What is activated carbon?
Activated carbon is a term for a manufactured carbon either coal-based or coconut shell-based. The process is varied for each medium but essentially the carbon is exposed to oxygen to create tiny pores in the carbon at a molecular level. It is these pores that absorb contaminants by chemical attraction.
Types of activated carbon?
There are two sources of activated carbon used in water filtration. One is a coconut shell-based carbon where the husks of coconut shells are burned and then processed. The other type is a coal-based carbon. Both of these types of activated carbon take on three forms in water filtration; granular, block and impregnated fiber.
Granular carbon is the most popular form of activated carbon for water filtration. It is comprised of tiny loose granules that require the water to pass through them . The benefit of this type is that it has a significantly high flow rate. Water can travel easily through the carbon while still getting exposed. A negative aspect about granular carbon is over time pathways or channels can develop in the granules so water may not be exposed to the carbon.
Block carbon is the most effective form in water filtration because of the high exposure rating to the water. As it sounds, a block carbon is a single compressed medium. No pathways or channels can develop in a block form. The downside of this form is it has a very low flow rate. Water has to be either pushed or pulled through the medium with some force such as with a pump style water filter.
Impregnated Carbon Fiber
When activated carbon is impregnated into a fiber the result is a medium that has a high flow rate and a high exposure rate. The compressed fibers ensure no pathways or channels are formed. Either types of activated carbon, coal-based and coconut shell-based carbon can be used in an impregnated carbon fiber. For this reason the Oasis has an impregnated activated carbon fiber as a medium.
Activated carbon is only effective as long as the carbon can absorb the contaminants. The effectiveness of activated carbon is slightly decreased over time but can be re-activated through a process that can be done at home.
The benefits of activated carbon are many and should be an element in everyone's water treatment arsenal.