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Gerenciamento de estoques de defensivos agrícolas banidos: estudo de casos brasileiros / MANAGEMENT OF BANNED CROP PESTICIDE STOCKPILES: BRAZILIAN STUDY CASESNishio, Renata Stringueta 15 April 2016 (has links)
Apesar de os defensivos agrícolas atualmente classificados como Poluentes Orgânicos Persistentes (POPs) terem sua produção e uso banidos na maior parte do mundo desde a década de 1980, o gerenciamento de estoques remanescentes permanece um desafio até a atualidade. Com estimativas que variam entre 500 mil (FAO, 2015) e 2 milhões de toneladas (VIJGEN et al., 2011), poucas informações sobre seu efetivo gerenciamento e destruição são encontradas nas principais bases de dados acadêmicas sobre o tema e nos documentos oficiais da Convenção de Estocolmo sobre Poluentes Orgânicos Persistentes. O Brasil integra a lista de signatários da Convenção, mas a fabricação, o armazenamento e o uso dos agrotóxicos POPs foram proibidos em 1985, por meio da Portaria do Ministério da Agricultura nº 329. Este abrupto banimento do armazenamento colocou o agricultor brasileiro imediatamente fora da lei, uma vez que não foram planejadas medidas e procedimentos legais para dar destino adequado aos produtos que ainda estivessem em estoque nas propriedades rurais. De forma independente da Convenção de Estocolmo e das ações nacionais relacionadas a este tratado, dois estados brasileiros elaboraram programas para o levantamento de estoque dos defensivos agrícolas banidos e planejamento de sua destinação. Finalizado em 2013, o Paraná incinerou cerca de 1.200 toneladas que estavam estocadas em mais de 2.000 propriedades rurais do estado. São Paulo finalizou o inventário em 2012, resultando em 420 toneladas estocadas em aproximadamente 330 propriedades rurais. O grupo de trabalho paulista planejou as etapas seguintes e em abril de 2016, o projeto se encontrava em fase de alocação de recursos para execução das fases finais de acondicionamento, transporte e destinação. A proposta deste projeto de pesquisa é apresentar como Paraná e São Paulo gerenciaram os estoques remanescentes de agrotóxicos banidos há décadas, avaliando como os grupos de trabalho foram formados, as normativas de apoio utilizadas, como foram realizadas as etapas de levantamento de inventário e de que forma foram planejadas, financiadas, comunicadas e executadas as etapas de coleta, acondicionamento, transporte e destinação. Dessa forma, busca-se contribuir para um aumento de conhecimento prático sobre o tema e para a construção de uma política pública para gerenciamento de agrotóxicos banidos em outros estados brasileiros. / Although the pesticides currently classified as Persistent Organic Pollutants (POPs) have had their production and use banned in most of the world since the 1980s, the management of remaining stocks remains a challenge to the present. With estimates ranging from 500,000 (FAO, 2015) and 2 million tons (Vijgen et al., 2011), little information about its effective management and destruction are found in major academic databases on the subject and official documents of the Stockholm Convention on Persistent Organic Pollutants. Brazil is one of the signatories but the manufacture, storage and use of pesticides POPs were banned in 1985 by the Ministry of Agriculture Decree No. 329. However, this abrupt ban put the Brazilian farmers immediately outside the law since the government did not plan measures and legal procedures to give proper destination to the products that were still in stock on farms. Independently of the Stockholm Convention and the National Plans related to this treaty, two Brazilian states have developed programs to inventory banned pesticides and plan their destination. Finished in 2013, Paraná State incinerated about 1,200 tons that had been stored in more than 2,000 rural properties. Sao Paulo finished its inventory in 2012 resulting in 420 tons stored in about 330 rural properties. The São Paulo working group has planned the next steps and, in April 2016, the project was waiting for resource in order to implement the final stages of packaging, transport and disposal. The purpose of this research is to present as Parana and Sao Paulo managed the remaining stocks of banned pesticides evaluating how the working groups were formed, the support normative used, how the inventory has been planned and carried out and how the projects have financed, communicated and executed the steps of collection, packaging, transportation and disposal. Thus, it is expected to contribute to increase the practical knowledge on the topic and to construct a public policy for pesticide management banned in other Brazilian states.
