I am not a chemist but I have a question regarding electrolytes in electrolysis. I have done a lot of reading but cannot find the answer I'm looking for regarding Sodium Sulfate (or Sulfide)
I intend to clean a film off a Stainless Steel plate, so that will be my cathode.
For my Anode I will be using a Platinum coated Titanium plate.
At a small scale I have been using Sodium Carbonate (Na2CO3) and it has worked fine, however I intend to scale it up to ~1m^2 plates for the Anode and Cathode, as well as 150A @ 15v DC for ~3min in Deionised water with many repeats, so temperature rise of the water should also be accounted for.
I would like to make this as safe/clean as possible and am considering switching out the electrolyte at this stage to something more stable. I have read that Sodium Carbonate can precipitate directly onto the electrodes at high currents. I believe this is not an issue with Sodium Hydroxide but want to avoid that for obvious reasons. I have stumbled upon Sodium Sulfate as an alternative but very little information on its breakdown and potential pollutants. Is there any other that I am missing/suggestions?
I will be using a fume hood, however Sodium Chloride is definitely not an option.
Thanks for your time,
So I have done some reading and have mostly worked out the half equations of Sodium Sulfate (Na2SO4):
Cathode: (2)H+ + (2)e- -> H2(g)
Anode: (2)O2- -> O2(g) + (4)e-
Remaining in aqueous solution: NaOH (aq) + S (?)
As an update then, can I ask what, if anything, happens to the NaOH and Sulfur? Also, what form will the Sulfur remain in? I assume it will try to re-bond with oxygen, which will be abundant in the system? Will either be outgassed?
Assuming the NaOH is constantly building up, at what point does it become overwhelming in the system and need to be removed?
Thanks so much for reading this far.