Heterogeneous catalytic treatment of synthetic dyes in aqueous media using Fenton and photo-assisted Fenton process (original) (raw)
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There is something intriguing and at the same time fascinating that a simple reaction (Fe 2+ ions with H202), which was observed by H.J.H. Fenton over 110 years ago, proves to be very difficult to describe and understand. Yet the nature of oxidizing species obtained in Fenton reaction is still a subject of deliberation, which may be explained by the fact that it is very common in both chemical and biological systems in natural environment. Advance oxidation process (AOPs) show great promise for application in many wastewater treatments areas. AOPs are emerging technology that may be employed for specific goals in wastewater treatment. The Application of Advance Oxidation process (AOPs) for dyes wastewater treatment is the focus. Fenton reagents as one of AOPs were applied for the minimization of organic content of coloured synthetic wastewater. Methylene Blue (MB) Dye was used as the model organic pollutants. Fenton type process was examined in orders to established optimal operating condition (pH, Hydrogen Peroxide (H202) concentration, ferrous ion catalyst concentration (Fe 2+) [Fe 2+ ] / [H202] Fenton ratio, dye concentration and temperature for maximum degradation of the investigated simulated coloured wastewater. It was found out that optimum conditions were obtained at pH of 3, hydrogen peroxide of concentration 70mM, Iron catalyst concentration of 4mM, the Fenton ratio [Fe 2+ ] / [H202] of 1: 17.5 and temperature of 45ᵒC. Degradation of Methylene blue dye from textile wastewater using Fentons reagent is very promising since the system achieved high reaction yield, compared to other and there is no needs for special treatment.
Catalytic Oxidation of Triactive Blue Dye (TAB) by Using Fenton’s Reagent
Abstract The oxidative degradation of Triactive Blue dye (TAB) in aqueous solution as a reactive dye model substance was investigated in laboratory-scale experiments, using Fenton reagent (Fe2+ and H2O2). Results show that Triactive Blue dye is decomposed in a two-stage reaction. In the first stage, dye is decomposed rapidly and somewhat less rapidly in the second stage. The effect of different system variables like pH values of the medium, initial H2O2/COD ratios, initial Fe2+/H2O2 ratios, reaction temperature and added HCO3- on the efficiency of color and COD removal of the TAB dye have been investigated. The efficiency of color and COD removal is strongly dependent on the initial concentrations of Fe2+ and H2O2. The results indicate that Fenton reaction has been proved to be highly effective for the removal of Triactive Blue dye in aqueous medium of pH 3 at an initial H2O2/COD ratio of 2 and initial Fe2+/H2O2 ratio of 0.18. At the optimum operating conditions, the results obtained showed that after 60 min reaction time for the Fenton treatment, a color removal of 98% and COD reduction of more than 82% were already achieved. The degradation of TAB dye obeys first order kinetics with respect to the concentration of the dye in the second stage of oxidation. In addition to various process parameters, the presence of HCO3- ions in water might also alter the rate of radical forming reactions as well as the rate of reactions which consume the radicals though scavenging and consequently decrease the oxidation rate of Triactive Blue dye. Finally a rough cost estimate shows that Fenton reaction is a cheap and economic available process. The results will be useful in designing wastewater treatment plants. Therefore, the Fenton process seems to be appropriate as the pre-treatment method for decolorisation and detoxification of effluents from textile dyeing and finishing process containing reactive dyes.
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Advanced Oxidation Processes (AOPs) have emerged as a promising technology for the treatment of wastewaters containing toxic, recalcitrant organic compounds such as dyes, pesticides etc. This review paper focuses on the Fenton and photo- Fenton technique which is one of the most efficient AOPs developed to decolorize and/or degrade organic pollutants. This oxidation method can produce biodegradable intermediates and mineralize complex organic pollutants effectively and efficiently. In this paper Fenton and photo-Fenton methods are categorised into two broad groups as homogeneous and heterogeneous Fenton and photo-Fenton processes. Applications of fundamental and advanced combined Fenton and photo-Fenton processes are also discussed.
Removal of Azo Dyes From Aqueous Solution Using Fenton and Modified Fenton Processes
Health Scope, 2014
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.
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Environmental Chemistry Letters, 2018
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