BARROS, T. R. B.; http://lattes.cnpq.br/3149481445946471; BARROS, Thiago Rodrigo Barbosa.
Resumo:
This thesis aimed to prepare NaY zeolite using an alternative source of silica and modify
the zeolite with the surfactant cetryltrimethylammonium bromide and evaluate its
potential as an adsorbent for removing reactive yellow dye. The NaY zeolites were
prepared by two distinct hydrothermal synthesis routes, a conventional one having
sodium silicate as silica source and the other sustainable using vermiculite clay as a silica
source. The vermiculite was subjected to an acid treatment, followed by a basic treatment
to obtain silica. NaY zeolites were modified by an organic surfactant CTABr using the
ion exchange method. Chemical stability tests were carried out in the presence of the
yellow reactive dye solution, with a temperature of 25 °C, varying the time from 1 to 7
days and thermal stability in a muffle furnace in the temperature range of 200 to 500 °C
for 1 hour, in order to evaluate the structural strength of NaY zeolites. After these tests,
XRD analyzes were performed. In batch studies, the influence of pH, kinetic evolution
and equilibrium isotherms were evaluated. The results showed that the use of vermiculite
treated with acid and base as a source of silica was effective for obtaining zeolite NaY.
The heat treatment tests showed a stable thermal stability for the adsorbent materials. The
chemical stability tests, using a yellow reactive dye solution, showed to be higher for the
modified adsorbents due to the CTABr surfactant properties. The CTABr-modified
zeolites showed better results in the removal of the reactive yellow dye and in relation to
the kinetics, being better suited to the pseudo-second order model. The adsorption
isotherms were fitted to the Langmuir and Freundlich models to the experimental data of
adsorption of the reactive yellow dye BF-3R, the model with the best fit was the Langmuir
model for zeolites, assuming that homogeneous adsorption was predominant.
