Papers by Keyword: Fenton-Like

Abstract: In order to enhance the catalytic activity of the heterogeneous Fenton-like reaction, the catalyst of Fe₃O₄ composites was synthesized. The Fe₃O₄ was used as catalyst of the heterogeneous Fenton-like reaction to degrade methylene blue in aqueous solution. The influencing factors, such as pH, initial H₂O₂ concentration, dye concentration and catalyst concentration, were investigated. The results showed that the dye was effectively degraded at pH 3-8. The optimal condition was at pH3.5. The degradation efficiency of dye increased with the increase of the initial H₂O₂ concentration and reached maximum when the H₂O₂ concentration was 15 mmol/L. The degradation efficiency of dye increased with the catalyst concentration was 650 mg/L. The coexisted anions decreased the degradation efficiency of dye.

Abstract: Ultrasonic-degradation of the antimicrobial triclocarban (TCC) in aqueous solution with Fenton-like enhancement as a new treatment method was investigated. The effects of several important factors on TCC degradation were researched, including H₂O₂ concentration, solution pH. The results showed that US/Fenton-like system can effectively remove the TCC in aqueous solution. The removal rate of TCC can reach more than 94% at optimal conditions ( [H₂O₂]=2.0 mmol/L, pH=3.0).

Abstract: The study combines the UV/TiO₂ and an ultrasonic procedure to degrade the azo dye wastewater of Acid Yellow 17 and investigates the effects of various factors including the quantities of TiO₂ and iron ions added on the efficiency of the removal of the azo dye wastewater of Acid Yellow 17. The experimental results reveal the a significant additive effects occurs through the combination of the two procedures under the 13 watts UV irradiations and 10 watts ultrasound. The analysis of the catalyst properties indicates that there are no evident changes of the appearance of the crystal and TiO₂ catalyst when UV/TiO₂ is combined with ultrasonic procedures. Since the formation of hydrogen peroxide (ND≦1 mg L^-1) was not detected during the reactions, the additions of Fe (II) and Fe (III) are unable to induce the Fenton-like reaction effectively. Nevertheless, the additions of Fe ions significantly affect the degradation rate of the dye. Moreover, the effect of Fe (III) was found to be superior to that of Fe (II) under the same concentration.

Abstract: Fenton reactions have been increasingly applied to emergent pollutants degradation. Although homogeneous reaction by classical Fenton enables organic wastewater degradation, long treatment time and high iron catalyst concentrations are needed, raising environmental concerns. This paper proposed an innovative and cheap solution to degrade Rhodamine B (RmB) by combining magnetic nanomaterials of Fe₃O₄ as the catalyst with microwave-enhanced fenton-like system. The main operational parameters were optimized systematically (hydrogen peroxide concentration; Fe₃O₄ dosage; catalyst cycles; reaction time and reaction temperature). The degradation rate of Rhodamine B was increased and accelerated due to the assistance of microwave irradiation, with value of 99% after heated for only 5 min, even higher than that of treated by traditional Fenton process for 20 min. Moreover, six cyclic tests for Rhodamine B degradation showed that the magnetic catalyst was very stable, recoverable, highly active, and easy to separate using an external magnet. Hence, microwave-enhanced Fenton-like system with magnetic nanomaterials of Fe₃O₄ as the catalyst has potential use in organic pollutant removal.

Abstract: As the Fenton-like oxidation reaction based on iron-bearing minerals could solve some problems of the traditional Fenton oxidation reaction, it became a talking point in academic circles worldwide recently. For the Fenton-like reaction, catalyst selection is an important research parameter. The new Fenton-like reaction uses iron-bearing cinder as catalyst by employing Reactive Black 5 (RB5), the object of investigation, as the target pollutant. By examining the dosage of catalyst, hydrogen peroxide, initial pH, reaction time, concentration of pollutants, optimized reaction conditions can be obtained. Results show that pyrite cinder gives rise to high catalytic activity in the Fenton-like reaction. When 5ml/L of hydrogen peroxide and 10g/L of cinder were added to 75mg/L of dye, the removal rate of RB5 was found to be 96% in 4 hours. Compared to the traditional Fenton reaction, it has a wider pH range and higher catalytic oxidation activity, especially under alkaline condition.

