Ferrous ion oxidation

Nourooz-Zadeh J. 1999. Ferrous ion oxidation in presence of xylenol orange for detection of lipid hydroperoxides in plasma. Methods Enzymol 300 58-62. 

Tomita, M. Hieda, K. Watanabe, R. Takakura, K. Usami, N. Kobayashi, K. Hieda, M. Comparison between the yields of DNA strand breaks and ferrous ion oxidation in a Fricke solution induced by monochromatic photons, 2.147-10 keV. Radiat. Res. 1997,148,490 91. 

Osaki, S. (1966). Kinetic studies of ferrous ion oxidation with crystalline human ferroxidase (ceruloplasmin)./. Biol. Chem. 241, 5053-5059. 

The 300 ml. of ozone solution from the scrubber is divided and analyzed in various ways. When crystals of iodide are added to an aliquot of the ozone solution at pH 2.0, much more iodine is liberated than when a second aliquot of the solution is first adjusted to pH 7.0 and iodide is added. Also, more iodine is produced at pH 7.0 than at pH 9.0. The solution with iodide at pH 9.0 liberated an amount of iodine equivalent to the amount of ferrous ion oxidized to the ferric ion at pH 2.0. This agrees with the observations of Manley (11). Observation of the ozone and iodide equation indicated that the newly liberated oxygen or some intermediary substance might be responsible for the increasing iodine as the hydrogen ion concentration increases. An experiment was designed to determine the difference in the concentration of dissolved oxygen after the reaction of ozone with iodide at pH 2.0 and 9.0... 

Beck, J.V., 1960. A ferrous-ion-oxidizing bacterium. I. Isolation and some general physiological characteristics. J. Bacteriol., 79 502—509. 

V. Jiricny, A. Roy and J. W. Evans, Copper Electrowinning Using Spouted Bed Electrodes Part II. Copper Electrowinning with Ferrous Ion Oxidation as the Anodic Reaction, Metall. Mater. Trans., B 33, 677-683 (2002). 

Takai etal. (2001) have obtained from A. ferrooxidans TI-1, a cytochrome a-type iron oxidase. The enzyme catalyzes the oxidation of ferrous ion at pH 3.0 and at 45°C in vitro V for oxygen consumption is 13.8 pmol mg 1 min-1 (242 mol Fe2+s 1). As the enzyme has neither cytochrome c nor cytochrome b, the ferrous ion-oxidizing pathway is constituted of only cytochrome a in the bacterium. Cytochrome c oxidase purified from a mercury-resistant strain of A. ferrooxidans was shown to reduce mercuric ion to elemental mercury (Sugio et al., 2001). 

Elbehti A, Lemesle-Meunier D (1996) Identification of membrane-bound c-type cytochromes in an acidophilic ferrous ion oxidizing bacterium Thiobacillus ferrooxidans. FEMS Microbiol Lett 136 51-56... 

The evolution of oxygen during the ferrous ion oxidation arises from the catalytic decomposition of hydrogen peroxide according to... 

At high values of R i the above mechanism is reduced to reactions (o), (2), (3), and (4). Under these conditions the variation of n and the kinetics of the ferrous ion oxidation with reagent concentrations have been shown to be consistent with these reactions, and Barb et al. have obtained numerical values for fc4/fc3 from both. They find that Aq/fcg increases with decrease in acid concentration, and this accounts for the increased catalytic decomposition observed in more alkaline solutions. Quantitatively ki/ki is given by... 

Using values of such that both reactions (1) and (2) occur, and at the same time having high concentrations of ferric or cupric ion present, the reaction scheme reduces to (0), (1), (2), and (4) "or (5). In these conditions n was found to vary as expected with reagent concentrations, but the kinetics of the ferrous ion oxidation were considerably affected by the presence of traces of organic impurities which could not be removed. However, it was possible to make allowance for this and show that the kinetics agreed with those predicted. Values of fc2/fcj calculated from n and from the kinetics show it to be independent of acid concentration,... 

The experimental data of Lamb and Elder (96), however, are not in agreement with this predicted rate expression for they find the initial rate proportional to the square of the ferrous ion concentration and directly proportional to the oxygen pressure. This has recently been confirmed by the author (97), and it would appear that either the autoxidation is subject to a true catalysis by trace impurities (an induced reaction is excluded by the total ferrous ion oxidized being large, about M/20) or the actual mechanism is different from that suggested by Weiss. 

Neutral and acid solutions of ferrous ion oxidize less rapidly with increasing acidity (despite the fact that the potential of the oxidation reaction becomes more positive). This is because Fe111 is actually present in the form of hydroxo complexes, except in extremely acid solutions, and there may also be kinetic reasons. 

Tomita, M. Hieda, K. Watanabe, R. Takakura, K. Usami, N. Kobayashi, K. Hieda, M. Comparison between the 5nelds of DNA strand breaks and ferrous ion oxidation in a Fricke solution induced by monochromatic photons, 2.147-10 keV. Radiat. Res. 1997,148,490-491. Maezawa, H. Ito, T. Flieda, K. Kobayashi, K. Ito, A. Mori, T. Suzuki, K. Action spectra for inactivation of dry phage T1 after monoehromatic (150-254 nm) synchrotron irradiation in the presence and absence of photoreactivation and dark repair. Radiat. Res. 1984, 98 (2), 227-233. 

Redox polymerizations are among the most popular techniques for grafting reactions, and of the possible initiator systems, ferrous ion oxidation and those based on ceric ion reduction are widely used. In a redox polymerization, a hydroperoxide or similar group is reduced to a free radical plus an anion, while the metal ion is oxidized to a higher valency state, and at the same time a... 

The reaction is third older overall widi first-order dependence on oxygen and second-order dependence on ferrous ion. These authors and others have noted the catalytic effect of cupric ions on the kinetics of ferrous ion oxidation, explained by the reaction... 

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