Fenton catalyst

Mineralization of Indigo Carmine at Neutral pH Using a Nanocomposite as a Heterogeneous Photo-Fenton Catalyst... 

To determine the stability of the Fe-B nanocomposite as a heterogeneous photo Fenton catalyst, the Fe concentrations in solution after 120 minutes were measured by ICP. The results obtained indicate that the Fe concentration in solution after 20 minutes reaction is less than 1 mg/L, which is negligible. 

Kennedy, T.P., Dodson, R., Roa, N.V., Ky, H., Hopkins, C., Baser, M., Tolley, E. and Hoidal, J.R. (1989). Dusts causing pneumoconiosis generate hydroxyl radicals and produce hemolysis by acting as Fenton catalysts. Arch. Biochem. Biophys. 269, 359-364. 

Puppo, A. and Halliwell, B. (1988). Formation of hydroxyl radicals from hydrogen peroxide in the presence of iron. Is haemoglobin a biological Fenton catalyst Biochem. J. 249, 185-190. 

The main experimental drawback raised in a homogeneous Fenton catalyst is analyzed in this chapter. In order to overcome its deficiency a heterogeneous catalyst is proposed. 

The degradation of the B02 was conducted by using iron oxide catalyst supported on cerium oxide as a heterogeneous Fenton catalyst in the presenee of H2O2. The effect of the... 

Other iron species have also been evaluated as potential Fenton catalysts. These include magnetite [59], pyrite [60], and basic oxygen furnace... 

A second application of anchored Fenton catalysts is depollution by wet oxidation with aqueous H2O2 at temperatures between 293 and 363 K. Typical pollutants are formic, acetic, propionic, and benzoic acids and phenol (138-140). The degree of immobilization of the catalytic Fe species is largely determined by the pH. For example, with Fe-ZSM-5 a pH that is too-low induces leaching, possibly by competitive exchange of protons. Thus, solutions of higher pH are preferred, even if the catalyst is slightly less active in those conditions. 

The photo-Fenton method of wastewater treatment is developed in two main fields fitting of the usable radiation range to the solar light and immobilization of the photo-Fenton catalyst. 

The study of the possible cooperation of the photo-Fenton reagent with a semiconductor photocatalyst showed that the Fenton catalyst immobilized in Ti02 reveals enhanced photocatalytic activity and is more effective in pollutant degradation this was revealed in the case of such electron donors as citric acid [20], maleic acid [41], chlorinated solvents [42], resorcinol [43], quinoline [44], herbicides [45, 46], and pesticides [47], The optimization of the combined photocatalytic systems... 

Kennedy TP, Dodson R, RaoNV, etal. 1989. Communication. Dusts causing pneumoconiosis generate OH and produce hemolysis by acting as Fenton catalysts. Arch Biochem Biophys 269 359-364. 

Navalon, S. Alvaro, M. Garcia, H., Heterogeneous Fenton Catalysts Based on Clays, Silicas and Zeolites. Applied Catalysis B Environmental 2010, 99 (1-2), 1-26. 

Synthesis of liquid oxygenates from light alkanes (C1-C3) Superacid catalytic membranes, Fenton catalyst, symmetric Flat The oxidant is in the liquid phase, alkanes are in the gas phase Frusteri et al. (1999), Espro et al. (2001, 2003, 2006)... 

Thackrah s (1832) account of morbidity and mortality among mine workers was, as Rosen (1943) stated, not very far removed factually from that of Ramazzini. Thackrah conceived that his own observations in practice were avowedly imperfect. When he wrote The pulmonic diseases, however, chiefly prevail among the miners of coal, which is loaded with pyrites, and which produces consequently considerable dust , we can now say that the dust contained the Fenton catalyst by itself to produce most pathogenic reactive oxygen intermediates. 

Silicates causing pneumoconiosis function as Fenton catalysts to generate hydroxyl radicals when incubated with hydrogen peroxide and a reducing substance (Kennedy et aL 1989). In contrast, silicates, which do not cause pneumoconioses demonstrate no Fenton activity. Catalytic activity is decreased by pre-treatment of silicates with the iron chelators, deferoxamine or transferrin. Haemolysis from silicates is decreased by interventions, which remove superoxide anion or hydrogen peroxide from the mediiun, or by pre-treatment of dusts with iron chelators. 

HO (Kalyanaraman et al. 1983). However, it remains unclear if such a process would be catalysed in vivo by the heme iron itself, or by iron released from heme (Cadenas 1989). Indeed, whether any form of free heme or hemoprotein can act as a true Fenton catalyst to generate HO remains controversial (Ryter and Tyrrell 2000). 

Citrate-chelated iron, reduced by ascorbic acid to Fe acts as a Fenton catalyst to generate HO which induces DNA singlestrand breaks. 

In aged rhesus monkeys Macaca mulatta) the expression of ubiquitin, a B-crystallin, and the heat-shock protein 27 was revealed in spheroid bodies predominantly localized in the globus palli-dus and pars reticulata of the substantia nigra (Schultz et al. 2001). The majority of the palhdo-nigral speroids expressing the stress proteins also accumulated iron, a Fenton catalyst. 

Kasiri MB, Aleboyeh H, Aleboyeh A (2008) Degradation of Acid Blue 74 using Fe-ZSM5 zeolite as a heterogeneous photo-Fenton catalyst. Appl Catal Environ 84 9-15... 

Solar photocatalytic degradation of water contaminants with titania and photo-Fenton catalysts has been carried out on a pilot-plant scale at the solar photochemical facilities of the Plataforma Solar de Almeria (PSA) in Spain, and show how solar photocatalysis is likely to become important within the next few decades in wastewater treatment and development of new AOP technologies [93, 94]. 

The Fenton oxidation, particularly using solid catalysts, is especially suitable for (a) domestic wastewater treatment, (b) wastewater reclamation and reuse (destruction and removal of harmful substances from the water streams to substantially promote the reuse of safe, treated water in industry or in agriculture), (c) sludge production reduction, and (d) water disinfection. The use of solid catalysts allows some of the drawbacks of homogeneous Fenton catalysts to be overcome, including ... 

Particles that catalyze the formation of AOS can also cause oxidation of individual bases, as well as DNA strand breaks, if the particle enters the nucleus and is in close approximation to chromosomes. For the most part, this process is mediated by the iron-catalyzed formation of highly reactive species, such as hydroxyl radical, either using the surface iron on the particle itself as a Fenton catalyst, or using surface iron leached from the particle into the cytosol, where it acts in a fashion similar to a mobile source of hydroxyl radical formation (5,6). 

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