Solubilities of oxygen and hydrogen

FIGURE 9.3-1 Solubility of oxygen and hydrogen i produced from Pray et al,1)... 

As reported in literature the diffusivity and solubility of oxygen and hydrogen in phosphoric acid depends on the temperature and concentration [148-152]. Furthermore, it was suggested that the diffusivity and solubility exhibit exponential reciprocal temperature dependence. Various polynomial functions were used to correlate these properties with experimental data (Table 18.3). 

At the present time, sodium purification technique with the use of cold traps based on decreasing solubility of the major part of impurities in sodium with temperature decrease has found the most wide practical application [5.3, 5.4]. In the cold trap sodium is cooled within the settling tank and the section upstream the filter. This results in reduction of oxygen and hydrogen concentrations respectively to 1 and 0.05 ppm. Cold trap is capable of retaining impurities in amount up to -30% of its volume [5.5]. 

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]. 

Carotenoids are lipid-soluble terpenoids derived from the isoprenoid pathway and are located in hydrophobic areas of cells. All have a 40-carbon isoprene backbone with a variety of ring structures at one or both ends (Fig. 8.2) [25]. The carbon skeleton is derived from five-carbon isoprenoid groups and contains alternating conjugated double bonds. There are two kinds of carotenoids (Fig. 8.2) carotenes composed of carbon and hydrogen and xanthophylls composed of carbon, hydrogen, and oxygen. 

Three anodic partial reactions are considered active dissolution of two metals M and M with different kinetics in the absence of their ions in bulk solution and decomposition of water with the evolution of oxygen. The kinetics of the latter process is so slow on most corroding metals that only at very negative potentials can oxygen present in the solution be electroreduced and this eventually becomes limited by mass transport due to the limited solubility of oxygen in water. At even more negative potentials, hydrogen evolution takes place on the electrode surface. The cathodic reduction of some metal ions present on the electrode surface as a consequence of corrosion is also considered in Fig. 13(b). 

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