Author Topic: Brown scum  (Read 5134 times)

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Brown scum
« on: July 11, 2010, 16:14:58 pm »
Many people experimenting with electrolysis have experienced the formation of brown particles in form of flakes. I've heard that this may be chlorine or other harmful chemicals.
Our tapwater or well water does not contain chlorine in considerable amounts but the brown scum forms nevertheless, so what is this stuff?

My guess is that it's indeed rust (iron ions), but they do not come from the stainless steel used, they come from the water, which contains iron. tap water here contains between 0.2mg/l and 0.5mg/l iron, mineral water does contain iron in even larger quantities, if it's not de-ironed. When this water stands for a longer time, it will look like this:
Larger amounts of iron particles have sunken onto the ground.

Now i have various clues that it may indeed be iron:
  • Optical impression does match that of the flakes
  • Flakes sink onto the ground (at least in my dry cell where i can watch the process)
  • Brown particles are at the positive electrode, but not at the negative (rust is Fe2+, which is created out of Fe. The equation is Fe -> Fe2+ + 2e-. The positive electrode 'absorbs' electrons, so the reaction would make sense if it happened at the positive)
  • Plates seem unharmed and shiny as before

  • I thought it may be important to know that probably the visible by-products of electrolysis in drycells/tubecells/... are not necessarily harmful for humans or material.

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    Re: Brown scum
    « Reply #1 on: July 11, 2010, 16:31:58 pm »
    HI Haithar,

    That was my conclusion with my tube cell and tests with distilled water and tap water.  Distilled water remained clear while tap water precipitated reddish particles.  The particles in my case would float until disturbed and then would coagulate and fall to the bottom.  My "processed" tap water would maintain a reddish tint after filtration.  It is an eye opener to see what is hidden in tap water.


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    Re: Brown scum
    « Reply #2 on: July 11, 2010, 18:23:08 pm »
    Stan says rain water is ideal in the tech brief somewhere... talks about the evaporation process removing most of the contaminates, its also natural water... which he says a lot. and its free.

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    Re: Brown scum
    « Reply #3 on: July 12, 2010, 08:09:49 am »
    rainwater in most cities is far more "contaminated" then you may think... You know that fresh air smell once it has rained??? that is because the rain has "absorbed" most of the toxins out of the air. Most of these are filtered out or diluted (adding underground/fresh water to it so that it is at a more "satisfactory" level). This is more apprent in cities, the larger the worse the effect. Then ontop of that there is also all the garbage that it picks up when it runs off. Far less "natural" then you thought. Properly distilled water should have the best effect buy removing most of the "heavy" minerals that is in our water.
    Side note the biggest differnece you will find is that there is less salt in rain water than in tap water.