Activated carbon is a porous substance derived from organic material (usually woody, fibrous stuff). The useful thing about activated carbon is that it can filter out contaminants from both water and air, which makes it an important substance in filtration system.
We examined a variety of methods (we considered 40+ samples to be adequate) to create activated carbon; through testing, we believe that we have found the optimal material and protocol to create the closest thing to commercial-standard activated carbon. We tried to create the easiest solution that implemented tools you already have around the household (because not everyone has a drum-steel burner on their hands).
This Instructable is meant for those DIYers with a bit of time (ok, only about two days) who aren't afraid to burn, burn, and burn. This flexible method takes all sorts of food waste and turns them into activated carbon for filtration. Use it while camping, biking, or even at home!
Our hope is that this method will eventually help impoverished areas improve overall health by providing an easy and flexible filtration option.
SO LET'S GET COOKING.
Step 1: Materials
When thinking of materials, we tried to be flexible so that you wouldn't have to go out and buy everything (that kinda defeats the purpose, doesn't it?). Here's what you need to make the carbon.
A metal container, with a lid
An oven (or something that gets hot)
A fireplace, grill or pit (something you can burn on)
A strong acid, base, or salt (we'll explain later. Some examples we have tested include 25% Calcium Chloride, Bleach, and Lemon Juice Solutions).
The food waste.
Now, picking the food waste is by far the most important step here. You want a nice, fibrous substance that already has a lot of pores. For example, commercial carbon is made with hardwood or coconut husk (that's what you see above). These are fine, but we have also tested banana peels, orange peels, nut shells, and rye husks with similar results. Feel free to explore. If you choose something with a lot of water content, you might want to dry it beforehand to prevent steam buildup.