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Previous issue date: 2008-12-17 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The decontamination of the materials has been subject of some studies. One of the factors that it increases the pollution is the lack of responsibility in the discarding of toxic trash, as for example the presence of PCB (Polychlorinated Biphenyls) in the environment. In the Brazilian regulations, the material contaminated with PCB in concentrations higher than 50 ppm must be stored in special places or destroyed, usually by incineration in plasma furnace with dual steps. Due to high cost of the procedure, new methodologies of PCBs removal has been studied. The objective of this study was to develop an experimental methodology and analytical methodology for quantification of removal of PCBs through out the processes of extractions using supercritical fluid and Soxhlet method, also technical efficiency of the two processes of extraction, in the treatment of contaminated materials with PCBs. The materials studied were soils and wood, both were simulated contamination with concentration of 6.000, 33.000 and 60.000 mg of PCB/ kg of materials. Soxhlet extractions were performed using 100 ml of hexane, and temperature of 180 ?C. Extractions by fluid supercritical were performed at conditions of 200 bar, 70?C, and supercritical CO2 flow-rate of 3 g/min for 1-3 hours. The extracts obtained were quantified using Gas chromatography-mass spectrometry (GC/MS). The conventional extractions were made according to factorial experimental planning technique 22, with aim of study the influence of two variables of process extraction for the Soxhlet method: contaminant concentration and extraction time for obtain a maximum removal of PCB in the materials. The extractions for Soxhlet method were efficient for extraction of PCBs in soil and wood in both solvent studied (hexane and ethanol). In the experimental extraction in soils, the better efficient of removal of PCBs using ethanol as solvent was 81.3% than 95% for the extraction using hexane as solvent, for equal time of extraction. The results of the extraction with wood showed statistically it that there is not difference between the extractions in both solvent studied. The supercritical fluid extraction in the conditions studied showed better efficiency in the extraction of PCBs in the wood matrix than in soil, for two hours extractions the obtain percentual of 43.9 ? 0.5 % for the total of PCBs extracted in the soils against 95.1 ? 0,5% for the total of PCBs extracted in the wood. The results demonstrated that the extractions were satisfactory for both technical studied / A descontamina??o de materiais tem sido tema de v?rios estudos. Um dos fatores que aumenta a polui??o ? a falta de responsabilidade no descarte do lixo t?xico, como por exemplo, a presen?a de PCBs (Bifenilas policloradas) no meio ambiente. Nos regulamentos brasileiros, o material contaminado com PCBs nas concentra??es acima de 50 ppm deve ser armazenado em lugares especiais ou ser destru?do, geralmente por incinera??o em forno de plasma com duplo est?gio. Devido ao custo elevado deste processo, novas metodologias para remo??o de PCBs est?o sendo pesquisadas. O objetivo deste estudo foi desenvolver uma metodologia experimental e anal?tica para a quantifica??o da remo??o de PCBs de materiais contaminados atrav?s de extra??o pelo m?todo Soxhlet e por flu?do supercr?tico, como tamb?m avaliar e comparar a efici?ncia t?cnica dos dois processos de extra??o. Os materiais avaliados foram: solo e madeira ambos contaminados com PCBs via contamina??o simulada. Os materiais foram contaminados com a concentra??o de 6.000, 33.000 e 60.000 mg de ?leo Ascarel/ kg de material. A extra??o pelo m?todo Soxhlet foi realizada usando 100 mL de solvente org?nico (hexano ou etanol), 180 ?C e press?o atmosf?rica. A extra??o com flu?do supercr?tico foi realizada nas seguintes condi??es: 200 bar, 70 ?C e 3 g de CO2 / min. Os extratos obtidos foram quantificados usando a cromatografia gasosa acoplada a um espectr?metro de massa (CG-EM). Foram realizadas extra??es pelo m?todo convencional usando a t?cnica de planejamento fatorial 22, com a finalidade de estudar os efeitos da concentra??o inicial de contaminante e o tempo de extra??o no percentual de remo??o de PCBs. As extra??es pelo m?todo Soxhlet foi eficiente para extra??o de PCBs em solo e em madeira para os dois solventes em estudo (hexano e etanol). Nos experimentos de extra??o em solos, o melhor percentual de remo??o de PCBs usando etanol como solvente foi de 81,3% e 95% para a extra??o que usa hexano como solvente, com o mesmo tempo de extra??o. Os resultados dos ensaios de extra??o com madeira, mostraram que estatisticamente n?o h? diferen?a entre as extra??es mudando o solvente. A extra??o por fluido supercr?tico nas condi??es estudadas teve melhor desempenho para extrair PCBs na matriz madeira do que no solo. Em duas horas de extra??o foi obtido percentual de 43,9 ? 0,5 % para a soma do total de PCBs extra?do no solo contra 95,1 ? 0,5 % para a soma total de PCBs extra?do na madeira. Os resultados foram satisfat?rios para ambas as t?cnicas de extra??o estudadas
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/15758 |
| Date | 17 December 2008 |
| Creators | Silva, Dannielle Janainne da |
| Contributors | CPF:27111541812, http://lattes.cnpq.br/8055289812908100, Melo, Josette Lourdes de Sousa, CPF:10200720406, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4787094H6, Chiavone Filho, Osvaldo, CPF:08580772800, http://lattes.cnpq.br/2621516646153655, Nascimento, Cl?udio Augusto Oller do, CPF:99642298872, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4781533Z6, Moraes, Jos? Erm?rio Ferreira de, Pereira, Camila Gambini |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Engenharia Qu?mica, UFRN, BR, Pesquisa e Desenvolvimento de Tecnologias Regionais |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| 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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