Decolorization of dye pollutants by fenton-like oxidation process using zeolite and natural clay based catalysts
Loading...
Date
2011
Authors
Hassan, Hamizura
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The decolorization of Acid Red 1 (ARl) and Reactive Blue 4 (RB4) dye by
the Fenton-like oxidation process using zeolite and natural based catalysts in batch
system were studied. Fe-zeolite Y type (Fe-ZYT), Fe-natural zeolite (Fe-NZ), Fe-ball
clay (Fe-BC), and Fe-Kuala Kangsar clay (Fe-KKC) were successfully prepared via
impregnation method. The prepared catalysts were characterized by Scanning
Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Xray
powder diffraction (XRD), Nitrogen adsorption/desorption and Energy Disperse
X-ray (EDX). The effectiveness of these catalysts in the decolorization of the dye as
well as the influence of reaction parameters like effect of iron loading on the
supports, catalyst dosage, pH, initial concentration of hydrogen peroxide and dye and
reaction temperature were assessed. Besides, the reusability and the amounts of iron
leached from the catalyst after the reaction completed was evaluated. Through a
number of batch decolorization experiments under various conditions, it is found that
the activity of the catalysts increased until they reached an optimum value by
increasing iron loading on the supports, catalyst dosage, temperature, initial
hydrogen peroxide concentrations and decreasing the pH. The excess of iron on the
supports, catalyst dosage and initial hydrogen peroxide concentration may lead to the
scavenging effect of hydroxyl radical and decreased the decolorization rate. The best
conditions obtained for the decolorization process for both dyes were
0.60-1.0 wt.% Fe-contained supports, 2.50--5.0 giL of catalyst dosage, pH from 2.5--
3.0 and 8.0-20 mM of initial concentratiOn of hydrogen peroxide with 50 mg/L ot
initial dye concentration at 30 oc reaction temperature. Under best conditions, more
than 98% decolorization efficiency of ARl and RB4 were achieved within 60-210
min reaction time. The amounts of iron leaching from all the catalysts prepared
comply with the Environmental Quality (Industrial Effluents) Regulations, (2009) for
both decolorization of ARl and RB4. The result indicates that the heterogeneous
catalyst had a long term stability and activity. Significantly lower concentration of
iron ions in the bulk after the treatment could give a great advantage of the
heterogeneous Fenton over the homogeneous Fenton type systems. The experimental
results showed that the heterogeneous Fenton process was an effective process for
the decolorization of ARl and RB4 dyes.