What exactly is a charcoal water filter, and what is “activated carbon”?
If you’ve been learning a little about water filters because you’re convinced of the benefits of drinking clean purified water you will have come across “charcoal water filters” or “carbon water filters” or “activated carbon water filters”. What are these?
A charcoal water filter is a water filter that uses charcoal for the filter process to remove the impurities. Charcoal is carbon that has been created by heating organic material in the absence of oxygen. The good ones are derived from coconut husks.
Charcoal is quite porous and absorbs many compounds in it’s pores and it is this quality that is relied on for successfully filtering the water. That’s why charcoal is used in gas masks, it absorbs things quite easily, both from gases and liquids. The pores are tiny holes made in the charcoal, or carbon, and the contaminants are absorbed into the charcoal. This is achieved by means of chemical attraction, because a wide range of organic compounds are attracted to carbon.
What then, is activated carbon? Activated carbon is charcoal that has been treated with oxygen in the manufacturing process to result in a much higher percentage of pores. In other words it is more porous than ordinary charcoal. The best charcoal water filters use activated carbon.
It’s so porous in fact that it can have up to 20000 square yards of surface area per ounce of activated carbon. That’s really porous.
Because the carbon filter absorbs contaminants it slowly fills up with these contaminants, so needs to be replaced periodically.
An activated carbon water filter works well filtering a wide range of contaminants, but doesn’t filter all of them, and for this reason the best water filters use a multi stage water filtration process. Not only is the carbon block, or activated carbon filter used but there is a second stage to the process that removes the contaminants that are not removed by activated carbon filtration.
For instance in Aquasana water filters, considered to be the best water filters, there is a 2 stage filtration process. The second stage is used to filter those contaminants not removed by the first, like lead. This is achieved by an ion exchange process where the lead ions are replaced by potassium ions. Potassium is a mineral that occurs naturally in water and is not harmful.
And the second stage of an Aquasana water filter removes tiny organisms that remain in the water after stage 1 like cryptosporidium and giardia through the use of an extremely fine filtration process. These are the most dangerous water contaminants.
Some activated carbon filters do not remove heavy metals like lead, but Aquasana water filters remove 99% of lead, as well as synthetic chemicals which are not removed by some other forms of water purification. Read the rest of this entry
Written by - Best Drinking Water Filter
