RU_KLO - 6-12-2022 at 08:06
Hi,
I need ammonium sulfate and have an excess of Persulfate.
I know that ammonium sulfate is cheap and readly available, but as stated I have a lot of persulfate (and probably it will decompose over time)
1) Is there a way to get Sulfate from persulfate?
or
2) maybe I could use persulfate instead of the sulfate. (using half as sulfate needed)
It will be used in an electrolytical cell for Manganse production .
("The optimum catholyte manganese concentration is 12 g/L. A lower manganese concentration resulted in a lower current efficiency. A higher manganese
concentration (above 15 g/L) resulted in precipitation of manganese hydroxide and then a lower current efficiency. An optimum ammonium sulfate
concentration is around 125 g/L (Araujo et al., 2006). In the industry, the ammonium sulfate concentration ranges from 130 to 150 g/L. Due to
diffusion and migration of ions, the ammonium sulfate concentration is 20 to 30 g/L higher in the catholyte than that in the anolyte or in the feed."
Source: Electrolytic manganese metal production from manganese
carbonate precipitate - Jianming Lu a,⁎, David Dreisinger a,b, Thomas Glück
"The actual function of (NH4)2S04 as an aid in the deposition
of manganese from sulphate solutions is not clearly understood.
S. M. Sheltonl,3 claims it reduces the ohmic reSistance of the
electrolyee. Fink and Kolodney state that the salt prevents the
precipitation of Mn(OH)2 which would reduce the hydroxyl ion
concentration and make the catholyte acidic.
However, results have shown that the addition of (NH4)2S04 improves the deposit of metallic manganese and reduces the rate of brown preoipitation."
Source: 5-1-1939 - Electrolytic Manganese - George T. Derana
Thanks
Bedlasky - 6-12-2022 at 22:28
Don't use ammonium persulfate as electrolyte. Persulfate oxidize Mn2+ to MnO4-. And it will damage your electrodes (I suppose you don't plan to use
gold or platinum electrodes).
Boiling aqueous ammonium persulfate for a long time should convert it to ammonium sulfate and oxygen. But this will be surely tedious and it take
quite a long time to decompose all persulfate to sulfate. Buying ammonium sulfate will be not just cheaper, but also much more less time consuming.