Survivalist Forum banner

DIY Activated Charcoal

75K views 38 replies 22 participants last post by  cleatis 
#1 ·
Greetings, fellow carbon-based life forms! I was reading in a couple of different threads about the uses of activated charcoal and how you really should have some in your emergency first aid kit; and about how it's really hard to make. Actually, it isn't all that hard to make, just tedious, and not something you want to do in the basement.

Charcoal is made from heating wood in a low-oxygen environment. The heat drives off all the moisture and hydrocarbons (wood gas) in the wood, leaving just carbon (charcoal). To activate the charcoal, you treat it with acid and heat it again.

Check out YouTube and you'll find half-a-dozen or so videos on making your own charcoal cooker. Some of these are just for making charcoal (very useful if you like to pound dull steel into sharp, pointy things) (also useful if you want to make your own black powder, but that's another post); others are primarily for making wood gas to run cars and trucks.

The common features are: 1. being able to seal up the container so that air doesn't get into the oven (otherwise the wood burns, not chars), and 2. a small hole or tube to allow the wood gas to escape so you don't have a pressure bomb.

If you're making activated charcoal, in the end you're going to want to grind the result into a powder, so start with small pieces of wood. I know someone who swears by old pallets. They're easy to cut into small pieces and they char very well. (If you're planning on using the activated charcoal for filtering water, apparently coconut shells are the best. Where to find large numbers of coconut shells in, say, Minnesota, is YOUR problem.)

Put the wood into your cooker, seal it up, and light a fire underneath it. As it heats, you'll see steam/wood gas come out of the small hole. After the steam starts coming out, cook the wood for at least 4 hours -- you'll have to experiment to see how long it will take depending on the amount of wood, etc. After 4 or 5 hours, take the cooker off the heat and let it cool naturally. You'll want to make sure it's thoroughly cool before opening it because otherwise the char inside will burst into flame when the oxygen hits it.

After it's cooled and you've opened it up to expose the charcoal, test a few pieces to make sure they've charred all the way through. If not, you can still use that batch for burning but not for making into activated charcoal; and remember to cook it longer next time. If all you're looking for is charcoal to make black powder, or charcoal to burn in your forge, you're done. Otherwise, read on.

Here's where it gets tricky. Get some battery acid from your local auto supply store. Using a glass pan, plastic or rubber tongs, rubber gloves, goggles, and all the other safety equipment you can muster, pour the acid into the glass pan. Then carefully place each piece of charcoal into the acid and let it soak for four or five minutes. Remove each piece from the acid, let it drain a bit, then put it back into the cooker.

When all the pieces have been treated, seal the cooker back up, put it back on the heat, and cook the charcoal for another 4 hours or so. Let the cooker cool, open it up, grind up the pieces, and you've got activated charcoal.

If you're not into all that waiting and cooking, you can buy activated charcoal at a tropical fish supply store (make sure it's JUST the charcoal, and nothing else.) If you're planning on using the charcoal for water filtration, etc., though, you may find it more cost effective to burn your own.
 
See less See more
#2 ·
Okay, just a suggestion or two:
1) this stuff isnt as activated as store bought charcole, so adjust your quantities accordingly. 50% less porous is where id aim, though its probably way too low.
2) dont just make a hole to let out wood gases! use a bit of pipe to re-route the gases back into the fire; its basically coal gas, and burns really hot. on that same not, dont breathe in the fumes.
3) generally, charcoal is ready a bit (30 min?) after it stops giving off coal gas (see post two)
 
#3 ·
Replies:

1. I don't know how activated the end product is. As with any other home-made product like corn likker or babies, there's a lot of variations possible. You're sacrificing the precision of milliliters and precise temperatures for something that gets it done without costing a lot.

2. If I could take a class in welding, I would. Then I'd make a cooker that routed the gas back into the flame. As it is, though, my version of a cooker is a clean paint can with a nail hole in the lid. It doesn't make much, but it makes enough for me.

(Of course, now that I'm thinking about it, I could put the nail hole in the bottom of the can and prop it up so the output feeds into the fire. Or just flip it upside down. Hmmm...)

3. One reason I'm using the paint-can cooker is that right now I'm still experimenting, not ready yet for any kind of "large scale" production. As it is, the times I've tried relying on the appearance (or lack thereof) of wood gas my results have been inconsistent. It's happened often enough that I would have sworn no more gas was appearing, then after cooling the cooker large pieces of the wood aren't charred all the way through, that I just use a timer: cook for 4 hours while I'm in the area doing other stuff; then take it off the fire and let it cool for an hour before opening it. I've had good luck with that timing, and "overcooking" the wood doesn't seem to hurt it.
 
