Britas, like most gravity-fed water filtration systems, use gravity to pull water through a disc of activated carbon. Activated carbon is pretty much charcoal, it's just a pure form of it that's been treated in order to increase the amount of space between the carbon atoms it's made from.
Traditionally, charcoal is made through a process called pyrolization. In pyrolization, organic (carbon-based) material like wood or agricultural waste is superheated in an environment devoid of oxygen. In the absence of oxygen, the material can't catch fire and instead its volatile compounds evaporate and leave behind the carbon they were once bonded to. There are a variety of chemical and physical processes available in order to bring about this pyrolytic reaction but all of them yield the same result, a highly porous form of carbon. Its value as a filter comes from two things: the purity of the carbon and the surface area made possible by all of its pores. Get this, a gram of activated carbon can have a surface area that ranges between 300 and 2,000 square meters according to my pals at How Stuff Works.
Carbon filters work through a process called adsorption. That's adsorption with a D and not a B. As water passes through the microscopic pores in the activated carbon filter, specific organic and inorganic chemicals and elements stick to the surface of the carbon. Think of the difference between adsorption and absorption this way. In absorption, material A gets sucked into the volume of material B. In adsorption, material A sticks to the surface of material B. An even simpler way to think of this that's more or less still accurate is when you wipe up a spill with a paper towel, the paper towel absorbs the spill. When you have a dusty floor and you wipe up the dust with a Swiffer, the Swiffer adsorbs the dust. Make sense?
Carbon filters work terrifically and they remove all manner of organic and inorganic stuff from tap water. Over time though, all of the surface area in the filter available for adsorption gets covered over and they stop being effective. You can't really clean a spent carbon filter, so you just replace them every couple of months. Simple and effective, and once again chemistry is your friend.
Well, a well-meaning but highly suggestible internet pal sent me a link to a solution to a problem that I didn't know I had. Apparently, my disposal of spent carbon filters every couple of months is an environmental crime on par with driving a Hummer or burning coal. Please. Anyhow, she sent me to a link to something called Sort of Coal. I don't really want to provide a link back to them but I suppose I owe them that much since I'm about to use a bunch of their images.
Sort of Coal sells pseudo scientific crap and snake oil and they do it in the form of something they call "white charcoal." The charcoal's still black of course, but in a world where reality doesn't matter, a consistent vocabulary must not be too important either.
My well-meaning internet pal sent me a link to this product:
It's what Sort of Coal calls Bottle and Kinshu Binchotan. It costs €68 plus Denmark's 25% VAT. That's €85 ($122.45 US) plus shipping. Oh yeah, carbon filtration doesn't happen by osmosis so it's pretty much ineffective as a filter. Sort of Coal doesn't mention how big the bottle is so I can't figure out the cost per serving. So despite the omission of the bottle size it does tell me this:
Serving and drinking local tap water becomes a pure and beautiful daily experience – with Bottle and Kishu Binchotan, each product is given its perfect complement.What a load of BS. Tap water as a "pure and beautiful" daily experience? It's a frickin' glass of water, not an orgasm. It's not even a filtered glass of water at that.
Kishu Binchotan soaks up chlorine from tap water while releasing natural minerals into it. Kishu Binchotan softens the water and improves the overall taste.
Sort of Coal goes on to ascribe all manner of nonsense to its pyrolized wood. Here's what's called a Hakutan Tray and it's made from charcoal and plastic.
A decorative, purifying tray, made from cross-sections of White Charcoal set with compressed charcoal powder and resin. White Charcoal is produced by hand and is naturally activated during a controlled burning process. Use a Hakutan tray in the kitchen or living room. Fruit will remain fresh longer when placed on the Hakutan tray. Wipe it clean with a damp cloth. Do not use soap. It remains active for years if exposed to direct sunlight occasionally.CO2 friendly? How can something made from partially burned wood and plastic be CO2 friendly? What does CO2 friendly mean anyway? How can a company make a claim like "Fruit will remain fresh longer when placed on the Hakutan Tray" and get away with it? Can they be held responsible for bananas that rot at the same rate that they would on a tray not made from "white charcoal?" If anybody wants to part with €160 ($230.50 US) to find out, let me know how it goes.
This product is organic and C02 friendly.
The unproven assertions just keep on coming with these people. Check out this:
Welcome to the Hakutan Large. The Hakutan Large is described thus:
Korean White Charcoal stems. White charcoal is made by hand and is naturally activated through a controlled burning process. Hakutan absorbs gases, pollution and odors from the air. It can be placed in your bathroom to regulate humidity, in the living room and kitchen to absorb cooking steam and odours. For generations people in Asia have used it to freshen air and create a better indoor environment. Charcoal is also used in spaces where there is intensive computer use, because it creates natural anions and thus has a positive effect on mental well-being. Keep free from dust. If you refresh it once in a while by placing it in direct sunlight, you can keep the Hakutan active for years. Charcoal should be recycled. White charcoal has a positive effect on the environment even when you dispose of it.So using this €120 ($172.87) stick of charcoal will have a positive effect on my mental well-being because it releases natural anions. I love how they pair their absurd claims with they mystery of the Orient. I'm not Asian but I think I'd be insulted if I were. But at least they explain how they get CO2 friendly from this.
When the time comes to get a new Hakutan, crush it and mix it with soil so plants can benefit from it. This makes Hakutan CO2 friendly
Some day soon, I promise, we'll have a chat about ions and anions but I think I may have exhausted you guys by now.
Part of me admires the gall of these people to make the claims they do and charge what they do for this useless garbage. A bigger part of me is appalled at how this sort of new-agey clap trap can be lapped up so readily by an uncritical public.
The world faces a host of serious environmental problems that need to be addressed if it's to remain a planet fit for human life. The solutions to those problems will come from the fields of chemistry, biology, physics and their allied scientific disciplines. The mechanisms that underlie the physical world can be understood and that understanding only increases their wonder. Really.