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Previous issue date: 2010-10-15 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The wet oxidation of organic compounds with CO2 and H2O has been
demonstrated to be an efficient technique for effluent treatment. This work focuses on the
synthesis, characterization and catalytic performance of Fe-MnO2/CeO2, K-MnO2/CeO2/
palygorskite and Fe/ palygorskite toward the wet oxidative degradation of phenol. The
experiments were conducted in a sludge bed reactor with controlled temperature, pressure and
stirring speed and sampling of the liquid phase. Experiments were performed on the following
operating conditions: temperature 130 ? C, pressure 20.4 atm, catalyst mass concentration of 5
g / L initial concentration of phenol and 0.5 g / L. The catalytic tests were performed in a
slurry agitated reactor provided with temperature, pressure and agitation control and reactor
liquid sampling. The influences of iron loaded on the support (0.3; 7 and 10%, m/m) and the
initial pH of the reactant medium (3.1; 6.8; 8.7) were studied. The iron dispersion on the
palygorskite, the phase purity and the elemental composition of the catalyst were evaluated by
X-Ray Difraction (XRD), Scanning Electron Microscopy (SEM) and X-Ray Flourescence
(XRF). The use of palygorskite as support to increase the surface area was confirmed by the
B.E.T. surface results. The phenol degradation curves showed that the Fe3+ over palygorskite
when compared with the other materials tested has the best performance toward the (Total
Organic carbonic) TOC conversion. The decrease in alkalinity of the reaction medium also
favors the conversion of TOC. The maximum conversion obtained from the TOC with the
catalyst 3% Fe / palygorskite was around 95% for a reaction time of 60 minutes, while
reducing the formation of acids, especially acetic acid. With products obtained from wet
oxidation of phenol, hydroquinone, p-benzoquinone, catechol and oxalic acid, identified and
quantified by High Performance Liquid Chromatography was possible to propose a reaction
mechanism of the process where the phenol is transformed into the homogeneous and
heterogeneous phase in the other by applying a kinetic model, Langmuir-Hinshelwood type,
with evaluation of kinetic constants of different reactions involved. / A oxida??o ?mida de compostos org?nicos a CO2 e H2O tem demonstrado ser
uma t?cnica interessante no tratamento de efluentes. Este trabalho tem como objetivo a s?ntese
e caracteriza??o dos catalisadores Fe-MnO2/CeO2, K-MnO2/CeO2/paligorsquita e
Fe/paligorsquita, assim como, a avalia??o na degrada??o oxidativa do fenol. Os experimentos
foram realizados em um reator de leito de lama, com controle de temperatura, de press?o e de
velocidade de agita??o e com coleta de amostras da fase l?quida. Os Experimentos foram
executados nas seguintes condi??es operacionais: temperatura de 130 oC, press?o de 20,4 atm,
concentra??o m?ssica do catalisador de 5 g/L e concentra??o inicial do fenol de 0,5 g/L. Os
par?metros avaliados foram: teor de ferro impregnado (0,3; 7 e 10% em massa) e o pH do
meio reacional (3,1; 6,8 e 8,7). Os resultados da caracteriza??o por DRX, MEV e FRX
mostraram a dispers?o do ferro na paligorsquita, a pureza das fases e, finalmente, a
composi??o dos elementos que constituem o catalisador. O uso da paligorsquita como suporte
eleva a ?rea especifica superficial do catalisador que foi confirmada por an?lise BET. As
curvas de degrada??o do fenol indicam que o catalisador Fe3+ suportado em paligorsquita tem
um papel preponderante na convers?o de Carbono Org?nico Total (COT) quando comparado
aos demais catalisadores. A diminui??o da alcalinidade do meio reacional favorece tamb?m a
convers?o de COT. A convers?o m?xima de COT obtida com o catalisador 3%
Fe/paligorsquita, foi em torno de 95 % para um tempo de rea??o de 60 minutos, reduzindo ao
mesmo tempo a forma??o de ?cidos, em especial o ?cido ac?tico. Com os produtos obtidos da
oxida??o ?mida do fenol, hidroquinona, p-benzoquinona, catecol e ?cido ox?lico,
identificados e quantificados por Cromatografia L?quida de Alta Efici?ncia, foi poss?vel
propor um mecanismo do processo reacional onde o fenol ? transformado em fase homog?nea
e os demais em fase heterog?nea. Aplicou-se um modelo cin?tico, tipo Langmuir-
Hinshelwood, com avalia??o das constantes cin?ticas das diferentes rea??es envolvidas
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/15904 |
| Date | 15 October 2010 |
| Creators | Santiago J?nior, Aristides Felipe |
| Contributors | CPF:12270202449, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4783510Y4, Abreu, C?sar Augusto Moraes de, CPF:02103516320, http://lattes.cnpq.br/4153191049728440, Ruiz, Juan Alberto Chavez, CPF:00744293456, http://lattes.cnpq.br/5051286289341242, Silva, Antonio Osimar Sousa da, CPF:96668253415, http://lattes.cnpq.br/5289388662589522, Melo, Josette Lourdes de Sousa, CPF:10200720406, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4787094H6, Benachour, Mohand, Sousa, Jo?o Fernandes de |
| 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/doctoralThesis |
| 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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