Can Electrochemical Degreasing be Affected by Chlorides and Soap?

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Contamination of the electrochemical degreasing bath by chlorides or soap negatively impacts the degreasing process by reducing the effectiveness of alkaline cleaners like sodium hydroxide. Chlorine production instead of hydrogen or oxygen alters the chemical reactions, leading to the formation of soluble compounds that do not assist in removing grease. The current primarily causes water electrolysis, producing hydrogen or oxygen, but may also facilitate additional reactions with grease, enhancing surface cleaning. The presence of chlorides can interfere with the bath's ability to react with contaminants, ultimately decreasing degreasing efficiency. Understanding the electrochemical series is crucial to predict which reactions will occur first and how they affect the overall process.
roadrunner1994
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Hi,
Why contamination of the bath for electrochemical degreasing by chlorides or soap adversly affects degreasing of parts?
What's the difference if chlorine is produced instead of hydrogen or oxygen? I thought that this gases only help the grease to break away from the part's surface.

I'm really courious about mechanism of degreasing. Does the current only cause water electrolysis which results in hydrogen production in cathodic degreasing or oxidation of hydroxyl ion which results in oxygen production in case of anodic degreasing? In this case degreasing process is exactly the same as in chemical degreasing except that produced gases helps the grease to break away from the surface.
Or does the current cause any additional reactions with grease which helps to clean the part's surface?
Thanks for your help!
 
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I would expect the tank to contain an alkaline cleaner such as sodium hydroxide. That will react with contaminants such as chlorine or a polar detergent. Such a reaction will reduce the availability of the alkaline cleaner.

https://www.researchgate.net/publication/332192238/figure/download/tbl1/AS:743977351393288@1554389431909/Composition-of-degreasing-solution-and-process-parameters.png
 
Thanks, I understand the chlorine will react with bath constituents which mostly gives us soluble compunds which will dissociate on ions, right? So we are back to square one and we have chlorides in the bath again.
So is the decrease of the degreasing efficiency due to the fact that the bath ingredients are constantly reacting with chloride or chlorine instead of reacting with grease and surface contaminants?
 
You will need to study the electrochemical series to identify which reaction will take place first, at the lowest voltage. Where does the current flow ?
I suspect the oil on the metal surface is being broken down into a hydroxide sludge or soap, that then floats to the surface and can be skimmed off. Will that reaction continue in the presence of NaCl ? Will chlorine be released as a gas into the workplace ?
 

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