Activated Charcoal
When a piece of wood or sugar or a coconut shell is burned, a black or dark gray residue is left behind. This residue is called charcoal. Charcoal is made of carbon atoms that are arranged in layers. Between these layers, there would be impurities like water, gases, and other organic-based substances. By itself, charcoal is extremely useful. Its uses range from art (charcoal pencils) to gastronomy (cooking) to warfare (in gun powders). But when charcoal is heated at extremely high temperatures, it transforms into activated charcoal. Activated charcoal is still made of layered carbon atoms but its uses have greatly increased.
The wide-ranging uses of activated charcoal is due to its great adsorptive abilities. Adsorption occurs when the tiny particles attach themselves to the surface of charcoal. These particles, called adsorbate, can be gaseous like fumes, liquid like water, or even solid like dust and particulates. Adsorbates would not chemically react with carbon but will simply attach, forming a thin layer, to the surface area of charcoal. Obviously, the greater surface areas will adsorb more materials. Activated charcoal will have a greater surface area than ordinary charcoal.
Charcoal can be activated using a process called carbonization. In this process, the charcoal is pyrolized or heated up to 900 degrees Celsius in the absence of air. Without oxygen in the air, carbon cannot be burned to form carbon dioxide. Instead, gaseous impurities, such as methane and hydrogen gas, evaporate. The volume and density of activated charcoal are usually higher than ordinary charcoal. Activated charcoals with higher densities are considered high quality. At the same time, the emptied layers of carbon are ready to adsorb materials.
The great adsorptive power of activated charcoal leads to a wide variety of uses. Activated charcoal is used in sewage treatments to remove sludge and parasites. Activated charcoal is used in air filters to trap volatile organic compounds (VOCs) that may come from paint and other chemicals. Activated charcoal is used in gas masks to protect the person from noxious fumes. Activated charcoal is a key substance in water purifiers because it adsorbs water impurities. In the field of medicine, the used of activated charcoal has replaced stomach pumps in treating food poisoning. And in various industries, activated charcoal is utilized to trap mercury. For example, when activated charcoal is mixed with iodine, it can be used to entrap mercury vapors that come from coal-fired power plants.
