dann2 - 25-9-2011 at 12:53
Hello,
Has anyone any ideas on how to control the pH of a Perchlorate cell.
Adding Perchloric acid would be the ideal solution but I don't have any. I could of course make some in the future. By making and adding it to the
cell you will end up with the same amount of Perchlorate in the long run. Adding HCl acid has the disadvantage of adding Chloride to the cell which I
would rather avoid. I don't know how much Chloride there is in the cell at the moment. There cannot be much as it has a very high concentration of
Perchlorate and not much Chlorate.
Someone suggested adding Sodium Hydrogen Carbonate (bread soda). Would this do the job? You will get CO2 going off as gas, you are adding some Na ions
(not a problem) and pH will decrease.
Perhaps it would be feasible to make some dilute Chloric acid for the job?
The current effeciency of the cell doe's not change with pH but I have read that the higher the pH the more erosion on a Lead Dioxide Anode. My cells
are currently running at 11.5
I have no idea how much it takes to reduce and keep the pH at around neutral.
Cheers,
Dann2
plante1999 - 25-9-2011 at 13:11
Chloric acid is HClO3... Ading acetic acid should do the job , it will goes as CO2.
dann2 - 25-9-2011 at 18:48
Can't use Acetic acid as I will end up with Acetate in the cell which will appear as Sodium Acetate at the end of the day.
I was totally wrong in suggesting Sodium H Carbonate as that will raise the pH, I need to lower it.
I added some Sulphuric acid to the cell and got a precipitate. Lead Sulphate I presume 
I will have to get rid of all the Lead and proceed with Sulphuric acid. Sulphate is said to raise CE anyways as per the link.
http://www.oxidizing.110mb.com/chlorate/further/jes_aug_61.p...
Dann2