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Histórico deposicional de Poluentes Orgânicos Persistentes em testemunhos sedimentares do ecossistema estuarino da Ilha do Marajó (Pará - Brasil) / Historical records of Persistent Organic Pollutants in sediment cores of the estuarine ecosystem of the Marajó Island (Pará - Brazil)Leonardo Henriques Mello 11 November 2016 (has links)
A distribuição espacial e o histórico deposicional de poluentes orgânicos persistentes (POPs) em sedimentos foram avaliados no ecossistema marino-estuarino da Ilha do Marajó, Pará. Os pesticidas predominantes nos sedimentos da camada superficial foram os HCHs (<0,04 e 0,90 ng g-1) e DDTs (<0,02 - 2,72 ng g-1), em peso seco. PCBs e PBDEs não foram detectados. HCHs predominaram no Estuário do Rio Paracauari indicando uso recente provavelmente relacionado à atividade madeireira. DDTs foram detectados na Praia do Pesqueiro e nos testemunhos sedimentares (<0,02 - 12,31 ng g-1 peso seco) do Mercado, Fazenda e Paracauari. Os valores máximos de DDT ocorreram entre 1982 e 2008 e são associados com campanhas de saúde púbica. Há uma redução gradativa até o presente que coincide com a substituição do DDT por piretróides. A razão ΣDDDs / ΣDDEs, predominantemente < 1, indicou a ocorrência de processos decomposicionais aeróbicos. No geral, as condições ambientais não favorecem o acúmulo de pesticidas nos sedimentos, sendo que os valores estão abaixo do limite provável para causar efeitos adversos exceto para HCHs no Estuário do Rio Paracauari. O presente trabalho estabeleceu a distribuição de POPs na Ilha do Marajó e poderá contribuir para o processo de gestão costeira e ambiental da região. / The spatial distribution and depositional history of persistent organic pollutants (POPs) in sediments were evaluated in marino-estuarine ecosystem of Marajó Island, Pará. The predominant pesticides in sediments of the surface layer were HCHs (<0.04 and 0, 90 ng g-1) and DDTS (<0.02 to 2.72 ng g-1) by dry weight. PCBs and PBDEs weren\'t detected. HCHs predominated in Paracauari Estuary indicating recent use probably related to logging. DDTs were detected in Praia do Pesqueiro and sediment cores (<0.02 to 12.31 ng g-1 dry weight) Mercado, Fazenda and Paracauari. Maximum levels of DDT residues occurred between 1982 and 2008 and are associated with pubic health campaigns. There is a gradual reduction up to the present which coincides with the substitution of the DDTs by pyrethroids. The ratio ΣDDDs / ΣDDEs predominantly < 1 indicated the occurrence of decomposicional processes under aerobic conditions. Overall, the environmental conditions do not favor the accumulation of pesticides in sediments, and the values are below the threshold likely to cause adverse effects except for HCHs in Paracauari Estuary. This work established the distribution of POPs in Marajó Island and could contribute to the process of coastal and environmental management in the region.