#4 ·
If you're not into all that waiting and cooking, you can buy activated charcoal at a tropical fish supply store (make sure it's JUST the charcoal, and nothing else.) If you're planning on using the charcoal for water filtration, etc., though, you may find it more cost effective to burn your own.
Yeah, I was going to suggest that very same thing.

I just think it would be easier to have on hand ready to go in bulk than have to buy acid and cook your own post SHTF.
 
#5 ·
Not honestly sure what the point of the acid post-burning is, i admit.

I know people use acids before the combustion because you can then use a lower temperature and for less time yet achieve the same results.

You dont actually need H2SO4 (battery acid) though. You could use HCl or NHO3 or whatever else is at hand i would think...
 
#8 ·
Hmmmm... I don't know about the chemistry behind this, but I don't know that I would like to use any "Acid treated activated charcoal" to filter my water or in my stomach to help me with poisons. I can't see how the acids would cook off completely at low temps or be completely infused within the charcoal. Injesting battery acid isn't my idea of good eats. But heck I could be wrong on this.
 
#9 ·
Any commercial activated charcoal you buy will have been treated with acid at some point in the process. The commercial products use low temps because it's less expensive; that also means they have to take a long time to process the carbon into activated charcoal.

If you're using battery acid (strong sulfuric acid) the chemical reaction SHOULD be like this (it's been some time since I've taken college chem): H2SO4 + C = H2 + S02 + CO2. As the acid eats pits into the carbon, it generates hydrogen gas, sulfur dioxide, and carbon dioxide.. Keep adding heat and you keep creating sulfur dioxide and carbon dioxide. Eventually, all the sulfur cooks off
 
#11 ·
Okay, as someone who has made lots of charcoal in the past here is the best charcoal maker you can get for the money:

Step 1: Get one 55 and one 35 gallon steel drum (with lid). Also get two pieces of thick rebar.

Step 2: Cut a 12"x12" square out of the 55 gallon drum on the side at the bottom. Also cut four holes above the square cutout (these are to pass the rebar through so you can rest the 35 gallon drum on them.).

Step 3: Poke about 9 or 10 holes in the bottom of the 35 gallon drum to let the gas out. Then rest it on the rebar inside the 55 gallon drum.

Step 4: Fill the 35 gallon drum with whatever wood you want to char and seal it up. Fill the 55 gallon drum up with as much scrap wood as you can and light it.

Step 5: Keep it burning for hours. When you're done, pull out the rebar so the 35 gallon falls into the ashes (will cover the gas holes) and let it cool. You now have some charcoal.

The gas will blow right into the fire in the bottom of the 55 gallon drum and burn up. It's a very good little coal maker.
 
#12 ·
(If you're planning on using the activated charcoal for filtering water, apparently coconut shells are the best. Where to find large numbers of coconut shells in, say, Minnesota, is YOUR problem.)
Mabey a swallow droped it I dont know if it is African or Europian though :D:

But yeah to get the acid just go into a homedepot or a lowes tell them you need muratic acid they usually sell it in two one gallon jugs in a box for 10 bucks or somthing A WHOLE LOT CHEAPER then the batterie

Plus if you need to make Chloreine gas you can always use what you got left of the acid put it in a bottle and throw some Aluminm foil in and put a ballon ontop

Though I dont really know what you would need chlorine gas for :xeye:
 
#19 ·
I would think citric would work a little better or even tomato paste tomato paste will eat through aluminum but it might not work so well on making active charcole

I can tell you from experince that muratic has a very very strong Lime flavor
I had some spalsh onto my toungh one time while I was cleaning bricks
 
#20 ·
DO NOT REACT HCL/muriatic acid with carbon

I stumbled across this forum while researching water filtration, and felt the need to inform you on the possible effects of reacting HCl and C.

These are some possible results of this reaction:
Reacting Carbon with HCl could produce
  • Carbon tetrachloride (Freon) - potent greenhouse gas
  • Trichloromethane (Chloroform) - CNS depressant, converts to phosgene in the presence of oxygen and heat
  • Chlorohydrocarbons -some are highly toxic, some are greenhouse gasses, many are flammable.
  • Various hydrocarbons - toxic, flammable, and potent greenhouse gasses
  • Chlorine gas - toxic
  • Hydrogen gas - flammable

HCL almost completely dissociates in H20 into protons and chloride ions. Both of which would readily bind to carbon to form all kinds of nasty compounds.

