Fenton oxidant

Chemical processes include reduction and oxidation. Conventional chemical (coagulation-flocculation) and advanced oxidation processes (AOPs), such as chemical oxidation (ozonation, Fenton oxidation, Fe2+/H202), ultrasonic chemical oxidation, photocatalysis oxidation (UV/H2Q2, UV/O3, and W/O3/H2O2),... 

Cuzzola et al. have studied, using ionspray and electrospray MS and SPME-GC-MS, the Fenton oxidation products of surfactants such as lauryl sulfate [90] and AES [91]. The oxidation leads to the formation of products with hydroxyl and epoxide groups because of insertion of oxygen atoms or aldehydes [90] or terminal ethoxylic moieties [91] derived from the loss of the hydrophilic sulfate group. 

M. Perez, F. Torrades, X. Domenech and J. Peral, Fenton and photo-Fenton oxidation of textile effluents. Wat. Res., 36 (2002) 2703-2710. 

Lucas, MS Peres JA. Decolorization of the azo dye Reactive Black 5 by Fenton and photo-Fenton oxidation. Dyes and Pigments, 2006 71, 236-244. 

Chen, R Pignatello, JJ. Role of quinone intermediates as electron shuttles in Fenton and photoassisted Fenton oxidations of aromatic compormds. Environmental Science Technology, 1997 31, 2399-2406. 

Muruganandham, M Swaminathan, M. Decolourisation of Reactive Orange 4 by Fenton and photo-Fenton oxidation technology. Dyes and Pigments, 2004 63, 315-321. 

Henle and Linn recently reviewed the formation, prevention, and repair of DNA damage by tron/hydrogen peroxide (so-called Fenton oxidants). Berlett and Stadt-... 

A major development since the previous review is the discovery that some orga-nohalogen compounds can form in soils by a purely abiotic mechanism involving a Fenton oxidation pathway and the concomitant reduction of Fe(III) to Fe(H) (2384-2386). The formation of alkyl halides by this mechanism is shown in Scheme 4.6 (2387). The rates of production from soils decreased in this order ... 

Kang N, Lee DS, Yoon J (2002) Kinetic Modeling of Fenton Oxidation of Phenol and Monochlorophenols. Chemosphere 47 915... 

Duesterberg CK, Waite TD (2006) Process Optimization of Fenton Oxidation Using Kinetic Modeling. Environ Sci Technol 40 4189... 

Because Fenton oxidation of chlorophenols should follow the same mechanism, the activated complex in the transition state should have a similar structure. Therefore, Equation (6.64) can be applied to mono-, di-, and trichlo-rophenols. It is not certain, however, that it can be applied to tetra- and penta-chlorophenols due to steric hindrance therefore, when the above general equation is applied to chlorophenols, the equation becomes ... 

As discussed earlier, the effects of the meta, para, and ortho positions of chlorine on the dechlorination kinetics of monochlorophenols, dichlorophenols, and trichlorophenols during Fenton oxidation were evaluated by comparing the rate constants of the kinetic model (Tang and Huang, 1995). This study proposed a pseudo first-order steady state with respect to organic concentration. The proposed reaction pathways considered that the hydroxyl radicals would attack unoccupied sites of the aromatic ring. 

Sonolytic decomposition of chlorophenol in water was enhanced in the presence of Fe(II), assuming that the Fenton oxidations occur ... 

O3/UV/H2O2 AOTs, together with other processes treated in different chapters (such as Fenton oxidation), can be named ambient (temperature and pressure), advanced oxidation technologies, in contrast with other AOTs such as hydrothermal oxidation processes that require pressures and temperatures above 1 MPa and 150°C, respectively, and which are more suitable for the treatment of concentrated wastewaters. It is evident that appropriate ranges of concentrations for the different oxidation technologies cannot be exactly established but some recommended values have been reported [29]. Fig. 1 shows some possible recommended ranges of concentrations for these types of AOTs. 

Examples of direct reactions are mainly with inorganic compounds such as cyanides and sulfides or ozone and Fe2+. Both reactions of ozone and Fe2+ with hydrogen peroxide represent the initiating steps of advanced oxidation processes 03/H202, treated later in this chapter, and the Fenton oxidation, presented in another chapter, respectively. Hydrogen peroxide, on the other hand, does not significantly react with most organic compounds, at least at appreciable rates for water treatment [6],... 

Whereas only a few examples have been discussed here, it is obvious that the exact kinetics and mechanisms for Fenton oxidations are highly depen-... 

The final products of Fenton oxidation are dependent on several factors. The amount of hydroxyl radical is clearly important. In addition, the amount of hydroxyl radical scavengers and the amount of pollutant present will affect the array of final products. The concentrations of Fe2 + and Fe3 +, as well as those of other metals, also affect product distributions because these species are involved in some degradation pathways. The presence of... 