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Degradation of persistent pesticides via advanced oxidation and reductive processes. / Degradação de pesticidas persistentes através de processos oxidativos avançados e redutivos.Graça, Cátia Alexandra Leça 23 May 2017 (has links)
In this Thesis either advanced oxidation or reductive processes are investigated for the degradation of two pesticides considered persistent in the environment: amicarbazone (AMZ) and chlorpyrifos (CP). In chapter I, different advanced oxidation processes (AOPs) driven by sulfate (SO4o-) and hydroxyl radicals (oOH) were applied to the degradation of AMZ. In the first study, several persulfate (PS) activated reactions were explored for AMZ degradation, namely activation with UVA radiation, Fe(II) and H2O2, as well as the combination of UVA radiation with Fe(II), Fe(III) and Fe(III)-complexes. Here, the influence of different reaction variables, such as solution pH, reactants and pesticide initial concentrations, addition of a second oxidant (H2O2) and the addition of different iron catalysts were also investigated. Control experiments regarding the photolysis of iron species in the absence of PS captured our interest and, with the aim of exploring more deeply this process on AMZ degradation, a second investigation was carried out. In this second study, a Doehlert experimental design was applied to investigate the simultaneous effects of two variables on AMZ degradation: pH and Fe(III):carboxylate ratio, where the carboxylate could be oxalate, citrate or tartrate. A response surface model for the observed degradation rate (kobs) as a function of pH and Fe(III):carboxylate ratio was obtained. The processes explored in both aforementioned studies revealed to be effective for AMZ removal, although nothing is known yet about their effectiveness regarding toxicity removal. Given that, a third study was carried out, where the toxicity of AMZ solutions, before and after submission to the processes studied was evaluated towards five microorganisms: Vibrio fischeri (acute toxicity), Tetrahymena thermophile, Chlorella vulgaris (chronic toxicity), Escherichia coli and Bacilus subtilis (antimicrobial activity). The last investigation detailed in chapter I is related with the application of zero-valent-metals on PS activation, which is a subject that links this chapter with the following one. For that, zero-valent-iron (ZVI) was investigated as a PS activator and the influence of variables that help to assess the environmental applicability of this process. In general, organochlorine pesticides reveal a higher resistance to oxidation than reduction, the latter process preferred when the aim is to degrade that important class of contaminants. Therefore, in chapter II the reductive degradation of CP by means of zero-valent-metals and bimetallic particles was investigated. ZVI has been extensively applied for that purpose. However, besides iron, other zero-valent metals can be potential reactive materials for reductive degradation and hence, in this study, the effectiveness of Zn0 and Cu0 was also explored in comparison to that widely reported for ZVI. Furthermore, two different ways of enhancing metals reactivity were here explored: i) by coating ZVI or Zn0 with a more noble metal (Cu), in order to analyze the copper catalytic effect on the bimetallic system; ii) by different surface pretreatments. / Na presente Tese de Doutorado foram abordados tanto processos oxidativos avançados (POA), como processos redutivos por metais de valência zero, na degradação de dois pesticidas considerados persistentes no meio ambiente: amicarbazona (AMZ) e clorpirifós (CP). No capítulo I são apresentados os estudos realizados com diversos POA, mediados por radicais sulfato (SO4o-) e hidroxila (oOH), aplicados da AMZ. Num primeiro estudo foi explorada a ativação do oxidante persulfato (PS), de diferentes formas, tais como radiação UVA, H2O2 e Fe(II), assim como a combinação de radiação UVA com Fe(II), Fe(III) e complexos de Fe(III). Aqui também foram investigados os efeitos de diversas variáveis reacionais, tais como pH, concentração inicial de reagentes e de pesticida, adição de um segundo oxidante (H2O2) e adição de diferentes espécies de ferro. Os testes realizados, para efeito de controle, referentes à irradiação das espécies de Fe(III) na ausência de PS, despertaram o interesse