MP2019 - 18-7-2019 at 15:44
I live in Southern California. Recently an earthquake "inspired" me to buy some 5 gallon jerrycans. They had previously had sodium permanganate in
them. I found a formula for neutralizing the sod-per using 3 parts vinegar (5%), 3 parts hydrogen perozide (3%) and water. The most leftover sod-per
is a thin film on the inside of these cans.
The seller says (and he's in the chemical biz), that vinegar and water will neutralize the sodium permanganate.
I put half a gallon of vinegar and 1 gallon of water in the can. I will allow this solution to rest on all sides of the jerrycan by rotating it on
it's six sides.
How long does this reaction take? Minutes? Hours? Days? That is, how long should I let the vinegar solution rest on each side of the container before
rotating it?
[Edited on 19-7-2019 by MP2019]
mayko - 18-7-2019 at 17:27
I'm not sure I believe that vinegar will react with permanganate! I just started a test-tube reaction to check. Ethanol definitely will. Another thing
to consider is that the neutralizing permanganate (+7) means converting it to a manganese compound with a lower oxidation state, like manganese (+4)
dioxide or manganese (+2) acetate, so the manganese is still going to be there, and insoluble manganese dioxide powder might be harder to clean out
than soluble permanganate.
If it were me, I'd probably wash the cans out with small amounts of water. Permanganate is brightly colored so once the wash water is colorless you've
removed almost all of it. Then the wash water can be treated with a reducer like everclear, metabisulfite hombrew sanitizer, sugar, etc
MP2019 - 18-7-2019 at 17:45
Si como No?
From: https://www.ccc-chemicals.com/blog/permanganate-neutralizing...
about 2/3 down the page:
"Cleaning/Neutralizing Solution
This solution consists of products that can be purchased from a local food or drug store. This solution is especially effective for removal of brown
stains on skin; however, it has also been used as a neutralization solution for small spills. It would not be economical for anything but the smallest
volumes of dilute permanganate."
30 parts water: 40 parts white vinegar: 30 parts 3% hydrogen peroxide
Is this a mistake or inaccurate?
mayko - 18-7-2019 at 18:17
I had thought it might be the peroxide doing the work, but it's correct; there is manganese dioxide precipitating within ~15 minutes
happyfooddance - 18-7-2019 at 18:33
Wow. The manganese dioxide will be far more difficult to get out of a jerrycan than the NaMnO4. I would suggest dilute HCl but that isn't great for
steel.
Sulaiman - 18-7-2019 at 20:23
Sodium permanganate is water soluble so I would rinse, rinse, rinse ...
until there is negligible colour,
then fill the can with water and leave for a day.
If the water comes out colourless then you have finished.
A small ammount of sodium permanganate should cause no harm to you as it can be used to sterilise water,
but it can corrode a steel can, so I assume that your jerrycan is plastic ?
j_sum1 - 18-7-2019 at 21:08
Rinse. Rinse. Metabisulfite. Rinse.
MP2019 - 19-7-2019 at 10:12
Jerrycans are PET -polyethylene terephthalate. Blue in color.
Thank you all for your knowledge.
[Edited on 19-7-2019 by MP2019]
AJKOER - 26-7-2019 at 08:24
The reaction with acidified H2O2 is said to proceed as follows (see, for example, https://chemistry.stackexchange.com/questions/43256/why-is-t... ):
2 KMnO4 + 3 H2O2 → 2 MnO2 + 2 KOH + 2 H2O + 3 O2
The presence of H+ help moves the reaction to the right. The acetate may serve as a complexing agent..
As such, one may try a stronger acid than vinegar, like 'Lemon Juice', as sold in stores which is a mix of citric and ascorbic acid, and also serves
as a good complexing agent.
------------------------------------------------------------------------
I suspect an alternate process, albeit slower, but avoids the use/expense of H2O2, would be to employ O2 (from an air pump), vinegar, a very small
amount of sea salt and added iron filings (the finer the Fe powder, the faster the reaction, however, caution, likely induced iron contamination). The
introduction of turbulence from air flow along with the possible presence of sunlight (assuming some diffused light entering the plastic containers)
may also be beneficial (see https://advances.sciencemag.org/content/5/5/eaav7689 ).
[Edited on 26-7-2019 by AJKOER]
Herr Haber - 29-7-2019 at 03:33
Rinse, rinse, rinse and dont forget that KMnO4 can be found in surplus / survival store to... purify water !
So even if theres a few PPM left, maybe it's a good thing.