doctoralThesis
Avaliação da remoção catalítica de compostos orgânicos monoaromáticos em água utilizando materiais nanoestruturados de sílica
Fecha
2013-04-29Registro en:
FARIAS, Mirna Ferreira de. Avaliação da remoção catalítica de compostos orgânicos
monoaromáticos em água utilizando materiais nanoestruturados de sílica. 2013. 127 f. Tese (Doutorado em Físico-Química; Química) - Universidade Federal do Rio Grande do Norte, Natal, 2013.
Autor
Farias, Mirna Ferreira de
Resumen
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