Fenton chemistry encompasses reactions of hydrogen peroxide in the presence of iron to generate highly reactive species such as the hydroxyl radical and possibly others. In this review, the complex mechanisms of Fenton and Fenton-like reactions and the important factors influencing these reactions, from both a fundamental and practical perspective, in applications to water and soil treatment, are discussed. The review covers modified versions including the photoassisted Fenton reaction, use of chelated iron, electro-Fenton reactions, and Fenton reactions using heterogeneous catalysts. Sections are devoted to nonclassical pathways, by-products, kinetics and process modeling, experimental design methodology, soil and aquifer treatment, use of Fenton in combination with other advanced oxidation processes or biodegradation, economic comparison with other advanced oxidation processes, and case studies.

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Advanced Oxidation Processes for Organic Contaminant Destruction Based on the Fenton Reaction and Related Chemistry

2.2. Fenton’s Chemistry 6575 2.2.1. Origins 6575 2.2.2. Fenton Process 6575 2.3. Photo-Fenton Process 6577 3. H2O2 Electrogeneration for Water Treatment 6577 3.1. Fundamentals 6578 3.2. Cathode Materials 6579 3.3. Divided Cells 6580 3.4. Undivided Cells 6583 4. Electro-Fenton (EF) Process 6585 4.1. Origins 6585 4.2. Fundamentals of EF for Water Remediation 6586 4.2.1. Cell Configuration 6586 4.2.2. Cathodic Fe2+ Regeneration 6586 4.2.3. Anodic Generation of Heterogeneous Hydroxyl Radical 6587

Electro-Fenton process and related electrochemical technologies based on Fenton's reaction chemistry

Advanced oxidation processes (AOPs) constitute important, promising, efficient, and environmental-friendly methods developed to principally remove persistent organic pollutants (POPs) from waters and wastewaters. Generally, AOPs are based on the in situ generation of a powerful oxidizing agent, such as hydroxyl radicals (•OH), obtained at a sufficient concentration to effectively decontaminate waters. This critical review presents a precise and overall description of the recent literature (period 1990–2012) concerning the main types of AOPs, based on chemical, photochemical, sonochemical, and electrochemical reactions. The principles, performances, advantages, drawbacks, and applications of these AOPs to the degradation and destruction of POPs in aquatic media and to the treatment of waters and waste waters have been reported and compared.

Advanced Oxidation Processes in Water/Wastewater Treatment: Principles and Applications. A Review

Advanced oxidation processes (AOPs), defined as those technologies that utilize the hydroxyl radical (·OH) for oxidation, have received increasing attention in the research and development of wastewater treatment technologies in the last decades. These processes have been applied successfully for the removal or degradation of toxic pollutants or used as pretreatment to convert recalcitrant pollutants into biodegradable compounds that can then be treated by conventional biological methods. The efficacy of AOPs depends on the generation of reactive free radicals, the most important of which is the hydroxyl radical (·OH). The authors summarize the formation reactions of ·OH and the mechanisms of pollutants degradation. They cover six types of advanced oxidation processes, including radiation, photolysis and photocatalysis, sonolysis, electrochemical oxidation technologies, Fenton-based reactions, and ozone-based processes. Controversial issues in pollutants degradation mechanism were discussed. They review t...

Advanced Oxidation Processes for Wastewater Treatment: Formation of Hydroxyl Radical and Application

The application of strong electric fields in water and organic liquids has been studied for several years, because of its importance in electrical transmission processes and its practical applications in biology, chemistry, and electrochemistry. More recently, liquid-phase electrical discharge reactors have been investigated, and are being developed, for many environmental applications, including drinking water and wastewater treatment, as well as, potentially, for environmentally benign chemical processes. This paper reviews the current status of research on the application of high-voltage electrical discharges for promoting chemical reactions in the aqueous phase, with particular emphasis on applications to water cleaning.

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Electrohydraulic Discharge and Nonthermal Plasma for Water Treatment

A novel process of an oxidative degradation of aqueous phenol effluent with hydrogen peroxide produced by electroreduction of oxygen dissolved in the effluent was studied. Effects of operational conditions such as pH, cathode potential, ferrous ion concentration and phenol concentration on the degradation rate of phenol were clarified. Phenol was successively degraded to carbon dioxide at pH 3 with higher efficiency rather than the other pH''s. The COD current efficiency at pH 3 was higher than that for the anodic oxidation process of phenol and was more than 60% for complete degradation in the range of 260-2600 ppm of initial COD.

Oxidative degradation of aqueous phenol effluent with electrogenerated fenton''s reagent

Effect of anodic and cathodic reactions on oxidative degradation of phenol in an undivided bipolar electrolyzer

Production of hydrogen peroxide by electroreduction of oxygen in alkaline solutions was experimentally carried out using a packed-bed electrode of graphite particles or graphite felts. Oxygen sparging into the bed was found to increase overall yield of hydrogen peroxide for a one-pass operation because of the increase in concentration of dissolved oxygen. The current efficiency decreased with increasing concentration of hydrogen peroxide. Effects of packing materials, sparging rate of oxygen and operational conditions on production rate were analysed by measuring potential distribution within the bed. The production rate for the electrolysis using graphite felts was found to be larger than that using graphite particles. The felt cathode had a large electrode surface area and a large volumetric ratio of gas to electrolyte, which might enhance the mass transfer rate of dissolving oxygen. The consumption of electric power for producing hydrogen peroxide was found to range from 2 to 6 kWh·kg–1-H2O2 in the packed-bed electrode with graphite felts.

Effect of oxygen sparging into packed-bed electrode on production rate of hydrogen peroxide

The effect of anodic and cathodic reactions of a bipolar electrode on the oxidative degradation of phenol in an undivided bipolar electrolyzer was reported in the previous paper.3) The purpose of this work is to clarify the change in product concentration and CODwith total coulombs under various conditions of electrolysis. The relationship between energy consumption for reducing the CODand operating conditions will also be discussed.

Takamasa Kodera

Papers

Oxidative degradation of aqueous phenol effluent with electrogenerated fenton''s reagent

Effect of anodic and cathodic reactions on oxidative degradation of phenol in an undivided bipolar electrolyzer

Effect of oxygen sparging into packed-bed electrode on production rate of hydrogen peroxide

Oxidative degradation rate of phenol in an undivided bipolar electrolyzer

Thermal desorption processes of H2 and CH4 from Li2ZrO3 and Li4SiO4 materials absorbed H2O and CO2 in air at room temperature