Fenton-type reagents

Walling C (1998) Intermediates in the reactions of Fenton type reagents. Acc Chem Res 31 155-157 Wardman P, Candeias LP (1996) Fenton centennial symposium. Fenton chemistry an introduction. Radiat Res 145 523-531... 

A fuel cell with Nation as electrolyte has been used by Otsuka et al. [121] for the spontaneous production of Fenton-type reagents in aqueous HC1 or H2S04 with Fe or Cu ions at Pd or Au cathodes. A diagram of this cell is presented in Fig. 19. The OH radicals produced in the aqueous phase were utilized to transform benzene into phenol. On the other hand, Tzedakis et al. [122] obtained about 70% current efficiency for phenol by a continuous extraction of phenate ions, using a Hg pool cathode in the presence of... 

Bandara j, Morrison C, Kiwi J, Pulgarin C, Peringer P (1996) Degradation/De-coloration of Concentrated Solutions of Or-gane 11. Kinetics and Quantum Yield for Sunlight Induced Reactions via Fenton Type Reagents, J. Photochem. Photobiol. A. Chem. 99 57-66. 

Cao, H. and Wang, Y. (2007) Quantification of oxidative single-base and intrastrand cross-link lesions in unmethylated and CpG-methylated DNA induced by Fenton-type reagents. Nucleic Acids Res., 35, 4833-4844. 

There is considerable interest in the direct conversion of benzene to phenol to decrease the number of steps and to avoid the acetone by-product which could become a serious drawback in the future. Fenton type reagents utilizing are the most suitable for effecting this... 

The hydroxylation of benzene to phenol and/or hydroquinone can be effected by generating OH radicals using Fenton-type reagents. Systems based on copper(I) chloride in aqueous H SO have been studied in... 

In many cases, a combination of physical, chemical, physico-chemical, and biotechnological treatments may be more efficient than one type of treatment (Table 3). Efficient pretreatment schemes, used prior to biotechnological treatment, include homogenization of sohd wastes in water, chemical oxidation of hydrocarbons by H2O2, ozone, or Fenton s reagent, photochemical oxidation, and preliminary washing of wastes by surfactants. 

The technology behind Fenton s treatment dates back over a hundred years to 1894 when M.J.H. Fenton reported that ferrous ion promoted the oxidation of tartaric acid with aqueous hydrogen peroxide." Ferrous-catalysed hydrogen peroxide at acidic pH has since come to be known as Fenton s reagent and is widely used in both oxidative treatment of industrial effluents and in the manufacture of several types of polymers and polyelectrolytes. Subsequently,... 

Sudoh et al. demonstrated the destruction of phenol via electrolytically generated Fenton s reagent in a ferrous sulfate/sodium sulfate electrolyte. These studies were performed in an H-type electrolyzer (Fig. 12) on a graphite plate cathode [52]. At an operating potential of -0.6 V vs. Ag/AgCl, a solution pH of 3, and a ferrous concentration of 2 mol/m, a phenol degradation current efficiency of 60% was reported for initial phenol values ranging from 260 to 2600 ppm. 

Fig. 12. H-type electrolyzer for the electrogeneration of Fenton s reagent [52], (By permission from Society of Chemical Engineers, Japan).

As discussed earlier, organic compounds with double bonds, especially with chlorine, react quickly with hydroxyl radical. On the other hand, saturated organic compounds such as 1,1-dichloroethane and chloroform, are better removed by UV photolysis. Depending on the type of organic compound, initial contaminant concentration will affect the performance of the process. For high contaminant level, multiple AOPs can be used. For example, for a COD > 5000 mg/L, sequential treatment using Fenton s reagent followed by UV oxidation may be chosen. 

Based on these results, it can be concluded that BEA zeolite can be simultaneously detemplated and Fe-exchanged by treating the parent zeolite with a Fenton s-type reagent (Fe /HaOa) at low temperature. The catalyst shows excellent performance on N2O decomposition compared to conven-... 

Whereas the reactions included in the second group require direct contact between a molecule of the C-H compound and the metal complex (albeit via the ligand). In the processes belonging to the third type, the complex activates initially not the hydrocarbon but the other reactant (e.g H2O2 or O2) The reactive species formed (a carbene or radical, e.g hydroxyl radical) attacks then the hydrocarbon molecule without any participation in the latter process of the metal complex which has generated this species. Oxidation of alkanes by Fenton s reagent [4a-c] is an example of a such type process ... 

Chemical oxidation reducing resorcinol from 350 mg/l using Fenton s reagent to Carbon type Carbon adsorption following treatment with Fenton s reagent Bloaugmentatlon following carbon adsorption ... 

Significant efforts have been made to reproduce functional aspects of the nonheme di-iron enzymes. A few examples are now available in which well-characterized high-valent di-iron species participate in the key C H/O activation steps. Differentiation of radical-free vs. free-radical processes is an important issue to be addressed for the catalytic systems that employ hydrogen peroxide or alkyl peroxides as terminal oxidants. In the following sections, selected nonheme di-iron systems that effect either stoichiometric or catalytic oxidation of organic substrates are described. Detailed accounts of Gif chemistry and Gif-type reagents can be found elsewhere. Reviews of related C—activation by Fenton-type processes are also available. " ... 

Pump and Treat Aerobic Flushing Bioreactor Landfill (PTAFBL), in which recalcitrant organics are oxidized both in-situ and ex-situ to the landfill (Fig. 4.2) is the new modified version of an aerobic landfill. This type of aerobic bioreactor was tested in pilot-scale by Bolyard et al. (2013). The Fenton s reagent was used for ex-situ leachate treatment because of its high efficiency in the removal of COD from leachate (Batarseh et al. 2007). The leachate containing oxidized organic compounds is returned to the landfill, where it was treated... 

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