Oxygen dissolved, reduction

Because of its significance to fuel cell technology and air-depolarized batteries, the cathodic reduction of oxygen dissolved in aqueous electrolytes has been the subject of numerous mechanistic studies. They had been reviewed repeatedly (103-111), and today the mechanistic details are well... 

We use water quality indicators, such as pH, temperature, conductivity (specific conductance), dissolved oxygen, oxidation-reduction potential (ORP), and turbidity, as groundwater well stabilization parameters. Stable values of three consecutive measurements of these parameters are considered an indication of a stabilized well. 

It has been found that the viscosity of water in microcells (micropores) is by an order of magnitude higher than that of common free water and is about 10 cps in the temperature range from +10 to -6 °C (the effect of oxygen dissolved in free water which leads to a two-fold reduction of was taken into account). In macrocells at 0—10 °C, the water viscosity is 2 cps and at temperatures below -4 °C,about 4cps ... 

Because of the nonreversibility of the biological mediation of the NO, N, conversion, the NOt -N2 couple cannot be used as a reliable redox indicator. For example, NOj may be reduced to N, in an aquatic system even if the bulk phase contains some dissolved oxygen. The reduction may occur in a microenvironment with a pe value lower than that of the bulk, for example, inside a floe or within the sediments the N2 released to the aerobic bulk phase is not reoxidized although reoxidation is thermodynamically feasible. 

The oxidation of Cr(III) to Cr(IV) by oxygen dissolved in water is very slow and takes place only in alkaline media. On the other hand, reduction of Cr(VI) in natural waters by bivalent iron is possible especially in acid media and by sulphites and hydrogen monosulphide. The maximum concentration of Cr(VI) in drinking water permitted by the World Health Organization is 0.05 mg. ... 

Hydrogen sulphide and its ionic forms are labile in waters since they can be oxidized to sulphates via chemical or biochemical reactions. In waters they can occur permanently only in anaerobic media and therefore they are evidence of reduction processes taking place in such waters. Chemical oxidation of hydrogen sulphide by oxygen dissolved in water is a very com-... 

Redox conditions Conditions defined by the presence of either dissolved oxygen or some other species capable of providing oxygen bioactivity (reduction—oxidation). 

The reactions taking place at the corrosion cells may be described by the following equations. The primary cathodic reaction is the reduction of oxygen dissolved in the electrolyte film ... 

The solute oxygen content is of primary importance as a component influencing the corrosion behaviour of most metals in seawater. The solute oxygen content can either increase or inhibit corrosion. In nearly neutral aqueous salt solutions, i.e. in seawater as well, the reduction of solute oxidants is the principal cathodic reaction step. The cathodic reaction step in corrosion of metals in seawater is the reduction of the oxygen dissolved in the water as per this formula... 

Metal corrosion usually consists of anodic metal dissolution and a compensating cathodic process like hydrogen evolution or the reduction of dissolved oxygen. The reduction of other oxidants, like Fe, HNO3, or dissolved CI2, are further examples of compensating processes. These processes... 

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