Activated carbon filters water by absorbing contaminants onto its porous surface.
Activated carbon is a highly effective material used in water filtration primarily because of its unique structure and properties. The process can be understood simply:
Activated carbon acts like a sponge with an incredibly large surface area. This large surface area is covered in countless tiny pores. As water flows through the activated carbon, dissolved impurities and contaminants in the liquid are attracted to these pores.
The filtration process relies on absorption. This means that the contaminants are not just trapped mechanically (like a sieve) but are chemically or physically drawn to and held onto the surface of the carbon particles. According to the reference, the liquid's dissolved impurities move to the areas with the strongest attractive forces on the activated carbon. Think of it as the carbon surface having a stronger "pull" on certain substances than the surrounding water does.
This mechanism is highly effective for removing a wide range of impurities, particularly organic chemicals that cause bad tastes, odors, and colors.
What Activated Carbon Filters Remove
Activated carbon is excellent at removing:
- Chlorine and chloramine (common disinfectants)
- Organic compounds (like pesticides, herbicides, and industrial solvents)
- Substances that cause bad taste and odor (like hydrogen sulfide)
- Volatile Organic Compounds (VOCs)
However, it's important to note that activated carbon is less effective at removing:
- Minerals (like calcium, magnesium, sodium)
- Dissolved salts
- Heavy metals (some specialized forms of activated carbon or combination filters are needed for these)
- Microorganisms (bacteria, viruses)
Practical Insights
- The effectiveness of an activated carbon filter depends on the contact time between the water and the carbon, the type of carbon used, and the size of the carbon particles.
- Activated carbon filters eventually become saturated with contaminants and need to be replaced to maintain filtration effectiveness.
