Photo Fenton process

Lurascu B, Siminiceanu I, Vione D, Vicente MA, Gil A (2009) Phenol degradation in water through a heterogeneous photo-Fenton process catalyzed by Fe-treated laponite. Water Res 43 1313-1322... 

Segura Y, Molina R, Martmez F, Melero JA (2009) Integrated heterogeneous sono-photo Fenton processes for the degradation of phenolic aqueous solutions. Ultrason Sonochem 16 417 424... 

Kavitha, V Palanivelu, K. The role of ferrous ion in Fenton and photo-Fenton processes for the degradation of phenol. Chemosphere, 2004 55, 1235-1243. 

Cameiro, PA Pupo Nogueira, RF Zanoni, MVB. Homogeneous photodegradation of C.l. Reactive Blue 4 using a photo-Fenton process under artificial and solar irradiation. Dyes and Pigments, 2006 in press. 

J. Ermfrio, F. Moraes, F. H. Quina, C. A. O. Nascimento, D. N. Silva, and O. Chiavone-Filho, Treatment of Saline Wastewater Contaminate with Hydrocarbons by the Photo-Fenton Process, Environ. Sci. Technol. 2004,... 

The three intermediate products that reached the highest concentrations in the case of quinoline degradation by the photo-Fenton process were in the order ... 

Regarding the main products corresponding to the opening of the pyridine moiety of quinoline, 2-aminobenzaldehyde and, to a lesser extent, its A -formyl derivative were formed by photocatalysis, whereas only traces of this latter product were detected when the photo-Fenton process was employed. Also, (2-formyl)phenyliminoethanol was detected only in the case of the degradation over Ti02. 

As previously discussed, the concentration of Fe2+ is an important factor in the rate of hydroxyl radical formation from hydrogen peroxide. Consequently, any process that can speed the reduction of Fe3+ to Fe2+ will increase the formation rate of hydroxyl radical. UV or visible radiation can play this role by photoreducing iron. However, the photo-Fenton process involves three additional mechanisms that can contribute to pollutant degradation (a) direct photolysis of H202 to yield two hydroxyl radicals (Eq. (22)) (b) photolysis of Fe(OH)2+ to form hydroxyl radical (Eq. (23)) and (c) degradation of pollutants by direct photolysis (i.e., absorption of a photon by the pollutant molecule followed by decomposition of the photoexcited pollutant molecule). 

One of the most important effects is generation of OH radicals from the hydroxo complexes of Fem the reaction is the basis of the so-called photo-Fenton processes [63-78] (for details see Chapter 21). 

Bautitz IR, Nogueira RFP. Degradation of tetracycline by photo-Fenton process - Solar irradiation and matrix effects. J Photochem Photobiol A Chem 2007 187 33-9. 

Chacon JM, Leal MT, Sanchez M, Bandala ER. Solar photocatalytic degradation of azo-dyes by photo-Fenton process. Dyes Pigments 2006 69 144-50. 

Rodriguez M, Malato S, Pulgarin C, et al. Optimizing the solar photo-Fenton process in the treatment of contaminated water. Determination of intrinsic kinetic constants for scale-up. Solar Energy 2005 79 360-8. 

Kiwi J, Denisov N, Gak Y, et al. Catalytic Fe3+ clusters and complexes in nation active in photo-Fenton processes. High-resolution electron microscopy and femtosecond studies. Langmuir 2002 18 9054-66. 

Fem complexes were reported as effective photocatalysts for oxidation of many different organic pollutants, eg alcohols and their derivatives [20,29] organic acids, such as formic [50,53,56], oxalic [37], citric [57], and maleic [58] EDTA [11,20-23], phenol and its derivatives [35, 36, 45,59,60], other aromatic pollutants [38,43,51, 61-64], non-biodegradable azo dyes [40, 41, 48, 55, 59, 65], herbicides [54, 66-70], pesticides [32, 46, 71, 72], insecticides [44], pharmaceuticals and wastewater from medical laboratories [39,47,73], chlorinated solvents [33,74], municipal wastewater [75], and many others [20], The photo-Fenton process was explored as photochemical pre-treatment to improve its biodegradability, especially of biorecalcitrant wastewater from the textile industry [76, 77] the method was also proposed for water disinfection [78,79],... 