Iron solubility is an obvious factor in Fenton oxidation because the rate of hydroxyl radical formation is directly proportional to [Fe2+]. At elevated pH values, iron hydroxides and oxides form and precipitate, causing a dramatic decrease in hydroxyl radical formation rate. Iron chelators can be used to offset this factor. A related issue is the rate of Fe3 + reduction to Fe2+, which, if insufficient, can result in Fe2+ concentrations that are too low to... 

Fenton oxidation has been applied at many sites for in situ remediation of contaminated soils. Typical applications have involved the degradation of... 

Research conducted at Washington State University, as well as in situ applications by commercial entities, has indicated that stabilization of hydrogen peroxide is necessary for effective subsurface injection [39]. Without stabilization, added peroxide decomposes rapidly through interaction with iron oxyhydroxides, manganese oxyhydroxides, dissolved metals, and enzymes (e.g., peroxidase and catalase). Some of these peroxide decay pathways involve nonhydroxyl radical-forming mechanisms, and therefore are especially detrimental to Fenton oxidation systems. 

Without added iron, 7 mol of hydrogen peroxide were needed per mole of PCP oxidized, whereas the peroxide demand for TCE degradation was 3.7 mol of peroxide per mole of TCE oxidized. With Fe2+, these peroxide demands decreased to 4.3 and 2.1 for PCP and TCE, respectively. Chloride release was 80-90% of the theoretical value for each compound and was only slightly higher with added iron. This early study demonstrated the potential to perform in situ Fenton oxidation without added iron. However, the added complexity of most real systems increases the need for added soluble iron. 

Because of the slower kinetics for hydroxyl radical formation with mineral catalysts, most applications of Fenton oxidation for in situ remediation or waste stream treatment involve the addition of dissolved iron(II). 

Kang S-F, Liao C-FI, Po S-T. Decolorization of textile wastewater by photo-Fenton oxidation technology. Chemosphere 2000 41 1287-1294. 

Lee B-D, Hosomi M, Murakami A. Fenton oxidation with ethanol to degrade anthracene into biodegradable 9,10-anthraquinone. A pretreatment method for anthracene-contaminated soil. Water Sci Technol 1998 38 91-97. 

Lee B-D, Flosomi M. A hybrid Fenton oxidation-microbial treatment for soil highly contaminated with benz(a)anthracene. Chemosphere 2001 43 1127-1132. 

Panizza, M., Zolezzi, M. and Nicolella, C. (2006) Biological and electrochemical oxidation of naphthalenesulfonates. J. Chem. Technol. Biotechnol. 81,225-232 Park, T.J., Lee, K.H., Jung, E.J. and Kim, C.W. (1999) Removal of refractory organics and color in pigment wastewater with Fenton oxidation. Water Sci. Technol. 39, 189-192 Perret A., Haenni, W., Skinner, N., Tang, X.M., Gandini, D., Comninellis, Ch., Correa B. and Fori G. (1999) Electrochemical behaviour of synthetic diamond thin film electrodes. Diam. Relat. Mater. 8, 820-823... 

Boye,B.,Farnia, G., Sandona, G.,Buso, A. andGiomo, M. (2005) Removal of vegetal tannins from wastewater by electroprecipitation combined with electrogenerated Fenton oxidation. J. Appl. Electrochem. 35, 369-374. 

Lindsey ME, Tarr MA (2000) Quantitation of Hydroxyl Radical during Fenton Oxidation following a Single Addition of Iron and Peroxide, Chemosphere 41 409-417. 

Bauer R, Fallmann H (1997) The Photo-Fenton Oxidation - A Cheap and Efficient Wastewater Treatment Method, Res. Chem. Intermed. 23, No. 4 341-354. 

Cuzzola et al. [25-26] identified and characterized Fenton oxidation products of lauryl sulfate and AES. The Fenton reaction is a frequently applied oxidative treatment in STPs. The degradation prodncts of anionic surfactants have been objects of stndy as well, because their biodegradation products might involve the loss of the snlfate group, resulting in essentially nonionic surfactants (see below). According to Schroder [27], the biodegradation of nonylphenol ethoxy sulfates does not involve a loss of the sulfate. 

Following previous studies on lauryl sulfate and AES, Cuzzola et al. [44] also studied the Fenton oxidation products of AEO and NPEO. The aerobic biodegradation of AEO and NPEO and anaerobic biodegradation of NPEO were studied by Schroder [27] by means of FIA-MS and LC-MS and MS-MS in positive-ion and/or negative-ion APCI. Methyl ethers of AEO ate persistent in aerobic conditions. NPEO degradation results in NPEC. Anaerobic biodegradation of NPEO results in nonylphenols. 

A. Cuzzola, A. Raffaelli, A. Saba, S. Pucci, P. Salvadori, Identification and characterization of Fenton oxidation products of surfactants by ESI-MS and SPALE GC-MS. 1. Lauryl sulphate. Rapid Commun. Mass Spectrom., 13 (1999) 2140. 

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