With various types of water filters becoming more and more popular, it is not surprising that more people are beginning to wonder what exactly is it that these filters do and how do they work? And with words like “Activated carbon” and “charcoal” being quite noticeable in most filters, whether whole house filters, under sink filters, countertop filters or even filter bottles, the understandable question arises: “What exactly is activated carbon and what is charcoal? And what is their function in filters and what exactly do they filter out?”
Well, fear not – that’s exactly what we are here to answer!
What Is The Difference Between Activated Charcoal And Carbon Filters?
Charcoal is carbon, that’s about as simply as we can put it. And activated charcoal or activated carbon is charcoal that has been treated with oxygen. When this is done, the carbon atoms in the charcoal open up millions of tiny pores and hence – they are “activated”. This is done because when the pores in the carbon atoms open up they become highly absorbent – they absorb odorous or colored substances from gases or liquids, as well as a large amount of other chemicals and substances that pose danger to our health.
When this is done with a special manufacturing technique, a highly porous charcoal can have a surface area of 300 – 2,000 square meters per gram. This is a lot of absorption for a surprisingly small amount of charcoal. According to the Home Water Purifiers and Filters website, one pound of carbon has a surface area of approximately 125 acres.
The reason why some people use “Activated carbon” and others use “Charcoal” or “Activated charcoal” is because carbon becomes charcoal when activated. So, for the purpose of water filters, activated carbon and charcoal is one and the same thing – there are no water filters with non-activated carbon.
Where Are Activated Carbon And Charcoal Filters Used?
You can find charcoal filters in all types of filtration systems, not just in water filters. All of them can be summarized in two categories, however: powdered block filters and granular activated filters.
The first one uses Powdered activated carbon (PAC) and the second one uses Granular activated carbon (GAC). Pac has an overall smaller particle size compared to GAC and therefore presents a larger surface to volume ration. As a result, the former is typically more effective at removing larger quantities of contaminants than the latter.
Silver or other secondary elements are also often used in both PAC and GAC filters to help prevent the spread of bacteria within the filter itself.
Both Powdered activated carbon and Granulated activated carbon can be used for whole house water filters, under sink water filters, countertop water filters, faucet water filters, water filtering pitchers, as well as water filtering bottles or straws.
So, What Do They Filter Out?
Activated carbon filters are known to remove at least 81 known chemicals. They also effectively help against 30 other chemicals, and have a moderate effect on 22 others. According to the EPA (the U.S. Environmental Protection Agency) activated carbon is the only filter recommended to remove all 32 identified organic contaminants including THMs. The same is true for all 14 listed pesticides and 12 herbicides. For a more detailed breakdown of all these chemicals, check the Drinking Water Treatability Database or the US National Library of Medicine.
Most notably, activated carbon is used to filter the chlorine and fluoride from municipal tap water. Most public tap water in North America and Europe is highly regulated and with excellent drinking qualities – it is intensively tested and certified for drinking. However, some countries – like the U.S. – still include chlorine and fluoride in the purification process. These chemicals used to filter the water for a lot of different natural borne bacteria and contamination and they do this quite well. They are also generally safe in the doses that they are used in, but tend to add an unpleasant smell or taste in some cases. Plus, some people are concerned that by drinking a lot of water or breathing in the evaporation in the shower, we are actually taking in much more fluoride and chlorine than we are supposed to be.
And activated carbon does a great job at removing both fluoride and chlorine, as well as the nasty taste and odor that sometimes accompanies them. Carbon filtration is also the primary method used in increasing the pH levels of water such as through the use of advanced alkaline water pitchers.
Other chemicals that activated carbon is effective against include: benzene, radon, solvents trihalomethane compounds, volatile organic chemicals such as pesticides and herbicides and hundreds of other man-made chemicals that may come into contact with tap water as it proceeds through the system.
What Doesn't Activated Carbon Or Charcoal Filters Remove?
Some of the things that are not filtered by activated carbon or are not filtered to a significant degree include:
- Dissolved solids like minerals, salts, or metals, a lot of which – like iron – are not really considered contaminants.
- 3 out of 4 microbiological types of contaminants, including various types of bacteria, cyst and coliform.
- Various inorganic contaminants such as lead, arsenic, asbestos and others.
- Radionuclides are reduced by activated carbon, but not by 100%.
- TDS (Total Dissolved Solids) is also something that is not reduced by activated carbon, although a lot of sales people advertise that it is.
But let’s take a closer look at some of these “carbon-resistant” chemicals as some of them are very popular:
- Lead is very frequent in areas with soft water and old pipes. Standard activated carbon is not effective against lead, but there are filters that include both charcoal and other filtering methods that are effective against lead.
- Microbiological contaminants come in a lot of different shapes and sizes, but they are generally not a problem in developed countries, as the municipal water is filtered from them (with the help of chlorine, fluoride and other methods). In developing countries, however, microbiological contaminants can lead to a lot of health concerns and diseases such as gastrointestinal diseases. These problems affect tourists and visitors more than the native people, because tourists from developed countries are not used to such contaminants. Therefore, if you are going to a developing country and are not fond of the idea of diarrhea you might want to invest in a portable water filter that includes other filtration methods in addition to activated carbon as it is not effective against microbiological contaminants.
- Arsenic is another famous offender in water. It is not typically found in municipal tap water but it can be found in places where the groundwater has been contaminated with it. Activated carbon is not useless against arsenic – in fact, it filters between 30% and 70% of arsenic from the water, but that is not enough in places with high amounts of arsenic. So, if this is a concern in your particular situation, look for a filter that includes more than just charcoal.
Are There Any Advances That Are Yet To Be Made In Activated Carbon Filters Which Could Further Improve Their Absorption?
There are a lot of advancements that are constantly made. In fact, there are some newer carbon block filters that have been proven and certified to remove a lot of the contaminants that are typically “resistant” to activated carbon. These are not as wide-spread as we might like them to be, however, so it is largely dependent on the filter. Also look at each water filter on a case by case basis and check if they are properly certified. The other best thing to do is to look for filters that combine activated carbon with other filtration methods such as Ion Exchange.
So, In Conclusion, Should We Invest In Activated Carbon Filters? Are They Effective Enough To Matter?
Activated carbon or charcoal is a truly brilliant technology for filtering water. A good activated carbon filter can easily solve a lot of water contamination problems both in developed countries, as well as in developing countries. It is important to remember, however, that it is not the end all be all of filtration – there are contaminants that activated carbon is not very effective against.
Therefore, when you are looking for an all-purpose water filter, be it for your home or for travelling, the best advice we can give you is to look for a filter that utilizes several different methods of filtering, not just activated carbon (with activated carbon still being one of the most important and effective of them).