pela formação de radicais livres com alto poder oxidante. Diante desses aspectos, o presente trabalho teve como proposta o estudo da degradação dos herbicidas hexazinona e diuron, aliada ao planejamento experimental do tipo composto central, a fim de otimizar o processo de degradação. Para tanto, realizaram-se as degradações através dos processos H2O2/UV e foto-Fenton em concentrações iniciais próximas a 7 e 20 mg L-1 para a hexazinona e diuron, respectivamente. Os experimentos foram conduzidos em um reator fotoquímico (200 mL a 25 °C) com aplicação de irradiação UV, proveniente de uma lâmpada de Hg (degradação H2O2/UV) e de luz negra (degradação foto-Fenton). No processo via H2O2/UV foram avaliadas a concentração de H2O2 (0,65 a 13,34 mmol L-1) e pH (2,77 a 11,23), e para o processo foto-Feton avaliou-se a concentração de H2O2 (0,09 a 29,1 mmol L-1) e Fe (II) (0,01 a 0,92 mmol L-1). Como variável independente, utilizou-se a remoção de Carbono Orgânico Total (COT) nos dois casos. A eficiência na degradação dos herbicidas foi determinada através das técnicas de Espectroscopia UV-Vis, Cromatografia Líquida de Alta Eficiência (HPLC/UV), remoção de Carbono Orgânico Total e Cromatografia de Íons. A análise dos modelos matemáticos, obtidos a partir dos planejamentos, possibilitou a avaliação da influência das variáveis, determinando as melhores condições. No processo H2O2/UV observou-se que a influência da variável H2O2 é maior comparada ao pH. A melhor condição de degradação apresentou concentrações de H2O2 iguais a 7 mmol L-1 e valores de pH de 2,8. Como resultado, obteve-se 96 % de remoção do COT e a não detecção de ambos os herbicidas após 2 minutos de reação. No processo foto-Fenton, a realização de três planejamentos foi necessária para a otimização do sistema. Primeiro e segundo planejamentos indicaram a melhor condição, enquanto que o terceiro planejamento revelou que concentrações elevadas de H2O2 e Fe2+ não garantem maior eficiência. As condições ideais encontradas foram iguais a 0,291 mmol L-1 para o Fe2+ e 2,91 mmol L-1 para o H2O2, obtendo-se 76 % de remoção do COT e não detecção dos herbicidas nos primeiros minutos de degradação. Em ambas as degradações não foi possível observar diferenças em relação a cinética de degradação para os herbicidas. A degradação via H2O2/UV mostrou melhor desempenho, pois apresentou maior taxa de mineralização além de não necessitar o emprego do íon Fe(II). / Pesticides are often reported in the literature on aquatic environments contamination, being a result of soil leaching, improper disposal of agricultural packages, among others. In this context, advanced oxidation processes (AOP) have been studied as an alternative to treat these compounds in aqueous medium. The AOP consist in the oxidation of organic compounds through the formation of free radicals with a high oxidizing power. Considering these aspects, the present work aimed to study degradation of the herbicides diuron and hexazinone, coupled with an experimental setup as central compost, in order to optimize the degradation process. For this purpose, the degradation was carried out by H2O2/UV and photo-Fenton processes at initial concentrations close to 7 and 20 mg L-1 to hexazinone and diuron, respectively. The experiments were conducted in a photochemical reactor (200 mL at 25 ° C) with application of UV irradiation from Hg lamp (H2O2/UV degradation) and black-light (photo-Fenton degradation). In the H2O2/UV process, the concentrations of H2O2 (0.65 to 13.34 mmol L-1) and pH (2.77 to 11.23) were evaluated, and in the photo-Fenton process, the concentrations of H2O2 (0.09 to 29.1 mmol L-1) and Fe (II) (0.01 to 0.92 mmol L-1) were analyzed. In both processes, the removal of Total Organic Carbon (TOC) was used as an independent variable. The efficiency of the herbicide degradation was determined by UV/Vis spectroscopy, high performance liquid chromatography (HPLC/UV), removal of the Total Organic Carbon and ion chromatography. The analysis of the mathematical models obtained from the experimental setup allowed the evaluation of the variables influence ,determining the best conditions. The H2O2/UV process showed that the influence of the H2O2 is higher compared to that of the pH. The best degradation condition presented H2O2 concentrations of 7 mmol L-1 and a pH value of 2.8. As a result, 96% TOC removal was observed, and none of the herbicides were detected after 2 minutes of reaction. In the photo-Fenton process, the conduction of three setups was necessary to confirm the best condition. The first and second setups indicated the best condition, while the third one showed that high concentrations of H2O2 and Fe2+ do not guarantee a greater degradation efficiency. Ideal conditions were equal to 0.291 mmol L-1 for Fe2+ and 2.91 mmol L-1 for H2O2, where 76% of TOC removal was obtained and also no herbicides detection was seen in the early minutes of degradation. In both processes, it was not possible to observe differences in the degradation kinetics of the herbicides. The H2O2/UV degradation showed better performance because of a greater mineralization rate besides not requiring the ion Fe (II) use.

During recent decades metallic nanoparticles have been found very interesting due to their unique characteristics which make them suitable for different applications. In this research, for the very first time, we tried to perform selective surface photo activation chemistry on the targeted facets of nanoparticles while they are in suspension. This technique enabled us to form desired assemblies of nanoparticles. We focused on elongated shaped gold nanorod due to its unique surface plasmon resonance and probable biomedical applications. In this research we formed a dumbbell shape assembly of nanoparticles in suspension. A probable application for these assemblies can be in vivo imaging. Initially, we reproduced gold nanorods using existing techniques in prior papers and optimized them according to our research needs. A low rpm centrifugal separation technique was developed to efficiently separate synthesized gold nanorods from other shapes. Several characterization techniques were utilized to characterize nanoparticles at each step including UV-absorbance, zeta potential, and dynamic light scattering. Different generations of oligomers were synthesized to be used as gold nanorods coating, and each coating was tested and characterized using appropriate techniques. Our two-step coating replacement method using one of these photocleavable oligomers enabled us to achieve, for the very first time, selective UV photo activation of gold nanorod tips. The photo activated tips were then exposed to oppositely charged gold nanospheres to form dumbbell shape assemblies of gold nanorods and nanospheres. Furthermore, dumbbell shape assembly of nanoparticles was investigated and characterized. / Master of Science

This chapter reviews the literature examining interventions to reduce indoor tanning (IT). The first objective was to highlight programs that show promise for large scale dissemination. The second objective was to promote criteria and standards for future intervention research efforts. The scope of interest for this review includes universal (for everyone in the population), selective (for those in the population who are at a greater risk), and indicated (for those who already are experiencing conditions that identify them as at risk) programs. The evaluation of the interventions resulted in three levels of evidence: (1) most promising, (2) emerging, and (3) mixed. For an intervention to be considered “most promising”, it was required that ten criteria be met through examination of research findings in published reports consistent with Flay and colleagues (Prev Sci 6(3):151–175, 2005). Interventions that were classified as “emerging” met most of the criteria. Finally, interventions classified as “mixed” did not reach threshold on more than two criteria that were deemed critical. The results revealed that there was very limited research on IT interventions that meet all the evaluation criteria. Only one intervention approach met all of the criteria (Appearance Booklet) (Hillhouse and Turrisi, Behav Med 25(4):395–409, 2002; Hillhouse et al., Cancer 113(11):3257–3266, 2008). Although the number of published papers in the IT area has increased dramatically over the past decade, these efforts have yet to translate into rigorously conducted intervention trials. The review points to important issues that need to be addressed in future research on the prevention of IT. Keywords