Decolorization Of Dye Pollutants By Fenton-Like Oxidation Process Using Zeolite And Natural Clay Based Catalysts

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Date
2010-12
Authors
Hassan, Hamizura
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Publisher
Universiti Sains Malaysia
Abstract
The decolorization of Acid Red 1 (AR1) 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), X-ray 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 g/L of catalyst dosage, pH from 2.5–3.0 and 8.0–20 mM of initial concentration of hydrogen peroxide with 50 mg/L of initial dye concentration at 30 °C reaction temperature. Under best conditions, more than 98% decolorization efficiency of AR1 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 AR1 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 AR1 and RB4 dyes.
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Keywords
The decolorization of Acid Red 1 , oxidation process using zeolite
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