Carbon filters trap volatile organic compounds (VOCs) and odors in your house. They are primarily made of activated carbon, which is processed to open up many more pores and therefore increase its surface area.
This allows it to absorb chemicals by the process of adsorption. They are very good at removing chlorine and disinfection byproducts like trihalomethanes as well as bad tastes and odors.
Removal of Chlorine
The pore structure of activated carbon makes it an excellent choice for removing chlorine, bad tastes, and odors. It is also used in some systems to remove chlorine byproducts of water treatment, such as THMs and VOCs. These byproducts are cancer-causing chemicals that linger in drinking water, tainting it with an unpleasant chemical flavor. Activated carbon can also trap some volatile organic compounds (VOCs) that are released into indoor air from paint, thinning compounds, cleaning products, and cigarette smoke.
Other contaminants that a carbon filter can help remove include coliform, cysts, lead, arsenic, and iron through mechanical filtration. It can also reduce the amount of fluoride, nitrates, and sodium in drinking water through reverse osmosis or distillation.
Activated carbon filters are the most effective way to eliminate harmful chlorine byproducts from your drinking water. These byproducts can cause long-term adverse health effects, including cancer and reproductive disorders. These byproducts form when chlorine reacts with naturally occurring compounds in the water. Filter carbon that has been activated by high levels of heat and steam in the absence of oxygen is the best option for eliminating these contaminants.
Some types of carbon filters can also be effective at removing pesticides from your drinking water, including herbicides, insecticides, and fungicides. However, the adsorption capabilities of carbon filters vary depending on their level of activation and the thickness of the carbon bed they use. Thicker carbon beds offer more surface area for adsorption and can be used longer before they begin to degrade or lose their effectiveness.
Removal of VOCs
Carbon filters remove VOCs through a process called adsorption. The carbon particles have a lot of surface area, which allows them to absorb chemicals like a sponge or Velcro. The molecules that cause odors and VOCs attach to the surface of the carbon filter, which is covered with cracks and pores.
To make a carbon filter, the carbon is treated through high temperatures and steam to open up its pores and fissures. Activated carbon is the most common type of carbon used to filter air. It is also used in water filtration to eliminate chlorine and its byproducts, as well as other organic chemicals like VOCs and odors.
When VOC gases come into contact with the carbon filter, they pass through the largest pores on its surface. Then, through a process of diffusion, they move into the smallest pores until they are trapped and can no longer escape. This is how a carbon filter can capture VOCs like tobacco smoke, paint fumes, disinfectant sprays, and air fresheners.
To reduce VOCs in your home, it is a good idea to increase ventilation and use less products that release these chemicals. It is also a good idea to store any opened containers of paint or other VOC-releasing products in a separate storage space, away from living areas. You can also reduce VOCs by using fewer chemicals and by choosing green cleaners.
Removal of Pesticides
Carbon filters remove many different types of pesticides. They do this through a process called adsorption, which adheres chemical contaminants to the surface of carbon much like Velcro sticks to fabric. Activated carbon has an enormous surface area and can be used to treat liquids, air or even solids.
Besides removing chlorine, bad tastes and odors, carbon can also reduce VOCs and a wide range of other toxic chemicals including herbicides, pesticides, pharmaceuticals and industrial solvents. A good carbon water filter can also remove PFAS, which are synthetic chemicals found in a variety of household and commercial products such as firefighting foam, metal plating and stain repellents. They’ve been shown to bioaccumulate in humans and can leach into groundwater.
High-quality activated carbon filters can be used to remove the most common 14 pesticides, including lindane, chlordecone, chlordane, heptachlor and glyphosate (Round-up). They can also reduce a dozen commonly used herbicides, such as 2,4-D, atrazine and pyrethrins. Most of these are used hand-in-hand with pesticides to kill weeds and increase the production of desired crops in agriculture, but they can often end up in local water supplies through improper or uncontrolled agricultural runoff.
Removal of Heavy Metals
Carbon filters can remove heavy metals through a process called adsorption. This occurs when a particle with a negative charge is attracted to a positively charged molecule such as a metal ion. This is how carbon is used in air and water filtration, in some methods of coffee decaffeination, and in adsorption beds for industrial gas processing.
Carbon water filters use granular or block carbon that is “activated” using either heat or chemicals to increase its surface area, which dramatically increases its ability to attract and hold contaminants. One gram of activated carbon has a surface area that’s equal to more than 30,000 square feet. This massive surface area is why carbon’s adsorption powers are so effective.
Activated carbon’s capacity to remove contaminant particles from drinking water depends on the quality of the carbon, the design of the filter, and the size of the carbon granules or blocks. Generally speaking, solid carbon block filters perform better than granular activated carbon (GAC) filters.
Several heavy metals, such as copper and lead, are toxic at low to moderate concentrations over prolonged periods of time. They can cause gastrointestinal issues, liver or kidney damage, and even lead to nerve problems, memory loss, or seizures. Carbon water filters are very effective at removing these and other harmful metals from drinking water. However, they are not as effective at removing fluoride, nitrates, and sodium. These contaminants are best removed through reverse osmosis or distillation in combination with a high-quality carbon filter.