I am using glass wool in a funnel to filter KMnO4 solution i made to get rid of impurities like MnO2 etc.
After filtration is done i have a glass funnel with a dirty glass wool filter. It looks near black due to KMnO4 solution still being there. After washing it out with DI water I have the filter wool at different stages of brown, depending how many times i filtered KMnO4 solution through it. I can clean it up and get the glass wool back to white by use of dilute Oxalic or sulphuric acids. Oxalic acid seemed to do a better job.
My question is this:
1.When my KMnO4 solution is properly filtered, should i expect the glass filter to wash up to pure white with just water?
2. Since sulphuric acid cleans the filter better than just water I am guessing i still have contamination getting caught by the filter, hence indicating that further filtering of KMnO4 solution is needed. BUT since Oxalic acid cleans the filter better than sulphuric, i am left to wonder if the "remaining dirt" is just KMnO4 which is getting reduced by oxalic acid rather than impurities. Which brings me to the first question about being able to clean filter with just DI water if the solution being filtered is "clean".
Thanks ahead