Ozonate anion radical

The first of the reaction steps in the amine-ozone interaction also consists of one-electron transfer from the amine to ozone, with the formation of the corresponding cation and anion-radicals. The ozone anion-radical has been revealed at low temperatures. Formation of the superoxide ion and the amine nitroxide are the understandable results of the reaction (Razumovskii and Zaikov 1984, reference therein). 

Ozone might interfere with the intracellular bactericidal capabilities of alveolar macrophages by inactivating lysosomal hydrolases, or perhaps through the destruction of heme-containing enzymes that are apparentiy involved in producing superoxide anion radical. Further evaluation of the process by which relatively low concentrations of ozone potentiate bacterial infection would be of value. 

The reaction between hydroxide ions and ozone leads to the formation of one superoxide anion radical 02° and one hydroperoxyl radical H02°. 

The ozonide anion radical (030-) formed by the reaction between ozone and the superoxide... 

The decomposition of ozone is catalyzed by the hydroxide ion. Ozone dissociates in the presence of OH to H02°/02°. Further decomposition via the ozonide anion radical 03°7 HO,° results in the formation of OH° (see Figure 2-1, Part A, p. 11). They may react with organic compounds, radical scavengers (HC03, C032-) or ozone itself. 

The formation of oxygen anion radicals and molecules of ozone also should be counted with at the ionization initiation of oxidation [26]. Initiation reaction caused by oxygen anion radicals may play an important role within the polymer bulk while the effect of ozone forming in the surrounding air atmosphere will include only the formation of radicals on the polymer surface. The latent effect of ionization initiation on polymer oxidation which is very distinct may be documented on a relatively fast increase of concentration of carbonyl groups, observed over 1 year after irradiation crosslinking of polyethylene [27]. 

In contrast with the results in the absence of light, alkaline pH reduces the reaction rate, as has been observed in the case of 2,6-DNT degradation. The decrease of the rate is due to the dissociation of the hydroxyl radical in the less active oxygen anion radical (Eq. 36) and to the lower solubility of ozone at high pH [40]. 

A varying and much more complex mechanistic situation exists in heterogeneous photocatalysis (Fig. 5-13). With respect to the transient oxygen species, comparable overall oxidation reactions are usually observed, but the set of primary reactive oxygen species is slightly different. It is commonly assumed, that superoxide radical anions and hydroxyl radicals are the primary species formed after photogeneration of the electron-hole pair of a semiconductor catalyst in the presence of water and air (Serpone, 1996). In the presence of ozone, ozonide radical anions or are formed by fast electron transfer reaction of superoxide radical anions with O3 molecules. The combination Ti02-03-UV/VIS is called photocatalytic ozonation (Kopf et al., 2000). For example, it was applied for the decomposition of tri-chloroethene in the gas phase (Shen and Kub, 2002). 

The past two decades have seen the establishment of a very extensive literature on the application of boron-doped diamond electrodes for the decoloration and the removal of COD and TOC from effluents, the disinfection and quality improvement of water, and the complete oxidation of particular organic molecules [26, 38, 39, 71-75]. There can be no doubt that boron-doped diamond anodes allow the effective killing of microorganisms and the complete oxidation of a wide range of organic compounds to carbon dioxide (and other inorganic fragments). Both direct and indirect mechanisms have been invoked. The direct mechanisms involve electron transfer and oxidation via weakly adsorbed OH radicals, while the indirect mechanisms have seen a role for solution-free OH radicals, ozone, sulfate radicals, or chlorine compounds if suitable anions are present or added. Indirect routes via ozone [20, 21] and sulfate radicals [40, 74, 76-78] can, of course, become dominant with appropriate selection of the conditions. This literature has been extensively reviewed and the interested reader is referred to these reviews [26, 38, 39, 71-75]. 

The lack of knowledge about the behavior of fluoro chemicals in water treatment also includes incomplete understanding of their behavior in the enviromnent, because some processes discussed as water or waste treatment techniques are related to chemical and physical processes in nature (combustion, UV-photolysis, formation of reactive species (e.g., ozone, hydroxyl radicals, and sulfate radical anions)) as well as biological processes. The knowledge about the fate of fluorinated chemicals in the environment can also contribute to improve treatment technologies. 

The formation of superoxide anion radicals by 0.2 X10 lavaged cells was not changed after a 7-day exposure of rats to 0.5 ppm ozone compared to the control group, but was increased after a two months ozone exposure (Creutzenberg et al. 1995). 

The preparation, properties and uses of ozonides have been reviewed comprehensively [1]. Many pure ozonides (trioxolanes) are generally stable to storage some may be distilled under reduced pressure. The presence of other peroxidic impurities is thought to cause the violently explosive decomposition often observed in this group [2], Use of ozone is not essential for their formation, as they are also produced by dehydration of c cF-dihydroxy peroxides [3], A very few isomeric linear trioxides (ROOOR) are known, they are also explosively unstable. Inorganic ozonides, salts of the radical C>3 anion, are also hazardous. 

Photolysis Abiotic oxidation occurring in surface water is often light mediated. Both direct oxidative photolysis and indirect light-induced oxidation via a photolytic mechanism may introduce reactive species able to enhance the redox process in the system. These species include singlet molecular O, hydroxyl-free radicals, super oxide radical anions, and hydrogen peroxide. In addition to the photolytic pathway, induced oxidation may include direct oxidation by ozone (Spencer et al. 1980) autooxidation enhanced by metals (Stone and Morgan 1987) and peroxides (Mill et al. 1980). 

Ozone, 17 63 depletion, 46 109-110 fluoride, see Trioxygen difluoride Ozonide radical anion, chemistry, 33 76... 

Hydrogen abstraction by RH02 could also participate in the process of initiating a chain of thermal oxidation reactions (pathy). In aqueous systems, cations will further react by solvolysis, and superoxide anion will readily disproportionate to yield H202 (path i). This is in contrast to the fate of superoxide anions in ozonation advanced oxidation processes (AOPs), where they react primarily with ozone to produce hydroxyl radical. This description of the chemical pathways of UV/H202 oxidation of organics illustrates that, when oxygen is present, the major paths directly or indirectly create more... 

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