I need to know the method of water purification of double destilation with MnO4K. Could anybodie help me?

I don not know this method, but permanganate and sulfuric acid are used to oxidize organic compounds. If you look in an old USP or the current Japanese Pharmacopeia under water, you will see a test for determination organic compounds in water by the decolorization of permanganate. My guess would be that you add the permanganate to the water and then distill. The permanganate should stay behind, but the water, minus any organics, would distill over.

Chris is correct, the permanganate is added to oxidize any organics present. I have used this in the past, but I found the permanganate quickly expired. A better reagent is dichromate/sulphuric acid. Be aware that, unless measures are taken to reduce the carry over of aerosols from the still, you will find highish (>10ppb!) levels of sulphate, etc. in the distillate. Be careful that heating elements can take this treatment.
For completeness, permanganate is used to assess the oxygen requirement of a water sample to oxidise those organic (and I suppose inorganic) species able to be oxidised with this reagent, and is expressed as the 'permanganate value' or 'pv'. The dichromate/sulphuric acid mixture is used to do the same thing for contaminated water samples, etc. and is called the 'chemical oxygen demand' or 'cod'. It is also the reaction that occurred in the little orange tubes used by various police forces to assess alcohol content of breath samples, turning orange dichromate to green chromate, its a pity it was that way around, but natures funny that way!
Cheers
Bryan

Thanks a lot. In Journal of Chrom.Science (1977) was publicated this method to eliminate organic contaminants in water for HPLC gradients. I have problems with water supply and can't find this paper to assay that.
Thanks

while the other responses answered part of the question of what permanganate does, they did not answer your question of what/how of double distilled water. For a reference see Kolthoff,Quantitative Chemical Analysis page 449 or about any other very old analytical book.

The first distillation from alkaline permanganate removes ammonia , dissolved solids and organic stuff capable of being oxidized by alkaline permanganate, a very potent oxidant. after the addition of a small amount of sulfuric acid, the second distillation removes last traces of ammonia and base carried over in mist from first distillation.

Now you see why Millipore sold bunches of water purification units that replaced this procedure.

Thanks a lot everybody