Abstract: The decolorization kinetic of C.I. Reactive Black 5 was studied using Fenton-like oxidation. The effect of the major system parameters, such as initial pH of the solution, concentration of H2O2, concentration of Fe3+ and reaction temperature on the kinetics was determined. The results indicate that the operating parameters, such as initial pH of dye solution, initial concentration of Fe2+ and H2O2, reaction temperature, have strong influences on the degradation of C.I. Reactive Black 5 by Fenton-like oxidation process. In addition, it was also found that the decolorization of C.I. Reactive Black 5 followed the first-order kinetics well.

Abstract: The reactive red 3 was degraded by catalytic wet oxidation process over Fe-RH-MCM-41 prepared by Direct Hydrothermal Technique (DHT) at Si/Fe molar ratio of 10 using silica from rice husk. The extended reaction conditions were studied as a function of reaction temperatures, initial H2O2 concentrations and initial pH of solutions designed by Box-Behnken design (BBD) based on Response Surface Methodology (RSM) to achieve the optimal condition and interaction of independent variables. The characterizations of catalyst were studied by XRD, BET surface area and TEM to explain the morphology of surface and to confirm the hexagonal structure. The results showed the 2theta peak can be indexed to hexagonal lattice that also confirmed by TEM result and surface area about 650 m2/g. All of independent variables showed significant on the degradation of reactive red 3 except for initial H2O2 concentration.

Abstract: Fenton-like reaction technologies are attracting considerable attention due to the high oxidizing ability, especially in the treatment of refractory chemical contaminants. However, some disadvantages in traditional Fenton reagents limited its wide application. In this study, pyrite, a natural iron bearing mineral, was used as a new kind of Fenton-like catalyst in the treatment of textile wastewater. The catalytic activity of pyrite and the parameters influencing the removal of Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD5), such as pyrite dosage, H2O2 concentration, pH, and suspended solids (SS) had been systematically examined. Results showed that pyrite exhibited a high catalytic reactivity over a wide pH value range. At the optimal conditions, a COD removal rate of 70% and an increase in the mass ratio of BOD5/COD (B/C) from 0.25 to 0.56 were achieved in the presence of 9.7 mM H2O2 and 10 g/L pyrite at initial solution pH value of 9.0. And what’s more, a rapid decrease in solution pH and a high level of iron were observed when pyrite was added to the wastewater, probably due to the oxidative dissolution of pyrite. Consequently, Apart from the heterogeneous process, it was found that a homogeneous interaction between ferrous iron and H2O2 in a classical Haber-Weiss mechanism was also occurred. The wonderful reactivity of pyrite makes it be used as catalyst for the oxidative technology to treat the original wastewater without the need to pre-adjust the solution pH.

Abstract: Fenton and Fenton-like reactions are regarded as high efficient methods in advanced treatment of nitrobenzene wastewater but both restrained in degradation of nitrobenzene in groundwater because of the low pH condition( less than 4 ) requirement and other problems such as secondary pollution by the irons in contaminated sites. This paper reports a new Fenton-like technology combined irons extraction from aquifer materials which were found in a nitrobenzene contaminated site in China with hydrogen peroxide catalytic oxidation. The simulate experiments were conducted to investigate the oxidation of nitrobenzene in groundwater by this method under the condition of neutral pH and 8~10°C. The comparison of different extraction agent and production rule of hydroxyl radical were both studied in this research. The results indicated that extraction had hysteresis property because the highest extracting efficiency occurred after 36h. Extraction agent DCB has the highest efficiency, for Fe³⁺ was 62.92% and Fe²⁺ was 30.17%. The highest removal efficiency could reach 80.2% while the mole ratio of nitrobenzene to H₂O₂ was 1:200. Three stages could found in hydroxyl radical generation process, in the first stage hydroxyl radical generated rapidly in 0~30min, then decreased slowly between 30min and 120min, at last the generation tended to be steady after 120h. The results could possess a good potential for application in the treatment of nitrobenzene contaminated groundwater and provide theoretical basis on in-situ chemical remediation technology of nitrobenzene contaminated sites.

Abstract: A new Fenton-like catalyst was prepared to degrade Orange IV in water by catalytic decomposition of H2O2. The optimal preparation conditions were discussed. The catalytic activity of catalyst was evaluated by the degradation of Orange IV and the decomposition of H2O2. The results show that solid super acid (S2O82-/FexOy) soaked in (NH4)2S2O8 is the most effective catalyst among the synthesized iron oxides soaked in other oxidants. The optimal conditions for solid super acid preparation are calcined at 500 for 2 h in the air.