Solubility of oxygen

The solubility of oxygen in water with a salt content up to 1 mol L is only dependent on the temperature. The oxygen concentrations in equilibrium with air amount to (in mg L- ) 0°C, 14 10°C, 11 20°C, 9 and 30°C, 7. The depth of water has no effect in the case of ships. In Hamburg harbor in summer, 7.3 mg L are measured in depths up to 7 m. The value can be much lower in polluted harbors and even fall to zero [8]. In the open sea, constant values are found at depths of up to 20 m. With increasing depth, the Oj content in oceans with low flow rates decreases [12] but hardly changes at all with depth in the North Sea [13]. 

At elevated temperatures where titanium alloys could be the adherend of choice, a different failure mechanism becomes important. The solubility of oxygen is very high in titanium at high temperatures (up to 25 at.%), so the oxygen in a CAA or other surface oxide can and does dissolve into the metal (Fig. 12). This diffusion leaves voids or microcracks at the metal-oxide interface and embrittles the surface region of the metal (Fig. 13). Consequently, bondline stresses are concentrated at small areas at the interface and the joint fails at low stress levels [51,52]. Such phenomena have been observed for adherends exposed to 600°C for as little as 1 h or 300°C for 710 h prior to bonding [52] and for bonds using... 

Arctic Drilling. Corrosion problems encountered in arctic area drilling are no different from problems faced in other areas of the world. It is a general misconception that during arctic drilling corrosion-related problems are either not very severe or totally absent due to low temperatures. Cool temperatures may slow down the corrosion process. However, they also increase the solubility of oxygen, carbon dioxide and hydrogen sulfide. Therefore, the net result can be an increase in the rate of corrosion. While cold temperatures may cause problems, the temperature fluctuation common in arctic environments can be a more severe source of corrosion-related problems [215]. 

Dissolved oxygen reduction process Corrosion processes governed by this cathode reaction might be expected to be wholly controlled by concentration polarisation because of the low solubility of oxygen, especially in concentrated salt solution. The effect of temperature increase is complex in that the diffusivity of oxygen molecules increases, but solubility decreases. Data are scarce for these effects but the net mass transport of oxygen should increase with temperature until a maximum is reached (estimated at about 80°C) when the concentration falls as the boiling point is approached. Thus the corrosion rate should attain a maximum at 80°C and then decrease with further increase in temperature. 

The solubility of oxygen in water is influenced by several factors but, generally, most waters contain, at equilibrium, about 8mg/kg at 25°C, although supersaturation may increase this considerably. Some indication of the amount of dissolved oxygen relevant in different situations is shown, on the one hand, by the value of 0-1 mg/kg found in central heating systems and, on the other hand, by the value of 0 005 mg/kg specified by most users of large boilers as the upper limit at the economiser inlet (see Section 5.5). 

Table 21.20B Solubility of oxygen in certain electrolyte solutions ...

Let us assume the solubility of oxygen does not affect on C or kLa, the factor affected on the oxygen uptake rate that is 12.5/3 = 4.167, then xmm is ... 

Gas and liquid systems are explained by solubility. The solubility of oxygen at room temperature is about 10 ppm therefore the concentration of oxygen is 10 ppm (oxygen flux, Na). The solubility of oxygen at 0 °C is double that at 35 °C. Also, the solubility decreases if the electrolyte concentration is increased. The concentrations of oxygen in the gas phase and liquid phase are related to each other by the Raoult-Dalton equilibrium law. 

NOTE The proportionality constant k is reduced with increase in temperature. Under these hot DA conditions, the solubility of oxygen is very low (as per Henry s Law). 

FIGURE 8.21 The variation of the molar solubilities of oxygen, nitrogen, and helium gases with partial pressure. Note that the solubility of each gas doubles when its partial pressure is doubled. 

Self-Test 8.7A At the elevation, 2900 m, of Bear Lake in Rocky Mountain National Park, the partial pressure of oxygen is 0.14 atm. What is the molar solubility of oxygen in Bear Lake at 20.°C ... 

The same rate must be found when the rate is expressed as kiAiCfj, where a is the solubility of oxygen in water at 20°C and 1.018 atm. Henry s law... 

In contrast to the fire refining of copper, where the oxidation stage needs to be followed by a deoxidation step, no deoxidation step is necessary in the fire refining of lead. This is because the solubility of oxygen in liquid lead at typical refining temperatures is quite low (2 10 2 to ltT1 at-% at 600 to 700 °C). 

Example Calculate the solubility of oxygen in water at ambient conditions. Assume air-water contact at 20°C (68°F) and sea level (1 atmosphere). 

When the contaminated zone is located below the water table, the availability of oxygen becomes a critical problem due to the low solubility of oxygen in water. In adding the required oxygen, two kinds of systems are usually applied ... 

Because of the high water solubility of oxygenates, groundwater extraction may be effective in removing a significant mass of these contaminants. Key factors that affect the performance and cost of the extraction component of a pump-and-treat system include... 

Windrem, D. A. and W. Z. Plachy. 1980. The diffusion-solubility of oxygen in lipid bilayers. Biochim. Biophys. Acta 600 655-665. 

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