Please, do not do this, and leave chemistry to the chemists.
 
#21 ·
I stumbled across this forum while researching water filtration, and felt the need to inform you on the possible effects of reacting HCl and C.

These are some possible results of this reaction:
Reacting Carbon with HCl could produce
  • Carbon tetrachloride (Freon) - potent greenhouse gas
  • Trichloromethane (Chloroform) - CNS depressant, converts to phosgene in the presence of oxygen and heat
  • Chlorohydrocarbons -some are highly toxic, some are greenhouse gasses, many are flammable.
  • Various hydrocarbons - toxic, flammable, and potent greenhouse gasses
  • Chlorine gas - toxic
  • Hydrogen gas - flammable

HCL almost completely dissociates in H20 into protons and chloride ions. Both of which would readily bind to carbon to form all kinds of nasty compounds.

Please, do not do this, and leave chemistry to the chemists.
There's a few things wrong with this post. Freon is made with fluorine, not chlorine.

As to your chemistry credentials, I don't find them convincing, and your whole focus on 'greenhouse gasses' marks you as a critter that lives under bridges and pesters billygoats.
 
#23 ·
Carbon tet was used for dry cleaner fluid when I was a kid. The TFCs are tetrafluorocarbons, used as refrigerants, and not chlorine based. Freon compounds range from the old Freon 12 and Freon 22, through the relatively inactive Freon 134 that is in current common use. Again, anything can be deemed toxic if it is misused. HCL would not be my choice for scavenging the lignins out of charcoal to activate it, but your comments aren't all that helpful to the effort either.

Myself, I use superheated steam for applications like this.
 
#26 ·
#32 ·
Activated charcoal is different than regular charcoal in the amount of surface area it has due to the cracking and fissures. The acid should aid in creating these fissures and cracks, Most common activated charcoals involve using a vacuum though I believe. I would still have concern about using sulfuric acid.
 
#31 ·
My understanding is that carbon absorbs stuff(airborne or waterborn) in its pores. The acid increases the surface area of the carbon (on a molecular level) which increases the amount of pores that are available for absorption purposes.
But I'd double check that data, I'm sure a quick google search can probably explain it better than I can.
 
#33 ·
What the acid does is to dissolve out the things that are not carbon, which is what increases the surface area. Same thing can be done with steam. The volatiles burn, most of 'em, and make a fairly good liquid fuel, though it is hard on internal combustion engines....
 
#34 ·
For a quick and cheap experiment in making charcoal, here is what I did. I took a #10 can, fully open at one end. On the other end I punched a tiny hole using a sharp nail. I loaded the can with wood, yellow burch if I recall correctly. I started a fire at the pit by the lake, once there was a nice bed of coals, I put the can on it, open end down, puched it in a bit and loaded wood around it. The next morning everything had cooled down and I had nice hard charcoal.
 
#37 ·
I have spent a lot of time experimenting with making char cloth and charcoal. I want to caution anyone from using a galvanized can to make charcoal. Heating galvanized metal even to a relatively low temperature (aprox 450 deg F ) releases gaseous zinc ! Very toxic and not something you would want hanging around as a trace element in your activated charcoal. There are a lot of everyday food cans that are galvanized so just be careful what you use. My favorite reaction chamber is an old steel pot. Work good on a hot plate that I set up on my back porch and allows me to quickly test different materials to make charcoal. Currently I'm using grass clippings. They are already a super fine structure and grind into powder very quickly.
 
#36 ·
I don't think rgambord is a troll and I think they have some points
I'm not a troll either. I am trying to create carbon to filter air in my house.
And possibly water if I am confident enough that I am not taking relatively decent water and making it worse. (Trying not to die here)

Wood burning itself creates poisons for example, dioxin and furan.

Some of the worst poisons contain Cl (chlorine)
Stomach acid is HCl (Hydrochloric Acid)

However unless you are a dragon in disguise, I doubt you have belched at 500 degrees Fahrenheit before.

The thing that you have failed to consider is that some reactions can't occur except when we meddlesome humans create some unnatural circumstance for them to occur, for example unusually high temperatures.

Arrogance is not a wise idea with such things. When it comes to our own soft insides, it really is a good idea to let chemistry up to chemists. And I am not a chemist either. Not to be condescending or anything . . .

