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Previous issue date: 2016-07-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A possibilidade de preparar diamante sint?tico aumentou o interesse da comunidade cient?fica para aplica??o destes materiais, devido as suas caracter?sticas peculiares. Entretanto, a dopagem do diamante sint?tico com N, P, B e F torna-o semicondutor podendo ser aplicado na eletroqu?mica. No decorrer das pesquisas ficou estabelecido que o diamante dopado com boro, BDD (sigla em ingl?s) ? um ?nodo que n?o favorece a adsor??o qu?mica das esp?cies na sua superf?cie. Por?m, recentemente a influ?ncia das caracter?sticas do filme (rugosidade, espessura, teor de boro e impurezas sp2) foi determinada; e estes par?metros podem afetar a efic?cia do ?nodo na produ??o de oxidantes fortes e na degrada??o de compostos org?nicos. Por estas raz?es, estudar a influ?ncia da raz?o sp3/sp2 fornece informa??es sobre a escolha de um ?nodo espec?fico de BDD para aplica??es eletroqu?micas. Este trabalho tem como objetivos comparar ?nodos de BDD com diferente raz?o sp3/sp2 para avaliar o desempenho na produ??o de persulfato aplicando diferentes densidades de corrente, bem como, abordar ? atua??o dessa esp?cie fortemente oxidante na degrada??o de um composto modelo, Acid Violet 7. Al?m disso, o desenvolvimento de um estudo toxicol?gico empregando Lactuca Sativa atrav?s da efici?ncia de descontamina??o do efluente sint?tico mediante persulfato eletroquimicamente gerado. Os resultados claramente demonstram que o eletrodo de BDD, contendo maior teor de grafite e maior propriedade de adsor??o na superf?cie, favorece a produ??o significativa do oxidante de interesse. O melhor tempo de eletr?lise para a produ??o m?xima/ideal da esp?cie foi de 120 minutos. O tratamento eletroqu?mico para o Acid Violet 7 usando eletrodos de BDD com diferente raz?o sp3/sp2 (175 e 329) mostrou que, para ambos os casos, a elimina??o da cor e a degrada??o da mat?ria org?nica foram atingidas, por?m um maior n?vel de mineraliza??o foi observado com o BDD 329, indicando uma melhor descontamina??o do efluente. Ap?s o tratamento eletroqu?mico, an?lises toxicol?gicas comprovaram que o efluente tratado com o BDD 175 permitiu a germina??o das sementes de Lactuca Sativa. Por?m, o resultado obtido ? contr?rio ao grau de mineraliza??o obtido com o BDD 329. Esse comportamento foi devido ? significativa produ??o de oxidantes e de ?cidos alif?ticos no final do tratamento eletroqu?mico com BDD 329, evitando a germina??o de Lactuca Sativa. / The possibility of preparing synthetic diamond has increased the interest of the scientific community for application of these materials due to their unique characteristics. However, the synthetic diamond films doping with N, P, B and F become the semiconductor for application in electrochemistry. During the research it was established that the boron-doped diamond, BDD is an anode that does not favor the chemical adsorption of the species on its surface. Recently, however, the influence of film characteristics (surface roughness, thickness, and impurities boron content sp2) was determined; and these parameters can affect the effectiveness of the anode in the production of strong oxidants and degradation of organic compounds. For these reasons, study the influence of ratio sp3/sp2 provides information about choosing a specific anode BDD for specific electrochemical applications. Thus, this work has as main objectives to compare anodes BDD with different ratio sp3/sp2 to evaluate performance in the production of persulfate by applying different current densities, as well as addressing the role that strongly oxidizing species during the degradation of a model compound, Acid Violet 7. Furthermore, the development of a toxicology study using Lactuca sativa through the decontamination efficiency of the synthetic effluent using electrochemically generated persulfate was performed. The results clearly show that BDD electrode containing higher graphite content and higher adsorption property on the surface favors the significant production of the oxidant of interest. The best electrolysis time for high production of persulfate was 120 minutes. The electrochemical treatment of the Acid Violet 7 using BDD electrodes with different sp3/sp2 ratio (175 and 329) showed that for both cases, the elimination of color and degradation of organic matter were affected for this parameter. However, a significant mineralization was observed with BDD 329 than that obtained with BDD 175, indicating a better decontamination of effluent. After the electrochemical treatment, the toxicological analyzes showed that the effluent treated with BDD 175 allowed the germination of Lactuca sativa. However, the result is opposite to the degree of mineralization obtained with BDD 329. This behavior was due to the production of significant concentrations of oxidizers and aliphatic acids at the end of electrochemical treatment with BDD 329, preventing seed germination Lactuca sativa.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/22255 |
| Date | 20 July 2016 |
| Creators | Barreto, J?ssica Pires de Paiva |
| Contributors | 01139059980, http://lattes.cnpq.br/2485073932883264, Guedes, Ana Paula de Melo Alves, 03330987499, http://lattes.cnpq.br/5738717177200782, Ara?jo, Danyelle Medeiros de, 00974778427, http://lattes.cnpq.br/5376210566183962, Melo, Jailson Vieira de, 50073788449, http://lattes.cnpq.br/7275955550556570, Cano, Leonardo Andres, 00000000000, http://lattes.cnpq.br/2094160709385440, Huitle, Carlos Alberto Martinez |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM QU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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