Removal of Azo Dyes From Aqueous Solution Using Fenton and Modified Fenton Processes

Abstract

Background: Fenton (Fe 2+ and H 2 O 2) and modified Fenton (Fe 3+ and H 2 O 2) are two popular methods used in advanced oxidation processes (AOP) and degradation of persistent organic pollutants (POPs), such as dye compounds. In these processes, Fe 2+ and Fe 3+ as catalysts and H 2 O 2 as the oxidizing agent are added to the reactor. Objectives: The aim of the current study is to assess the abovementioned methods for removal of Reactive Red 198 and Blue Reactive 19 from aqueous solutions. Materials and Methods: This research was carried out using lab-scale. After preparation of RB-19 and RR-198 stock solutions (1000 ppm), optimum pH and temperature were determined within the range of (3-11) and (15°C-40°C) respectively, and specific amounts of Fe 2+ and Fe 3+ (0.8, 1, 3, 7, 14 and 32 mM) were prepared by adding FeSo 4. 7H 2 O and FeCl 3 , and H 2 O 2 30% W/W (2, 5, 11, 23, 47 and 94 mM) were added to the solutions to establish the H 2 O 2 /Fe 2+ , Fe 3+ molar ratios. Standard jar tests were conducted using jar test apparatus. After sedimentation time, samples were filtered through a 0.45 µm fiber membrane, and then final dye concentrations were measured using a UV/VIS spectrophotometer. Results: The highest dye removal efficiency in both Fenton and modified Fenton methods were obtained at the optimum pH = 3, optimum reaction time of 10 minutes, optimum temperature at 25°C and H 2 O 2 /Fe 2+ and H 2 O 2 /Fe 3+ concentrations of 11.3 and 5.1 mM, respectively. In the Fenton reaction the maximum efficiency was obtained at 94.70% and 99.31% for reactive red 198 and reactive blue 19, respectively. Moreover, by the modified Fenton method the maximum removal efficiency for reactive red 198 and reactive blue 19 was 94.8% and 99.43%. Conclusions: Fenton and modified Fenton processes could be used as very effective methods for removal of reactive red 198 and blue reactive 19 from aqueous solutions.

Catalytic Activity of Iron Doped Hexagonal Mesoporous Silica (Fe-HMS) for Degradation of Reactive Green-19 Dye in Water

“…for Amaranth Red Dye [9,19,30]. The lower number of dye molecules initially seemed to result in higher decolorization rate.…”

“…Both samples show typical type-IV isotherm in Figure 2b, mainly due to the capillary condensation and desorption of nitrogen. According to IUPAC classification [19][20][21][22][23][24][25][26], this type of hysteresis with loop and the shift of sharp inflection of P/P 0 are typical for 2D-hexagonal mesoporous material.…”

“…The addition of metal irons such as Fe has been reported to shows positive effect on the internal structure of HMS catalyst [18]. Since then, a lot research works have been carried out and the Fentonlike process employed to be the most attractive method to degrade dye pollutants with the use of supported catalyst [19].…”

Experimental Design Methodology Applied to the Degradation of a Cytostatic Agent the Imatinib Mesylate Using Fenton Process

“…According to the literature, applying a large initial dose of H 2 O 2 is less efficient than its stepwise addition [29]. Thus, it is judicious to control the initial concentration of H 2 O 2 to have a sufficient amount for the degradation of IM without having an adverse effect on the removal rate or the cost of the treatment.…”

A Study on Dyeing Wastewater Treatment by Applying Pulsed Non-Thermal Plasma

“…In the past, dyeing wastewater was typically treated with coagulation and sedimentation methods and/or biological treatment processes. As technology has advanced, Advanced Oxidation Processes (AOPs) including the O 3 /H 2 O 2 , UV/TiO 2 , Fenton and Plasma Methods, have been introduced [3][4][5][6][7]. In this study, a plasma process in the form of high voltage pulsed discharge was applied to decolorize dye in wastewater over a short time.…”