Remember CCA lumber? The 'A' in CCA stands for Arsenic. You know what that is right? Don't make your charcoal out of your old pressure treat lumber. For one thing it's illegal in some places for that very reason. When it burns in a fire, ALL of the arsenic is left in the ash when it's done and its a pretty high concentration at that. And the whole claim with CCA that they were even permitted to produce it was that it does not leach out of the wood with weather exposure. That means almost ALL the arsenic they put in the wood on day 1 - 30 years ago will be in your charcoal you are filtering your water with. Obviously a wood gasifier aka charcoal maker burns it less thoroughly that than a plain fire. In fact it doesn't burn it. I believe the correct term is pyrolyzes it. In any case, anything that would be in the ash if you were to completely burn it, will certainly be in the charcoal.

So you are best to pick up some sticks in the woods. Avoiding anything but just plain NATURAL wood. No lumber. No bark. No fungus. No foxfire. Pure and natural as possible. And I think I read somewhere that pinewood produces more dioxin than other wood. (check me on this) But dioxin probably comes out with the gas not sure. (don't breathe the smoke while you are doing this. Anything that somebody else has touched, handled, exfoliated upon etc you'll have no idea what might be in it. I am excessively paranoid I admit it. And even if they say it's a certain thing, how do you know they don't have a load of something else they need to "unload"? Nature tells no lies. If it grows out of the ground as a tree 350 yards into the woods somewhere, your pretty sure no one has touched it before you did. The only question I have is what kind of tree is safest for this or does it matter. It might matter more the mineral content of the soil that the tree grows in actually . . .

As far as acid goes, we are trying to accomplish something physical and using a chemical to do it. Now technology is great but isn't all of our technology the reason we have to be afraid to drink water from a stream in the first place that we are trying to filter it with a carbon filter to remove organic chemical toxins that will poison us?

The point is to increase surface area. The extreme of which would be nano-carbon I guess. Why not just powder the charcoal by grinding it up to increase the surface area?
Why not just use more of it and save the risk. We are talking about burnt wood . . . it not like its that huge of a rarity. . . go around and pick up sticks. You don't even have t chop down a tree and harm nature.

For that matter every piece of charcoal I have ever seen was naturally porous to begin with since it was made from wood. Wood is made of cells. all the cells loose part of themselves as gas leaving tiny (millions of) intermittant patchs of void surounded by a foam of carbon. Break it into small pieces and you have even more porous surface. Grind it into powder and you at least approach nano-carbon.

Now maybe somebody out there has scientifically observed better performance with acid treatment. But which of us has the capability to measure performance well enough to detect the difference and see if we are even doing the acid thing right?

Sure, go-ahead and put battery acid in your drinking water, says the for profit entrepenuer producer of charcoal to try to poison their potential competition. . . before they ever get started. . . Better yet, burn it and inhale deeply as you do so . . . nothing personal HHOS.

Now I am just fooling around here and you'll have to double check this theory.
I have built myself a "rocket stove" and in it I was able to create charcoal without the sealed chamber. A single chamber stove with limited oxygen. I simply put the wood in and left it burn until all flame and smoke were gone indicating that all the wood gas came out and burned. There was nothing left but burning embers. I then extinguished the embers to stop their burning with a little bit of water (same water I might try to filter a 100 gallons of with it later for example) I know that the wood got hot enough to fully remove the wood gas because each coal was red hot and undergoing the carbon oxidation (the charcoal itself starting to burn until I extinguished it) Nothing magic, charcoal burning is HOT! Hot enough to blacksmith steel if you want to. Its like boiling off the juice when cooking a hamburger. At the point where there is no water left to vaporize, rather quickly at that point the food will start to burn. Well the coals are like the hamburger when there is no juice left in them to evaporate.

Now this method is of coarse not as efficient because some of the carbon in the wood inevitably burns and goes away as CO2 no matter how carefully you extinguish. (not to early, not too late) But the apparatus is simpler. There will be some pollutants (ash) mixed in. But all the substances in the ash again would have been in locked in a matrix in the charcoal anyway had not some of it burned. The only think is that they are not locked in a matrix because parts of it burned away.

I later washed the coals with more water by hand to remove a lot of that ash, and dried them out. Once dry they could be powdered.