para um estudo mais aprofundado sobre o efeito da fotólise destas espécies na degradação da AMZ, surgindo assim o segundo trabalho. Neste utilizou-se um projeto experimental de Doehlert, para avaliar o efeito de duas variáveis em simultâneo quanto à degradação da AMZ: pH e proporção Fe(III): ligante, sendo o ligante um dos seguintes carboxilatos: oxalato, citrato ou tartarato. Um modelo de superfície de resposta, que correlaciona a taxa de degradação observada (kobs) em função do pH e proporção Fe(III):ligante foi obtido para cada um dos complexos de Fe(III) estudados. Os processos explorados, tanto no primeiro como no segundo estudo, se mostraram eficazes na remoção da AMZ, porém nada se sabe acerca da remoção da toxicidade. Para tal, foi desenvolvido um terceiro estudo dedicado à avaliação da toxicidade da solução de AMZ, antes e após a aplicação de cada um dos processos anteriormente abordados, contra cinco micro-organismos: Vibrio fischeri (toxicidade aguda); Tetrahymena thermophila, Chlorella vulgaris (toxicidade crônica); Escherichia coli e Bacilus subtilis (atividade antimicrobiana). O último estudo abordado no capitulo I é referente à aplicação de metais de valência zero também nos POA, correlacionado assim o capítulo I e o capítulo II. Como tal, foi feito um estudo de ativação de PS por meio de ferro de valência zero (Fe0), em que se investigou a influência de diversas variáveis por forma a inferir sobre a aplicabilidade prática deste processo. Pesticidas organoclorados apresentam maior resistência à degradação por processos oxidativos do que redutivos, sendo preferível o último na degradação desta importante classe de contaminantes. Como tal, o capítulo II se refere à degradação redutiva, por meio de diferentes metais de valência zero e partículas bimetálicas, do pesticida organoclorado CP. Além do amplamente explorado Fe0, outros metais podem ser aplicados neste processo, pelo que, neste estudo, explorou-se a potencialidade de Zn0 e Cu0 comparativamente ao primeiro. Ainda neste estudo foram investigadas duas formas de aumentar a reatividade dos metais: i) no caso do Fe0 e Zn0, revestindo com um metal mais nobre (Cu), por forma a observar o efeito catalisador do último no sistema bimetálico; ii) realizando um pré-tratamento à superfície dos metais.
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Health risk assessment of POPs and heavy metals in Hong Kong residents based on their concentrations in selected food items and different human tissues (blood plasma and adipose tissues)Qin, Yanyan 01 January 2010 (has links)
No description available.
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Persistent organic pollutants in aquaculture systems in the Pearl River Delta, with focus on their bioaccessibility via fish consumptionWang, Hongsheng 01 January 2011 (has links)
No description available.
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Cyber Attacks Detection and Mitigation in SDN EnvironmentsJanuary 2018 (has links)
abstract: Cyber-systems and networks are the target of different types of cyber-threats and attacks, which are becoming more common, sophisticated, and damaging. Those attacks can vary in the way they are performed. However, there are similar strategies
and tactics often used because they are time-proven to be effective. The motivations behind cyber-attacks play an important role in designating how attackers plan and proceed to achieve their goals. Generally, there are three categories of motivation
are: political, economical, and socio-cultural motivations. These indicate that to defend against possible attacks in an enterprise environment, it is necessary to consider what makes such an enterprise environment a target. That said, we can understand
what threats to consider and how to deploy the right defense system. In other words, detecting an attack depends on the defenders having a clear understanding of why they become targets and what possible attacks they should expect. For instance,
attackers may preform Denial of Service (DoS), or even worse Distributed Denial of Service (DDoS), with intention to cause damage to targeted organizations and prevent legitimate users from accessing their services. However, in some cases, attackers are very skilled and try to hide in a system undetected for a long period of time with the incentive to steal and collect data rather than causing damages.
