Activated carbon is a specially processed form of carbon used for filtration purposes. Activated carbon can come from a variety of natural (carbonaceous) materials such as bamboo, coconut husk, willow peat, wood and coal. Typically, he carbonaceous material is developed into activated carbon using hot gases.
The finished product has an incredibly large surface area and a network of submicroscopic pores where "adsorption" takes place. Physical adsorption is the primary means by which activated carbon works to remove contaminants from liquids. Carbon’s large surface area allows for contaminants to adhere to the activated carbon media.
Activated carbon is used in refrigerator water filters and many other point of use (and sometimes point-of-entry) water filtration systems. Activated carbon has been proven to reliably remove dissolved impurities and disinfection byproducts (like chlorine tastes and odor) that can make water taste bad.