The demand for activated carbon filters is increasing due to government regulations on water purification by environmental agencies on industrial discharge. In 2020, the estimated market size for carbon filters in the US is USD 267 million, which is now estimated to reach USD 330 million by 2025. These figures indicate how much important activated carbon filters are for the future. This article is primarily written to make the reader aware of the importance of activated carbon filters and their role in water filtration.
What is an Activated Carbon Filter?
Activated carbon filters are commonly used in processes to remove organic compounds or extract free chlorine from water. Removing organics in drinking water, such as humic and fulvic acids, prevents chlorine from chemically reacting with acids to form trihalomethanes, a class of known carcinogens.
Like other water treatment methods, activated carbon (AC) filtration cannot remove all possible types of contaminants. For example, sodium, microbes, fluoride, and nitrates cannot be removed by AC filters. Even an AC filter cannot soften water. Additionally, heavy metals such as lead can only be removed with a specific type of activated carbon treatment typically only used in household filters.
Sources of Activated Carbon
Activated carbon is a natural substance made from overheated wood or other organic material. The heat breaks the raw material into carbon atoms, forming a charcoal-like substance called activated carbon. Activated carbon is available from a variety of sources, including
- Organic matter such as peat charcoal
- Coconut shell
However, most of the activated carbon in water purifiers comes from coconut shells, as it is a clean and renewable resource. The most common type of activated carbon used in filters is granular activated carbon (GAC). It is a black porous solid that looks like granules or pellets.
A carbon block filter can also be used for water filtration instead of GAC. In these filters, carbon is compacted into dense blocks with very high surface area and high adsorption capacity.
Role of Activated Carbon Filter in Water Filtration
Activated carbon has a large surface area and tiny pores that can absorb contaminants like a magnet. Carbon also has catalytic properties that change the composition of some pollutants through chemical reactions with activated carbon particles.
Adsorption is the process by which molecules stick to the exterior of activated carbon. Unwanted molecules are attracted to the activated carbon since they are hydrophobic (water repellent) or have a strong affinity for the surface of the activated carbon filter. This makes activated carbon an excellent choice for removing contaminants in both water filters and air purifiers.
Advantages of Activated Carbon Filtration
Activated carbon filtration has many advantages over other water filtration techniques.
Natural Filter Media
Activated carbon is made from natural materials such as coconut shells and wood without using other substances or chemicals. In this way, air and water can be filtered completely, safely, and naturally.
Easy and Inexpensive Maintenance
Activated carbon is one of the cheapest filter materials and needs less maintenance. Once the activated carbon filter reaches capacity, simply replace the filter.
Eliminates Bad Tastes and Odors
No other reasonable filtration technology is as effective as activated carbon filtration in removing bad tastes and odors from your air and drinking water.
Combats a Variety of Contaminants
In addition to tastes and odors, activated carbon effectively filters other organic chemicals, pollutants, gases, and microorganisms depending on the application.
Disadvantages of Activated Carbon Filtration
Activated carbon filtration has some drawbacks also. Read below what could be the disadvantages of an activated carbon filtration technique.
Not all Pollutants Can Be Removed
Activated carbon is very effective at removing certain groups of pollutants but cannot be used to decontaminate air and water completely. Some chemicals and contaminants are not attracted to carbon media; other filtration techniques may be required.
Activated carbon filters have a specific maximum filter capacity. Once this maximum capacity is reached, the filter will no longer function and must be replaced. The life expectancy of activated carbon filters is 2 to 6 months, depending on filter size and air or water contaminants treated.
Long Contact Time Required
The longer the filter is in contact with air or water, the better the filtration. This means you have to wait a few minutes for filter results.
May Harbor Bacteria
Activated carbon cannot be used to remove viruses or bacteria. In fact, this type of filter is known to harbor bacteria. Manufacturers can add trace amounts of substances like silver to filter media to prevent bacterial growth.
Activated carbon filters are some of the most effective tools for filtering air and water. Activated carbon is not only a purification technology but is superior to other filters in removing contaminants that affect taste and odor. Activated carbon has many uses, but AC filters are most commonly used in water and air purifiers.