Quid N, Morgada ME, Piperata G, Babay P, Gettar RT, Litter MI. Oxalic acid destruction at high concentrations by combined heterogeneous photocatalysis and photo-Fenton processes. Catalysis Today 2005 101 253-60. 

We focus initially on the photochemical behaviour of complexes of Fe(III) with simple carboxylic acids and give particular attention to oxalic acid. This compound is prevalent in atmospheric aerosols [28], provides a simple example of environmentally important light-mediated ligand-to-metal charge transfer (LMCT) processes which result in ligand decarboxylation [27] and is used to initiate the degradation of contaminants both in the absence and presence of added hydrogen peroxide (via the so-called modified photo-Fenton process [29,30]). In addition, the photochemistry of Fe(III)-oxalate complexes has been studied in detail, as it is the basis of... 

Photolysis of iron carboxylates has been used to initiate the degradation of contaminant species (often via photo-Fenton processes) but the process results in degradation of the carboxylate ligand. Alternate ligands which are more resistant to oxidation (either via LMCT processes or hydroxyl radical attack) would appear necessary if such approaches are to be adopted in practice. 

One practical use of Fenton and photo-Fenton processes is the removal of natural organic matter (NOM) from organic rich waters before the chlorine disinfection of drinking water. It was observed that, under optimal conditions, both processes achieved more than 90% TOC removal, leading to the potential formation of trihalomethanes at concentrations below 10 ig IT1, well under UK and US standards [78]. 

A recent paper [84] presents a very complete study of the influence of different operational parameters on the FeOx process, such as light intensity, concentration of the reagents, and the presence of anions and HO scavengers. The case study was the herbicide 2,4-D. It was demonstrated that the system presented a higher efficiency than the photo-Fenton process, that the removal rate increased with fight intensity and that ferrioxalate concentration determined the fight absorption fraction, then controlling the removal rate. 

Their solubility in water is strongly dependent on the pH of the solution. For a detailed discussion of the aqueous solution chemistry of Fe(II) and Fe(III) the reader should refer to Sigg and Stumm (1996). Kim and Vogelpohl (1998) described the experimental realization of the ferrioxalate photo-Fenton process in detail. 

Owing to the different and distinct absorption properties of the individual auxiliary oxidants or photocatalysts, the photo-initiated AOPs presented in Fig. 5-15 must be utilized at specific spectral bands covering the VUV, UV-C, UV-B, UV-A and parts of the visible range of the electromagnetic spectrum. This is outlined in Fig. 5-16. The photo-Fenton process using Fe(III) oxalate is probably the most favorable for solar photochemistry, since the quantum yield 0 is high (cf Tab. 6-4), and ferrioxalate absorbs up to X of 500 nm. 

Kim S-M, Vogelpohl a (1998) Degradation of Organic Pollutants by the Photo-Fenton-Process, Chem. Eng. Technol. 21, No. 2 187-191, and Kim S-M, Vogelpohl A (1998) Einsatz von Ee(III)-Oxalat zur che-misch-oxidativen Abwasserbehandlung, Chem.-Ing. Tech. 70, No. 8 1010-1013. Kirk-Othmer (1998) Encyclopedia of Chemical Technology, 4 ed., )ohn Wiley Sons, New York. 

The photo-Fenton processes are explored as photochemical pretreatment of nonbiodegradable and ubiquitous environmental pollutants and/or extremely toxic compoimds in wastewaters, such as persistent organic dyes under visible light irradiation (151,154,180,181) and under UV irradiation (139,182), azo dye factory wastewaters (140,162,183-185), herbicides (186-188), pesticides (152,153,189,190), insecticides (191), pharmaceuticals and wastewaters from medical laboratories (192-197), smdactants (198), industrial effluents with persistent toxic pollutants (199), industrial solvents and wastewaters (167,200), chlorinated solvents (201), and municipal wastewater (202). The photo-Fenton process was proposed to improve the biodegradability of especially biorecalcitrant wastewater, coming from textile industry, and the method was also suggested for water disinfection (203-205). 

General Aspects of Use of Solid Catalysts in Water Purification Technologies. -1.1.1 Photocatalytic Treatments of Wastewater. There are several excellent reviews on photocatalytic treatments of wastewater which include not only the use of Ti02 as a photocatalyst, but also its combination with H2O2 or Fe /H202 (the so-called photo-Fenton process) in order to improve the effi-... 

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