Activated Charcoal

If you've ever ingested a poison, you've probably heard of Activated Charcoal or Activated Carbon. If you've not, count yourself lucky, as it's a horrible-tasting substance. However, it is wonderfully useful for a variety of purposes, and is something you should be aware of.

What is Activated Charcoal?

Activated charcoal is a form of carbon that has undergone chemical or physical processes that give it a large number of very small pores, effectively increasing its surface area. This process is so effective that one gram of activated charcoal can have a surface area of 500m^2. This makes for extreme adsorptive properties, where larger surface area directly relates to effectiveness. The process to make activated charcoal requires specialized equipment, so creating your own is beyond the capacities of most folks.  It is, however, available fairly readily on the commercial market, depending upon your uses.

"Activated Carbon" by Self (en:User:Ravedave).
Licensed under Creative Commons Attribution 2.5 via Wikimedia Commons

What is it good for?

Activated charcoal is good for all manner of things.  It has a number of scientific applications, and it can be used to form certain sound barriers.  Doctors use it to treat poisonings (it adheres to toxins, neutralizing them) and it can be bought over the counter for this purpose, used per the directions on the package.

My favorite use, and the primary purpose of this article, is filtration.  Activated charcoal can pull all sorts of nasty contaminants out of any water you come across, and comprises a major component of a filtration system.

Filtration with charcoal

A charcoal filter is quite effective, fairly simple to create, and can be made in any size you like. I personally helped install one in a 55 gallon drum, and I've seen them built in 250 gallon totes for industrial uses. For most folks' use and utility, a five gallon bucket will do.

1. Either drill a hole in the bottom and put another bucket below it, or install a spigot on the side of the bucket, as low as possible.
2. Line the bottom of your bucket with some manner of cloth.  An old t-shirt will do wonderfully, as long as it's clean.  
3. Put in a layer of small pebbles, roughly 1/5 the depth of the bucket, followed by a layer of fine sand, about the same thickness.  
4. On top of the sand, put another cloth, then your layer of activated charcoal, covered by another layer of cloth.  
5. Repeat a sand layer, then a pebble layer, and your filter is ready.

To use your filter, start by collecting the cleanest water you can find: Better starting water makes better output water.  If your water is muddy or silty, let it settle some before you run it into the filter.  Pouring it through a cloth into the filter helps pull large particles out as well.

Once your water has been run through the filter, all of the sediments, particulates, and organic contaminants should be removed.  However, bacteria, viruses, and other biological contaminants can remain, so further treatment is necessary.  Boiling, distillation, bleach, or chemical treatment will remove those contaminants, and render your water entirely safe to drink.

Water, water everywhere; just make it safe to drink.

Lokidude