Oxidation of inorganic species

The amount of chloride ions produced after 3 min of sonication was 12.19 pmol. 

Another hypothesis for the generation of chlorine acids is related with the interaction of dissolved oxygen with water and CCI5 to produce phosgenium, which would then decompose to CO2 and CI2 at temperatures above 100°C [40]. 

Reactions involving OH- and H produced by water sonolysis may also yield chlorine acids from dissolved CCI4. However, this mechanism is less likely for the following reasons (1) the increased vapour pressure of CCI4 favours diffusion of these molecules into bubble cavities, (2) the energy needed to break a C-CI bond (73 kcal/mol) is lower than that for an 0-H bond in water (119 kcal/mol). Thus, aqueous solutions saturated with CCI4 that are sonicated for tens of seconds contain oxidant species such as those from reactions 7.2-7.4, or even CI2 formed as follows  

Ultrasound-assisted generation of iodine and other oxidized-iodine species from iodide 

Oxidation of iodide to iodine (Eo = -0.615 V) promoted by sonication was one of the earliest tests demonstrating the sonochemical effects on solutions. The following effects were detected in water-sonicated systems with and without CCI4 and (or) iodide  

Although Pb(IV) is sufficiently strong an oxidant to oxidise halides, no kinetic data are available. Complexes of Pt(IV) and Au(III) oxidise iodide and thiocyanate ions but the other oxidants are weaker and form stable halo-complexes. However, some simple molecules such as hypophosphorous acid, carbon monoxide and molecular hydrogen are oxidised by the weaker members. 

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OXIDATION OF INORGANIC COVALENT SPECIES 2.2.1 Halide ions... 

One major difference between the published accounts of oxidation of inorganic and organic species is the more prevalent use of non-aqueous solvents for the latter, which gives rise to several complicating features. 

The electron transfers in the oxidation-reduction reactions of organic compounds are not fundamentally different from those of inorganic species. In Chapter 7 we considered the oxidation of a reducing sugar (an aldehyde or ketone) by cupric ion (see Fig. 7-10a) ... 

Sulfate and Organic Sulfates. Inorganic sulfate ion (SO L-) occurs widely in nature. Thus, it is not surprising that this ion can be used in a number of ways in biological systems. These uses can be divided primarily into two categories (1) formation of sulfate esters and the reduction of sulfate to a form that will serve as a precursor of the amino acids cysteine and methionine and (2) certain specialized bacteria use sulfate to oxidize carbon compounds and thus reduce sulfate to sulfide, while other specialized bacterial species derive energy from the oxidation of inorganic sullur compounds to sulfate. 

Oxidation-reduction reactions of inorganic species can be described in many different ways. For example, hydrogen exhibits oxidation states of -1, 0, and +1. In acidic aqueous solution, these oxidation states occur in the half-reactions... 

In a review of the mechanisms of homogeneous reductions of inorganic species by tetrahydroborates, Hanzlik was able to compare the mechanism of the redox process proper with the homo- and hetero-geneous oxidation of alkali-metal tetrahydroborates.30... 

A number of inorganic species also absorb. We have noted that many ions of the transition metals are colored in solution and can thus be determined by spectrophotometric measurement. In addition, a number of other species show characteristic absorption peaks, including nitrite, nitrate, and chromate ions, the oxides of nitrogen, the elemental halogens, and ozone. 

Chemiluminescence methods are known for their high sensitivities. Typical detection limits range from parts per million to parts per billion or lower. Applications include the determination of gases, such as oxides of nitrogen, ozone, and sulfur compounds, determination of inorganic species such as hydrogen peroxide and some metal ions, immunoassay techniques, DNA probe assays, and polymerase chain reacrion methods.- ... 

To follow the environmental law and to remove small but sometimes persistent concentrations of pollutants activated carbons seem to be the media of choice. They are relatively inexpensive, easily to obtain, and owing to their enormously high surface area and pore volume, they are able to remove and retain even traces of air and water pollutants. Activated carbons, due to their unique surface chemistry act not only as adsorbents but also as catalysts for oxidation of inorganic and organic species. Moreover, their surface can be modified and tailored toward desired applications. 

Figure 7.5. The reduction and oxidation sequence in soil solutions at pH 7. Theoretical potentials are indicated by solid lines, assuming equal activities of reduced and oxidized species unless otherwise noted (the pressure of H2 is arbitrarily set at 10 atmosphere). Measured ranges of soil potentials over which the indicated species react (change concentration) during soil reduction and oxidation are specified by boxes (shaded for reduction, open for oxidation, black for initial appearance of the reduced form during reduction). (Data, in part, from W. H. Patrick and A. Jugsujinda. 1992. Sequential reduction and oxidation of inorganic nitrogen, manganese, and iron in flooded soil. Soil Sci. Soc. Am. j. 56 1071-1073.)...

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