Nowadays, not only the variety of attack types and the way they are launched are important. However, advancement in technology is another factor to consider. Over the last decades, we have experienced various new technologies. Obviously, in the beginning, new technologies will have their own limitations before they stand out. There are a number of related technical areas whose understanding is still less than satisfactory, and in which long-term research is needed. On the other hand, these new technologies can boost the advancement of deploying security solutions and countermeasures when they are carefully adapted. That said, Software Defined Networking i(SDN), its related security threats and solutions, and its adaption in enterprise environments bring us new chances to enhance our security solutions. To reach the optimal level of deploying SDN technology in enterprise environments, it is important to consider re-evaluating current deployed security solutions in traditional networks before deploying them to SDN-based infrastructures. Although DDoS attacks are a bit sinister, there are other types of cyber-threats that are very harmful, sophisticated, and intelligent. Thus, current security defense solutions to detect DDoS cannot detect them. These kinds of attacks are complex, persistent, and stealthy, also referred to Advanced Persistent Threats (APTs) which often leverage the bot control and remotely access valuable information. APT uses multiple stages to break into a network. APT is a sort of unseen, continuous and long-term penetrative network and attackers can bypass the existing security detection systems. It can modify and steal the sensitive data as well as specifically cause physical damage the target system. In this dissertation, two cyber-attack motivations are considered: sabotage, where the motive is the destruction; and information theft, where attackers aim to acquire invaluable information (customer info, business information, etc). I deal with two types of attacks (DDoS attacks and APT attacks) where DDoS attacks are classified under sabotage motivation category, and the APT attacks are classified under information theft motivation category. To detect and mitigate each of these attacks, I utilize the ease of programmability in SDN and its great platform for implementation, dynamic topology changes, decentralized network management, and ease of deploying security countermeasures. / Dissertation/Thesis / Doctoral Dissertation Computer Science 2018
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Persistence heatmaps for knotted data setsBetancourt, Catalina 01 August 2018 (has links)
Topological Data Analysis is a quickly expanding field but one particular subfield, multidimensional persistence, has hit a dead end. Although TDA is a very active field, it has been proven that the one-dimensional persistence used in persistent homology cannot be generalized to higher dimensions. With this in mind, progress can still be made in the accuracy of approximating it. The central challenge lies in the multiple persistence parameters. Using more than one parameter at a time creates a multi-filtration of the data which cannot be totally ordered in the way that a single filtration can.
The goal of this thesis is to contribute to the development of persistence heat maps by replacing the persistent betti number function (PBN) defined by Xia and Wei in 2015 with a new persistence summary function, the accumulated persistence function (APF) defined by Biscio and Moller in 2016. The PBN function fails to capture persistence in most cases and thus their heat maps lack important information. The APF, on the other hand, does capture persistence that can be seen in their heat maps.
A heat map is a way to visually describe three dimensions with two spatial dimensions and color. In two-dimensional persistence heat maps, the two chosen parameters lie on the x- and y- axes. These persistence parameters define a complex on the data, and its topology is represented by the color. We use the method of heat maps introduced by Xia and Wei. We acquired an R script from Matthew Pietrosanu to generate our own heat maps with the second parameter being curvature threshold. We also use the accumulated persistence function introduced by Biscio and Moller, who provided an R script to compute the APF on a data set. We then wrote new code, building from the existing codes, to create a modified heat map. In all the examples in this thesis, we show both the old PBN and the new APF heat maps to illustrate their differences and similarities. We study the two-dimensional heat maps with respect to curvature applied to two types of parameterized knots, Lissajous knots and torus knots. We also show how both heat maps can be used to compare and contrast data sets.
This research is important because the persistence heat map acts as a guide for finding topologically significant features as the data changes with respect to two parameters. Improving the accuracy of the heat map ultimately improves the efficiency of data analysis. Two-dimensional persistence has practical applications in analyses of data coming from proteins and DNA. The unfolding of proteins offers a second parameter of configuration over time, while tangled DNA may have a second parameter of curvature.
The concluding argument of this thesis is that using the accumulated persistence function in conjunction with the persistent betti number function provides a more accurate representation of two-dimensional persistence than the PBN heat map alone.
