Abstract
In the process of sea water distillation, the concentration of the dissolved oxygen (DO) in the circulating brine is decreased, in ordinary cases, to be 10μg/l in order to prevent the corrosion of metallic materials in the plant. Trace amounts of DO are usually determined by Winkler method. This chemical method is interfered by the oxidizing and reducing substances of samples.
In the present study, the influence by ferric, ferrous, cupric, nitrate, and nitrite ions on this analysis and the preventive measures for them were examined in deionized water samples. The results obtained were applied to sea water samples.
The interferences caused by ferric, ferrous, and nitrite ions could be eliminated by adding phosphoric acid,o-phenanthroline hydrochloride, and sodium azide, respectively. The influences of cupric and nitrate proved to be negligible. An apparatus was developed for the preparation of water and sea water samples containing trace amounts of DO.
