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Previous issue date: 2013-04-29 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Statistics of environmental protection agencies show that the soil has been contaminated
with problems often resulting from leaks, spills and accidents during exploration, refining,
transportation and storage oil operations and its derivatives. These, gasoline noteworthy,
verified by releasing, to get in touch with the groundwater, the compounds BTEX (benzene,
toluene, ethylbenzene and xylenes), substances which are central nervous system depressants
and causing leukemia. Among the processes used in remediation of soil and groundwater
contaminated with organic pollutants, we highlight those that use hydrogen peroxide because
they are characterized by the rapid generation of chemical species of high oxidation power,
especially the hydroxyl radical ( OH), superoxide (O2
-) and peridroxil (HO2
), among other
reactive species that are capable of transforming or decomposing organic chemicals. The pH
has a strong effect on the chemistry of hydrogen peroxide because the formation of different
radicals directly depends on the pH of the medium. In this work, the materials MCM-41 and
Co-MCM-41 were synthesized and used in the reaction of BTEX removal in aqueous media
using H2O2. These materials were synthesized by the hydrothermal method and the techniques
used to characterize were: XRD, TG/DTG, adsorption/desorption N2, TEM and X-Ray
Fluorescence. The catalytic tests were for 5 h of reaction were carried out in reactors of 20
mL, which was accompanied by the decomposition of hydrogen peroxide by molecular
absorption spectrophotometry in the UV-Vis, in addition to removal of organic compounds
BTEX was performed as gas chromatography with detection photoionization and flame
ionization and by static headspace sampler. The characterizations proved that the materials
were successfully synthesized. The catalytic tests showed satisfactory results, and the
reactions containing BTEX + Co-MCM-41 + H2O2 at pH = 12.0 had the highest percentages
of removal for the compounds studied / Dados estat?sticos das ag?ncias de prote??o ambiental demonstram que o solo tem sido
contaminado frequentemente com problemas decorrentes de vazamentos, derrames e
acidentes durante a explora??o, refino, transporte e opera??es de armazenamento do petr?leo
e seus derivados. Destes, a gasolina merece destaque, verificado pela libera??o, ao entrar em
contanto com a ?gua subterr?nea, dos compostos BTEX (benzeno, tolueno, etilbenzeno e
xilenos), que s?o subst?ncias depressoras do sistema nervoso central e causadoras de
leucemia. Dentre os processos utilizados em remedia??o de solos e ?guas contaminadas por
poluentes org?nicos, destacam-se os que utilizam o per?xido de hidrog?nio por serem
caracterizados pela r?pida gera??o de esp?cies qu?micas de alto poder de oxida??o,
principalmente o radical hidroxil ( OH), super?xido (O2
-) e peridroxil (HO2
), dentre outras
esp?cies reativas que s?o capazes de transformar ou decompor produtos qu?micos org?nicos.
O pH tem um forte efeito na qu?mica do per?xido de hidrog?nio, pois a forma??o dos
diferentes radicais depende diretamente do pH do meio. Neste trabalho, os materiais MCM-41
e Co-MCM-41 foram sintetizados e utilizados na rea??o de remo??o dos BTEX em meio
aquoso utilizando H2O2. Estes materiais foram sintetizados atrav?s do m?todo hidrot?rmico e
as t?cnicas utilizadas na caracteriza??o foram: DRX, TG/DTG, adsor??o/dessor??o de N2,
MET e Fluoresc?ncia de Raios-X. Os testes catal?ticos ocorreram durante 5 horas de rea??o e
foram realizados em reatores de 20 mL, onde foi acompanhada a decomposi??o do per?xido
de hidrog?nio por espectrofotometria de absor??o molecular na regi?o do UV-Vis, al?m da
remo??o dos compostos org?nicos BTEX que foi realizada por cromatografia em fase gasosa
com detec??o por fotoioniza??o e ioniza??o de chama e amostrador por headspace est?tico.
As caracteriza??es comprovaram que os materiais foram sintetizados com sucesso. Os testes
catal?ticos apresentaram resultados satisfat?rios, sendo que as rea??es contendo BTEX + Co-
MCM-41 + H2O2 em pH = 12,0 apresentaram os maiores percentuais de remo??o para os
compostos estudados
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/17789 |
| Date | 29 April 2013 |
| Creators | Farias, Mirna Ferreira de |
| Contributors | CPF:35530502415, http://lattes.cnpq.br/9770622597949866, Guedes, Ana Paula de Melo Alves, CPF:03330987499, http://lattes.cnpq.br/5738717177200782, Castro, Francisco Laerte de, CPF:77862589491, http://lattes.cnpq.br/2913544384537886, Fernandes, Glauber Jos? Turolla, CPF:72074442491, http://lattes.cnpq.br/6067867622712912, Gabardo, Irene Terezinha, CPF:27460266949, http://lattes.cnpq.br/7734138385292211, Ara?jo, Ant?nio Souza de |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Qu?mica, UFRN, BR, F?sico-Qu?mica; Qu?mica |
| 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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