The corrosiveness of sodium persulfate solution
Thread Content
Dear experts and colleagues: Recently, the factory used sodium persulfate solution (Na2S2O8). During the pilot test, 30% sodium hydroxide solution was first added to a common diesel barrel, and then sodium persulfate solid was poured into it. The concentration was about 25%, and then iron filings were used to stir and mix. However, within half a day, both the diesel barrel and the iron shovel corroded. As shown below. Our factory also plans to use carbon steel to store these solutions. Is sodium persulfate very corrosive?
The corrosion is very serious. Alkali will not corrode carbon steel. It is mainly sodium persulfate or the substances produced by the reaction with alkali that are corrosive.
It should be possible to use an enamel reactor with stirring. For additional storage, you can use plastic-lined storage tanks or plastic storage tanks.
Thank you for your reply. Do you think sodium persulfate is corrosive to carbon steel?
Check the pH of sodium persulfate in water. Does it hydrolyze or not?
This post was last edited by qugd on 2019-8-5 16:53 Sodium persulfate is a strong oxidizing agent. Under alkaline or acidic conditions, its oxidizing properties are equivalent to free oxygen. But its corrosiveness to metals should not be very strong. Judging from the poster's picture, there should be other causes of corrosion in the system, but the corrosion is accelerated by the action of sodium persulfate. Also, what is the equivalent concentration of each in the system that the poster mixed? If the amount of alkali is insufficient, the system will become highly acidic after sodium persulfate decomposes and releases oxygen. Refer to the following reaction equation: Na2S2O4 + H2O ===> 2NaHSO4 + 1/2O2. When the amount of alkali is insufficient, the system will become sulfuric acid acidic. I personally think it should be the reason I mentioned later.
Thank you for your reply. In the presence of sodium hydroxide, will it react with the sulfuric acid produced by the hydrolysis of sodium persulfate, thereby continuously promoting the reaction to proceed in the forward direction?
Generally, sodium persulfate reacts with sodium hydroxide to form sodium sulfate, which generally does not corrode carbon steel. However, the sodium bisulfate produced by the reaction of sodium persulfate with water is an acidic salt that corrodes metals. Therefore, when there is more sodium persulfate than alkali during the solution preparation process, it will hydrolyze into sodium bisulfate and corrosion will occur.
Yes, alkaline conditions will promote the decomposition of sodium persulfate, new ecological oxygen will precipitate, and the solution system will be acidic when the alkalinity is insufficient. When sodium persulfate is added with alkali, the pH value of the system can be monitored to ensure that the system is obviously alkaline, which can reduce the degree of corrosion.