Spray aeration method

The spray aeration method comprises a grid network of piping and nozzles over a pond or basin. Contaminated water is simply sprayed through the nozzles and into the air to form droplets. Mass transfer of the contaminant takes place across the air-water surface of the droplets. Mass transfer efficiency can be increased by multiple passing of the water through the nozzles. This method has three disadvantages ... 

There are many methods to introduce fresh air for air stripping, including diffused aeration, tray aerators, spray basins, and packed-towers methods. 

Aeration. In a water system that uses this method, there are huge nozzles near the reservoirs that spray the water into the air as if they were tremendous fountains. As the nozzles break the water into small droplets, they also expose... 

Chemicai reduction of ionio mercury. In 1963 Poluektov and Vitkun reported an increase in the sensitivity by about one order of magnitude, when Sn(ll)-containing mercury solutions were analyzed according to Lindstrom (1959). They associated the increased sensitivity with the reduction and release of Hg(0) from the test solution, which was introduced through a spray chamber. Poluektov et al. (1964) presented a "cold vapour" AAS method with the spray chamber and the flame replaced by an aeration vessel, where Sn(ll) was added to a defined volume of sample solution, and the liberated Hg(0) was carried by an air stream to a gas cell. The principle of aeration was, in fact, the same as was utilized by Kimura and Miller (1962) for sample clean up prior to colorimetric determination. 

Chemical and Corrosion Resistance The corrosion resistance of CCCs depends on thickness and coating age. Corrosion resistance has been observed to scale with total chromium content [153]. Some studies have found that corrosion resistance does scale with Cr(VI) content [154], while others have found no such correlation [155]. Corrosion resistance is evaluated by continuous or cyclic accelerated exposure testing and electrochemical methods. On aluminum alloys, heavy CCCs will resist pitting for as long as 400 to 1000 h [156]. CCC-coated surfaces will exhibit total impedances of 1 to 2 Mf2 cm after exposure to aerated 0.5 M NaCl solution for 24 h. Such coatings can be expected to withstand 168 h of salt spray exposure without serious pitting [157]. CCCs usually perform well in mild neutral environments, but do not fare as well under... 

Fig. 22-2a shows some of Wrobleski et al. s results for P(ANi)-Tos before and after 12 weeks immersion exposure in aerated 3.5% NaCl. More importantly, these workers confirmed the prediction of Jain et al. [938] that scratches of significant width were protected. This is seen in the results of immersion for 8 weeks in aerated 0.1 M HCl shown in Fig. 22-2b. These authors also confirmed their results with other methods such as Salt Spray For and electrochemical methods.

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