Is it possible to clean used activated carbon

Discussion in 'Advanced Techniques' started by sky valley, May 12, 2008.

  1. sky valley

    sky valley Registered+

    I was wondering if it was possible to "wash" old or used activated carbon in a solution to clean it, so that it can be reused again? Thanks

  2. JaySin

    JaySin Registered+

    Pretty sure it's not possible. I think it actually chemically reacts, which is what neutralizes the smell. So in order to "clean" it you would need to chemical re-activate it. I think that would be more work then it is worth.
  3. stinkyattic

    stinkyattic CultiModerVatorAtor

    Yes. You can bake it off in a kiln at very high temperatures- in excess of 800'C. Know a potter? More specifically, know a potter whose kiln is in a spot where a severe case of two-skunks-fucking-stank wafting out of a warming kiln won't arouse suspicion? ;)
  4. sky valley

    sky valley Registered+

    Yes as matter of fact I blow glass, and shape metal in my kiln. So I will try it. Miss Stinkyattic would you khow how long and at what temp would that be needed? Thanks for the help Stinkyattic:thumbsup:
  5. deleafer2220

    deleafer2220 Registered+

    I was told by gardener that you just have to boil carbon to reactivate it...same way they do water purifiers..I know this is a old thread..but might help in future
  6. emilya

    emilya Future Dispensary Owner

    I searched for this thread because of a conversation going on today, and I am surprised that I had not responded to this yet. I wrote a piece on another forum sometime back about this and it seems that I neglected to post it here too. Next week when I get back to my archive, I will try to find the pictures showing how I drilled out the rivets and was able to re-activate my 16 pound commercial inline filter.

    To briefly describe the process, you simply dump all the charcoal into a couple of 5 gal buckets and then you flush them. The first several times you add water to the half a bucket of charcoal, it will boil and stink and throw off some of the nastiest stuff you have ever seen, and using a garden hose I send this down the driveway. I keep adding clean water and stirring until all the reaction stops... and with some well used charcoal, it takes a while and a lot of water to get to this point.

    Now put the charcoal in a large pan (I used a throw away turkey roasting pan) and put it in the BBQ at 500 degrees for about 20 minutes. You need to get the charcoal hot enough to drive all the water out and open the surface again, and it will go from being shiny to a dull sheen as it cools.

    You have just cleaned and re-activated your charcoal. You will lose a little bit of the charcoal in this process, so buy a pound or so from Amazon, and you will have enough for 2 or 3 years. Your old used filter will work as good as new for about another year after this, when you can simply repeat the process and go again.

    I hope this helps. When I learned of this process I was happy to buy my second (and last) carbon filter unit, so that I could always have a clean one ready to go when I needed it.
    • Like Like x 5
  7. GigaBud

    GigaBud Registered+

    As usual Emmie is giving up great info......!
  8. SSDIPainGuy

    SSDIPainGuy Registered+

    Em is like a momma bird, she continually takes in great knowledge, chews it up, then spits it back into our mouths so we can grow into master gardeners like her. You go girl lol
    • Like Like x 1
  9. SSDIPainGuy

    SSDIPainGuy Registered+

    Unless you have a large operation, it's probably more economical to just get a new jug of carbon for $10 or so. By the time you take your time, the electric or gas needed to boil the water etc I'm sure you're over the cost of the carbon. Just my thought, have a good one guys
  10. emilya

    emilya Future Dispensary Owner

    let me clear up one point... you dont boil the water. You simply run the garden hose in the half bucket of used carbon and it will begin to off gas all that it has absorbed. it does produce some heat, but you do not apply anything but water. Yes, it takes a bit of LP gas to heat up your BBQ to 500 degrees for 20 minutes, but its not too bad and I am sure comes in under $10. Then you don't waste 16 pounds of perfectly good carbon either.
    • Like Like x 3
  11. piercedc

    piercedc Registered+


    lol, I am going to try it and post my results! I am NOT doubting you but I was just wondering about this and have no knowledge on the subject so I searched just now. So here I am and have 3 filters(one in use). I will wash, cook and BBQ some used carbon then post the results. I AM NOT ON MUCH so it might be a few days till I post again but I will.
    Thanks in advance or not. :D
    • Like Like x 1
  12. SSDIPainGuy

    SSDIPainGuy Registered+

    Not having to boil it, then I'd give it a shot. I agree, why throw it out
  13. QueenGreen

    QueenGreen Registered+

    Same rough Process I used for my fish tank carbon 19 years ago. I just rinsed and then baked at 500f very close to what EM put out there, just different tools. :0)
  14. piercedc

    piercedc Registered+

    ok, I have one filter torn apart and rinsed the charcoal several times. Holy bat-turds, that was some nasty looking stuff on the first rinse. Blackish-brown with what SEEMED like a oily sheen to it. All follow on rinses were blackish in color without the oily look. Makes me think I am losing charcoal, no? The cloth filter liners rinsed out the same color but not as bad. Might go try to find a cheap a/c filter to make new liners with. More to follow later.
    • Like Like x 1
  15. emilya

    emilya Future Dispensary Owner

    you do lose about 1-2% of your charcoal in the process. I bought a pound of the stuff from Amazon and have used a bit of it each time to fill in the gaps.
  16. DirtyBlueGene

    DirtyBlueGene Registered+

    If you don't mind me asking, could you give me an estimate of the layer thickness of charcoal, in a factory made inline filter?
    Being for the most part broke, I went with a DIY and created a .5 inch thick cylinder
    wall, which seemed to work well. I'm just curious about the ideal thickness of the layer. TIA :)
  17. emilya

    emilya Future Dispensary Owner

    im guessing about 5 or 6 inches?
  18. DirtyBlueGene

    DirtyBlueGene Registered+

    Wow! I would not have expected that, thanks. I may have to rethink the whole DIY thing, lol.

    Though my homemade unit, served me well, in a very small 2 plant scrog. :)
  19. MichiGreen

    MichiGreen Registered

    I did something similar even prior to reading this post... I opened up a carbon filter and poured the carbon pellets into a pot of water. Boiled it for an hour or so until there were no more bubbles coming from the pellets. (I did this in the kitchen and found that the steam coming off did not have carbon making the kitchen black.) Then drained it and used a turkey pan on the grill to dry the pellets.
    QUESTION: The rinse water had a bunch of carbon powder in it... I poured it on my fire pit outside, and then wondered if I should have saved it to add 10ml/gal or so to compost tea. Would this be a beneficial thing for the soil and microbial activity?
  20. TomSawyer2112

    TomSawyer2112 Registered+

    Watching this thread :cyclops:

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