Utilização de carvão ativado e nanopartículas de magnetita na adsorção do corante reativo azul BF- 5G
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2016-09-12
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Universidade Federal de Goiás
Resumo
The removal of textile dyes requires special attention due to their effects on the
environment and human health. At least 20% of dyes used in the textile reach the environment
through industrial effluents. This pollution of water sources by dyes affect the biological cycles
and the photosynthetic processes. Thus, the adsorption with activated carbons stands out for its
versatility, high efficiency and low operating costs. This work seeked to study the adsorption
mechanism of the commercial textile reactive blue BF - 5G dye in activated bone charcoal, pure
and magnetized with magnetite nanoparticles in batch system, as well as in fixed bed columns but
with pure carbono only. The adsorbents were characterized by determining the point of zero charge
(PZC), adsorption and desorption of N2, infrared spectroscopy, Boehm method, diffraction of x -
rays, magnetization curves, transmission electron microscopy and transmission electron scanning.
For the activated bone charcoal, the PZC was 8.04, confirmed by the Boehm method that
quantified 1.4 meq.g-1 basic groups. The N2 adsorption showed the predominance of mesopores.
The infrared spectrum revealed peaks mainly attributed to the structure of the hydroxyapatite. As
for the synthesized magnetite nanoparticles, it was possible to calculate the average particle size
from the x – ray diffractogram and the Scherrer equation. The value found was approximately 18
nm. By the magnetization curve, it was concluded that the material has superparamagnetic
characteristics. The equilibrium time for the adsorption experiments was approximately 8 hours,
and the pseudo-second order model showed the best fit to the experimental data. Adsorption
isotherms were adjusted and the best model for the tests in batch system, for both pure coal as well
as the magnetized coal, was the Langmuir model. The pure coal revealed a maximum 192.31 mg.g-
1 of amount adsorbed and the magnetized carbon revealed an amount of 93.81 mg.g-1 at 50 ° C.
The process showed endothermic behavior, increasing the adsorption with the increase of
temperature. The process in fixed-bed columns was more efficient with the flow rate adjusted to 2
mL.min-1 and it was only possible to be adjusted through the linear Freundlich model. A final
evaluation was made in which the effluent was characterized before and after the adsorption
process aiming a disposal in accordance with the current legislation. The analyzed parameters were
respecting the maximum permissible values, except for COD.
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MELO, N. H. Utilização de carvão ativado e nanopartículas de magnetita na adsorção do corante reativo azul BF- 5G. 2016. 99 f. Dissertação (Mestrado em Química) - Universidade Federal de Goiás, Goiânia, 2016.