Many NSF-certified filters use activated carbon filters to reduce and eliminate pollutants from drinking water, which can include chlorine, pharmaceuticals, chemicals, metals (lead and mercury), among other contaminants, that can make your water have a bad taste and smell.
This method of filtering uses activated carbon on a large surface to remove these impurities. It does this through absorption. Absorption soaks up particles to its surface like a magnet. Debris bonds or attaches to the surface of the carbon filter because water and contaminants are polar compounds that attract. The large and porous surface area that carbon filters have makes them efficient in minimizing poor taste, odor, and other particles found in water.
The pores that make up the filter are measured in microns. The smaller the micron, the finer the filtration capacity. The slowdown in flow rate gives pollutants time to attach to the carbon. Another feature of activated carbon filter is that they allow healthy minerals such as ions, fluoride, calcium, and magnesium, to by-pass the filter and still make its way into your water.
Sometimes carbon filters are referred to as charcoal filters, however there are different types of material that these filters can be made up of:
- Bituminous coal – no longer used as often.
- Wood-based media – made from burned wood.
- Coconut shell media – made from the shell of a coconut and is the most renewable.