Activated charcoal is a form of charcoal that has been specially treated to create an especially high surface area. Technically, any form of carbon, not just charcoal, can be used to make activated carbon products, but charcoal is one of the most common sources for activated carbon. There are a wide range of uses for it, ranging from water filtration to the treatment of poisoning. Activated charcoal is often included in products like filters which can be bought in the store, and it is also possible to buy it alone in bulk.
The most common way to produce activated charcoal is to heat it. Heating causes the gases inside to escape, leaving behind an extremely porous, lightweight substance. Under magnification, a pellet looks sort of like a rumpled pile of fabric, with each twist and fold providing more surface area. The large surface area is what makes it so very useful.
Instead of absorbing things, activated charcoal adsorbs them, which means that certain materials will actually stick to the surface and form a film. Obviously, the more surface area there is, the more material will stick to the charcoal. A wide range of substances will bond with it, and a few pellets or grains can go a long way.
In medicine, activated charcoal is used to treat suspected cases of poisoning. If given in time, it will adsorb the poison before it reaches the intestinal tract, limiting the amount absorbed by the body. It is also used in gas mask filters and hospital air filters, to adsorb various substances in the air that could be harmful.
Some industrial processes require the use of activated carbon, such as metallurgy and sewage treatment. Activated charcoal is also used as a filter for some gases and chemicals, and it appears in the food industry as a filter for alcoholic beverages. Environmental agencies also use it to adsorb various pollutants in the natural environment.
Although activated charcoal is used in cases of poisoning, it should not be given to a patient without the supervision of a medical professional. If you suspect a case of poisoning, you should call a poison control center for directions, and seek medical care immediately. Try to bring the container the poison came in when seeking medical help, as it may be useful to the doctor.