Degradation of Acid Blue 161 by Fenton and photo-Fenton processes

Abstract

Degradation kinetics of azo dye, Acid Blue 161 (AB161), by Fenton and photo-Fenton processes in aqueous solution was investigated. At pH 3.5, the effects of H 2 O 2 , Fe 2? , and H 2 O 2 /Fe 2? molar ratios, on the AB161 decolorization kinetic rates, were evaluated. Experimental results confirmed that the optimal H 2 O 2 /Fe 2? molar ratio of 12 is close to the theoretical value of 11 as predicted by previously developed model. The influence of azo bond loading (L azo bond ), from 0.25 to 1.0, and pH values from 2.5 to 4.0 were evaluated on AB161 decolorization kinetic rates. A correlation between the natural logarithm of the decolorization rates and L azo bond was established at the different pH values. The decolorization rate increased linearly with decreasing L azo bond , in the order of pH: 3.5 [ 3.0 [ 2.5 [ 4.0. UV radiation of Fenton processes increases degradation of AB161 more than 40 % due to the regeneration of Fe 2? through photo-catalytic reactions. This phenomenon was confirmed by measuring H 2 O 2 concentration during the photo-Fenton processes. The results suggest that Fenton processes can effectively decolorize or degrade wastewater containing azo dye, AB161. Photo-Fenton processes may further increase the degradation efficiency of AB161 by 40 %.

The Kinetic Model for Decolorization of Commercial Reactive Red 120 Azo Dye Aqueous Solution by the Fenton Process and Study the Effect of Inorganic Salts

“…The parameters for color removal (decolorization) efficiencies such as loading azo bond factor (L azo bond ) or COD loading factor (L COD ) was studied; which are defined by Eqs. (4) and (5), respectively [10]. The stoichiometry requirements of Fenton's reagent dose should depend on the amount of available O 2 in H 2 O 2 to produce hydroxyl free radical during the oxidation of azo bond and its organic intermediates [10].…”

“…H 2 O 2 was quantified spectrophotometrically as described by Nogueira [16]. The degradation of RR 120 was carried out by Fenton process using a batch reactor (total volume of 1L) under constant agitation with a magnetic stirrer and room temperature ranged from 35±2 ο C. The experiments were conducted as the following: 1) To achieve the effects of the initial H 2 [10,19]. While to measure the COD concentration in the treated water the interference from residual H 2 O 2 was removed by addition of Na 2 CO 3 (20 g/L) and placed in a water bath at 90 ᵒ C for 60 min [20].…”

“…Fe 2+ In Fenton oxidation process, hydroxyl free radical prefer to attack the azo bond (-N=N-) of the dye molecule by cleaving it to produce aromatic amines and inorganic ions such as NH 4 + [9,10]. For treatment industrial textile wastewater containing dyes; the AOPs are effective techniques for degradation aromatic compounds due to the electrophilic aromatic substitution of hydroxyl radical which then lead to open the aromatic ring [11,12].…”

Strategy for Treating a Landfill Leachate by Integration of Physico-Chemical and Photo-Fenton Processes

“…This procedure is necessary since particulate materials and color tends to inhibit the access of light to the reaction medium, affecting negatively the photo-Fenton process, 7,35 especially considering that the treatment proposed in this study involves the combination between these physico-chemical processes and Fenton reactions.…”

Decreasing COD in Sugarcane Vinasse Using the Fenton Reaction: The Effect of Processing Parameters

“…Determination of the favorable amount of the Fenton reagent is highly important because excess H 2 O 2 could scavenge hydroxyl radical and would increase the cost of wastewater treatment. Meanwhile, an inadequate amount of H 2 O 2 could not provide enough hydroxyl radical needed for the Fenton process [25]. The H 2 O 2 dosage depends heavily on the initial COD value.…”