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Predictors and Moderators of Sexual Distress in Women with Persistent Genital Arousal DisorderSquibb, Lisa 01 January 2017 (has links)
Persistent Genital Arousal Disorder (PGAD) is a complex, poorly understood condition characterized by unremitting, unwanted, distressing genital arousal which occurs frequently and for extended periods of time, often in the absence of sexual stimuli. The pathophysiology is unknown. Researchers have hypothesized underlying disorders of neurological, vascular, pharmacological and psychological origins. Possible causalities have been suggested including anxiety disorder, SSRI use, and pudendal nerve neuropathies among others. Despite the uncertainty of etiology, other aspects of the disorder are clearer, including distress and poor quality of life for many. In this study, I used a biopsychosocial model to examine three potential psychological predictors 'depression, stress, and anxiety' as well as moderators including erotophobia and perceived partner support on a sample of 51 women with PGAD. Quantitative survey methodology was used to collect information from women with PGAD who had sought care for their condition from a sexual medicine specialty clinic (San Diego Sexual Medicine) and members of an online PGAD support group. Results of the study indicated depression as the most significant predictor of distress of the three psychological variables under study. Neither erotophobia nor perceived social support moderated any of the psychological factors studied. Scores on the Female Sexual Distress Scale-Revised demonstrated clinically important levels of distress. The findings highlight the need for a biopsychosocial treatment approach to the condition, including psychological therapy. Implications for social change include the preservation of quality of life and reduced depression rates in women with PGAD.
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INVESTIGATING THE ATTITUDES OF GRADUATE SOCIAL WORK STUDENTS TOWARD SEVERE AND PERSISTENT MENTAL ILLNESSThompson, Jennifer Nicole 01 June 2017 (has links)
Stigma is one of the foremost barriers to effective mental health treatment of consumers. Social workers currently provide the majority of mental health treatment in the United States. Examining levels of stigma present in social work students would be valuable in providing future interventions. A quantitative study was conducted utilizing an online questionnaire. The survey was distributed by the CSUSB Department of Social Work to graduate social work students. Statistical analysis utilizing SPSS software was conducted following data collection. Data analysis indicated that there was no significant difference in the attitudes regardless of exposure to severe mental illness. The findings of this study indicate that exposure to severe mental illness may not be the only factor in determining one’s attitude. Implications of these findings for social work research include outlining the need for further examination of stigma to identify more specific factors in the formation of stigmatic attitudes.
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Fotocatálise heterogênea aplicada na degradação de poluentes orgânicos utilizando catalisador híbrido de óxido de zinco-xerogel de carbono / Heterogeneous photocatalysis applied to the degradation of organic pollutants using a zinc oxide-carbon xerogel hybrid catalystMoraes, Nícolas Perciani de 01 February 2019 (has links)
Foi explorado o desenvolvimento de fotocatalisadores híbridos ZnO/Xerogel de carbono, visando aumentar a eficiência quântica do processo de degradação de poluentes orgânicos persistentes. Especificamente, foi estudada a preparação do híbrido ZnO-xerogel de carbono, sendo esta, a maior inovação tecnológica deste projeto, considerando que o efeito catalítico deste híbrido não foi estudado na literatura. O uso do xerogel de carbono na preparação do semicondutor-material carbonoso é justificado pela excelente condutividade elétrica, elevada área superficial e porosidade, além de sua estrutura porosa ser facilmente manipulada por modificações nos parâmetros de síntese. A escolha do tanino como precursor do xerogel visa à diminuição de custos e impactos ambientais, além de acrescentar valor à inovação tecnológica proposta. A influência do pH e rota de síntese foram avaliados, assim como a influência da temperatura de calcinação nas propriedades dos materiais. A espectroscopia por refletância difusa foi a técnica empregada para determinação da energia de gap das amostras. A morfologia, a análise elementar, a estrutura cristalina dos materiais, a estrutura química e a constituição dos materiais foram determinadas por microscopia eletrônica de varredura, espectrometria de energia dispersiva, difratometria de raios X, infravermelho e espectroscopia Raman, respectivamente. O balanço de cargas na superfície do material foi analisado pela metodologia do ponto de carga zero (PZC). A ação fotocatalítica do material foi avaliada através da decomposição de 4-clorofenol e bisfenol A, determinada através da espectroscopia no UV-Visível. Todos os materiais apresentam a estrutura cristalina hexagonal do óxido de zinco (wurtzita). Os materiais sem tanino em sua composição também apresentam a fase de hidroxicloreto de zinco mono-hidratado. Os difratogramas de raios-X e valores de bandgap obtidos confirmam a incorporação do carbono na estrutura cristalina do óxido de zinco. Os materiais produzidos via rota alcoólica apresentam menores valores de tamanho de cristalito e partícula, assim como um maior teor de grafite em sua composição e maior área superficial, enquanto que os materiais produzidos em solução aquosa apresentam menores valores de energia de gap. Todos os materiais apresentaram atividade fotocatalítica quando submetidos à radiação solar e visível, sendo que os materiais com proporções intermediárias entre xerogel de carbono e óxido de zinco se mostraram superiores para o processo de fotodegradação. Os materiais produzidos via alcoólica são superiores aos produzidos em solução aquosa, no que tange o processo de fotocatálise. Os valores máximos encontrados para a degradação de 4-clorofenol e bisfenol A foram de 88% e 78%, respectivamente, obtidos pelo material XZnC 3.0 (EtOH). A temperatura de calcinação e quantidade de hidróxido de potássio utilizados na síntese influenciam significativamente as propriedades dos materiais, de modo que as condições ótimas para a síntese dos materiais foram de calcinação em 300oC e 8 g de hidróxido de potássio utilizadas na síntese. O mecanismo de fotocatálise é fortemente influenciado pela geração de radicais hidroxilas e os materiais apresentam estabilidade para reciclo em processos industriais. / The development of ZnO/Carbon xerogel hybrid photocatalysts was studied, in order to increase the quantum efficiency of the degradation process of persistent organic pollutants. Specifically, the preparation of the ZnO-carbon xerogel hybrid was studied, being this the most significant technological innovation of this project, considering that the catalytic effect of this hybrid was not studied in the literature. The use of carbon xerogel in the preparation of the semiconductor-carbonaceous material is justified by its excellent electrical conductivity, high surface area and porosity, the latter being easily manipulated by modifications in the synthesis parameters. The choice of tannin as the precursor of the xerogel aims at reducing costs and environmental impacts, adding value to the proposed technological innovation. The influence of the pH and route of synthesis were evaluated, as well as the influence of the calcination temperature on the properties of the materials. Diffuse reflectance spectroscopy was the technique used to determine the gap energy of the samples. The morphology, elemental analysis, crystalline and chemical structure of the materials were determined by scanning electron microscopy, dispersive energy spectrometry, X-ray diffractometry, infrared and Raman spectroscopy, respectively. The charge balance on the material surface was analyzed by the point of zero charge methodology (PZC). The photocatalytic action of the material was evaluated by the decomposition of 4-chlorophenol and bisphenol A, determined by UV-Visible spectroscopy. All materials have the hexagonal crystalline structure of zinc oxide (wurtzite). The materials without tannin in their composition also present the zinc hydroxychloride monohydrate phase. The X-ray diffractograms and bandgap values obtained confirm the incorporation of the carbon in the crystalline structure of the zinc oxide. The materials produced via the alcohol route have lower values of crystallite and particle size, as well as a higher content of graphite in their composition and larger surface area, while the materials produced in aqueous solution have lower values of gap energy. All the materials presented photocatalytic activity when subjected to visible and solar radiation, and the materials with intermediate proportions between carbon xerogel and zinc oxide were superior for the photodegradation process. The materials produced via alcohol route are superior to those produced in aqueous solution, as far as the photocatalysis process is concerned. The maximum values found for the degradation of 4-chlorophenol and bisphenol A were 88% and 78%, respectively, obtained by the material XZnC 3.0 (EtOH). The calcination temperature and amount of potassium hydroxide used in the synthesis significantly influence the properties of the materials, so that the optimum conditions for the synthesis of the materials were calcination at 300 °C and 8 g of potassium hydroxide used in the synthesis. The mechanism of photocatalysis is strongly influenced by the generation of hydroxyl radicals and the materials present stability for recycling in industrial processes.
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