My understanding of the theory is that the carbon being liberated of all of its more complex organic bonds, acts like a chemical magnet for other organic compounds. It wants its bonds back because now it is missing them. So when it comes into contact with pure carbon, it tends to grab them and keep them. More surface area simply means more incidence and more contact so more reaction. It may also neutralize them by reaction making them less nasty even if they go through the filter and you drink them. (not sure about that though. Maybe this is why the powdered form would not be good for water filtration. Too much of the carbon itself might be bad for you. It would be good maybe for air filtration as long as there is sufficient distance between your intake vents (nose and mouth) to prevent you from inhaling the powder which will have grabbed the bad stuff and then you will take it into yourself anyway.

If for a gas mask extreme careful design should be used, as inhaling particulate matter is the worst thing that can happen. Probably worst than what you are trying to protect yourself from. But say to create a general air pollution reducer for your home . . . powdered would be perfect for that. In adition to other measures keep carbon dust inside the filter so dust will be trapped by a stage 2 HEPA high-MIRV particulate filter (from home depot). Maybe impregnate some kind of fabric with it or quilt stitch it between two layers or something . . .

With powder, you get lots of surface area but you have to make sure that the carbon stays in the filter somehow, keeping contaminants in there with it.

This is what pre-flush is for in a water filter. Any particle carbon that is going to go through, does so in the first few gallons hopefully.

~~~

My theory is this. How often do you take a drink?

Now how often do you take a breath? Dead quicker see?

LOL Just Kidding . . . . filter both your air and your water.

Out-gas from you carpets and the lawnmower oil on your overalls . . . no problem. All organic compounds. Most of the stuff that poisons us is "organic" or organically reactive.

Carbon is just so reactive. That must be why it is the key to life. So let the poisons bond to / react with / poison the pure carbon from some sacrificial tree limb instead of bonding to reacting with and poisoning the organic compounds inside of your body. And live longer, happier and healthier.

Just don't make charcoal with anything besides the most natural wood you can find. Some poisons can't be neutralized or removed by the carbon, such as arsenic.

Even a tree in the woods will uptake a tiny bit of arsenic but nothing to the degree CCA wood will have in it or even to the degree a tomato stalk planted next to a CCA fence will . . .
I have read the speal . . . err "expert reports", of certain anonymous strangers that claim neither leaching nor postsequent uptake do not happen but . . . we all can speculate about the real truth.

And don't put in or allow anything to get into your char after its done cooking, that you wouldn't otherwise put in your drinking water unless you are sure you know for certain that you can burn it off. And that you need to do so for that matter. You can't clean something, with something that is dirty. That means finding out for yourself from a textbook, or trusting somebody else. And when it comes to trusting some stranger who says yes, right next to some stranger who clearly says no . . . that not certainty in my book. If you can be a lot more certain than I am that you have fully burned off your acid . . . then go for it.

All that being said, carbon is the substance of life. It has to be good. Just make sure its pure carbon.

And don't catch Chloracne:
http://en.wikipedia.org/wiki/Chloracne

And do wash your hands before you eat and after you touch anything. In fact, try to just walk with your hands in your pockets. Or you could eat your sandwich while changing the oil in your car or worse, bleeding your brakes, and make this whole discussion marginally irrelevant. The cake is a lie. And don't spill it all over the dang floor. There is no data on the web about what kind of no good silicate dioxide does a body and they will keep it that-a-way till after they are done selling it to the public.

Most of all the really bad things are made in fires. So if you don't give a fire the building blocks for poison, like Cl or S or P . . . you help limit the possibilities. And don't burn anything with PTFE teflon, or you'll have that Flourine you were missing before.

But dioxin is made of nothing but C4H4O2 all that stuff comes in the wood and air itself. . . But again I think dioxin is a gas, especially at those temps. So it floats away or burns into something else if you do things responsibly (such as a property tuned and regulated pyrolyzer/wood gasifier)

Dioxin rhymes with toxin. hah. Just realized that.

The EPA says four trash burning barrels produce as much dioxin as a full scale incinerator. And that is because yet while the incinerator burns tons of waste at a time, it burns hot and burns fully and then post processes the exhaust with catalysts. (one of the catalysts/reactants used to get rid of the dioxin in an municipal incinerator, by the way, is powdered activated carbon (PAC) which is "sprinkled" into the exhaust air and burns, all happening at around 392 - 446 F)

Right about now, the more carbon I make and have around me, the safer I feel. . .

I feel purer and cleaner already.

I think I am less carcinogentastic. . .

Anybody got a cigarette or some whiskey to split? No? I will I still have my Molly . . . She's made of pure C12H22O11 so I'm 99.5% sure she is good for me.

Stay well and pure everybody. Hope I helped.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top