Health hazard from using stainless steel electrodes for electrolysis

[ta89742379]

Hi everyone! I have a question about making large amounts of hydrogen and oxygen via electrolysis.

If you use (passivized) stainless steel plates as electrodes and potassium hydroxide as electrolyte, you risk making small amounts of chromate. So of course the electrolyte solution has to be handled as hazardous waste.

But what about the yielded gas? Should you worry about tiny amounts of chromate particles polluting the hydrogen and oxygen gas?

Thanks!

[ChenBeier]

The stainless steal contains chromium metal. To get Chromate you need strong oxidising of the chromium. This is in aqueous solution not possible. It would work if you have molten KOH and only at the anode.
So don't worry there is no risk to get these during electrolysis.

[Benzene]

When potassium hydroxide (KOH) and stainless steel plates serve as electrodes in water electrolysis, they could form potentially a chromium compound.
The passivation of the stainless steel plates creates a protective layer of chromium oxide that prevents corrosion. The chromium layer is a natural barrier that prevents K^+, OH^-, and H^+ ions from penetrating the plates.
KOH in solution does not react with the electrodes to form the chromium compound mentioned above. Caustic potash removes grease, oil, and other substances from stainless steel surfaces without any surface damage.
The pH of the solution is very high, around 13–14, making the formation of the chromium compound almost impossible.The electrode passivation and the high pH value during electrolysis make KOH insignificant.